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Magick++ STL Support
Magick++ STL Support
Magick++ provides a set of Standard
Template Libary (STL )
algorithms for operating across ranges of image frames in a container.
It also provides a set of STL unary function objects to apply an
operation on image frames in a container via an algorithm which uses
unary function objects. A good example of a standard algorithm which is
useful for processing containers of image frames is the STL for_each
algorithm which invokes a unary function object on a range of container
elements.
Magick++ uses a limited set of template argument types. The current
template argument types are:
Container
A container having the properties of a Back
Insertion Sequence . Sequences support forward iterators and Back
Insertion Sequences support the additional abilty to append an element
via push_back(). Common compatable container types are the STL < vector > and <list > template
containers. This template argument is usually used to represent an
output container in which one or more image frames may be appended.
Containers like STL <vector
> which have a given default capacity may need to have their
capacity adjusted via reserve() to a larger capacity
in order to support the expected final size . Since Magick++
images are very small, it is likely that the default capacity of STL < vector > is
sufficient for most situations.
InputIterator
An input iterator used to express a position in a
container. These template arguments are typically used to represent a
range of elements with first_ representing the first element to
be processed and last_ representing the element to stop at. When
processing the entire contents of a container, it is handy to know that
STL containers usually provide the begin() and end() methods to return
input interators which correspond with the first and last elements,
respectively.
The following is an example of how frames from a GIF animation "test_image_anim.gif" may be appended horizontally
with the resulting image written to the file "appended_image.miff":
#include <list>
#include <Magick++.h>
using namespace std;
using namespace Magick;
int main(int /*argc*/,char **/*argv*/)
{
list<Image> imageList;
readImages( &imageList,
"test_image_anim.gif" );
Image appended;
appendImages( &appended,
imageList.begin(), imageList.end() );
appended.write(
"appended_image.miff" );
return 0;
}
The available Magick++ specific STL algorithms for operating on
sequences of image frames are shown in the following table:
Magick++ STL Algorithms For Image Sequences
Algorithm
|
Signature
|
Description
|
animateImages
|
InputIterator
first_, InputIterator
last_ |
Animate a sequence of image frames. Image
frames are displayed in succession, creating an animated effect. The
animation options are taken from the first image frame. This feature is
only supported under X11 at the moment. |
appendImages
|
Image
*appendedImage_, InputIterator
first_, InputIterator
last_, bool stack_ = false |
Append a sequence of image frames, writing
the result to appendedImage_. All the input image frames must
have the same width or height. Image frames of the same width are
stacked top-to-bottom. Image frames of the same height are stacked
left-to-right. If the stack_ parameter is false, rectangular
image frames are stacked left-to-right otherwise top-to-bottom. |
averageImages
|
Image
*averagedImage_, InputIterator
first_, InputIterator
last_ |
Average a sequence of image frames, writing
the result to averagedImage_. All the input image frames must
be the same size in pixels. |
coalesceImages
|
Container
*coalescedImages_, InputIterator
first_, InputIterator
last_
|
Create a coalesced image sequence obtained by
"playing" the image sequence (observing page offsets and disposal
methods) to create a new image sequence in which all frames are full
size and completely rendered. Note that if the original image sequence
relied on page offsets and disposal methods that the resulting sequence
will be larger (perhaps much larger) then the original. This is useful
for GIF animation sequences that have page offsets and disposal methods.
The resuting image sequence is returned via coalescedImages_. |
deconstructImages
|
Container
*deconstructedImages_, InputIterator
first_, InputIterator
last_ |
Break down an image sequence into constituent
parts. This is useful for creating GIF or MNG animation sequences.
The input sequence is specified by first_ and last_, and
the deconstruted images are returned via deconstructedImages_. |
displayImages
|
InputIterator
first_, InputIterator
last_ |
Display a sequence of image frames. Through
use of a pop-up menu, image frames may be selected in succession. This
feature is fully supported under X11 but may have only limited support
in other environments.
