Software: Apache/2.2.3 (CentOS). PHP/5.1.6 uname -a: Linux mx-ll-110-164-51-230.static.3bb.co.th 2.6.18-194.el5PAE #1 SMP Fri Apr 2 15:37:44 uid=48(apache) gid=48(apache) groups=48(apache) Safe-mode: OFF (not secure) /var/www/html/manage_22222/jpgraph/docs/html/ drwxr-xr-x |
Viewing file: Select action/file-type: 1 About this manual1.1 Version history
1.2 How was this manual produced?The bulk of the text was written directly in Emacs on a GNU/Linux system in a mixture of PHP and HTML. A number of PHP functions were used to automate the handling of formatting example code and figures. To generate the images automatically in the img directory a custom awk-script is used to extract all the used image script from the manual. The script then uses the client version of PHP generate the images from the scripts and stores them in the 'img' directory. The final set of HTML files was then processes by HTMLDOC to construct table of contents and chapter links. 2 Introduction2.1 VersionThis manual covers versions up to 1.18 of JpGraph. A 2D graph plotting library for PHP. Even though the library is known to work with version of PHP prior to 4.3 the library is not tested nor is it recommended to run with any older versions of PHP. 2.2 Software LicenseJpGraph is released under a dual license QPL 1.0 (Qt-License) for non-commercial (including educational) use of the library and the JpGraph Professional License for commercial use. 2.3 JpGraph FeaturesJpGraph library is an OO graph library which makes it easy to both draw a "quick and dirty" graph with a minimum of code and quite complex graphs which requires a very fine grain of control. The library tries to assign sensible default values for most parameters hence making the learning curve quite flat since for most of the time very few commands is required to draw graphs with a pleasing esthetic look. Some highlights of available features are
In addition to these high level features the library has been designed to be orthogonal and consistent in its' naming convention. For example, to specify color each object (i.e. axis, grids, texts, titles etc) within the graph implements the method SetColor() with the same signature. 2.4 Getting the latest versionThe latest version of jpgraph can always be found on http://www.aditus.nu/jpgraph/ The current version as of this writing for branch 1.x is 1.18 and for the 2.x branch it is 2.0-beta. Information on version numbering schema
2.5 Known bugs and omissions
2.6 AcknowledgmentsThe idea for writing this library grew out of our own need for a high quality graph drawing library for PHP. When evaluating potential existint libraries we found (at that time cirka 2001) these three were
All these libraries implements some fine graphic features but unfortunately none of those completely fulfilled our needs either for available functionality (for example none of these supported both two Y-scales, auto-scaling, and logarithmic scales), or general flexibility. We especially needed the option of two Y-scales, which none of the above packages supported. Our own preferences for design was closest to "chart 0.3" so we started by fixing some bugs in that package and adding some new features. However It was soon realized that to add all the features and flexibility we needed to "chart 0.3" it would require a complete rewrite since the original design wasn't flexible enough, especially adding a second Y-scale would require a more flexible OO architecture. 2.7 Reporting bugs and suggesting improvementsDefects or suggestion for new features can be entered using the JpGraph BugTracker available at http://www.aditus.nu/bugtraq/ Before reporting bugs or feature suggestions may we ask that the following facts are considered.
2.8 Getting supportCustomers who have aquired the pro-version of the library are entitled to prioritized e-mail support for a specific time after the purchase. Support tickets may be created by first logging in to http://www.aditus.nu/jpgraph/pro_login.php and then create a support ticket. For other users a public community forum is available at http://jpgraph.intellit.nl/ where many common questions are answered and discussed among the community of JpGraph. Please note that there is no guarantee that a specific questions will be naswered on thi forum. The forum is for-users-by-users. In addition there is a collection of FAQs available at http://www.aditus.nu/jpgraph/jpgraphfaq.php Finally, we regret that we are unable to provide general support regarding PHP/GD/TTF/Apache installation outside the specific scope of the JpGraph library. Please see the corresponding documentation and relevant FAQ for those products. 3 Installation3.1 PreparationIn order to make use of the library it is necessary to ensure that the script files can correctly access the library include files (as described below) and that the PHP installation supports at least one graphic format, i.e. it supports the "image" extension in PHP. This is easiest verified by eiether checking the output of the phpinfo() standard PHP function or by making sure the PHP installation make the 'imagecreate()' function available. This means that the insrtallation must have a working GD-library together with PHP before the library JpGraph can be used. Please make sure you have version 4.3.x or above of PHP since JpGraph is not actively tested with versions prior to PHP 4.3.x Ideally you should use at least PHP 4.3.8 Please note that the 1.x version of the library do not support PHP 5.x 3.1.1 Verifying that you have the GD library installedIn order to make sure that the GD installed the following example whould be run. The example creates a very simple image using just pure GD calls and outputs an image in PNG format. This could be considered a smoke-test to see that the GD libary is available from PHP. Please note that this is an absolute pre-requisite in order for the JpGraph library to work at all. Store the code snippet below somewhere in the document root and make sure it runs correctly.
$im = @
ImageCreate (
150, 100)
If the above script does not work or some error or warnings are printed on the screen then it is necessary to correct those problems before proceeding with the installation. 3.1.2 Verifying that you have GD2 installedTo access the more advanced features of JpGraph needs the GD 2.x library. This will allow the use of features such as alphablending and trucolor images. The GD 2.x libary is included in all standard PHP versions from 4.2.x and above. To make sure that the GD 2.x libary is installed the following script must be working.
$im =
imagecreatetruecolor (
300, 200);
After running this script you should now see a black rectangle in your browser. 3.1.3 Preparing True Type Font FilesJpGraph contains as default a standard set of bitmap fonts which only supports the standard ASCII 7-bit character set. In order to use accented characters, UTF-8, Chinese, Japanes, etc You need to download TTF fonts. Due to various legal issues no TTF fonts are supplied in the JpGraph package. To enable TTF fonts there are three alternatives:
It is also necessary to make sure that the PHP installation supports TTF fonts (either through FreeType 1 or FreeType 2 libraries). I n addition some suitable TTF font files must also be available. To make the font files available for the library the directory path to the location of the font files must be specified in the configuration file, jpg-config.inc JpGraph uses a standard naming convention for the TTF font files in order to be able to find the correct font files. This naming convention follows the standard naming of the available font files. If the installation of the library is made on a computer running MS Windows then it is recommended to use the already available font files in Windows (usually located in C:\WINDOWS\FONTS). If the installation is made on a UNIX derivate running X11 then the font location can differ between versions and UNIX brands. One commonly used path is "/usr/X11R6/lib/X11/fonts/truetype/". Finally we note that it is possible to install additional fonts not natively supported by the library. Since this requires augmenting the library files this is considered advanced use and not further discussed in this introduction. 3.1.4 Using non-latin based fonts with JpGraphIn addition to European font it is also possible to use non-latin based fonts such as Cyrillic, Japanese and Chinese. In all cases a suitable TTF font that supports the non-latin based language must be available. For Cyrillic support the define LANGUAGE_CYRILLIC in jpg-config.php must be set to true. It is then possible to use a suitable Cyrillic font as replacement for the ordinary fonts. For Chinese charcter set JpGraph supports both BIG5 and GB2312 encoding. For BIG5 encoding the PHP installation must have support for the "iconv()" function. Furthermore the define CHINESE_TTF_FONT must be set to the name of the Chinese BIG5 font that is to be used. By default this is set to "bkai00mp.ttf". To use the Chinese BIG5 font in the scripts one must then specify the font family as FF_CHINESE. To use the alternative font files "simsun.ttc" and "simhei.ttf" (which uses the GB2312 encoding) the only step needed is to install those fonts in the normal TTF font directory and then specify the font family as FF_SIMSUN, the "simhei.ttf" is used when the font style is specified as FS_BOLD. 3.2 Customizing the installationIn order for JpGraph to work it is necessary to adjust the cache and TTF directory to suit the specific installation. By default the TTF directory is "/usr/X11R6/lib/X11/fonts/truetype/" and for the cache "/tmp/jpgraph_cache/". These are defined as PHP defines at the top of jpg-config.inc Please make sure that PHP has write permissions to the cache directory if the cache feature snhould be used. If this is not the case a "Can't write file xxx.yyy" error will occur when a graph that uses the cache feature are generate. More information regarding the cache feature of JpGraph is availble in the section Making sense of caching system in JpGraph 3.3 Required filesThis is the base library files, which you must have
3.3.1 Plot extension modulesTo add plots to the graph you will need one or more of the following files plot extension files depending on what kind of graph you need to create.
In the pro-version the following additional modules are available
3.4 Image formats and external image librariesPer default the standard GD image library supports PNG graphic formats. You will need to have that installed together with your PHP module for this library to work at all. Please refer to PHP documentation on specifics. Note that the newer versions of GD does not support the GIF format due to copyright problems. Hence by default only PNG is supported. If you want JPEG support you will also need an additional library for PHP, again please see PHP documentation for specifics. For most practical purposes PNG is a better format since it normally achieves better compression then GIF (typically by a factor of 2 for the types of images generated by JpGraph). In comparison with JPEG format PNG is also better for the type of images generated by this library. So, the bottom line is, you should have a very good reason to choose any other format then PNG. By default the image format is set to "auto". This means that JpGraph automatically chooses the best available graphic using the preferred order "PNG", "GIF", "JPG". 3.5 Detailed steps to install JpGraph
3.6 Troubleshooting your installationFor 99% of the users this library will work directly with a recent installation of PHP without any problem. Experience shows that most of the trouble are caused by either an old buggy version of the free-type TTF library or using an old antiquated version of the GD library. In order to narrow it down the problem the following steps is helpfull.
3.7 Compiling PHP 4This is not meant to be a complete discussion about configuring or compiling PHP. It is meant as an example of a configuration of PHP that is known to work well with JpGraph. Below is an example of a standard configuration that can be used to configure and compile PHP for use with the JpGraph Library Please note that depending on the specific installation requirements other options might have to be specified, specifically the paths to external libraries might need to be adjusted. ./configure --prefix=/usr/share \ --datadir=/usr/share/php \ --with-apxs=/usr/sbin/apxs \ --libdir=/usr/share \ --includedir=/usr/include \ --bindir=/usr/bin \ --with-config-file-path=/etc \ --enable-mbstring --enable-mbregex \ --with-pdflib=/usr \ --with-mysql \ --with-ttf-dir=/usr/lib \ --with-freetype-dir=/usr/lib \ --with-gd --enable-gd-imgstrttf --enable-gd-native-ttf \ --with-zlib-dir=/usr/lib \ --with-png-dir=/usr/lib --with-jpeg-dir=/usr/lib --with-xpm-dir=/usr/X11R6 \ --with-tiff-dir=/usr/lib \ --enable-ftp \ --enable-memory-limit --enable-safe-mode \ --bindir=/usr/bin \ --enable-bcmath -enable-calendar \ --enable-ctype --with-ftp \ --enable-magic-quotes \ --enable-inline-optimization \ --with-bz2 \ --with-iconv 4 Quick Start: Dynamic Image GenerationThe purpose of this chapter is to put dynamic image generation in perspective and illustrate how HTML tags is used to call image generating scripts. Even if You are familiar with PHP it is stronly recommended to quickly browse through this chapter to make sure all concepts are known. If You fully understand and can explain the concept of MIME types, HTTP streams and why the "Headers already sent error" error is very common when generating dynamic images with PHP it is probably safe to skip this chapter. Otherwise it might be wise to read through this chapter once. 4.1 Scope of this chapeter4.1.1 What you will learn in this chapter
4.1.2 What you will NOT learn in this chapter
4.2 How to generate images with PHPAs a general rule each PHP script which generates an image must be specified in a separate file which is then called in an HTML <IMG> tag. For example, the following HTML excerpt includes the image generated by the PHP script in "fig1.php".
<img src="fig1.php"
border=0
align=center
width=300
height=200> Strictly speaking the "align", "width" and "height" are not necessary but helps the browser position the image correctly before the image has been fully sent back to the browser. The library will automatically generate the necessary headers to be sent back to the browser so that it correctly recognize the data stream received as an image of either PNG/GIF/JPEG format. The browser can then correctly decode the image Observe that you can't return anything else than an image from the image script. By definition each HTML page (or more correctly each HTTP stream) can only consist of one mime type which is determined by the header for that particular stream. A common mistake is to have a space in the beginning of the image script which the HTTP server will send back to the browser. The browser now assumes that the data coming back from this script is text since it hasn't received an explicit header. When then the image headers get sent back to the browser to forewarn the browser of the forthcoming image the browser will not like that as it has already assumed the data stream was a text stream. The browser will then give the infamous "Headers already sent error". To include several images together with text on a page you need to have a parent page with several <IMG> tags which each refers to an image script (or the same image script with GET/POST data). 4.2.1 Using the JpGraph library to send back imagesTo get access to the JpGraph library you will need to include at least two files, the base library and one or more of the plot extensions. So for example to create a basic line plot the top of your PHP file must have the lines:
Note: You might also use the PHP directive
require. The difference is subtle in that include will only include
the code if the include statement is actually executed. While require()
will always be replaced by the file specified. See PHP documentation
for further explanation. For most practical purposes they are
identical.
4.3 Using PHP directlyIt is also possible to generate images directly using the command line version of PHP. This works the same way as the normal "through the browser" generation with the exception that no HTTP headers will be generated. Only the bianry image data. Please make sure that you run the command line version of PHP (cli). Using the CGI SAPI version will not work since then the HTTP headers will be generated. You can easily check this by running php --version you should then get a response with something like PHP 4.3.8 (cli) (built: Aug 29 2004 22:48:10) Copyright (c) 1997-2004 The PHP Group Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies The important thing here is the (cli) marker. The JpGraph library check from what SAPI API it is invoked from and adjusts the header generation accordingly. If all the above requirements are met then images can be generated directly on the command line and stored in a suitable file. For example by $> php myimage.php > image.png Please note that the file extension on the image file must match the format in which the image is generated. 4.4 The basic principle of JpGraph and the creation of imagesThe common pattern for creating graphs is
Of course it is of perfectly possible to call the image script directly in the browser to just display the generated image in the browser. You should remember that it is also possible to pass arguments to the image script via the normal HTTP GET/POST arguments. For example <img src
="showgraph.php?a=1&b=2"
> This could for example be used to control the appearance of the image or perhaps send data to the image which will be displayed. Note that this is probably not the best way to send large amount of data to plot. Instead the only practical way, for large data sizes, is to get all the data in the image script, perhaps from a DB. Another alternative for large amount of data to be sent to the image script is by creating a POST request to the image script.
Note: Forcing the browser to update your image Some browser
may not send back a request to the web browser unless the user presses
"Refresh" (F5 - in most browsers). This can lead to problems that the
user is seeing old data. A simple trick is to add a dummy time argument
which is not used in the script. For example
echo '<img src="myimagescript.php?dummy='.now().'">';It is also important to be aware of any internal caching the browser might do. The general problem with dynamically generated images is that the image generating script (file) remains the same. This makes the browser believe that the data hasn't changed and if the browser already has issues a previous GET request and has the data cached it will not send a new GET if the timestamp on the file is the same since it then believes it my use the old cached version. When it comes to the structure of your imaging script they will generally have the structure
// ... Include
necessary headers
JpGraph is completely Object oriented so all calls will be action on specific instances of classes. One of the fundamental classes is the Graph() class which represents the entire graph. After the creation of the Graph() object all the code lines to construct the details of the graph are added. The final method called in an image script will most likely be the Graph::Stroke() method. This will send the constructed image back to the browser. A variation of this is used if the graph are supposed to have image maps. In that case the final method will be Graph::StrokeCSIM() In addition to this standard usage pattern you can also choose to
The cache system, which lessens the burden of the PHP server, works by avoiding o run all the code that follows the initial Graph() call by checking if the image has already been created and in that case directly send back the previously created (and stored in a file) image to the browser. When using the cache system a filename must be specified in the initial Graph() call which is used to store the image in the cache system and possibly also a timeout value to indicate how long the image in the cache directory should be valid. In many of the examples in this manual teh following pattern will be used
$graph = new
Graph(300,200
,"auto"); The two first parameters specify the width and height of the graph and the third parameter the name of the image file in the cache directory. The special name 'auto' indicates that the image file will be given the same name as the image script but with the extension changed to indicate the graphic format used, i.e '.jpg', '.png' and so on. Please note that the cache system by default is disbled and must be enabled by setting the proper define in the file "jpg-config.inc" 4.5 Choosing the image format for JpGraphBy default JpGraph automatically chooses the image format to use in the order PNG, JPEG and GIF. The exact format depends on what is available on your system. There are two ways you can influence the way the graphic format is chosen.
4.6 Alternatives to streaming back the imageIf you like to save the image directly to a file instead of streaming it back to the browser then you just have to specify an absolute filename in the final call to Graph::Stroke(), i.e.
$graph->
Stroke(
"/usr/home/peter/images/result2002.png"); Please note that the user running as Apache/PHP must have write access to the specified directory. There are also two predefined filenames which have special meaning.
4.7 Working with fonts in JpGraphJpGraph supports both a set of built in bit-mapped fonts as well as True Type Fonts. For scale values on axis it is strongly recommended that you just use the built in bitmap fonts for the simple reason that they are, for most people, easier to read (they are also quicker to render). Try to use TTF only for headlines and perhaps the title for a graph and it's axis. By default the TTF will be drawn with anti-aliasing turned on. In many of the example you can see examples of both TrueType and Bitmap fonts. There are a number of subtle differences in the way builtin fonts and TrueType fonts are rendered to the screen. However, JpGraph, abstracts away 99.9% of the differences so it will be, for the user, completely transparent to switch between the different fonts. 4.7.1 Installing TrueType fontsSince Internally TrueType fonts are rendered by locating a font specification file you must install the accompanying TrueType fonts in directory of your choice. You must then tell JpGraph where these fonts may be found by specifying the font-path in the FONT_PATH define (in jpg-config.inc). Please note that this must be the absolute file path and not relative to the htdocs directory. By default the path is set to
DEFINE(
"TTF_DIR",
"/usr/local/fonts/ttf/");
Since JpGraph must be able to tell the difference between the italic and bold versions of the same font family a standard naming convention is used to name the files. The available fonts are also defined by DEFINES and hence you can't just copy your own TTF files to the directory and expect it to work. At the moment there is no "easy" way to add new fonts but to make some (small) mods to the code. However this is expected to change in future version of JpGraph. 4.7.2 Verifying that the TTF fonts workIn order to get TTF fonts working with JpGraph you should first check that the following pure GD scripts work correctly. Please adjust the font path according to your installation.