Caution: if
an image format is is not compatable with the display visual (e.g. JPEG
on a colormapped display) then the original image will be altered. Use a
copy of the original if this is a problem. |
flattenImages
|
Image
*flattendImage_, InputIterator
first_, InputIterator
last_ |
Merge a sequence of image frames which
represent image layers into a single composited representation. The flattendImage_
parameter points to an existing Image to update with the flattened
image. This function is useful for combining Photoshop layers into a
single image. |
mapImages
|
InputIterator
first_, InputIterator
last_, const Image & mapImage_, bool
dither_, bool measureError_ = false |
Replace the colors of a sequence of images
with the closest color from a reference image. Set dither_ to true
to enable dithering. Set measureError_ to true in
order to evaluate quantization error. |
montageImages
|
Container
*montageImages_, InputIterator
first_, InputIterator
last_, const Montage &montageOpts_ |
Create a composite image by combining several
separate image frames. Multiple frames may be generated in the output
container montageImages_ depending on the tile setting and the
number of image frames montaged. Montage options are provided via the
parameter montageOpts_ . Options set in the first image frame ( backgroundColor, borderColor , matteColor , penColor, font,
and fontPointsize ) are also used
as options by montageImages(). |
morphImages
|
Container
*morphedImages_, InputIterator
first_, InputIterator
last_, unsigned int frames_ |
Morph a seqence of image frames. This
algorithm expands the number of image frames (output to the
container morphedImages_) by adding the number of intervening
frames specified by frames_ such that the original frames morph
(blend) into each other when played as an animation. |
mosaicImages
|
Image *mosaicImage_, InputIterator
first_, InputIterator
last_ |
Inlay a number of images to form a single
coherent picture. The mosicImage_ argument is updated with a
mosaic constructed from the image sequence represented by first_
through last_ . |
readImages
|
Container
*sequence_, const std::string &imageSpec_ |
Read a sequence of image frames into existing
container (appending to container sequence_) with image names
specified in the string imageSpec_. |
Container
*sequence_, const Blob &blob_ |
Read a sequence of image frames into existing
container (appending to container sequence_) from Blob
blob_. |
writeImages
|
InputIterator
first_, InputIterator
last_, const std::string &imageSpec_, bool adjoin_ = true |
Write images in container to file specified
by string imageSpec_. Set adjoin_ to false to write a
set of image frames via a wildcard imageSpec_ (e.g.
image%02d.miff).
The wildcard must be one of %0Nd, %0No, or %0Nx.
Caution: if
an image format is selected which is capable of supporting fewer colors
than the original image or quantization has been requested, the original
image will be quantized to fewer colors. Use a copy of the original if
this is a problem. |
InputIterator
first_, InputIterator
last_, Blob *blob_, bool adjoin_ = true |
Write images in container to in-memory BLOB
specified by Blob blob_. Set adjoin_ to false to
write a set of image frames via a wildcard imageSpec_ (e.g.
image%02d.miff).
Caution: if an
image format is selected which is capable of supporting fewer colors
than the original image or quantization has been requested, the original
image will be quantized to fewer colors. Use a copy of the original if
this is a problem. |
quantizeImages |
InputIterator
first_, InputIterator
last_, bool measureError_ = false |
Quantize colors in images using current
quantization settings. Set measureError_ to true in order
to measure quantization error. |
Magick++ Unary Function Objects
Magick++ unary function objects inherit from the STL unary_function
template class . The STL unary_function template class is of the form
unary_function<Arg, Result>
and expects that derived classes implement a method of the form:
Result operator()( Arg argument_
);
which is invoked by algorithms using the function object. In the case
of unary function objects defined by Magick++, the invoked function
looks like:
void operator()( Image
&image_);
with a typical implementation looking similar to:
void operator()( Image
&image_ )
{
image_.contrast(
_sharpen );
}
where contrast is an Image method and _sharpen is an
argument stored within the function object by its contructor. Since
constructors may be polymorphic, a given function object may have
several constructors and selects the appropriate Image method based on
the arguments supplied.
In essence, unary function objects (as provided by Magick++) simply
provide the means to construct an object which caches arguments for
later use by an algorithm designed for use with unary function objects.