DEFINE
("TTF_DIR","/usr/X11R6/lib/X11/fonts/truetype/"
);
The above script assumes you have the GD2 library and will create an image with the classical "Hello World!" text printed in black. 4.7.3 Specifying fontsAll graph objects that uses text allows you to specify the font to be used by calling the SetFont() method and specifying three parameters
For the builtin fonts the third, size, parameter is ignored since the size is fixed for the three builtin fonts. The available font families and the corresponding name (in JpGraph 1.7) are listed in the table below.
Please note that not all font families support all styles. The figure below illustrates each of the available font families and what styles you may use. We finally show some example of valid font specifications $graph
->title->SetFont(
FF_FONT2);
4.7.4 Adding additional fonts to JpGraphNote: This information is only given here for very advanced users. No free support will be given in the case you run into difficulties trying to add new fonts. At the moment adding new fonts require code modifications as outlined below. In order to add you favorite fonts there are three steps you need to follow :
4.7.5 Understanding text alignment in JpGraphFor everyday use of JpGraph understanding of the alignment of text strings in not necessary. However, if you like to add arbitrary strings to the graph (with Graph::AddText()) or when working directly on a canvas it will help understand this. Text is added to a graph with the creation of a Text() object. And the alignment is specified with Text::Align() Text alignment might actually be a misguiding name. What you specify is rather the anchor point for the text, i.e. when you specify that a text should be positioned at position (x,y) how is that coordinate to be interpretated. The image below shows a text string aligned in the 9 possible combinations. In the image the red crosses indicate what coordinate that text string was positioned at. The alignment used for each of the cases is shown below. 4.8 Specifying colors in JpGraphColors can be specified in three different ways
4.8.1 Adjusting the transparencyFrom version 1.10 JpGraph also supports the use of Alpha Blending together with GD2.x This lets you specify how much of the underlying color should be visible. You specify the amount of transparency for a color by adding an extra parameter to the color specification separated by an '@' (at) character. For example to specify a red color which is 40% transparent you write
SetColor(
"red@0.4");
or to specify 90% transperancy you write
SetColor
("red@0.9"); Below is an example of how a bar graph with a background image can make use of transperancy 4.8.2 Available named colors The chart below shows all available named colors. 4.8.3 Theme colors for pie'sFor more on how to use the different themes to set the colors of Pie plots please refer to "Working with 2D &3D pie plots" 5 Understanding the JpGraph caching systemTo reduce load on the web server JpGraph implements an advanced caching system which avoids the burden of always having to run the full image script. Depending on the complexity of the image script (for example if it is doing several DB lookups) this could significantly improve performance. The rationale behind this is of course performance, and the observation that very few graphs are really real-time, i.e. needs to be updated absolutely every time the graphing script is called. 5.1 Enabling the cache systemThe enabling disabling of the cache system is controlled by two defines (in jpg-config.php)
DEFINE(
"USE_CACHE",
true);
The first of these, USE_CACHE, is the master-switch which must be set to true to enable the caching system. The second switch READ_CACHE very seldom needs to be changed. This second switch basically tells whether or not JpGraph should ever look in the cache. Setting this to false and the master-switch to true would then always generate an new updated image file in the cache and this new image would be send back to the browser. The main use for this (admittedly) strange setting is if you like to have the side effect of the script that a fresh image is always stored in the cache directory. Once you have enabled the cache you must also make sure that a valid cache directory is setup. The cache directory is specified with the define
DEFINE(
"CACHE_DIR",
"/tmp/jpgraph_cache/");
You can of course change the default directory to whatever directory you fancy. But, you must remember one important thing. The cache directory must be writable for the user running Apache/PHP . 5.2 Using the cache in your scriptTo use caching in your script you must supply a suitable file name which will be used to store the image in the cache. You can also supply a timeout value indicating how many minutes the cached image should be considered valid. These parameters are supplied in the initial Graph() method call which should be among the first in your script. Instead of manually specifying a file name to be used you could often use the special name "auto". If the filename is specified as "auto" the cashed image will then be named the same as the image script but with the correct extension depending on what image format have been chosen. If you don't specify a file name no caching will be used no matter the settings of USE_CACHE (without a file name it is impossible!) The following call to Graph() shows a typical use of the cache.
$graph = new
Graph(300,200
,"auto",60)
The above code will use the automatic filename and a make the cache valid for 60 minutes. So, how does this all work now? The first time you call your script (no cached image) everything will be as usual, the script will run and you will in the end send back the image to the browser. However if you have the caching enabled JpGraph will automatically have stored a copy of the generated image in the cache directory. The next time you call the script the first thing that happens in the initial Graph() is that it will go and check in the cache directory if the named image exists there. If this is the case it will also checks that the image isn't too old (as compared to the specified timeout value). If the image is valid then the image will be streamed straight back from the image file to the browser and the script will end it's execution. Hence, if the image is found in the cache no code lines after the initial Graph() call will be executed The design decision behind this is that your image script code never has to include anything special to make full use of the cache. It will just automatically work. 5.3 Using the cache with Client Side Image MapsYou can also use the cache system for CSIM as well. The cache system interface is slightly different in this case since the cache needs to store both the cached image and the cached image-map. It also needs to change due to the way CSIM HTML paradigm work. The two major differences from the "standard" cache is
The performance benefits even for simple CSIM images is around 50% if the cache can be used and can of course be several 1000% if construction of the image requires DB calls and other complex operations which can be avoided. Before reading further you should have an understanding on how the CSIM works by reading the section "sing Client side image maps". Please remember that when using CSIM you must end your script with a call to Graph::StrokeCSIM() method instead of the Graph::Stroke() used for non-csim. To use the cache with CSIM you have to call the Graph::CheckCSIMCache(). As with the caching for non-CSIM you have to supply a name to be used for the cached version as well as an optional timeout value. The default timeout value if nothing else is specified is 60 minutes. The name argument requires some more explanations. You must specify a relative name here. For example "myimage" or perhaps "firstpage/image3". Depending on your installation of JpGraph this will now end up in the directory specified in the CSIMCACHE_DIR define. This must also be a directory accessible by the normal web server. By default a directory called "csimcache" will be created in the same directory as the image script itself. This has the drawback that the directory from where the script is executed must be writable by the process running PHP. Best practice for this is to keep the number of writable directory for PHP down to a minimum and re-use the same directory as is used for the standard cache. This however, require that your system administrator setup that cache directory so that it also accessible by the HTTP server from the htdocs root. The CheckCSIMCache() method checks the cache for an existing cached version and if found it returns it and halts execution of the script. So, this call should be the first call after the creation of the Graph() and before any heavy work is done to create the image so that you can minimize the execution of the script in the case a match is found. So, the general structure of a script that uses CSIM and the cache is
$graph = new
Graph(400,300
);
Please note that you do not need to pass any argument to the final call to StrokeCSIM() as you do when not using the cache. Note: The CSIM caching works by storing
two files in the cache directory. One file being the image and the
other file being the corresponding image map as a pure HTML file.
5.4 Some final comments
5.5 Common feature for all graphsThis is a summary of the available feature for all Graph based charts, i.e. line plots, error plots, scatter plots, etc. 5.5.1 ClippingBy default all plots are clipped outside the plot area. This means that if you manually specify a scale and then try to plot which has values smaller/larger than the scale those values will not show. The clipping algorithm is "perfect" in the sense that for example line plots where the plot area cuts the line between two data points the line will be drawn up to the edge of the plot area. The algorithm used is O(1) in number of data points. The disabling/enabling of clipping manually is controlled by Graph::SetClipping() 5.5.2 Commonly used properties
5.5.3 Commonly used methods
6 Using image maps with JpGraphImage maps, or client side image (CSIM) as they are known is fully supported in JpGraph. It gives you the opportunity to create hot-spots in the graphs which allows you to build a set of "drill-down" graphs. In the following section is based on the assumption that the reader is familiar with the basic concepts of client side image map in HTML. To shortly recapitulate. Client side image maps consiste of two parts. The first part is the actual image and the second part is a mapping that gives the coordinates for areas in the image which should be marked as hot spots (i.e. clickabe by the user). The library can automatically generate these coordinate maps from a given graph. Through out the manual areas of the graph that may be used as a hotspot is given in conjuction with the general description of that area. 6.1 The basic structure of an image map scriptThe standard structure for an HTML page using client side image maps would be something along the lines of // Image map specification with name "mapname" <MAP NAME=...> ... specification ... </MAP> // Image tag <img src="..." ISMAP USEMAP="mapname"> This poses an interesting question. Since we normally call the graphing script directly in the <img> tag how do we get hold of the image map (which is available only in the image script) in this "HTML wrapper" script? In JpGraph there is actually two ways of solving this.
The first (and preferred) way modifies the stroke method so that instead of returning an image (like the standard Stroke() method) StrokeCSIM() actually returns an HTML page containing both the image map specification and the correct <IMG> tag. This of course means that it is necessary to treat an image map returning image script differently from a non-CSIM image script, for example you can't use it directly as the target for the "src" attribute of the <IMG> tag since it sends back an actual HTML page containing both an image tag together with anj image map. 6.2 Specifying targets for image map plotsTo turn a standard image script into a CSIM script the first thing needed to do is to supply the appropriate URL targets for the hotspots in the image. What the hotspots represent depends on the type of plot you are doing. The following plot types and graph areas support image maps.
To specify a link for each hotspot you have to use the SetCSIMTargets() method for each plot (or specific area) in the graph which should be a hotspot. There are two arguments to this method
6.3 Using StrokeCSIM()The simplest way of creating a creating a CSIM image is with the StrokeCSIM() method. As mentioned before this method actually returns a (small) HTML page containing both the image-tag as well as the image map specification. Hence it is not possible to use a script that ends with this method in a standard image-tags src property. There are two ways to create CSIM (or get hold of) the image maps
Note: If there are several CSIM images on
the same page it is necessary to use "include_once" in the scripts for
the inclusion of "jpgraph.php" and the other jpgraph library files
since the files will be included multiple times on the same page and
one or more "Already defined error" will be displayed.
The process to replace Stroke() with StrokeCSIM() is straitforward. Replace all existing calls to Stroke() with the equivalent calls to StrokeCSIM(). The only difference is that it is necesasry ti supply a minmum of
ond file name in the StrokeCSIM() method. The first argument must be
the name of the actual image script file including the extension. So
for example if the image script is called "mycsimscript.php" it is
necessary to write
$graph->
StrokeCSIM(
'mycsimscript.php')
$graph->
StrokeCSIM(
basename(
__FILE__))
This is a better way since the script can now be renamed without having to change any code in the file which otherwise would be needed. Note: Why does the script name need to be used as
the first parameter? The reason is that in the creation of the HTML
page which is sent back we need to refer to the script in the image
tag. So why is it not possible to use the PHP_SELF reference? The
problem with PHP_SELF is that in the case where we include the
image-script in an HTML page and use the PHP_SELF we will get the name
of the HTML page and not the actual script in which the PHP_SELF is
used. We also can not use the __FILE__ trick in the library since in
the context __FILE__ is set to "jpgraph.php". Hence, this must be
specified by the client as shown above.
The other arguments to StrokeCSIM() are optional. Please note that if several CSIM images are used in the same HTML page it is also necessary to specify the image map name as the second parameter since all image maps must be unique to properly match each image map against each image. Please consult the class reference StrokeCSIM() for more details. 6.4 Examples of Image mapsIn the Example/ directory there are a number of examples of how to setup the various types of image maps. The following examples are currently available
In order to easily access all of these examples it is possible to call the testsuit.php example with an additional argument "t=2". By following the link testsuit.php?t=2 a separate window will open with all the possible CSIM examples. 6.5 How does StrokeCSIM() work?Knowledge of the exact technical details of the way StrokeCSIM() works is probably not needed by many people but for completeness we outline those details in this short section. The fundamental issue we have to solve is that we must be able to call the image script in two modes. When the user includes the image script the StrokeCSIM() method should return the HTML page but when the image script is later called directly in the image tag it must not return an HTML page but rather the actual image. The way this is solved is by using one HTTP argument which is passed on automatically when we use the image script name in the image-tag. If you look at the generated HTML you will see that the argument to the src-property of the image tag is not simply the script name but the script name with a additional argument. In the JpGraph internal code this pre-defined argument is checked for and if it exists the image is send back and not the HTML page. The name of this argument is defined by a DEFINE() statement in JpGraph. The define is _CSIM_DISPLAY. 6.6 Getting hold of the image mapIn the case where you want to store the image on disk and later use it in an img-tag you need to get hold of the image map. For this you will have to use the function Graph::GetHTMLImageMap() An example of the use of this is shown below. With these lines the image will be written to a file. The script then returns a HTML page which contains the Client side image map and an img-tag which will retrieve the previously stored file.
$graph->
Stroke(
"/usr/local/httpd/htdocs/img/image001.png"
);
6.7 Image maps and the cache systemFor version 1.9 the cache system has been extended to include even the CSIM maps. For each CSIM graph two files are stored in the cache, the image file itself as well as the wrapper HTML with the actual image map. For further information see the chapter on "Understanding the Cache system" 7 Working with orthogonal X,Y-plotsThe purpose of this chapter is to introduce the basic concepts of creating scripts with JpGraph that will generate various types of basic plots. Throughout the text it is possible to view the exact source for all the graphs by clicking on the "[src]" link in the caption of the image shown. This will open the image together with the source in a separate window. This way it is easy to compare the actual image with the script that generated the image. 7.1 Line plotsThe first example draws a line graph consisting of 10 Y-values. In this first example we show the full code. In the following examples we will only show interesting piece of the code.
(File: example0.php)
<?php
You might note a few things
This is a perfect fine graph but looks a little bit "sparse". To make it more interesting we might want to add a few things like
From looking at the previous example you can see that you access all properties of JpGraph through the objects you create. Graph(), LinePlot() and so on. In general all objects you can see in the graph is accessed through a named instance. For example the title of the graph is accessed through the 'Graph::title' property. So to specify a title string you make a call to the 'Set()' method on the title property as in:
$graph->title->Set
('Example 2'); So by adding just a few more lines to the previous code we get a graph as shown below. To achieve this we just needed to add a few more lines. (We only show the part of example 1 we changed, to look at the full source just click the [src] link in the caption. )
// Setup margin and
titles
Again there are a couple of things you should note here
A nice change would now be to have all the titles in a bold font and the line plot a little bit thicker and in blue color. Let's do that by adding the lines $graph->
title->SetFont(FF_FONT1
,FS_BOLD);
Again please note the consistent interface. To change font you just have to invoke the SetFont() method on the appropriate object. This principle is true for most methods you will learn. The methods may be applied to a variety of objects in JpGraph. So for example it might not come as a big surprise that to have the Y-axis in red you have to say:
$graph->yaxis->SetColor
("red") or perhaps we also want to make the Y-axis a bit wider by $graph
->yaxis->SetWidth(
2)
As a final touch let's add a frame and a drop shadow around the image since this is by default turned off. This is done with $graph
->SetShadow() The result of all these modifications are shown below. ![]() Figure 5: Making the image a little bit more interesting by adding som colors and changing the fonts [src] 7.1.1 Adding plot marks to line-plots XXXIt might sometimes be desirable to highlight the data-points with marks in the intersection between the given x and Y-coordinates. This is accomplished by specifying the wanted plot mark type for the "mark" property of the line graph. A full list of all available marks is given in the class reference PlotMarks For now let's just add a triangle shape marker to our previous graph by adding the line $lineplot->
mark->SetType(MARK_UTRIANGLE
); This will give the graph as shown below If you like you can of course both change the size, fill-color and frame color of the chosen plot mark. The colors of the marks will, if you don't specify them explicitly, follow the line color. Please note that if you want different colors for the marks and the line the call to SetColor() for the marks must be done after the call to the line since the marks color will always be reset to the lines color when you set the line. 7.1.2 Displaying the values for each data pointAs a final easy modification we can enable the display of the data value above each data point. The value is represented by the 'value' property in the plot. (You can read more about the possibilities of the display value in the class reference.) To enable the display of the value you just need to call the Show() method of the value as in
$lineplot->value->
Show()
Adding that line to the previous line plot would give the result shown below. We can of course change both color, font and format of the displayed value. So for example if we wanted the display values to be dark red, use a bold font and have a '$' in front we need to add the lines $lineplot
->value->SetColor(
"darkred");
This would then result in the following image Note: You can achieve more advanced
formatting by using not just the printf() style format string by a
format callback function. This could allow you to change the displayed
value with more advanced formatting such as displaying money values
with "," to separate thousands.