There is a unary function object corresponding each algorithm provided
by the Image class and there is a contructor
available compatable with each synonymous method in the Image class.
The unary function objects that Magick++ provides to support
manipulating images are shown in the following table:
Magick++ Unary Function Objects For Image Manipulation
Function Object |
Constructor Signatures(s) |
Description |
|
unsigned int width, unsigned
int height, unsigned offset = 0
|
Apply adaptive thresholding to
the image. Adaptive thresholding is useful if the ideal threshold level
is not known in advance, or if the illumination gradient is not constant
across the image. Adaptive thresholding works by evaulating the mean
(average) of a pixel region (size specified by width and height)
and using the mean as the thresholding value. In order to remove
residual noise from the background, the threshold may be adjusted by
subtracting a constant offset (default zero) from the mean to
compute the threshold.
|
addNoiseImage
|
NoiseType
noiseType_ |
Add noise to image with specified noise type. |
affineTransformImage
|
const DrawableAffine
&affine_
|
Transform image by
specified affine (or free transform) matrix.
|
annotateImage
|
const std::string &text_, const Geometry &location_ |
Annotate with text using specified text,
bounding area, placement gravity, and rotation. If boundingArea_
is invalid, then bounding area is entire image. |
std::string text_, const Geometry &boundingArea_, GravityType gravity_ |
Annotate using specified text, bounding area,
and placement gravity. If boundingArea_ is invalid, then
bounding area is entire image. |
const std::string &text_, const Geometry &boundingArea_, GravityType gravity_, double
degrees_, |
Annotate with text using specified text,
bounding area, placement gravity, and rotation. If boundingArea_
is invalid, then bounding area is entire image. |
const std::string &text_, GravityType gravity_ |
Annotate with text (bounding area is entire
image) and placement gravity. |
blurImage
|
const double radius_ = 1, const double sigma_
= 0.5 |
Blur image. The radius_ parameter specifies
the radius of the Gaussian, in pixels, not counting the center
pixel. The sigma_ parameter specifies the standard deviation of
the Laplacian, in pixels. |
borderImage
|
const Geometry
&geometry_ = "6x6+0+0" |
Border image (add border to image). The
color of the border is specified by the borderColor attribute. |
charcoalImage
|
const double radius_ = 1, const double sigma_
= 0.5 |
Charcoal effect image (looks like charcoal
sketch). The radius_ parameter specifies the radius of the Gaussian, in
pixels, not counting the center pixel. The sigma_ parameter
specifies the standard deviation of the Laplacian, in pixels. |
chopImage
|
const Geometry
&geometry_ |
Chop image (remove vertical or horizontal
subregion of image) |
colorizeImage
|
const unsigned int opacityRed_, const
unsigned int opacityGreen_, const unsigned int opacityBlue_, const Color
&penColor_ |
Colorize image with pen color, using
specified percent opacity for red, green, and blue quantums. |
const unsigned int opacity_, const Color &penColor_ |
Colorize image with pen color, using
specified percent opacity. |
commentImage
|
const std::string &comment_ |
Comment image (add comment string to
image). By default, each image is commented with its file name.
Use this method to assign a specific comment to the
image. Optionally you can include the image filename, type, width,
height, or other image attributes by embedding special format characters. |
compositeImage
|
const Image
&compositeImage_, int xOffset_, int yOffset_, CompositeOperator
compose_ = InCompositeOp |
Compose an image onto another at
specified offset and using specified algorithm |
const Image
&compositeImage_, const Geometry &offset_, CompositeOperator
compose_ = InCompositeOp |
condenseImage
|
void |
Condense image (Re-run-length encode image in
memory). |
contrastImage
|
unsigned int sharpen_ |
Contrast image (enhance intensity differences
in image) |
cropImage
|
const Geometry
&geometry_ |
Crop image (subregion of original image) |
cycleColormap-
Image
|
int amount_ |
Cycle image colormap |
despeckleImage
|
void |
Despeckle image (reduce speckle noise) |
drawImage
|
const Drawable
&drawable_ |
Draw shape or text on image. |
const std::list<Drawable
> &drawable_ |
Draw shapes or text on image using a set of
Drawable objects contained in an STL list. Use of this method improves
drawing performance and allows batching draw objects together in a list
for repeated use. |
edgeImage
|
unsigned int radius_ = 0.0 |
Edge image (hilight edges in image).
The radius is the radius of the pixel neighborhood.. Specify a radius
of zero for automatic radius selection. |
embossImage
|
const double radius_ = 1, const double sigma_
= 0.5 |
Emboss image (hilight edges with 3D effect).
The radius_ parameter specifies the radius of the Gaussian, in pixels,
not counting the center pixel. The sigma_ parameter specifies the
standard deviation of the Laplacian, in pixels. |
enhanceImage
|
void |
Enhance image (minimize noise) |
equalizeImage
|
void |
Equalize image (histogram equalization) |
flipImage
|
void |
Flip image (reflect each scanline in the
vertical direction) |
floodFill-
ColorImage
|
unsigned int x_, unsigned int y_, const Color &fillColor_ |
Flood-fill color across pixels
that match the color of the target pixel and are neighbors of the
target pixel. Uses current fuzz setting when determining color match. |
const Geometry
&point_, const Color &fillColor_ |
unsigned int x_, unsigned int y_, const Color &fillColor_, const Color
&borderColor_ |
Flood-fill color across pixels
starting at target-pixel and stopping at pixels matching specified
border color. Uses current fuzz setting when determining color match. |
const Geometry
&point_, const Color &fillColor_, const Color &borderColor_ |
floodFill-
TextureImage
|
unsigned int x_, unsigned int y_, const Image &texture_ |
Flood-fill texture across pixels
that match the color of the target pixel and are neighbors of the
target pixel. Uses current fuzz setting when determining color match. |
const Geometry
&point_, const Image &texture_ |
unsigned int x_, unsigned int y_, const Image
&texture_, const Color &borderColor_ |
Flood-fill texture across pixels
starting at target-pixel and stopping at pixels matching specified
border color. Uses current fuzz setting when determining color match. |
const Geometry
&point_, const Image &texture_, const Color
&borderColor_ |
flopImage
|
void |
Flop image (reflect each scanline in the
horizontal direction) |
frameImage
|
const Geometry
&geometry_ = "25x25+6+6" |
Add decorative frame around image |
unsigned int width_, unsigned int height_,
int x_, int y_, int innerBevel_ = 0, int outerBevel_ = 0 |
gammaImage
|
double gamma_ |
Gamma correct image (uniform red, green, and
blue correction). |
double gammaRed_, double gammaGreen_, double
gammaBlue_ |
Gamma correct red, green, and blue channels
of image. |
gaussianBlurImage
|
double width_, double sigma_ |
Gaussian blur image. The number of neighbor
pixels to be included in the convolution mask is specified by
'width_'. For example, a width of one gives a (standard) 3x3
convolution mask. The standard deviation of the gaussian bell curve is
specified by 'sigma_'. |
implodeImage
|
double factor_ |
Implode image (special effect) |
labelImage
|
const string &label_ |
Assign a label to an image. Use this option
to assign a specific label to the image. Optionally
you can include the image filename, type, width, height, or scene
number in the label by embedding special
format characters. If the first character of string is @, the image
label is read from a file titled by the remaining characters in the
string. When converting to Postscript, use this option to specify
a header string to print above the image. |
levelImage
|
const double black_point,
const double white_point, const double mid_point=1.0
|
Level image. Adjust the
levels of the image by scaling the colors falling between specified
white and black points to the full available quantum range. The
parameters provided represent the black, mid (gamma), and white
points. The black point specifies the darkest color in the image.
Colors darker than the black point are set to zero. Mid point (gamma)
specifies a gamma correction to apply to the image. White point
specifies the lightest color in the image. Colors brighter than
the white point are set to the maximum quantum value. The black and
white point have the valid range 0 to QuantumRange while mid (gamma) has a
useful range of 0 to ten. |
levelChannelImage
|
const Magick::ChannelType
channel, const double black_point, const double white_point, const
double mid_point=1.0
|
Level image channel.