7.1.3 Adding several plots to the same graphWhat if we want to add a second plot to the graph we just produced? Well, this is quite straightforward and just requires two simple step:
To create the second plot we need some data (we could of course use the same data as for the first plot but then we wouldn't be able to see the new plot!) The following lines show how to create the new plot and add it to the graph (we only show the new lines - not the full script) $ydata2
= array(1,19,
15,7,22
,14,5,
9,21,13
);
Making these changes to the previous graph script would generate a new graph as illustrated below. There is a few things worth noting here
7.1.4 Adding a second Y-scaleAs you saw in the preceding example you could add multiple plots to the same graph and Y-axis. However what if the two plots you want to display in the graph has very different ranges. One might for example have Y-values like above but the other might have Y-values in the 100:s. Even though it is perfectly possible to add them as above the graph with the smallest values will have a very low dynamic range since the scale must accomplish the bigger dynamic range of the second plot. The solution to this is to use a second Y-axis with a different scale and add the second plot to this Y-axis instead. Let's take a look at how that is accomplished. First we need to create a new data array with large values and secondly we need to specify a scale for the Y2 axis. This is done by the lines
$y2data = array(
354,200,265
,99,111,
91,198,225
,293,251);
and finally we create a new line plot and add that to the second Y-axis. Note that we here use a new method, AddY2(), since we want this plot to be added to the second Y-axis. Note that JpGraph will only support two different Y-axis. This is not considered a limitation since using more than two scales in the same graph would make it very difficult to interpret the meaning of the graph. To make the graph a little bit more esthetic pleasing we use different colors for the different plots and let the two different Y-axis get the same colors as the plots. The resulting graph is shown below. source) 7.1.5 Adding a legend to the graphWith more than one plot on the same graph it is necessary to somehow indicate which plot is which. This is normally done by adding a legend to the graph. You will see that each plot type has a 'SetLegend()' method which is used to name that plot in the legend. SO to name the two plots in the example we have been working with so far we need to add the lines $lineplot
->SetLegend("Plot 1");
to the previous code. The resulting graph is shown below As you can see the legend gets automatically sized depending on how many plots there are that have legend texts to display. By default it is placed with it's top right corner close to the upper right edge of the image. Depending on the image you might want to adjust this or you might want to add a larger margin which is big enough to accompany the legend. Let's do both. First we increase the right margin and then we place the legend so that it is roughly centered. We will also enlarge the overall image so the plot area doesn't get too squeezed. To modify the legend you access the 'legend' property of the graph. For a full reference on all the possibilities (changing colors, layout, etc) see class legend in the class reference For this we use the legends 'SetPos()' method as in $graph
->legend->Pos(
0.05,0.5,"right"
,"center"); Doing this small modification will give the result shown below The above method 'SetPos()' deserves some explanation since it might not be obvious. You specify the position as a fraction of the overall width and height of the entire image. This makes it possible for you to resize the image within disturbing the relative position of the legend. We will later see that the same method is just to place arbitrary text in the image. To give added flexibility one must also specify to what edge of the legend the position given should be relative to. In the example above we have specified "right" edge on the legend for the for the horizontal positioning and "center" for the vertical position. This means that the right edge of the legend should be position 5 % of the image width from the right. If you had specified "left" the the legends left edge would be positioned 5 % of the image width from the image left side. By default the legends in the legend box gets stacked on top of each other. The other possibility is to have them sideways. To adjust this you use the SetLayout() method. Using a horizontal layout with the previous example give the following result. 7.1.5.1 Adjusting the layout of the legendFor more advanced fomatting of the legend it is possible to adjust
In order to adjust the number of columns used in the legend the method Legend::SetColumns is used. So for example to have the legend lined up using three columns the follwing lines have to be added to teh script
$graph->
legend->
SetColumns(3); 7.1.6 Handling null-values in line plotsJpGraph offers two ways of handling null values (or discontinuities) in the data. You can either have a "whole" in the data or the line may be extended between the previous and next data point in the graph. If the data value is null ("") or the special value "x" then the data point will not be plotted and will leave a gap in the line. If the data value is "-" then the line will be drawn between the previous and next point in the data ignoring the "-" point. The following example shows both these possibilities. 7.1.7 Using the step-style to render line plotsStep style refers to an alternate way of rendering line plots by not drawing a direct line between two adjacent points but rather draw two segments. The first segment being a horizontal line to the next X-value and then a vertical line from that point to the correct Y-value. This is perhaps easier demonstrated by an example as seen below. You specify that you want the plot to be rendered with this style by calling the method SetStepStyle() on the lineplot. 7.1.8 Using logarithmic scaleUsing a logarithmic scale requires you to include the logarithmic add on module in "jpgraph_log.php". So you must have the line
include("jpgraph_log.php"
); on the top of your code. To Illustrate how to use a logarithmic scale let's make the right Y scale in the previous example a logarithmic scale. This is done by the line
$graph->
SetY2Scale(
"log");
This will then give the following result You can of course also use a logarithmic X-scale as well. The following example shows this. Even though we have so far only shown line graphs logarithmic scale can also be used for bar, error, scatter plots as well. Even radar plots supports the use of logarithmic plots. The following example shows how to use a logarithmic scale for a bar graph. 7.1.9 More on scalesAs you saw in the previous example it is possible to use different types of scales. In JpGraph you can use the following scales
Any combination of these may be used. Linear and logarithmic scales are pretty straightforward. The text scale might deserve some explanation. The easiest way to think of the text scale is as a linear scale consisting of only natural numbers, i.e. 0,1,2,3,4,... . This scale is used when you just have a number of Y-values you want to plot in a consecutive order and don't care about the X-values. For the above example it will also work fine to use a linear X-scale (try it!). However, the scale is now treated as consisting or real numbers so the auto scaling, depending on the size of the image an the number of data points, might decide to display other labels then the natural numbers., i.e. a label might be 2.5 say. This is not going to happen if you use a text scale. The normal practice for text scale is to specify text strings as labels instead as the default natural numbers. You can specify text strings for the labels by calling the SetTickLabels() method on the Axis. To specify the scale you use the SetScale() method. A few examples might help clarify this.
As you can see all your graphs will require at least one call to SetScale() in the beginning of your script. Normally it will come right after the creation of the Graph(). To specify the scale for the Y2 axis you use the SetY2Scale() Since you only specify one axis you only specify "half" of the string in the previous examples. So to set a logarithmic Y2 scale you will call SetY2Scale("log");'; ShowCodeSnippet($t); ?> 7.1.10 Adjusting the grid lines in the plotBy default only the Y-axis have grid lines and then only on major ticks, i.e. ticks which have a label. It is of course possible to change this. Both the X , Y and Y2 can have grid lines. It is also possible to let the gridlines also be drawn on the minor tick marks, i.e. ticks without a label. Lets see how we can apply this to the graph above. The grid is modified by accessing the xgrid (or ygrid) component of the graph. So to display minor grid lines for the Y graph we make the call
$graph->ygrid->Show
(true,true)
The first parameter determines if the grid should be displayed at all and the second parameter determines whether or not the minor grid lines should be displayed. If you also wanted the grid lines to be displayed for the Y2 axis you would call
$graph->
y2grid->Show(true
,true) Note. In general it is not a good idea to display both the Y and Y2 grid lines since the resulting image becomes difficult to read for a viewer. We can also enable the X-grid lines with the call $graph
->xgrid->Show(
true)
In the above line we will of course only just enable the major grid lines. To bring all this together we will display a graph with grid lines for both Y and X axis enabled. Note: If you think the first value of the
Y-axis is to close to the first label of the X-axis you have the option
of either increasing the margin (with a call to
SetLabelMargin() ) or to hide the first label (with a call to
HideFirstTickLabel() )
7.1.11 Using filled grid linesAnother option for the grid lines is the possibility to have the area between the grid lines filled with alternating two colors. The example below illustrates this. In the example above we have also made use of alphablending (requires GD 2.x or higher). By default the filled grid lines are disabled. To enable this style you have to call the Grid::SetFill() method. 7.1.12 Specifying text labels for the X-axisYou might want to have specific labels you want to use for the X-axis when this has been specified as a "text" scale. In the previous example each Y-point might represent a specific measurement for each of the first 10 month. We might then want to display the name of the months as X-scale. To specify the labels on the scale you make use of the SetTickLabels() method. To get a localized version of the name of the month you can use a nice feature in JpGraph, the global '$gDateLocal' object which is an instance of the DateLocale This class has a number of methods to get localized versions of relevant names for dates, (months and weekdays). So to specify the X-axis with the short form of the month names we use the construction $a =
$gDateLocale->
GetShortMonth();
This will, now result in the image displayed below Note: It is also perfectly legal to override
the default labels for the Y (and Y2) axis in the same way, however
there is seldom need for that. Please note that the supplied labels
will be applied to each major tick label. If there are insufficient
number of supplied labels the non-existent positions will have empty
labels.
7.1.13 Adjusting the ticks on a text scaleAs can be seen in the previous example the X-axis is slightly cluttered with the labels very close to each other. We might rectify this by either enlarging the image or just displaying fewer tick label on the x-axis. Specifying that we only want, for example, to print every second label on the axis is done by a call to the method SetTextLabelInterval() Which would result in the graph If the text labels are long (for example full dates) then another way might be to adjust the angle of the text. We could for example choose to rotate the labels on the X-axis by 90 degrees. With the help of the SetLabelAngle() Which would then result in the image below Note: The internal fonts which we have been
using so only supports 0 or 90 degrees rotation. To use arbitrary
angles you must specify TTF fonts. More on fonts later.
7.1.14 Using filled line graphsUsing a filled line plot is not much different from using a normal line plot, in fact the only difference is that you must call the method SetFillColor() on a normal line plot. This will then fill the area under the line graph with the chosen color. In the example below we have also, as an example, specified plot marks (see previous sections). Note 1. If you add multiple filled line plots to one graph make sure you add the one with the highest Y-values first since it will otherwise overwrite the other plots and they will not be visible. Plots are stroked in the order they are added to the graph, so the graph you want front-most must be added last. Note 2. When using legends with filled line plot the legend will show the fill color and not the bounding line color. Note 3. Filled line plots is only supposed to be used with positive values. Filling line plots which have negative data values will probably not have the appearance you expect. As you can see from the graph above the grid lines are below the filled line graph. If you want the grid lines in front of the graph you can adjust the depth with call to Graph::SetGridDepth() As the following example shows 7.1.15 Using accumulated line graphsAccumulated line graphs are line graphs that are "stacked" on top of each other. That is, the values in the supplied data for the Y-axis is not the absolute value but rather the relative value from graph below. For example if you have two line graphs with three points each, say [3,7,5] and [6,9,7]. The first graph will be plotted on the absolute Y-values [3,7,5] the second plot will be plotted at [3+6, 7+9, 5+7], hence the values of the previous graphs will be used as offsets. You may add any number of ordinary line graphs together. If you want to use three line plots in an accumulated line plot graph you write the following code
// First create the individual plots
You might of course also fill each line plot by adding the lines $p1
->SetFillColor
("red");
Using some appropriate data this might then give a graph perhaps like the one showed in the figure below 7.1.16 Constructing smooth line plots with Cubic SplinesIf you only have access to a few data points but still want a smooth curve between those data points JpGraph can help you achieving that by letting you construct cubic splines. If you never have heard of cubic splines before, don't worry. You only have to supply the data points you know tell JpGraph how many interpolated points in total you want in the graph. JpGraph will now take care of constructing a smooth curve between all you data points. The new, smooth, curve will be made up of exactly as many interpolated points as you have specified. To construct a spline you need both the X and Y coordinates for the known data points. You start by constructing a new Spline instance. To get access to the Spline class you must first remember to include the file "jpgraph_regstat.php". You instantiate this class by calling it with your two known data arrays (X and Y) as follows. $spline
= new Spline($xdata,
$ydata);
This call initializes the spline with the data points you have. These data points are also known as Control points for the spline. This helper class doesn't draw any line itself. Instead it is merely used to get a new (larger) data array which have all the interpolated values. You then use these new value in your plot. This way give you great flexibility in how you want to use this interpolated data. Continuing the above line we now use the Spline::Get() method to get an interpolated array containing a specified number of points. So for example the line
list(
$sdatax,
$sdatay) =
$spline->Get(50
); Will construct the two new data arrays '$sdatax' and '$sdatay' which contains 50 data points. These two arrays are constructed from the control point we specified when we created the '$spline' object. You would then use these two new data array in exactly the same way as you would form ordinary data vectors. The following example illustrates this In order to make the example more interesting we actually use two plots. First a line plot to get the smooth curve and then a standard scatter plot which is used to illustrate where the control points are. 7.1.17 Adding plot marks to a line plotTo emphasize the specific data points it is possible to add plot marks at each data point. Plot marks can be either
You access the plot mark through the "mark" instance variable in the plot, as in
$lineplot->
mark->SetColor("red"
); To choose between the different plot marks you call the PlotMark::SetType() method with the correct define to choose the plot type you want to use. The simple shape type of plot marks are
To specify an arbitrary image you use the special define
In this case you must also specify a image file name and an optional scaling constant. For example as in
$lineplot->mark->
SetTYPE(
MARK_IMG,
"myimage.jpg",
1.5);
If you want to use one of the built-in images the following images are available. Please note that not all images are available in all possible colors. The available colors for each image is listed below. The following shape (the first class) plot marks are available
For the second class (built-in images) the following table list the different images as well as what color they are available in. For the built-in images you specify the color with the second argument. Note that some of the images are available in different sizes. The reason is that even though you can scale them by the third argument there is a visual degradation to scale an image larger than it's original size since some pixels needs to be interpolated. Reducing the size with a scale < 1.0 gives much better visual apperance. The scaling works with both GD 1 and GD 2 but with GD 2 the quality of the scaling is much better. Built-in images and available colors:
7.2 Bar graphsJpgraph also supports 2D vertical bar plots. Before you can use any bar plots you must make sure that you included the file "jpgraph_bar.php" in your script. Using bar plots is quite straightforward and works in much the same way as line plots which you are already familiar with from the previous examples. Assuming you have a data array consisting of the values [12,8,19,3,10,5] and you want to display them as a bar plot. This is the simplest way to do this:
$datay=array(12,
8,19,3
,10,5);
If you compare this to the previous line examples you can see that the only change necessary was that instead of creating a new line plot (via the new LinePlot(...) call) we used the statement new BarPplot(). The other change we should do is to make sure the X-axis have an text-scale (it is perfectly fine to use a linear X-scale but in most cases this is not the effect you want when you use a bar graph, see more below). With this two simple change we will now get a bar graph as displayed in the following image You can of course modify the appearance of the bar graph. So for example to change the fill color you would use the BarPlot::SetFillColor() method. Making this small change to the previous example would give the expected effect as can be seen in the next example. Note: You should note from the
previous two graphs that slight change in appearance for the X-scale.
The bar graphs gets automatically centered between the tick marks when
using as text x-scale. If you were to use a linear scale they would
instead start at the left edge of the X-axis and the X-axis would be
labeled with a linear scale. As is illustrated in the (small) example
below.
7.2.1 Adjusting the width of the barsJpGraph allows you to easy customize the appearance of the bar graph, for example to change the width of each bar. The width of each bar can be specified either as a fraction of the width between each major tick or as an absolute width (in pixels). To set the width in fraction you use the method SetWidth() and to set the width in pixels you use the SetAbsWidth() As an example let's take the previous example and set the width to 100% of the distance between the ticks. The example will now become 7.2.2 Displaying the value of each barYou can easily choose to display the value (and it's format) on top of each bar by accessing the bar's 'value' property. So for example by just adding the line $barplot->
value->Show(); Will enable the values in it's simplest form and will give the result You cane see a small nuisance in this graph. The auto scaling algorithm chooses quite tight limits for the scale so that the bars just fit. Adding the value on top of the bar makes it collide with the top of the graph. To remedy this we tell the auto scaling algorithm to allow for more "grace" space at the top of the scale by using the method SetGrace() which is used to tell the scale to add a percentage (of the total scale span) more space to either one end or both ends of the scale. In this case we add 20% more space at the top to make more room for the values with the line
$graph->
yaxis->scale->SetGrace
(20); This will then give the graph as shown below You can also adjust the general position of the value in respect to the bar by using the BarPlot::SetValuePos() method. You can set the position to either 'top' (the default) , 'center' or 'bottom'. The graph below shows the value being positioned in the center. In this example we have also adjusted the format to just display the value as an integer without any decimals. It is also possible to specify a more fine grained control on how you want the values presented. You can for example, rotate them, change font, change color. It is also possible to adjust the actual value displayed by either using a printf()-type format string or with the more advanced technique of a format callback routine. To show what you can do we just give another example for you to examine without much further explanations. Just remember that to have text at an angle other than 0 or 90 degrees we have to use TTF fonts. Even though we haven't explained the SetFont() method it should be fairly obvious. 7.2.3 Adding a drop shadow to the barOne simple way of making the bar graph more attracting is to add a drop shadow to each bar. This is done by calling the SetShadow() method. An example will clarify this. 7.2.4 Adjusting the alignment of bars on a text scaleAs you have seen from the previous examples bar graphs are normally centered between the trick marks on a text scale. However, you can modify this behavior by calling the method BarPlot::SetAlign() 7.2.5 Using grouped bar plotsThese types of bar graph is used to easy group two or more bars together around each tick (X-value). The bars will be placed immediately beside each other and as a group centered on each tick mark. A grouped bar is created by aggregating two or more ordinary bar graphs and creating a GroupBarPlot() From two ordinary bar graphs along the lines of
// Create the bar plots
The following example illustrates this type of graph There is no limit on the number of plots you may group together. If you use the SetWidth() method on the GroupBarPlot() this will affect the total width used by all the added plots. Each individual bar width will be the same for all added bars. The default width for grouped bar is 70%. Setting the grouped with to 0.9 would result in the image below. 7.2.6 Using accumulated bar plotsThe final variety of group bars you can have are accumulated bars. They work in much the same way as accumulated line plots described above. Each plot is stacked on top of each other. You create accumulated bar plots in the same way as grouped bar plots by first creating a number of ordinary bar plots that are then aggregated with a call to AccBarPlot(); An example makes this clear. Let's use the same data as in the two examples above but instead of grouping the bars we accumulate (or stack) them. The code would be very similar (actually only one line has to change) 7.2.7 Using grouped accumulated bar graphsIt is perfectly possible to combine the previous bar types to have grouped accumulated bar plots. This is done by just adding the different accumulated plots to a group bar plot, for example the following code would do that.