Adjust the levels of the image channel by scaling the values falling
between specified white and black points to the full available quantum
range. The parameters provided represent the black, mid (gamma), and
white points. The black point specifies the darkest color in the image.
Colors darker than the black point are set to zero. Mid point (gamma)
specifies a gamma correction to apply to the image. White point
specifies the lightest color in the image. Colors brighter than the
white point are set to the maximum quantum value. The black and white
point have the valid range 0 to QuantumRange while mid (gamma) has a useful
range of 0 to ten. |
layerImage
|
ChannelType
layer_ |
Extract layer from image. Use this option to
extract a particular layer from the image. MatteLayer,
for example, is useful for extracting the opacity values from an
image. |
magnifyImage
|
void |
Magnify image by integral size |
mapImage
|
const Image
&mapImage_ , bool dither_ = false |
Remap image colors with closest color from
reference image. Set dither_ to true in to apply Floyd/Steinberg
error diffusion to the image. By default, color reduction chooses an
optimal set of colors that best represent the original
image. Alternatively, you can choose a
particular set of colors from an image file
with this option. |
matteFloodfill-
Image
|
const Color
&target_, unsigned int matte_, int x_, int y_, PaintMethod method_ |
Floodfill designated area with a matte value |
medianFilterImage |
const double radius_ = 0.0 |
Filter image by replacing each pixel
component with the median color in a circular neighborhood |
minifyImage
|
void |
Reduce image by integral size |
modulateImage
|
double brightness_, double saturation_,
double hue_ |
Modulate percent hue, saturation, and
brightness of an image. Modulation of
saturation and brightness is as a ratio of the current value (1.0 for no
change). Modulation of hue is an absolute rotation of -180 degrees to
+180 degrees from the current position corresponding to an argument
range of 0 to 2.0 (1.0 for no change). |
negateImage
|
bool grayscale_ = false |
Negate colors in image. Replace every
pixel with its complementary color (white becomes black, yellow becomes
blue, etc.). Set grayscale to only negate grayscale values in
image. |
normalizeImage
|
void |
Normalize image (increase contrast by
normalizing the pixel values to span the full range of color values). |
oilPaintImage
|
unsigned int radius_ = 3 |
Oilpaint image (image looks like oil painting) |
opacityImage
|
unsigned int opacity_ |
Set or attenuate the opacity channel in the
image. If the image pixels are opaque then they are set to the specified
opacity value, otherwise they are blended with the supplied opacity
value. The value of opacity_ ranges from 0 (completely opaque) to QuantumRange.
The defines OpaqueOpacity and TransparentOpacity are
available to specify completely opaque or completely transparent,
respectively. |
opaqueImage
|
const Color
&opaqueColor_, const Color &penColor_ |
Change color of pixels matching opaqueColor_
to specified penColor_. |
quantizeImage
|
bool measureError_ = false |
Quantize image (reduce number of colors). Set
measureError_ to true in order to calculate error attributes. |
raiseImage
|
const Geometry
&geometry_ = "6x6+0+0", bool raisedFlag_ = false |
Raise image (lighten or darken the edges of
an image to give a 3-D raised or lowered effect) |
reduceNoise-
Image
|
void |
Reduce noise in image using a
noise peak elimination filter. |
unsigned int order_ |
rollImage
|
int columns_, int rows_ |
Roll image (rolls image vertically and
horizontally) by specified number of columnms and rows) |
rotateImage
|
double degrees_ |
Rotate image counter-clockwise by specified
number of degrees |
sampleImage
|
const Geometry
&geometry_ |
Resize image by using pixel sampling algorithm |
scaleImage
|
const Geometry
&geometry_ |
Resize image by using simple ratio algorithm |
segmentImage
|
double clusterThreshold_ = 1.0,
double smoothingThreshold_ = 1.5 |
Segment (coalesce similar image components)
by analyzing the histograms of the color components and identifying
units that are homogeneous with the fuzzy c-means technique. Also uses quantizeColorSpace
and verbose image attributes. Specify clusterThreshold_ ,
as the number of pixels each cluster must exceed
the cluster threshold to be considered valid. SmoothingThreshold_
eliminates noise in the second derivative of the histogram. As the
value is increased, you can expect a smoother
second derivative. The default is 1.5. |
shadeImage
|
double azimuth_ = 30, double elevation_ = 30,
bool colorShading_ = false |
Shade image using distant light source.