// Create all the 4
bar plots
Putting this together in an example would then produce the graph as shown below 7.2.8 Horizontal bar graphsIt can often come in handy to have horizontal bar graphs especially if you have a large number of values to display. Even though JpGraph doesn't directly support horizontal bar graphs this is easy achieved by constructing a normal vertical bar graph which is then rotated 90 degrees. The example below shows a simple example of this In order to achieve this effect you should study the above example carefully and you might notice two things
We finally show three more examples of horizontal bar plots. In the first plot we have hidden the Y-axus and in the second we have positioned the Y - axis at top as opposed to the bottom as the first example shows. In the final example which is almost similar to the two first we illustrate the use of labels with more than one line. 7.2.9 Using gradient fill for bar graphsIt is possible to use color gradient fill for the individual bars in the bar graph. Color gradient fill fills a rectangle with a smooth transition between two colors. In what direction the transition goes (from left to right, down and up, from the middle and out etc) is determined by the style of the gradient fill. JpGraph currently supports 8 different styles. All supported styles are displayed in the figure below. To specify a gradient fill for the bar plots you make use of the method BarPlot::SetFillGradient() . See the class reference for details of this function. When using gradient fills there are a couple of caveats you should be aware of:
7.2.10 Creating semi-filled bar graphsSemi filled bar graphs are in principle the same as normal filled bar graphs but with the additional feature that you can choose to only fill a specified range (or ranges) of X-coordinates. The figure below illustrates this In this example we defined two areas along the X-axis to be filled. You can add filled areas by using the method AddArea() and specifying range and color for the filled area. 7.3 Error plotsError plots are used to visually indicate uncertainty in data points. This is done by for each X value by giving both a minimum and a maximum Y-value. Before you can use error plots you must remember to include the file "jpgraph_error.php" in your script. The following example illustrates a simple error bar. We will have 5 points, so we need 10 Y-values. We also would like the error bars to be red and 2 pixels wide. All this is accomplished by creating an ErrorPlot() in much the same way as, for example, a normal line plot. Doing this would now give the example shown below. You might notice that there is one displeasing esthetic quality of this graph. The X-scale is just wide enough to just accompany the number of error bars and hence the first bar is drawn on the Y-axis and the and last bar just at the edge of the plot area. To adjust this you might call the SetCenter() method which will adjust the X-scale so it does not use the full width of the X-axis. The following example illustrates the use of this feature by applying this technique to the previous example 7.3.1 Using line error plotsA line error plot is an error plot with the addition that a line is drawn between the average value of each error pair. You use this type of plot the exact same way you would use an error plot. The only change is that you must instantiated an ErrorLinePlot() instead and make sure you have included the "jpgraph_line.php" since the line error plot makes use of the line plot class to stroke the line. To control the various properties of the line drawn the "line" property of the error line plot may be accessed. So, for example, if you want the line to be 2 pixels wide and blue you would have to add the following two lines
$elplot->line->
SetWeight(2);
to generate the graph as shown below You may of course add legends to none, one or both of the line types in the above graph. So for example if we wanted the legend "Min/Max" for the red error bars and a legend "Average" for the blue line you would have to add the lines
$errplot->SetLegend(
"Min/Max");
The resulting graph will now look like (note that we are using the default placement of the legend box) 7.4 Scatter plotsScatter plots are very simple; they plot a number of points specified by their X- and Y-coordinate. Each point is stroked on the image with a mark as with line plots. The stroked marks can also be connected with an optional line. Note: Even
though it is only scatter plot that was designed to be used with X,Y
plots it is perfectly possible to use use both X,Y coordinates for bar
and line plots as well.
Even though you would normally supply X-coordinates it is still perfectly possible to use a text-scale for X-coordinates to just enumerate the points. This is especially useful when using the "Impulse" type of scatter plot as is shown below. Scatter pots are created by including the jpgraph extension "jpgraph_scatter.php" and then creating an instance of plot type of ScatterPlot(). To specify the mark you want to use you access the mark with the instance variable "mark" in the scatter plot. The default is to use an unfilled small circle. To create a scatter plot you will create an instance A simple example using just default values will illustrate this We can easily adjust the size and colors for the markers to get another effect as shown below Another possible variant of scatter plot is impulse-scatter plots. This is a variant of normal scatter plot where each mark have a line from the mark to the Y=0 base line. To change a scatter plot into an impulse scatter plot you have to call the method SetImpuls() on the scatter plot. This type of plots are often used to illustrate signals in conjunction with digital signal processing. The following two examples illustrates simple use of impulse plots. The next example shows how to modify the color and width of the impulse plot Note: You may draw impulse graphs without
any mark by specifying the mark type as (-1) . That way only the
impulse lines will be drawn.
As a final touch we show two more advanced impulse graphs . In these graphs we have used more advanced formatting for the Y-axis labels as well as adjusted the position of the axis position. ![]() Figure 61: In this imuplsplot we have adjusted the position of the X-axis to the bottom and also added more decimals to the labels on the Y-axis [src] 7.5 Field plotsA variant of scatter plot is the so called Field Plots this is basically a scatter plot where each scatter point is an arrow with a direction between 0 to 359 degrees. This effectively allows the visualization of 3 parameters at each point (x,y,angle). As an additional bonus there is also possible to define a callback for each scatter plot to also define the color for each point. To create a field plot you create an instance of FieldPlot in the same way as you created a normal scatter plot. The arguments to this method are Y-coordinate, X-coordinate and angle. To specify a callback you use FieldPlot::SetCallback() The following example (and code) illustrates the usage of the field plot type. In addition to the parameters mentioned above you can also adjust both the general size of the arrow and also the specific size of the arrowhead. The arrow size is specified in pixels and the arrow head is specified as an integers between 0 and 10. These sizes are specified with a call to FieldPlot::arrow::SetSize() 7.6 Box and Stock chartsJpGraph offers two variation on what is usually known as stock charts, candle-charts or box plot. 7.6.1 Stock ChartsStock charts is used to display data values where one is interested in 4 different values for each data point. This could for example be used to display a stock's open,close, min and max value during a specific day. Hence the name Stock chart (or Stock plot). The figure below illustrates a sample Stock chart plot For this type of plot the Y-data array must be consist of a number of quadruples of data where each quadruple consists of (open,close,min,max). The open and close values determine the min max for the middle bar and the min,max determine the end points of the "error-lines" at the top and bottom of of each bar. Note that the data follows the following rules
To separate the two cases where "open > close" or "open < close " different colors are used. These colors are specified with the SetColor() method. By default a positive bar (close > open) have a fill color of white and for the negative case where (close < open) the bars have a red color. You can specify the width of the bar by setting the width (in pixels) with a call to the method SetWidth() The final variation of stock plots you can have is to determine whether or not the end point for the min,max lines should have the horizontal line marking the end of the line or not. This can be adjusted with a call to method HideEndLine(). 7.6.2 BoxPLots : Stock charts with a median lineA minor variation of stock charts is the "BoxPlot()" this is almost the same as StockPlot() but with the very small difference that in addition to the open,close,min, max values you also specify a median value . The median lies between the open and close value and is illustrated as a horizontal line within the bar. You may modify the median line color for positive and negative data points / bars by using the SetMedianColor() method. 7.6.3 Image maps for Box and Stock chartsIn the same way as for other plots you may associate an image map with these plots. The "hot" area for each plot is the mid "bar" section. In the same way as other plot types you use the SetCSIMTargets() to set the URL's you want to use. These plot types, though normally used without explicit X-values, can of course handle a supplied X-coordinate array without any problem. 7.7 Combining different graph typesIt is perfectly legal to add several different plot types to the same graph. It is therefore possible to mix line plots with (for example) filled bar graphs. What you should keep in mind doing this is the order in which these plots are stroked to the image since a later stroke will overwrite a previous one. All plots are stroked in the order you add them, i.e. the first plot added will be stroked first. You can therefore control which plot is placed in the background and which one is placed in the foreground by the order you add them to the plot. To start simple we just mix a filled line plot with a non-filled line plot as the following example shows. Let's now go to something a little bit more complicated. How to mix bar and line graphs. Let's just take one of our previous bar graphs and add a line plot to it and see what happens. Not too bad. But we can't see the line so we change the order in which we add the lines to the graph and sees what happens. If you want the line points to be aligned in the center of the bars you can accomplish this is two ways. If you use a text scale then you need to call the LinePlot::SetBarCenter() You can also use an integer scale. This places both the bar and the line points centered at the tick marks. As the following example will show Note: In this example we also have
illustrated the fact that it is possible to add text labels to a linear
(or integer) scales as well.
As a final example we show how you can combine a scatter plot and a line plot which could be used to illustrate a regression line fitting. 7.8 Specifying the scale manuallyNormally the automatic scaling should be doing an adequate job in most circumstances but there might be cases where you like to manually set the scale. For example if you have several graphs where you like to be able to easily compare them and therefore want them all to have the same scale. To specify a manual scale you have to add arguments to the standard Graph::SetScale() method. So to specify that you want an Y-scale between 0 and 100 you need to write
$graph->
SetScale(
"textlin",0,100
); When you specify a scale manually there is one additional thing you need to decide. How the tick marks should be positioned. You have three choices
The three images below illustrates the difference between the possibilities of ticks for a manual scale. 7.9 Adjusting the automatic tick marksYou can adjust the automatic tick marks by telling JpGraph how dense you want them to be. You use the Graph::SetTickDensity() method. You can set the density setting in four steps
Taking the previous example with the manual scale but automatic ticks and using a denser ticks setting gives the following result 7.10 Handling date/time scalesWith date/time scale we refer to the plotting of data where the independent variable (X-axis) de-nominates a time value. This could for example be the temperature measured in intervals during a day. From version 1.18 and onwards there are two principal ways of handling date/time scales. The manual way and fully automatic using the special "dat" scale. For most cases the automatic "dat" scale is the preferred choice but in rare circumstances it might be more appropriate to use the manual way since it gives slightly more control (but not that much) of the overall handling of scales. To be able to use a date/time scale at all we will assume that the data points are represented by both an X coordinate (time-value) and a Y-value (anything else wouldn't make sense). We first start by describing the use of the "dat" scale. 7.10.1 Using the automatic date/time scaleThe easiest way to get a date time scale for the X-axis is to use the pre-defined "dat" scale. To be able to use that it is first necessary to include the module "jpgraph_date.php" and the specify the scale, for example as "datlin" in the call to SetScale() as the following code snippet shows.
require_once("../jpgraph.php");
The above code snippet would create a date/linear scale for the graph. We will first show a basic use of the date scale and then go on to illustrate how it is possible to tailor the exact formatting of the date axis. When using the fully automatic formatting the library will use the shortest possible string that uniquely identifieas a date/time. For example if the entire intervall falls within the same day only the time values will be displayed, if the intervall falls over several days then also the date will be added to the label. As usual it is also possible to manually force a certain label formatting to be used this is illustrated below. 7.10.1.1 Specifying the input dataThe first basic example below creates a data set that emulates a sample rate every S second and falls over a total period of two days. It is important to note that the input data on the X-axis must be a in the form of timestamp data, i.e. the number of seconds from the system epoch. In PHP the current timestamp value is returned by the function time(). This means that it is always mandatory to specify two input vectors for a plot. For example to specify a line plot
$line
= new LinePlot
($data,$xdata);
The example below show this in practice Please review the script (by following the [src] link) that creates this graph before continuing since we will base all further examples on the above example. 7.10.1.2 Adjusting the start and end alignmentAs can be seen from the above example the scale starts slightly before the first data point. Why? This is of course by purpose in order to make the first time label to start on an "even" value, in this case on an hour. Depending on the entire interval of the graph the start value will always be chosen to be the largest "even" time value, this could for example be on an even minute, even 30min, even hour, even day, even week and so on. The alignment of the start (and end) vdate alignment can also be adjusted manually by using the two methods
These method allow the alignment to be made by specifying one of the following constants. For the SetTimeAlign() the following symbolic constants can be used
For the SetDateAlign() the following symbolic constants can be used
Some examples will calrify the use of these methods. Example 1. We want the time adjustment to start on an even quarter of an hour, i.e. an even 15 minute period. $graph
->xaxis->scale->
SetTimeAlign(
MINADJ_15);
Example 2. We want the time to start on an even 2 hour $graph
->xaxis->scale->
SetTimeAlign(
HOURADJ_2);
Example 3. We want the start to be on an even day $graph
->xaxis->scale->
SetDateAlign(
DAYADJ_1);
7.10.1.3 Adjusting the label formatThe default label format always tries to use the shortest possible unique string. To manually set a manual scale the method SetDateFormat() is used for example as in
$graph
->xaxis->scale->
SetDateFormat(
'H:i');
The above example will force the labels to be displayed as hour (24h) and minutes. 7.10.1.4 Adjusting the date scale densityAs with the linear scale it is possible to indicate what density of scale ticks is needed. This is specified as usual with a call to Graph::SetTickDensity()
$graph->
SetTickDensity(
TICKD_DENSE);
7.10.2 Specifying a date/tiome scale with a manual call-backIn the following we will assume that all data points are specified by a tuple where the date/time is specified as a timestamp in second in the same format as is returned by the PHP function time(). The trick here is to use a label formatting callback routine which gets called to format each label on the scale. What we do is that we specify that the X-scale should be an ordinary "int" scale (remember that the data values are timestamps which are integers). We then install our custom label callback (with a call to SetLabelFormatCallback()) which given a timestamp formats it to a suitable human readable form. In our example we will use the PHP function Date() for this purpose. The callback we use will be
// The callback that
converts timestamp to minutes and seconds
Using some random data we can now generate the following graph ![]() Figure 78: Example on how to format an axis to hold a date/time scale using and integer scale and a callback routine [src] In the above example we have specified the X-scale manually to make sure that the min/max values on the X-axis exactly matches the min/max x-data values. SetLabelFormatCallback() will be called for each of the displayed labels and the argument passed on to the supplied function is the default label that the library is assigning that specific label. This means that if the data to be displayed is based on, for example, timestamps which are given in seconds the displayed value might not be aligned to how time/date values normally should be displayed. Using integer scales this will not work very well since the library determines label positions to be at even positions (e.g. every 2,5,10, 20,50,100 etc) to suit the auto-scaling since the library will assume that the data is integers and not timestamp values. The best way to solve this is to use an integer X-scale together with a a callback function with a manually specified scale. In order to setup the scale a bit of manually work is needed. Depending on the data to be displayed one should ensure that the scale starts and ends at suitable times and that the tick interval chosen fits with an even multiple of minutes, hours, days or what is best suited for the time range that is to be displayed. The following code example illustrates this. It creates some "fake" data that is assumed to be sampled time based data and sets up some suitable scales and tick interval. This script may be used as a basis for more advanced handling of the time data.
(File: timestampex01.php)
<?php
7.11 Adjusting labels on a text scaleIn the following section we will work through an number of examples on how to manipulate labels on a text scale. Primarily we will investigate how to best handle the case where you have a large number of values. As a remainder; Text scale is meant to be used on the X-axis when the X-axis doesn't have a numeric value, i.e you are only interested in linear ordering of the data. If you don't specify the labels manually they will be set automatically starting from 1 as the example below shows. To specify the labels on the X-axis as suitable text strings you call the method Axis::SetTickLabels() with an array containing the text-labels. If there are more data points than labels the non-specified labels will be given their ordinal number. If we augment the previous example with the name of the month we get the following new example Tip: To get hold of localized version of the month names (or weekdays) you can use the DateLocal class available in the global variable $gDateLocale If no locale has been specified the default locale for the installation will be used. What happen now if we have a larger number of bars? Let's try with 25 bars and see what result we get. Not all to impressive. The labels are to close and they overlap. Hence it is not a good idea to display every label. To adjust what labels are to be displayed you use the SetTextLabelInterval() method. The argument to this method is the interval between text labels. So to display only every 3 month you would add the line
$graph->xaxis->SetTextLabelIntervall(3
) Which would give the result shown below Much better, quite readable. If we have an even larger data set it might not longer be meaningful to display all the tick marks since they would simple become to close. In JpGraph there is a possibility to specify that you only would like every n:th tick mark to be visible ( SetTextTickIntervall() ). For bar graphs using text scale however, that might not be such a good idea since the tick marks are between the bars and the labels centered under the bars. If we only were to display, say, every 3 tick mark it wouldn't look to good. Not that we can't do it, as the example below shows, but it just doesn't look very good. A better way to handle large data set is simply to hide the tick marks all together. Tick marks may be hidden by calling the method Axis::HideTicks(); If we hide all the ticks on the X-axis we will get the result shown below 7.12 Adding arbitrary text strings to the graphTo add clarification or other information text strings to the graph you can add arbitrary lines of text anywhere you like onto the graph. The text might have multiple lines and you can choose the paragraph alignment. To add text you have to create one or more instances of the Text() object and then add the text object to the graph with the AddText() method. The position of these text boxes are given as fraction of the width and height of the graph. When you are positioning these text boxes you might also choose what part of the text box should be considered the anchor point for the position you specify. By default the anchor point is the upper left corner of the bounding box for the text. To show some ways of positioning the text we use a very simple bar graph not to distract from the text. We first just add a single text line with most of the settings their default value by adding the following lines to the graph
$txt=new
Text("This is
a text");
The result is shown below. Not too exiting. Let's make it more interesting by having a background color, using larger fonts and framing the text box and adding a drop shadow to the text box by using the methods SetBox() and SetBox() That's better. Now we get some attention. If you want to add a text with several lines you just need to separate the lines with a newline ('\n' character). The default paragraph alignment is left edge but you can also use right and center alignment. As an illustration let's add a couple of more lines to the previous text, center the text box in the middle of the graph and also use centered paragraph alignment for the text. To adjust the paragraph alignment of the text you have to use the Text::ParagraphAlign() Of course there is no limit to the number of text string you can add to the graph. From version 1.12 it is also possible to add text strings to a graph using the scale coordinates instead. This is accomplished by using the Text::SetScalePos() Which is completely analog to SetPos() with the only difference that the positions given are interpretated as scale values instead of fractions of the width and height. 7.13 Adding titles and footers to the GraphEach graph can have up to three different titles accessed by the three properties
All of these three properties is a standard text object which means that you can have individual font, colors, margins and sizes of these tree titles. The only thing you need to think of is that you probably want to add some extra margin to make room for the titles (using Graph::SetMargin() ) The individual positioning of these titles are done automatically and will adjust to the font size being used. If you for, esthetic reasons, would like increase the distance from the top where the title is positioned (or the intra distance between title and sub title) you can use the Text::SetMargin() method. For example the line
$graph->title->SetMargin
(20); will set the distance between the top of the title string and the top of the graph to 20 pixels. If you instead call the SetMargin() method for the subtitle it will adjust the distance between the top of the subtitle and the bottom of the title. The titles will be positioned at the top and be centered in the graph. Each of these titles may have multiple lines each separated by a "\n" (newline) character. By default the paragraph alignment for each title is centered but may of course be changed (using the ParagraphAlign()) method. Each graph can also have a footer. This footer is actually three footers. Left, center and right. The 'left' footer is aligned to the left, the 'center' at the bottom center and the right to the right. Each of these three positions is a standard Text object which means you can change color, font and size as you please individually on each of these footer positions. You access the footer through the Graph::footer property as the following example shows
$graph->
footer->left->Set
("(C) 2002 KXY"
);
Note: If you enable the brand timing
argument you should leave the left footer empty.
7.14 Adding a tab titleA variant of the titles is the tab title. This is just another option you have of putting a name on the graph. The appearance of this type is a tab on top of the plot area with text inside. You can access the tab using the 'tabtitle' property of the graph. The following figure shows an example of how this can look. As usual you have full freedom to specify font and colors for this type of title. Please see the class reference regarding GraphTabTitle() for more information. 7.15 Using background imagesInstead of having a single color background you can easily have an arbitrary image as the background. The image may be in either PNG, JPG or GIF format depending on what your installation supports. A note on GD: If you are using GD 2.xx you must make sure that the define USE_TRUECOLOR is set to true. This is also the default. Failure to do so in combination with GD 2.xx will make the background image just look like a solid black square. To use a specific image as the background you just have to use the method Graph::SetBackgroundImage() The arguments specify file-name, how the image should be positioned in the graph and finally the format of the image (if it is in JPG, PNG or GIF) format. If the format is specified as "auto" (the default) then the appropriate image format will be determined from the extension of the image file. The file name is of course obvious but the second argument might not be. This arguments determine how the image should be copied onto the graph image. You can specify three different variants here
The following section only applies to palette based images. True color images can NOT be manipulated this way. Applying the following sections to true-color images will have no affect. You might often find yourself wanting to use a background image as a "waterstamp". This usually means taking the original image, import it to some image editing program and then "bleaching" the color saturation, reducing the contrast and so on. Finally you save the modified image which you then use as a background image. This whole process can be automatically accomplished in JpGraph by using the method Graph::AdjBackgroundImage() which allow you to adjust color saturation, brightness and contrast of the background image.
$graph->
AdjBackgroundImage(...)
to achieve the "watercolor" effect to avoid the image being too intrusive in the graph. Note: The background image depicts a 1998
Triumph Tiger. This bike is a 900cc off-road bike.
7.16 Using a background gradientIn addition to the background image you can also add a background color gradient. This gradient can be covering the entire graph, just the plot area or just the margins. This flexibility allows you to combine a background image with a background color gradient. You can for example use a background image in the plot area and a color gradient out in the margins. You specify a color gradient background by calling the Graph::SetBackgroundGradient() method. All details are available in the class reference (follow the link above). We finally give a quick example on what kind of effect you can achieve using this feature. Finally we like to mention that in the "/utils/misc/" directory you will find a small utility script called "mkgrad.php". Running this script presents you with a UI that makes it a breeze to create a gradient image on it's own. The UI for the utility is so obvious that we won't discuss it
further, we just show it below. In the example below this utility is used to get a more interesting plot area. 7.17 Using callbacks for Plot marksAn interesting enhancement when using Plotmarks is the possibility to add a callback function to control the size and color of the plotmarks. This callback function will get called with the current Y-value (for the plotmark) as it's argument. As return value the callback function must return an array containing three (possible null) values. The values returned must be
The exact meaning of the parameters will of course depend on the type of plot marks being used. The callback must be a global function and is installed with a call to PlotMark::SetCallback() So for example to install a callback that changes the fill color for all marks with a (Y) value higher than 90 you could add the lines 90) $fcolor="red" else $fcolor=""; return array("","",$fcolor); } ... $plot->mark->SetCallback("MarkCallback"); ...'; ShowCodeSnippet($t); ?> As you can see in the above example we have left some of the return values blank. Doing this will just ignore any change of these value and use the global settings for the plotmarks. If you also let the (Y) value affect the size of the plot marks you can get what is sometimes known as a "balloon plot". The example below is basically a scatter plot that uses filled circles to mark the points. A format callback is then used to change the color and size depending on the Y-value for each plot. 7.18 Rotating graphs 90 degreesIn section 10.2 you can read about arbitrary rotation of the graphs. For most practical purposes rotation of 90 degrees is most useful. This could for example be used to plot horizontal bar graphs. The slight complication with general rotation is that the margins also rotates, this means that if you rotate a graph 90 degrees the left margin in the image was originally the bottom margin. In additional by default the center of the rotation is the center of the plot area and not the entire image (if all the margins are symmetrical then they will of course coincide). This means that depending on your margin the center of the rotation will move. You can read more about this and how to manually set the center for rotation in the section about rotation, 10.2 This is just a slight inconvenience which you have to take into account when you need to set an explicit margin with a call to Graph::SetMargin() However, in order to make a rotation of 90 degrees much easier you can easily rotate a graph 90 degrees and set the correct margin with a call to Graph::Set90AndMargin() The parameter to this method lets you specify the margins as you will see them in the image without having to think of what becomes what after the rotation. So, the only thing you need to do is call this method and then the graph will have been rotated 90 degrees. 7.19 Formatting the axisTo get the exact type of axis you want in your graph there are a number of adjustments available for you. You may change, color, size, position and general appearance. 7.19.1 Standard two axis graphsAssuming we start with the traditional two axis graph, one X and one Y axis. You may then change the position of each axis by calling Axis::SetPos($aPosition) You have to remember that you need to specify the position on the other axis. SO you need to specify the world-coordinate for the position. By default the axis are each positioned at the 0-point on the other axis, i.e. the axis will cross at the 0,0 point in the graph. In addition to the standard positioning you may also use the two special position markers "min" and "max". This will position the axis at the minimum (or maximum) position of the other axis. For example, to make sure that the X-axis is always at the bottom of the graph (at lowest possible Y-value) you would have to add the line
$graph->xaxis->SetPos
("min"); To change the color and width of the axis you have to make use of the Axis::SetColor() and Axis::SetWeight() methods. Invisible axis Even though JpGraph (1.7) doesn't directly support "hidden" axis where the labels are still drawn it is very easy to achieve this effect by setting the colors of the axis to be the same as the background. See the example barintex2.php in the Example directory. To completely hide an axis you can make use of the Hide() You might also want to add titles to the axis. This is done through the Axis::SetTitle() method. This is actually just a shortcut for accessing the title property direct. Axis::title::Set() which also allow you to set the alignment in one call. By default the position of the title is to the far right for the X-axis and in the middle (and 90 degrees rotated) for the Y-axis. You can adjust the position of the title with the help of the second argument to the Axis::SetTitle() method. The possible positions are "high","middle" and "low" which refers to the scale values on the axis. One common modification you might want to do to the title is to increase the margin between the axis and the actual title. This is often necessary to do for the Y-axis if the values displayed are large. You may adjust the distance (in pixels) between the axis and the title by using the method Axis::SetTitleMargin() So for example to increase the margin on the Y-axis you might add the line
$graph->yaxis->SetTitleMargin(40
); to your code. Finally we mention something about the positioning of tick marks and labels on the axis. You have the possibility to choose what side of the axis the tick marks and the labels should be at. For the X-axis this can be specified as either on the the top (inside the plot area) or at bottom (outside of the plotarea). In the same way you can specify for the Y-axis if the labels ( or ticks) should be on the left or right side. To adjust the label positioning you have to use the method Axis::SetTitleSide() and to adjust the position of the tick mark you have to use the method SetTickSide() Note: There is also an alias
for this method, SetTickDirection() which is deprecated from version
1.7 but kept for backwards compatibility. Valid arguments for
these methods are
For example, the following lines added to a script would change side of the labels and tickmarks for the X-axis.
$graph->xaxis->SetLabelPos
(SIDE_UP);
This technique is for example used if you position the X-axis at the top of the graph as the following example shows. ![]() Figure 93: Example of both how to adjust the position of the X-axis as well as adjusting the side for the tick and axis title [src] 7.19.2 Scientific style axisIn scientific style plots it is often common to duplicate each axis so that all sides of the graph have a labeled axis. This is of course also fully supported by JpGraph. Before we continue we show a small example to illustrate this feature The example above shows the basic configuration. There are now several modifications you may do to these axis like
The style of axis is determined by the method Graph::SetAxisStyle() The available type of axis are
7.19.3 Adjusting the position of the scale labelsHow to adjust the actual labels are discussed elsewhere in this manual (see ???,???). However we like to mention here that you can adjust the label margin (distance between the axis and the labels) with the method Axis::SetLabelMargin() to adjust the actual label format (like font, color, angle) you need to access the Axis::SetFont() and the Axis::SetColor() methods. If you investigate the Axis class you will discover more methods to adjust the many aspects of the axis layout. As a final note we also mention the methods Axis::SetLabelAlign() and Axis::SetLabelAngle() This first method is really only mentioned here for completeness since it is mostly used for internal purposes. However on some occasion you might want to adjust the alignment of the labels. By default they are centered in respect to the tick mark. By using the method you might override this positioning should you choose to do so. The second of these methods adjusts the angle of the label in regards to the axis. This is very useful for X-axis that have long labels. 7.19.4 Formatting the scale labelsIn order to have full control over the way that the labels are displayed it is possible to define a callback function that will be applied to all labels. The callback function will be called with the label as the only argument and should return the value that will be displayed in the graph. This could for example be used to turn seconds (used to position data points) into hour and minutes on the scale. For further reference see the two methods: Graph::SetLabelFormatCallback(); and Graph::SetLabelFormat(); 7.19.5 Inverting the Y-axisOne good way of illustrate the usefulness of label callbacks in a slightly different context is to show how we can achieve the effect of an inverted Y-scale. An inverted Y-scale has the lowest number at the top and the scale values increases downwards. Even though JpGraph doesn't directly support this feature it is quite easy to achieve with just a few extra lines of code in your image script. Before we continue we give an example of what we are referring to. Two achieve this effect there are two simple steps to take:
And that's it! We refer you to the code in the example above for the details. 7.20 Adjusting the auto-scaling limits - grace valueBy default the auto-scaling algorithm tries to make best possible use of screen estate by making the scale as large as possible, i.e. the extreme values (min/max) will be on the top and bottom of the scale if they happen to fall on a scale-tick. So for example doing a simple line plot could look like the plot shown in the below. However you might sometime want to add some extra to the minimum and maximum values so that there is some "air" in the graph between the end of the scale values and the extreme points in the graphs. This can be done by adding a "grace" percentage to the scale. So for example adding 10% to the y-scale in the image above is done by calling the SetGrace() method on the yscale as in
$graph->yaxis->scale
->SetGrace(10,
10);
These lines add a minimum of 10% to the top and bottom values of the scale. Note that we say "minimum" since depending on the specific tick values choose this might be a little bit more to make the end of the scale fall on an even tick mark. Adding this line to the previous graph will result in the following example Since we haven't adjusted the position of the X-axis it will remain at Y=0 which might not necessary be what we would like so we therefor also add the line
$graph->xaxis->SetPos
("min"); So that the X-axis always will remain at the lowest possible Y-value. Doing this will then result in the example below 7.21 Adding bands of pattern and color to graphsAs an additional way of emphasizing certain areas of the graph it is possible to add bands (either vertical or horizontal) to any one of the standard X-Y coordinate system based graphs. A band is a rectangular area that stretches one entire axis. This means that if you define a band between X-coordinates 3 and 5 the band area will occupy an area between the X-coordinates and the entire Y-range. In order to access this functionality you must first make sure that you include the additional library file jpgraph_plotband.php At the time of this writing (current as of JpGraph 1.8) the table below illustrates the 8 basic types of patterns available. We will shortly show you how you can customize these patterns, To keep these examples clear we have only used one pattern in each figure. To add a one of these patterns to your graph you need to call the method PlotBand::PlotBand() The arguments is fairly easy to understand. The pattern you would like to use is specified by using the correct constant. You can see the name of the correct constants in the figures above. You also need to specify if the band should stretch along the vertical or horizontal axis as well as the min and max coordinates for the band. As coordinates you may also use the special values "min" and "max" which automatically sets the value to the minimum/maximum value of the scale. The specified numeric value will be automatically truncated to fit within the plot area. We don't discuss the other arguments further here, instead we refer you to the class reference. 7.21.1 Customizing the patternsAll patterns can be customized by
Note: 3D planes actually carry another
possible modification. You can specify the vanish point to change the
perspective used. You can't access the method to change the horizon
directly but you can access it through
$band
->prect->SetHorizon(
$aHorizon)
assuming that the band is a 3D plane. To finish this section we give one final, more creative, example on how to use the bands. 7.22 Adding static lines to the plotIn addition to the bands you can also add static lines to the graph. An example of that is actually shown in figure 11 above. You create a line as an instance of class PlotLine . So for example the lines $sline
= new PlotLine
(HORIZONTAL,0,
"black",2);
will add a 2-pixel wide horizontal static line at Y-position zero. 8 Working with non X,Y-plotsNon X,Y plots includes
The fundamental difference is that these classes makes use of an extended version of the basic Graph class. Therefor you can not mix X,Y plots with non-X,Y plots. For example it is not possible to mix a line graph with a Polar graph.
8.1 Radar plotsSpider plots are most often used to display how a number of results compare to some set targets. They make good use of the human ability to spot symmetry (or rather un-symmetry) . the figure below show an example of a spider (sometimes called a web-plot). Spiderplots are not suitable if you want very accurate readings from the graph since, by it's nature, it can be difficult to read out very detailed values.
In the following section we show how to draw both simple and complex radar graph. As we will show all the settings will follow the same pattern as for the more standard linear graphs. 8.1.1 Simple radar plotsLet's start by creating a very simple radar plot based on 5 data points using mostly default values. As the first thing you must remember to include the extension module that contains the radar plot. "jpgraph_radar.php". A very simple radar plot is created by the code
(File: radarex1.php)
<?php
and would give the result To change the size and position of the radar graph is similar to the pie plot and you do it by using the methods SetSize() and SetCenter() If you want a filled radar plot you need to specify the fill color with the method SetFillColor() The following example shows these methods in action 8.1.2 Specifying titles for the axis and legends for the plotsWe normally would like something more meaningful as description of each axis than it's number. Specifying the titles are accomplished through the use of the method SetTitles() of the graph. Let's say that each axis corresponds to a month. We could then use the code $titles
= $gDateLocale
->GetShortMonth
();
As you can see the way radar plot is constructed will assign the titles (and plot points) in a counter-clockwise direction. If you want them in clock-wise order you will have to inverse your input data array as well as the title array. To specify a legend you (as with the other plot) make use of the SetLegend(); method on each radar plot. 8.1.3 Adding grid line to the radar plotEach major tick mark can also be connected together to create a grid. The grid is accessed through the 'grid' property of the graph. To enable the grid and set the line style to "dotted" you would have to add the lines
$graph->grid->Show
();
and would result in the following graph By design the plot is above the grid line but beneath the axis in image depth, hence some part of the grid lines are hidden. To have the grid lines more "visible" just change their color, say to, dark red by invoking the SetColor() method on the grid lines which would give the following result Another simple change we could do would be to just change the background color of the radar graph. This is (not surprisingly) done by a call to the method SetColor() invoked on the graph object. 8.1.4 Adding several plots to the same radar graphYou can easily create several radar plot which are added to the same radar graph. The thing to remember is that if you use filled radar plots and they overlap each other that the order which they are added will be the order they are drawn. A simple example of this is shown below 8.1.5 Adding plotmarks i radar graphsIn exactly the same way as for line graphs it is possible to add plot marks in radar plots. The mark property is accessed through the RadarPlot::mark The example below adds a red ball as a marker. 8.2 Pie plotsSo far we have just show plots based on an X-Y coordinate system. This is not the only types of graphs you can create with JpGraph. Another common type is Pie plots. JpGraph supports both 2D and 3D pie plots. For 2D pie plots there are also 2 versions, but more on that later. The main difference as compared to the X-Y plots is that to all pie plots are added to the PieGraph() instead of the Graph() object we used for the X-Y graphs we have drawn so far. For this you must first include the "jpgraph_pie.php" in your script (or "jpgraph_pie3d.php" if you want to use 3-dimensional pies). Below you cane see the code needed to create the simplest possible pie graph just using the default settings.
include (
"../jpgraph.php");
The above code would give the following pie graph There is a few things worth noting here
You can change almost all aspects of appearance of the pie graphs. For example you could change :
The next simplest addition we can do is to add a legend to the pie graph. We do this by using the SetLegends(); method. By adding the legends to the previous example we get the following image (In the figure above we also moved the center of the pie slightly to the left to make more room for the legend box.) The text for the legends can also contain printf() style format strings to format a number. This number passed on into this string is either the absolute value of the slice or the percentage value. How to switch between the is describe further down in this chapter. The next change you might want to change is the size and position of the Pie plot. You can change the size with a call to SetSize(); and the position of the center of the pie plot with a call to SetCenter(); The size can be specified as either an absolute size in pixels or as a fraction of width/height (whatever is the smallest). The position of the pie plot is specified as a fraction of the width and height. To put the size and positioning API to use we will show how to put several pie plots on the same pie graph. In the following example we have also adjusted the legends of the slice values to use a smaller font. What we do in this example is quite simple, create 4 pie plots, make them smaller and put them in the four corner of the graph. This will give the result as shown in the following example. 8.2.1 Adding guide lines to Pie PlotsFor very busy Pie plots it can become too little space for the labels to be printed just beside the pie slice. For this purpose it is possible to use guide lines for the labels. The library will then draw a line from the center edge of the slices to the label which will be positioned further out from the Pie Plot. There is one method that is primarily used to handle this, PiePlot::SetGuideLines() the simplest usage of this would be $pieplot
->SetGuideLines
(); An example of this could then be The above example will give guide lines very similar as what is produced by other programs, e.g. Excel. In addition to the above variant it is also possible to instruct the library to line up the labels vertically in a way that we think is easier to read. This is achieved by specifying the second parameter to the SetGuideLines() to 'false' as in $pieplot->
SetGuideLines(
true,false); The first parameter is to enable/disable the guide-lines. With the same example as above this would then produce the image It is also possible to configure the vertical distance between the labels. By default the distance between the labels is roughly 40% of the labels font height. By using the method PiePlot::SetGuideLinesAdjust() it is possible to specify a fractional value which is interpretated as the distance between the bottom of one label to the bottom of the next. This means that specifying a value of '1.0' the labels will have no space between them and the bottom of one label will touch the top of another label. By default this value is 1.4. By increasing or decreasing this value it is possible to make the labels become positioned more or less compact. Below we have taken the above example and reduced the distance to '1.1' and as can be seen this yields much more compact labeling. Note: As of 1.18 guide lines is only available in 2D Pie plots and not available for 3D Pie plots. This is planned for the 1.19 version. 8.2.2 Creating 3D pie plotsSo far we have only made use of 2D pie plots, creating 3D pie plots is no more difficult. Instead of creating the plots with a call to PiePlot() you create the plots with a call to PiePlot3D() If we just take the first simple pie plot and replace the call to PiePlot() with a call to PiePlot3D() we get the following result. 3D Pie plots have the same possibilities as the normal pie plots with the added twist of a 3:rd dimension. You can adjust the perspective angle with the method SetAngle() So for example to make the pie more "flat" you just set it to a smaller angle. Setting the perspective angle to 20 degrees in the previous example will give the following result. 8.2.3 Exploding pie slicesOne way to attract attention to some specific piece of information in a pie chart is to "explode" one or more slices. Both 2D and 3D pies support exploding one or several slices. Exploding slices is accomplished by the methods Explode() and ExplodeSlice() The first method is used if you want to explode more than one slices and the second is a shorthand to make it easy to just explode one slice. For example to explode one slice the default "explode" radius you would just have to say
$pieplot->ExplodeSlice(
1)
The above line would explode the second slice (slices are numbered from 0 and upwards) the default amount. Doing this to the two previous example would result in To explode all slices at once you can use the PiePlot::ExplodeAll() method. If you want to explode several slices you can use the PiePlot::Explode() method and supply a suitable array argument. 8.2.4 Specifying and adjusting labels on pie plotsBy default the values shown just outside the pie for each slice are the percentage value for each slice. If you instead wanted the absolute value you would just have to use the SetLabelType() method. So to use the absolute value you would call
$pieplot->
SetLabelType(
"PIE_VALUE_ABS");
Furthermore you could enhance the formatting of the value by either using a printf() style format string (using SetFormat() ) or by providing a formatting function callback (using SetFormatCallback() ) for doing more advanced formatting. You can also adjust the position of the labels by means of the PiePlot::SetLabelPos() method. The argument to this method is either the fraction of the radius or the string 'auto'. In the latter case JpGraph automatically determines the best position and the the first case The following example illustrates this If this formatting is not enough you can also "manually" specify the labels for each slice individually. You do this by using the PiePLot::SetLabels() method. This will let you specify individual text strings for each label. In each specification you can also add a printf() formatting specification for a number. The number passed on will be either the absolute value for the slice or the percentage value depending on what was specified in the call to SetLabelType() The SetLabels() method can also take a second parameter, the label position parameter. This is just a shortcut to the SetLabelPos() as described above. By default the position will be set to 'auto' if not explicitely specified. Note: The alignment of
the labels will be different depending on whether they are inside or
outside the pie. When inside the center of the strings will be aligned
with the center of the slice at the specified fraction of the radius.
When positioned outside the alignment will depend on the angle to avoid
that the labels inadvertely writes over the pie.
8.2.5 Specifying slice colors and using themesAnother typical change would be to change the colors of the slices. There are two fundamental ways of doing this. You either manually specify the colors for the slices as an array using the method SetSliceColors() If you specify fewer colors than the number of slices they will just wrap around. Another way is to use one of the pre-defined color "themes". This is just a predefined set of colors that will be used for the slices. You choose what "theme" you like to use with the method ( SetTheme() ) At the time of this writing the available themes are
The following example shows the same pie using the different "themes" in order. A complete color chart of all available colors in the different themes can be found here Another simple change is to remove the border ( or change it's colors ) that separates each slice. This can be done by a call to ShowBorder() 8.2.6 Adding drop shadows to the slicesAn additional visual enhancements can be made by adding a drop shadow to the individual slices. This is accomplished by means of the PiePlot::SetShadow() method. Adding a drop shadow is often more affective if the pie has one or more slices exploded as the following example shows 8.2.7 Another variant of 2D Pie plotsAs mentioned in the beginning there are two versions of the 2D pie plots. The normal pie plot created as an instance of class PiePlot and a variant created as an instance of class PiePlotC This variant is an extension of the standard PiePlot in the sense that it also have a filled circle in the center. The following example illustrates this Since the PiePlotC is an extension to the basic pie plot all the normal formatting you can do for pie plots you can also do for the PiePlotC . The additional formatting only concerns the filled middle circle. You have the option of adjusting size, fill color and all font properties. You perform these operations with the methods
In addition to the normal CSIM for PiePlot:s the center area is also a CSIM hotspot. You specify the target CSIM with a call to PiePlotC::SetMidCSIM() The next example shows an example with some more innovative formatting. In this example we have :
8.3 Polar plots8.3.1 OverviewEach data point in a polar plot is represented by a tuple consisting of a radius and an angle. The polar plot itself can be either outlined or filled. In addition each point may have a standard marker (the same as for line and scatter plots). The scale for the radius can be either linear or logarithmic. A polar graph is created by creating an instance of PolarGraph::PolarGraph(). The polar graph type inherits all the capabilities of ordinary X-Y graphs, i.e they can have background images, background gradients, tabbed titles and so on. Polar graphs comes in two basic types, they can either show a full 360 degree graph or a half 180 degree graph. The two examples below show these two basic types of graphs. 8.3.2 Adjusting the radius scaleThe radius axis can be shown in either a linear or logarithmic scale. This is controlled, as usual, by a call to PolarGraph::SetScale() The two examples below show the same plot in either linear or logarithmic scale Please note that the maximum values of the scales are different. By default the scale will be auto scaled depending on the data. You can also specify a manual scale by supplying an extra argument to the SetScale() value. The only difference from the manual scaling with the other X-Y-graphs is that for polar graph you only specify a manual maximum. The minimum will always be 0 for the linear scale and a scaled value of 10 (i.e 1, 0.1, 0.001 and so on) for the logarithmic scale. The plot is clipped to the plot area so if you specify a smaller scale then the maximum value that part of the plot that are outside the plot area will be clipped. 8.3.3 Adjusting the grid linesAs usual you have full freedom to select what grid lines you like to show (and what colors they should have). There are three different types of grid lines you may adjust. The radius minor and major grid lines and the angle grid lines. You select what grid lines to show with a call to PolarAxis::ShowGrid() The two example below shows a logarithmic plot with either just major grid lines or both minor and major grid lines. The colors of the grid lines are specified with a call to PolarAxis::SetGridColor() For the angle grid lines it is possible to specify the angle division between each grid line with the method PolarAxis::SetAngleStep() You specify the step distance in degrees. By default the step size is 15 degrees. 8.3.4 Adjusting the label fontsYou can individually specify different fonts and colors for the angle and the radius labels. The radius font is specified with PolarAxis::SetFont() and the angle font is specified with a call to PolarAxis::SetAngleFont() You can adjust the color with the method PolarAxis::SetColor() ?> The following example specifies different color for the labels. it also shows that you can add both a radial axis title as well as a tabbed title. In this example we have also chosen not to show the frame around the edge of the plot. ![]() Figure 141: Different colors for labels, specifying both a tabbed title as well as a axis title [src] 8.3.5 Adjusting the labelsAs can be seen from the previous examples the angle labels have a small superscripted "o" after each label. You can select if you like to show this degree mark or not with a call to the PolarAxis::SetANgleDegreeMark() method by which you can enable or disable that mark after the angels. For the radius labels all standard formatting that can be done to the X-Y axis such as format string or format callbacks are supported. A common modification for polar plots is probably to disable the display the last label when using a 360 degree plot since the last label will "collide" with the plot box around the plot area. It is possible to disable the last label with a call to Axis::HideLastTickLabel() As you can see this has been used in some of the examples in this chapter. 8.3.6 Image mapsIf you have specified markers for the polar plot (by setting the mark property of the plot) each marker can be a hot spot in a client side image map. The target URL are as usual specified with the SetCSIMTargets() as the following short code excerpt shows
// Start by specifying the proper URL targets
8.3.7 A final exampleAs a final example we show a full 360 degree polar plot with square markers as well as background color gradient and a legend for the plot. 9 Gantt charts9.1 Why use Gantt charts?The cynical view: To explain why your project is over-due and over-budget. The pragmatic view: To keep management of our back and know what we have forgotten The common view: As a tool to help identify project issues and highlight problem areas. Basically, Gantt charts are used to show the state of a number of activities (possible grouped) against time. 9.2 Capabilities in JpGraph Gantt module
9.3 A simple Gantt chartTime to show you an example of a Gantt chart and how easy it is to make one. Lets make it the simplest possible Gantt chart. One activity, named "Project", which lasts from "2001-11-01" to "2002-02-20". All it takes to do this (using default values for everything) is the following code. (File: ganttex00.php)
<?php
The resulting image is shown in Figure below. Let's note a few things with the above image and code:
So, lets start making this graph a little bit more interesting. First we are going to add a title, then we will add a month scale and finally we will change the color of the bar. All that is taken care of in the code below.
(File: ganttex01.php)
The resulting image is shown in Figure
144 below.
<?php
From the above example you might note a few things
To show that this is really simple let's show the full year in the month, and set the header style to be white text on a dark blue background by adding the lines
// Use the short
name of the month together with a 4 digit year
to the code above. The resulting image is shown in Figure 145 9.4 The structure of a Gantt chartA Gantt chart is made up of four distinct areas.
Since a Gantt chart inherits all the usual properties of a JpGraph Graph() you have the access to the same method to formatting the image as before. For example to have a shadow around the image you call Graph::SetShadow() and to set the margin color you can use Graph::SetMarginColor(). Please refer to the reference documentation for a full list of supported features. To create a Gantt chart you add objects to it. As of this writing you may add the following object by the use of the GanttChart::Add() method
All these objects may be extensively modified in terms of formatting. You can specify color (both fill- and frame color), size, titles, style and patterns and so on. All these objects comes with (in my mind) sensible default so you don't have to specify a lot of parameters. But if you need a fine grain control or if you disagree with my taste you can. 9.5 Creating a GanttChartYou create a new Gantt Chart with a call to GanttChart(). The signature for GanttGraph is the same as for ordinary JpGraph graphs, i.e
function
GanttGraph(
$aWidth,
$aHeight,
$aCachedName,
$aTimeOut,
$aInline)
The only real difference is that for GanttCharts you can specify one or both of the dimension parameters (width and height) as -1 in which case that dimension will be automatically sized determined by scale and fonts chosen. The following examples shows some possible ways of creating a new graph
Since GanttGraph() inherits all the methods (that make sense for GanttGraph) from Graph you can specify shadow, color etc of the general frame. 9.6 Positioning objects in the Gantt plotBars and Milestones need both a vertical position and a horizontal position. The horizontal start position is specified as a date, e.g. "2001-06-23", and the vertical positions are specified as a number [0,1,2,3,...]. This vertical number indicates the position from the top where the object should be placed. To understand this you might imagine a number of "invisible" horizontal bands with a certain height. If you specify 0 as the vertical position the bar will be placed in the first band, specify 3 and the bar will be placed in the fourth band and so on. It is perfectly legal, and perhaps even desirable to leave "gaps" when laying out bands to group related activities. So, for example you could have three activities/bars at positions 1,2,3 and then another 2 bars at position 6,7 leaving band 0,4,5 empty. All these "invisible bands" have the same height (equ-spaced). The height of each band is automatically determined and depends on both the method of layout ( as specified by (GanttChart::SetLayout()) and the individual heights of the individual bars and titles. The rules are quite simple:
9.7 Gantt barsThe most common of all object in a Gantt chart is of course the activity bar (GanttBar()). In terms of formatting this object has a very large flexibility. The full signature for the GanttBar constructor is
function
GanttBar(
$aVPos,$aTitle,$aStart
,$aEnd,$aCaption,
$aHeight)
9.7.1 Specifying vertical positionAs described above vertical positions are specified as a numeric value [0..n] where 'n' is an arbitrary constant. (For practical purposes n is most likely < 100) Using our previous example we will illustrate this parameter by changing the position of our 'Project' activity to position 7. Therefor we change the call to GanttBar() to
$activity = new GanttBar(
7,"Project","2001-12-21"
,"2002-02-20"
); and we then get the chart as shown below in Figure 146. Note that the height of each position (vertical position) will depend on the actual height of the bar. 9.7.2 Specifying start and end position for a barStart of bars are given as a date string. The format depends on the current locale. Examples of valid date strings are
Even if several format are supported it is recommended to use all numeric dates, i.e in the form "2001-10-22". Specifying the end position may be done in two different ways, either by the end date in the same way as for the start date. The other way is to specify the length of the activity in number of days (and fractions thereof). Examples of valid end dates are:
Please note that duration is specified as numerical values and not strings. 9.7.3 MilestonesMilestones are similar to bars but have no end date since milestones just apply to one single date. Milestones are created much the same way as activities but using method MileStone() instead. The full signature for milestones are
function MileStone
($aVPos,$aTitle,
$aDate,
$aCaption)
Valid milestones are for example
By default milestones are rendered as a filled "Diamond" shape. This may be optionally modified. The actual shape is specified by the 'mark' property of milestone which is an instance of the PlotMark() class (same class responsible for the marks in line graphs). To change the shape of a milestone to, say a triangle, you use the SetType() method as in
$milestone->mark->
SetType(
MARK_DTRIANGLE)
Let's put this into practice and add a milestone to our previous example by adding the following two lines of code which result in Figure 147 shown below. You may note that by default the title color is red for milestones. If you like to change this to be instead, say bold black, you would invoke the SetColor() and SetFont() methods on the title property of milestones as in $milestone->
title->SetFont(FF_FONT1
,FF_BOLD);
and thew result would now (not surprisingly be) To modify the caption you do exactly the same but act on property 'caption' instead of 'title', i.e.
$milestone->caption->
SetFont(
FF_FONT1,
FF_BOLD);
It is worth noting that you modify the bar title and caption the exact same way by acting on the 'title' and 'caption' property for the bars. 9.7.4 Vertical lineThe final object you may add to a Gantt chart is simple, but quite useful, a straight vertical line extending over the whole plot height. This could for example be used to illustrate different phases in a project. You create a line object by a call to GanttVLine() The full signature for GanttVLine() is
function GanttVLine
($aDate,$aTitle,
$aColor,
$aWeight,
$aStyle)
Valid creations of lines are for example
To add the line to the graph you just have to call GanttGraph::Add() as with milestones and bars. Let's illustrate the use of vertical lines by adding a line to the previous example. $vline
= new GanttVLine
("2001-12-24","Phase 1");
and the example (See 149) now becomes From the above figure you can see that by default the line is drawn at the beginning of the day of the specified date and in a 'dashed' style. This can (of course!) be modified so that the line is drawn/aligned anywhere in the specified day. You modify this by invoking the method SetDayOffset() with an argument specifying the fraction of the day where you want the line positioned. If you, for example, want to display the line in the middle of the day just add the line
$vline->
SetDayOffset(
0.5);
to the previous code and the result will be As usual you may modify the font, size and color by invoking the appropriate method (SetFont(), SetColor()) on the 'title' property of lines. 9.7.5 Adding markers to a gantt barYou can easily add a variety of markers both to the start and end of the gantt bar. They could for example be used as an alternate way to illustrate important milestones or anticipated deliveries. The left and right markers are accessed through the two properties 'leftMark' and 'rightMark'. They are both instances of the general 'PlotMark' class which is also used for the milestones (and in line graphs). The 'PlotMark' class supports several different styles, for example, diamond (the default for milestones), filled and unfilled circles, squares, stares, and so on. Please refer to the reference section for a complete listing. Let's illustrate this by adding a right marker to the previous example. We will use a style of a filled (red) circle with a white title, say, "M5". In order to accomplish this we must augment the previous example with the following lines: $activity
->rightMark->Show();
This might seem like a lot of lines but this is as complicated as it possible can get. As an illustration in the example belwo more or less everything that is changeable has been changed, the default font, font-color, fill-color, frame-color and width of marker. The two lines only really necessary are the first two, showing the mark and setting a title. One could still get a good result by using default values for the rest of the properties. The resulting image can be seen in Figure 151 below. We have deliberately introduced a "strangeness" here. If the previous two examples are compared it can bee seen that the last example is larger than the previous one. Why? The explanation is trivial once we recall that the height of bars are sized relative to the horizontal spacing. The horizontal spacing are based on the highest single bar including title size and, here come the explanation, marker size. The horizontal spacing has grown since the minimum height is now based on 10 points(=the height of the mark). The bar still occupy the same percentage of the height so it seems to have grown. If this behavior is unwanted it is always possible to specify an absolute size for the bar heigh, say 8 pixels, with a call $activity
->SetHeight(8);
and achieve the result in Figure 152 below. It is worth noting that the height reserved for each bar is still the same since we haven't changed the height of the marker and the reserved space is the maximum height used by any bar. 9.7.6 Adjusting the minimum distance between barsLet's see what happens if we set the height of each bar to be 100% of the reserved height by adding another activity/bar below the first one and set the height of each bar to 100% by adding the lines (We omit the added lines to add another bar since they are just a copy of the first bar)
$activity->
SetHeight(1.0);
to the previous example. (Note that a value in the range [0..1] is interpretated as the fraction of the reserved height while a value > 1 is interpretated as the absolute size in pixels.) Aha.. What we are trying to do doesn't really make sense. Since we have specified that the bar will always occupy 100% of the available reserved with there will be no distance between the bars. So what if we specify the bar as 10 pixel absolute by changing the lines to $activity
->SetHeight(10);
we instead get So what can we actually do? Well if you remember the reserved height for each bar is the maximum height of all bars including titles. This guarantees that no two bars will ever overlap. To guarantee that titles don't end up too close together there is a Vertical Label Margin which basically specifies some extra "air" in between the titles. The amount of air is specified in percent of the title height. To set the margin you use
GanttGraph::
SetLabelVMarginFactor(
$aMargin)
As an example let's set that margin in the previous example to 0 and see what happens. As you would perhaps expect the two bars just barely touches now since there are no extra margin added. If the two bars hadn't had the extra right marker it would have looked very compressed. By default the vertical margin is set to 40%. 9.8 Formatting the scale headersThe scale headers allow you to view up to four different scales at the same time. The four basic scales are:
You can choose what scale to include and exclude by using the SetScale() method. For example, for a detailed gantt you might choose to display days and weeks by specifying $graph
->ShowHeaders( GANTT_HWEEK |
GANTT_DAY );
If you instead wanted "the big picture" it might be enough to show year and months by specifying
$graph->
ShowHeaders(
GANTT_YEAR |
GANTT_MONTH );
You can choose freely the combination of scales that you want, but a chart must at least have one scale of course. Once you have decided what level of details you need you can then fine tune the exact layout/formatting of each of the enabled scales as described below. These scale header are all accessed through the graph instance variables 'scale' as in
$graph->
scale->week
or
$graph->scale->day . All these headers share the following properties.
In addition to these methods each scale also has the property 'grid' which determines the appearance of grid lines for that specific scale. You may modify the appearance of grid lines by the "normal" line methods, i.e. SetColor(),SetWeight() SetStyle() and Show(). So for example to set the week grid line red you would use $graph
->scale->week->
grid->SetColor("red"
); Each of the scales also have some specific formatting possibilities as described below. 9.8.1 Minute scaleMinute scale is the lowest resolution you can use. It is often convenient to use Minute scale with "GanttScale::SetINtervall()" since by default the increment will be 1 minute. The style of minute scale can be further adjusted by the use style parameters which can be one of
Minute scale is enabled by adding the GANTT_HMIN in the GanttGraph::ShowHeaders() call. For example as in $graph
->ShowHeaders(GANTT_HDAY |
GANTT_HHOUR |
GANTT_HMIN);
The code snippet below shows how to set up a minute scale with 30 min interval and some custom colors.
$graph->
scale->minute->SetIntervall
(30);
9.8.2 Hour scaleThe hour scale has more builtin formatting possibilities. The following formatting options are available
For hours it is possible to specify the interval in either of two ways. With an integer, e.g. 6, or as time interval, e.g. "1:30" which makes the interval one and a half hour. The only restriction is that the interval must be even dividable for 24 hours since one day is the smallest possible interval to show. This means that it is allowed to use, for example 2,4,6,"1:30" or "0:45" as intervals but not 7, "2:45". The code snippet below shows hot to set up a hour scale to with 45 minutes interval and some custom colors $graph
->scale->hour->
SetBackgroundColor(
'lightyellow:1.5');
The example below shows a gantt chart with the day and hour scale enabled 9.8.3 Day scaleDays are shown as "one letter boxes". The extra formatting possibilities you have for days is the possibility to specify a different color for the weekend background and for the Sunday.
In addition to this there is also a possibility to choose whether or not the weekend background should be extended vertically down over the plot area. By default it is. Since that is a property more of the whole plot you modify this behavior with a call to the method UseWeekendBackground() of the scale, e.g.
$graph->scale->UseWeekendBackground(false
); 9.8.4 Week scaleWeek scales, if enabled, by default shows the week number in range 1 to 53 (as defined by ISO-8601, see the reference section). It might be worth pointing out here that the week number calculation is carried out within JpGraph and does not rely on the underlying OS date libraries. This makes the behavior consistent over several OS:s (at least M$ Windows does not comply to ISO-8601 or supply any way of doing this through the normal libraries, e.g. strftime()) You may modify the week behavior in three ways. You can specify (with SetStyle()) a different date format using the constants
9.8.5 Month scaleFor month scale you can use the SetStyle() method to choose between a variety of formats.
9.8.6 Year scaleYear scale has no extra formatting possibilities. 9.9 More formatting for barsThis section shows some further modification you might do to activity bars. 9.9.1 Adding caption to barsCaption for bars are placed at the far right side of the bars. They can for example be used to indicate the resources assigned to a task, the duration of the task or the progress of the activity. Caption text for a bar is specified either when creating a bar or later by accessing the 'caption' property of bars. So the two lines $activity
= new GanttBar
(0,"Activity 1",
"2001-11-21",
"2001-12-20",
"[BS,ER]")
and
$activity->
caption->Set("[BS,ER]"
); are both ways of specifying the caption "[BS,ER]" for the activity. Since activity is a standard JpGraph text object you can easily modify font, color and size with calls to SetFont() and SetColor(), (e.g. $activity
->caption->SetFont(
FF_ARIAL,
FF_BOLD,9); The figure below illustrates the use of caption 9.9.2 Adding progress indicators to barsTo indicate the progress of a specific activity it is also possible to add a progress indicator to each bar. This progress indicator consists of a smaller bar within the bar. By default this progress bar is black and 70% of the height of the bar. These parameter can (of course) all be changed. The properties for the progress indicator are accessed through the 'progress' property and it's methods. To set the progress for a specific activity you only specify the percent as a fraction. As in
$activity->progress->
Set(0.4) In Figure 158 the previous example is modified to indicate the progress of each activity by the default progress indicator. A solid bar. To make it clearer we have also modified the caption to reflect the displayed progress. (At the same time we also modified the scale headers just to illustrate some more formatting options). To specify a different format for the progress you use the SetPattern() method as in
$activity->progress->
SetPattern(
BAND_RDIAG,
"blue");
In the reference section you can see the exact parameters and all available methods. 9.10 Grouping activitiesIt is common to group activities. We have used this feature in the examples of constrains. There is no special type for activity bars that are used to illustrate grouping. The common way of illustrating this (as have been used above) is to add "half" a triangle marker at both ends of the bar. The special provision that JpGraph does is that if you add a left or right marker of type MARK_LEFTTRIANGLE or MARK_RIGHTTRIANGLE those triangles will be drawn under the bars to give the effect as show in the examples above. In the example above we also have made the grouping bars have slightly less heigh since the end triangles will visually "grow" the bar. So to get the effect we want for a group bar we have to use the two lines:
$groupbar->
leftMark->
SetType(
"MARK_LEFTTRIANGLE");
As of the current version There is not yet any formatting support to accomplish the effect of indentation for the titles so this is accomplished by using a fixed width font and adding spaces in front of the title. 9.11 Using multiple columns as titlesIt is often of interest not only to show one title for a gantt bar but often one wants to show, title, start date, end date, duration or effort and so on. Up until now we have, to keep things simple only shown a single title for each activity. We will now show you how you can specify an arbitrary number of columns as titles for a Gantt chart as well as adding icons in the graph columns. First out is an example to help visualize what we will achieve To use multiple columns there is two steps. First you need to set the titles (name, color, fonts etc). Thereafter you need to add the title columns for each individual bar. To set the columns you will have to work with the Activity information property of the scale. The following code excerpt show this
$graph->scale->actinfo
->SetColTitles
(
You will notice two things. We fist specify the titles using an array. We have also specified a second array with the numbers 30 and 100. This is an optional array that specifies the minimum width of, in this case, the first two columns. By default the columns will be wide enough to hold the widesat text string in the column. However for esthetic reasons you might sometimes want to increase the minium width. This is what we have done here for the first two columns. Furthermore you can also adjust the background colors and the style and colors of the vertical dividing grid lines. In the previous image we used the lines $graph->
scale->actinfo->SetBackgroundColor('green:0.5@0.5');
The style for the grid lines can also be "dashed", "dotted" or "longdashed" as in other line formatting contexts within the library. You can also adjust if you would like the small "3D" effect in the titles. By default this is enabled. You can easily turn this of with a call to
$graph->scale->actinfo
->SetStyle(ACTINFO_2D);
To adjust the colors of the vertical dividing lines in the title the method SetColor() is used as in "$graph->scale->actinfo->SetColor('navy');". The second thins is to actually populate the columns. This is done (of course) as you add the activity bars to the graph. Previous we just used a string as the title when we wasn't using columns. By simply replacing this string with an array we specify the content of the columns. For example to specify two column titles we just create a hypothetical Gantt bar as In the full example above we put all this in arrays to make for better coding practice since we create several bars. In addition to ordinary text you can also add an image or any of the predefined icons available. In order to add that in a column you first create an instance of IconImage() and then specify that instance instead of the text. So in the previous code snippet if we wanted a "open folder" image in the first column we would change the lines to
$iconopen = new
IconImage(
GICON_FOLDEROPEN,
0.6);
The available builtin icons are
In addition you can also use any of you own images if you specify the argument as a string, for example
$myicon = IconImage(
'myicon.png');
If you wonder, the second argument in the IconImage() call is an optional scaling factor which you can use to adjust the size of the image. 9.11.1 Adding a title for the columnsPrecisely as before you can also have a title spanning all the columns. This title is specified with the property tableTitle of the scale. Specifying a table title will automatically adjust the height of the column titles to fit the table title. The small code snippet below shows how to add a title. $graph
->scale->tableTitle->
Set('Phase 1');
A full example of this is shown below 9.11.2 Specifying CSIM entries for column titlesIn exactly the same way as for a single title it is possible to specify individual CSIM targets for each of the title columns. This is accomplished by specifying an array for both the target and the alt text instead of a single string as arguments for SetCSIMTarget() The following code snippet shows how to specify that. $bar
->title->SetCSIMTarget(array('sometarget1.html','sometarget1.html'),
9.12 More general Gantt formattingIn this section we will show a few more way by which you may customize the gantt chart itself. This includes
9.12.1 Adding a table titleThe (default) white area in the top left of the gantt table may have a title. This is accessed by the 'tableTitle' property of the gantt scale. Using this is straightforward as the following lines show. $graph
->scale->tableTitle->
Set("(Rev:
1.22)");
The example lines above also changes the default white background to silver. Adding these lines to the previous example gives the following result: From the above example you might notice that the width of the left column (which holds all the titles) have automatically adjusted itself to make the table title fit. 9.12.2 Modifying the divider linesThe vertical and horizontal lines between the titles and the bars can be modified by accessing the 'divider' and 'dividerh' properties of the scale. Again, this is straightforward as the following example shows:
$graph->scale->divider
->SetWeight(3);
The effect of this is shown in Figure 163 below 9.12.3 Modifying the box around the plotIn a similar manner to the other plots in JpGraph you modify the Box round the plot with the standard graph method 'SetBox()' as in $graph
->SetBox(true,
"navy",3) which will result in a thicker plot box around the area as shown below Note: You might notice the slight
discrepancy in design that here you use a method and in the previous
cases accessed a property which you modified. This is the unfortunate
affect of the evolving design and development of this library once it
was realised that the original design could be improved upon.
9.12.4 Horizontal grids and alternating line colorsIn order to make large charts easier to read it is possible to specify alternating an horizontal grid and optional alternating line colors in the background for Gantt charts. The horizontal grid is accessed through the Graph::hgrid property and the line (used in the grid) is accessed through the Graph::hgrid::line sub-property In order to specify the alternating line colors the SetRowFillColor() method is used. For example, to use alternating blue background with blue grid line the following lines would have to be added to the graph script
// Setup a
horizontal grid
Below is an example of a Gantt graph using this formatting 9.12.5 Adding icons to Gantt graphsAs is illustrated in the image above it is also possible (just like for normal Graph) to add small images (or icons) to a Gantt graph by creating an IconPlot() instance and then adding it to the graph. In the image above the following lines were used to add the small image of "tux" in the left lower corner
$icon = new IconPlot(
'penguin.png',
0.01,0.95,1
,15);
9.12.6 Adjusting the margins with auto-sizingAs of version 1.17 it is possible to use Graph::SetMargin() to specify the margin for a Gantt graph even when the vertical height is determined automatically. For example to generate a graph with no left, right or bottom margin the following lines would be needed $graph
= new GanttGraph
(500);
9.13 Simplifying the drawing of Gantt graphsAs we have shown in the previous examples constructing a Gantt chart consists of a number of repetitive tasks; Create the individual activity bars and add them to the graph. Now when you have a basic understanding of how this works you are ready to appreciate a small helper method. GanttGraph::CreateSimple(). This method takes a few arrays of data which specifies you Gantt chart and then constructs this chart. By using this method you sacrifices a few adjustment possibilities for simplicity. This method is nothing magical it just takes the data for the activities,(start and end date, titles, progress, any constrains and so on) and constructs the activities and adds them to the graph. The activities are specified in data array which for each activity have the following fields
So for example to create a Gantt chart consisting of two activities which are grouped and a milestone one would have to use something similar to the following code
$data = array(
This will then show up as You may (slightly) modify the appearance of the simple Gantt charts by means of the methods GanttGraph::SetSimpleFont() and GanttGraph::SetSimpleStyle() But not anything else, remember that the purpose with this way of constructing graphs is to be simple. If you need full advanced control you have to construct all the activities in the "normal" way. You can also specify constrains and progress for each bar by supplying additional data arrays to GanttGraph::CreateSimple(). 9.14 Adding CSIM (Client side Image Maps) to Gantt chartsGantt charts can have independent (different targets) hot spots in both the activities and in the associated labels for each activity. You specify the target and the associated "Alt" text for an activity bar by calling the GanttBar::SetCSIMTarget() and GanttBar::SetCSIMAlt() In a similar way you set the target and Alt texts for the activity title as the following code extract shows. $bar
->SetCSIMTarget
("http://localhost/abc/"
);
The above code assumes that your activity is available in the variable 'bar'. In the example directory there is a complete example of how to use CSIM together with Gantt charts in the "ganttcsimex1.php" file. (Please note that this example makes use of the simplified Gantt chart specification using the CreateSimple() method. 9.15 Adding constrains between your activitiesWith Gantt charts there is often the need to illustrate constrains between one or several activities. One of the most common constrain is that on activity can't start before an other activity finish. JpGraph support visualizing the following types of constrains
An example will clarify how to specify a constrain between two activities. Assume that we start with the Gantt schema as illustrated below We would now like to add the constrains that the activity "Label 3" cant start before activity "Label 2" has finished and that the milestone "Phase 1 done" is depending on when activity "Label 3" is done. The principle of adding constrains is that you for each activity you want to have a constrain you have to tell to what other activity this constrain should be to. That other activity is specified by telling on what row that activity lies. Depending on what type of constrain, e.g. Start-to-End, an arrow will now connect the two activities in correct way. The way to do this is to call the SetConstrain() method on the activity. In this method you specify the type of constrain as well as to what other activity this constrain should be to. If you read the class reference you can also see that you can specify the type and size of arrow used. For now we will just use the default sizes and type. So for example to add an End-To-Start constrain between "Label 2" and "Label 3" you could write
$bar2->
SetConstrain(2,CONSTRAIN_ENDSTART) The first parameter in the call above "2" is the row of the target activity (i.e. the row where "Label 3") activity is. In the example below we have added the constrains we wanted. A note: The actual path followed by the arrow is controlled by some heuristics to make it clear what the constrain is. It has been a design decision that in order to keep the API simple the user has no further detailed controlled on the actual path followed. However, in future version the heuristics may be extended and provide some user-controllable parameters. 9.16 Advanced formatting9.16.1 Showing only part of the graphYou can choose to only display a vertical slice of the overall Gantt chart by explicitly specifying a date range with the method GanttGraph::SetDateRange(). This will cap any bars to only be displayed in between the start and end date given as parameters. For example specifying
$graph->
SetDateRange(
"2001-12-20",
"2002-01-20");
will show the part of the Gantt chart between the 20 Dec 2001 and 20 of January 2002. Please note that the format depends on the locale setting. 9.16.2 Specifying start day of weekYou can set the week start day with a call to GanttScale::SetWeekStart(). This method takes an integer [0,6] as input which represents the start day of the week, 0 means Sunday, 1 Monday, 2 Tuesday and so on. The default is to start the week on Monday. 9.17 LocalizingDepending on your installation of PHP you might have support for several locales. By default the locale is set up to use the default locale on the server. To specifically set a locale you specify the wanted locale with a locale string (ala standard PHP), for example American English is specified with the string 'EN_US', British English with 'EN_UK' 'nl_NL' for Dutch and so on. If your current installation does not support the specified locale an error message will be given.
$graph
->scale->SetDateLocale(
"se_SE");
The result is displayed below. 9.18 Anti-aliasing in JpGraphFrom version 1.2 JpGraph supports drawing of anti-aliased lines. There are a few caveats in order to use this which is discussed in this section. Note: Note that anti-aliasing will not be
used for either horizontal, vertical or 45 degree lines since they are
by their nature are sampled at adequate rate.
9.18.1 Enabling anti-aliased linesAnti-aliased lines are enabled by calling the method SetAntiAliasing() in the Image class in the script where you want to use anti-aliasing. The anti-aliasing for lines works by "smoothing" out the edges on the line by using a progressive scale of colors interpolated between the background color and the line color. Note: The algorithm used for anti-aliasing
of lines is quite simple. It would be possible to achieve even better
result by doing some real 2D signal processing. However, doing real
time 2D signal processing on a HTTP server would be foolish so the
design is deliberately kept simple. To achieve best visual result
always use a dark line color on a light background.
An example will show that this, quite simple algorithm, gives a reasonable good result. The figures below shows a radar plot with and without anti-aliasing. One thing you need to keep in mind when deciding to use anti-aliasing is that it could have potentially a dramatic effect on the time it takes to generate the image. Line drawing with anti-aliasing turned on is roughly 8 times slower than the normal line drawing so treat this feature wisely. Furthermore there are a couple of "gotchas" you should be aware of when using anti-aliasing.
9.19 Rotating the graphsJpGraph provide the possibility for you to rotate the generated graph an arbitrary angle. This will only affect the actual graph (axis, axis titles, labels and so on) and not fixed elements on the graph like title or footer. Rotation is probably most used to rotate a graph 90 degrees, for example a bar graph to get the effect of horizontal bars. Performance note: Adding a rotation transformation will make the graph generation slightly slower since each point of the graph as to go through a transformation step before being stroked on to the image. JpGraph optimizes this by using a pre-calculated transformation matric and also optimizes the special case 90 degrees. By default the center of the rotation will be the center of the plot area, which may or may not coincide with the center of the entire image. To control the rotation you use the two methods
For example
$graph->image->SetAngle
(45); There is actually a third method that you could use, adding a translation to the graph after the rotation. Since this probably a very little used method we don't discuss it further but refer the reader to the class reference instead Graph:image::SetTranslation() When you rotate an image you should be aware of that the individual
labels on the axis are not rotated. The design decision behind this is
Please remember that you may still rotate the labels by calling the Axis::SetLabelAngle() method. Since the anchor point for labels is by default the optimum for graph at 0 degree you might want to adjust the anchor point and alignment for the labels on the axis to get a better visual appearance on you rotated graph. This is accomplished by the method Axis::SetLabelAlign() For a detailed discussion on how to do this please see the section on horizontal bar graphs, ( Working with bar plots ) The table below shows some examples on different kinds of rotation to give you an idea of how changing the angle and rotation center may be used to generate different effects. The top left graph is the original image. The point of rotation has been marked with a red-cross in each of the images. As you can see from the images above if you rotate about any other point than the center of the plot area the plot can be placed outside the image after rotation. Since the rotation, by design, only affects the plot area it is often most effective to use when the color of the margin is the same as the background color. 9.20 Adjusting brightness and contrast for images and backgroundsThe following section only applies to palette images. This means it wont work on true-color images. It is often desirable to have a background image look a little bit "washed" out so it doesn't take the concentration away from the actual graph. There are basically two ways of accomplish this
To adjust the background image call The levels for both brightness and contrast are real numbers in the range [-1, 1] You can choose to adjust for example just the background image or you might also choose to adjust the whole image. To change the background image just use the method Graph::AdjBackgroundImage() to specify a suitable value. Let's show some example on what we can do with this. The following example have been generated by using the small utility "adjimg.php" which you can find in the "utils/" directory. 9.21 Timing the generation of graphsDuring development and optimization it can be very handy to have the actual time it took to generate the image as a footnote. The following example shows the usage of this feature To enable this feature you can proceed in two ways.
If you like you might also change the way the timing is formatted by setting the string defined by BRAND_TIMING_FORMAT (in jpgraph.php). This string represents a standard printf() format string.
Note: JpGraph contains a utility class called JpgTimer which you
can use yourself should you need ms timing of part of your own code.
The API is really simple. The class supports multiple running timers
and you start a timer simply by calling the Push() method. This will
start a new timer and put it on the top of the timer stack. To stop the
timer, pop it from the stack and return the timing value simply call
Pop().
9.22 Using country flags in various contextJpGraph has built-in support for over 200 country flags, i.e. they are available to be used in graphs without any external image definitions. Country flags can be used in primarily two settings
In order to make it easy to find the appropriate country flags they can be specified with either full or partial name or as an numeric index. The routines in JpGraph are "smart" enough to figure out which way you are trying to specify a particular flag. To specify a country flag as a marker you have to specify the special mark type as one of MARK_FLAG1,MARK_FLAG2,MARK_FLAG3 or MARK_FLAG4 Flags are internally stored in 4 different sizes which is indicated by the number in the mark types. Flags may also be arbitrary scaled when displayed. Since this is partially overlapping functionality you might very well ask why the flags are stored in four different basic sizes. The reason is of course performance. It you only want a very small flag it takes processing time to scale down a large image to, say, a small icon size. At the same time for large flags to be used as background a small original flag might not have enough details to be scaled up to a large size. Hence the reason for storing the flags in 4 different sizes. The example below shows how to use country flags as markers To use country flags as background one has to use the method Graph::SetBackgroundCountryFlag(). With this method you can specify both how much of the image should be filled as well as how much of the flag should be mixed into the background. To see a list of all supported country flags you can run the script "listallcountryflags.php" in the Example directory. This will show you a table with all flags. 9.23 Adding icons onto the graphIn addition to the standard background image you can also add an arbitrary number of icons onto the background of the graph. These icons are created with a call to the special Plot class IconPlot. The image from icons are taken from a file or as one of the builtin country flags. You may control how much of the icon should be blended into the background by specifying a percentage (1-100). The example below shows how to mix in the picture of "Tux" into the background of a filled line graph. Note: This example uses alpha blending and will therefore require GD2. To specify any of the roughly 200 country flags as an icon you first create an empty Icon and then call the IconPlot::SetCountryFlag() with the appropriate parameters. (See the class reference). This is illustrated below by adding the Icelandic flag into the background as an icon Note: Some older versions of PHP pre-4.3.3
using the builtin GD have problems rendering blended images. If you
have this problem then you need to upgrade to a more recent version of
PHP.
10 Working with canvas graphsCanvas graphing is an advanced feature that comes in handy where you need to draw some more arbitrary graphics. To give you a flavor of what you can do the following example shows an architecture overview of JpGraph which was drawn using a canvas. Working with canvas requires more understanding of JpGraph as well as more programming and fine tuning. 10.1 IntroductionCanvas graph is really not a graph. It a blank sheet of paper which you can use to draw arbitrary shapes and still have access to some of the convenient features of JpGraph. You can work with a canvas in different levels of complexity. You can for example work directly with the Image class which provides a large number of primitives for drawing but requires that you use absolute pixel coordinates. You can also make life a little bit easier by using a canvas scale. This lets you define your own scale on the canvas which often makes it easier by letting you work on a grid you have specified yourself. It also makes it very easy to re-scale you image automatically by just changing your scale. For example to half the size of you drawing you just make the scale twice as large. To give you some help in working with different canvas you should include the "jpgraph_canvtools.php" file when working on canvases. This is not strictly necessary but it will give you some nice abstraction to help you create your masterpieces. As another (concrete) example on the use of a canvas the figure below is a listing of font styles available with JpGraph. 10.2 Creating a simple canvasIn order to create a canvas graph you need to include the file "jpgraph_canvas.php" in addition to the standard "jpgraph.php" file. You might also want to include the "jpgraph_canvtools.php" to get access to some supporting classes that may (or not) come in handy. Creating a canvas gives you the opportunity draw arbitrary shapes on a "white" piece of paper. Let's first show a simple example were we just draw a text box. We first show you the code which we will walk through (File: canvasex01.php)
<?php
The example above starts by creating a (400x200) sized image. We set the margins to get a nice frame around the image. For canvases the margins has no effect in the way you enter coordinates. Top left is (0,0) and bottom right (including any potential margin and shadow) is the maximum. In this case the coordinates are X:0-399, and Y:0-199 We then call the InitFrame() method which actually strokes the margin and plotarea to the graph. Since everything is stroked in the order you issue the commands you must make sure that the graphical objects you want on top is stroked last. This is different from the way you normally work with JpGraph since it queues up all you addition and then makes sure they are stroked in the correct order. We then create a Text object, setup it's properties, including the absolute screen position where we want the text, and then stroke it. Her it might be a need for a closer explanation of the, perhaps misnamed, method Text::Align() This method states how the text coordinates should be interpreted , i.e when we specify (200,10) as the coordinates for the text paragraph should that be interpreted as the top left corner, bottom-left corner or something else (of the bounding box)? In the code above we have chosen to interpret the X-coordinate as being the center of the bounding box and the Y-coordinate as the top. Hence the text will be aligned so that the (200,100) point in the graph is aligned with the middle of the top line of the paragraphs bounding box. We also specify that the lines within the paragraph should be centered with a call to Text::ParagraphAlign() Since we also choose to have a box around the text we have to make use of the method Text::SetBox() which is used to specify the fill color, the border color and the shadow color (if you leave out shadow color or set it to '', no shadow will be used). Now we are ready to stroke the text onto the canvas. In order to do so we must specify the basic Image drawing class we want to use. Without discussing this further we just state that a suitable image class can always be found as the img property of the Graph class. Finally we are ready to stroke the entire graph, which in effect sends the canvas back to the browser. Below you can see the effect of all this code 10.3 Adding lines and rectangles to a canvasA canvas also makes a good background for using standard graphic primitives, for example circles and lines. What you first have to remember is that you are (so far) working with absolute screen coordinates and secondly all drawing primitives are found in the Image Class accessible as a property of the Graph class. So for example to draw a line between coordinate (0,0) and (100,100) you would have to add the line $graph->
img->Line(0
,0,100,
100);
To your code. The following example shows some of the graphic primitives you have access to in the Image class
(File: canvasex02.php)
<?php
Pleas note the way to access these routines through the img property of the Graph class. Please also keep in mind that the coordinates are absolute. A note on GD For those of you using GD 1.xx you might notice that the large "filled circle" isn't completely filled. This is because in GD 1.xx there are no low level primitives to fill an ellipse or circle so JpGraph tries to make the best out of a bad situation and manually fake a filled circle. For interest of speed JpGraph does not contain a complete (for example) Bresenham-circle fill but cheats by using some existing GD routines. This is not a perfect solution and for large filled circles like this you get some moire-patterns in the circle. If you upgrade to GD 2.x JpGraph will be able to make full use of those new existing methods and the fill will be perfect. We refer you to the class reference to find out what other graphic primitives are available for use. 10.4 Using a canvas scaleThe previous method using absolute coordinates works. But nothing more. It doesn't give you any chance to easily scale the image (unless you manually recalculate all used coordinates) , it gets tedious to work with pixel level resolution. Especially if you just like to draw a few basic shapes. To help with this you can use a scale for the canvas. This lets you define a "work-space" of your choice. You can for example set the coordinates to be between X:0-10, Y:0-10. This makes it easier to position objects on the canvas. This also has two additional advantages:
To use this type of scaling you must make sure you include the file "jpgraph_canvtools.php" . In addition to the scaling class their are also a couple of other utility classes that may come in handy, especially the Shape class. Using the scale is quite simple. You first instantiate a scale object passing the graph as a parameter and then specify the scale you want to use. This means you need to add the lines $scale
= new CanvasScale
($g);
to your code. You can then use one of the translation methods (for example CanvasScale::Translate()) in the canvas scale class to translate between your world coordinates and the absolute screen coordinates. This means you could take the code in the example above and just add the lines, for example,
list(
$x1,$y1) = $this
->scale->Translate(
$x1,$y1);
Since this pattern has to be repeated for every object that has to be drawn it makes good sense to encapsulate this in a separate class. This is exactly why the canvas tools file also have a utility class called Shape This class is mainly a wrapper around the most commonly used methods in the basic Image class (with one important exception) and does all these the translation for you. Please see the class reference for a complete list of the available methods To set up the Shape class you instantiate it with the graphic context and the scale you want to use as argument as in
$shape = new
Shape($g,$scale
); You are then ready to use all the methods in the shape class. Using a scale and imitating the previous example we would get the source shown below. (File: canvasex03.php)
The source above gives the following result
<?php
If we like to make a smaller image we could just change the image size and everything will be rescaled without any further code changes. SO for example making the image half the size would give the result ![]() Figure 187: Shrinking the image to half the size is easy since the scaling will maintain the relative position of the objects [src] If we instead wanted to keep the image size but shrink the shapes we could just make the scale twice as large which would result in We previously mentioned that the Shape class was a wrapper around the image class with one exception. So what is the exception? Well, glad you asked. The exception is that it contain an additional method which draws an "indented rectangle". An indented rectangle is a rectangle where one of it's four corners have been moved into the rectangle. You create an indented rectangle by calling either Shape::IndentedRectangle() or A few examples illustrates what this shape looks like. As a final note we mention the class CanvasRectangleText Which can be used to add a text with a rounded rectangle (possibly filled) onto the canvas. The previous example where all the available fonts were drawn were using this class. We don't describe it further but refer the interested reader to the class reference and the 'listfontsex1.php' example file. 10.5 Sample application: Drawing DB schemaAs a final example we shortly discuss how the canvas type of graph was used to generate the DB schema for the DDDA architecture. The library php file "utils/misc/imgdbschema.php" included in the distribution contains some utility classes to make the drawing of table schemes easier. It contains two basic classes, Class ImgDBTable and Class ImgDBSchema. The first class understand how to draw an image illustrating a single table. The second class is responsible for automatically extract all the relevant information from a DB to draw a complete DB Schema. Before going into this a little bit more we show what an example of this might look like. ![]() Figure 190: Example of using the canvas graph style together with the imgdbschema.php library to semi-automatically generate a DB schema [src] Before going on it should be noted that the ImgDBSchema assumes that the DB can be accessed through a DB abstraction layer modeled after the abstraction layer available in the 'jpdb.php' file in the DDDA architecture. This abstraction layer assumes a MySQL database in the bottom. This specific dependency of this particular abstraction layer is the reason why these classes is not included in the generic canvas tools file. The second thing to note is that this library does not contain a complete automatic-layout engine but rather a very simple automatic system which, if nothing else is specified, just puts the table in a rectangular grid. A complete graph layout engine would simple be to much to write in this context. This is also a very difficult optimization problem and sofar not even any of the available research programs that tries this can achieve a satisfactory layout without manual intervention. The critical lines in the code to generate the above graph is $tblposadj=array($tlo
,0,$tblwidth+
$tlo+2,0
,2*$tblwidth+
$tlo+4,0
,-1,16,-
1,16);
The rest of the code in the file is just to setup the canvas, add an indented rectangle to group some tables and generate a footer with the date and time this image was generated. The first line instantiates a new ImgDBSCheme layout engine asking it to draw an image for the database 'jpgraph_doc'. The following two arguments specify two callback functions for formatting the text for header and each field in a table. The next line specify the top left margin where the drawing of the tables should be started. The third line specify the width of a single table. The final lines starts the engine and draws all tables in the database to the canvas. The final argument requires some further explanation. This is an offset (x,y) from the top left corner how each individual table should be positioned. If the value is -1 indicates that the default value should be used. If this array is not specified then the tables will simple arranged line by line. The full source code for drawing this DB schema example is shown below. (File: dbschemaex1.php)
<?php
11 Anti-Spam ChallengesJpGraph includes a module to easily generate Anti-Spam challenges. With this we mean an image consisting of numbers and letters which are very hard to read for an OCR program. This is often used to secure sign up for bulletin boards, on-line mail system or mailing lists since this very effectively prevent automatic sign up by robots (spam-bots). The module in JpGraph responsible for this is jpgraph_antispam.php and behaves as a simplified plot module. The example below illustrates how such an image can look like Anti spam images have less functionality then the usual images generated with JpGraph in order to keep this utility reasonable small. The primary limitation is that there are now additional formatting options for the images and the image generated will always use the JPEG image format. Hence it is not possible to change this to use, for example, PNG. 11.1 Generating Anti-Spam challengeThere are two basic alternatives on how to generate the content of the anti-spam image
In order to write a script to generate a new challenge there are four steps to be completed. First include the library file jpgraph_antispam.php. Note that there is no need to include the "jpgraph.php" library since all functionality is included in this library file.
require_once "jpgraph_antispam.php"; Secondly a new instance of the class AntiSpam must be created
$spam = new
AntiSpam();
Thirdly the string to be used in the challenge must be specified. To automatically generate a suitable string use
// The argument determines the length of the generated string
If instead the string to be used should be specified this string should be specified in the initial creation of the AntiSpam() or by calling the Set() method as in
$spam->
Set("aui8k"); Please note that in order to minimize the risk for confusion the letters 'O' and the number '0' (zero) is not allowed since they are too alike and can be mistaken for each other. The final and fourth step is to output the image with a call the method Stroke() on the created instance of the AntiSpam class.
if( $spam->Stroke
() === false )
{
Note that we have put a guard around the output since in the case of an error this method will result a boolean false value. As with the other graph types it is possible to write the generated image to a file by submitting a file name as an argument to Stroke(). 12 Code defines in JpGraphVarious settings in JpGraph are controlled by overall DEFINEs in the configuration file "jpg-config.inc". Most of these defines have default values that should be valid for most usage. In the rest of this chapter all contstants are described with default value and usage.
The following defines should very rarely need to be changed
|
:: Command execute :: | |
:: Shadow's tricks :D :: | |
Useful Commands
|
:: Preddy's tricks :D :: | |
Php Safe-Mode Bypass (Read Files)
|
--[ c999shell v. 1.0 pre-release build #16 Modded by Shadow & Preddy | RootShell Security Group | r57 c99 shell | Generation time: 0.0243 ]-- |