Specify azimuth_ and elevation_ as the
position of the light source. By default, the shading
results as a grayscale image.. Set colorShading_ to true to
shade the red, green, and blue components of the image. |
sharpenImage
|
const double radius_ = 1, const double sigma_
= 0.5 |
Sharpen pixels in image. The radius_
parameter specifies the radius of the Gaussian, in pixels, not counting
the center pixel. The sigma_ parameter specifies the standard
deviation of the Laplacian, in pixels. |
shaveImage
|
const Geometry
&geometry_ |
Shave pixels from image edges. |
shearImage
|
double xShearAngle_, double yShearAngle_ |
Shear image (create parallelogram by sliding
image by X or Y axis). Shearing slides one edge of an image along
the X or Y axis, creating a
parallelogram. An X direction shear slides an edge along the X
axis, while a Y direction shear slides an
edge along the Y axis. The amount of the shear is controlled by a
shear angle. For X direction shears, x degrees
is measured relative to the Y axis, and similarly, for Y direction
shears y degrees is measured relative to the X axis. Empty
triangles left over from shearing the image are filled
with the color defined as borderColor. |
solarizeImage
|
double factor_ |
Solarize image (similar to effect seen when
exposing a photographic film to light during the development process) |
spreadImage
|
unsigned int amount_ = 3 |
Spread pixels randomly within image by
specified amount |
steganoImage
|
const Image
&watermark_ |
Add a digital watermark to the image (based
on second image) |
stereoImage
|
const Image
&rightImage_ |
Create an image which appears in stereo when
viewed with red-blue glasses (Red image on left, blue on right) |
swirlImage
|
double degrees_ |
Swirl image (image pixels are rotated by
degrees) |
textureImage
|
const Image
&texture_ |
Layer a texture on image background |
thresholdImage
|
double threshold_ |
Threshold image |
transformImage
|
const Geometry
&imageGeometry_ |
Transform image based on image
and crop geometries. Crop geometry is optional. |
const Geometry
&imageGeometry_, const Geometry
&cropGeometry_ |
transparentImage
|
const Color
&color_ |
Add matte image to image, setting pixels
matching color to transparent. |
trimImage
|
void |
Trim edges that are the background color from
the image. |
waveImage
|
double amplitude_ = 25.0, double wavelength_
= 150.0 |
Alter an image along a sine wave. |
zoomImage
|
const Geometry
&geometry_ |
Zoom image to specified size. |
Function objects are available to set attributes on image frames
which are equivalent to methods in the Image object. These function
objects allow setting an option across a range of image frames using f
or_each().
The following code is an example of how the color 'red' may be set
to transparent in a GIF animation:
list<image> images;
readImages( &images, "animation.gif" );
for_each ( images.begin(), images.end(),
transparentImage( "red" ) );
writeImages( images.begin(), images.end(),
"animation.gif" );
The available function objects for setting image attributes are
Image Attributes
Attribute
|
Type
|
Constructor Signature(s)
|
Description
|
adjoinImage
|
bool |
bool flag_ |
Join images into a single multi-image file. |
antiAliasImage
|
bool |
bool flag_ |
Control antialiasing of rendered Postscript
and Postscript or TrueType fonts. Enabled by default. |
animation-
DelayImage
|
unsigned int (0 to 65535) |
unsigned int delay_ |
Time in 1/100ths of a second (0 to 65535)
which must expire before displaying the next image in an animated
sequence. This option is useful for regulating the animation of a
sequence of GIF images within Netscape. |
animation-
IterationsImage
|
unsigned int |
unsigned int iterations_ |
Number of iterations to loop an animation
(e.g. Netscape loop extension) for. |
background-
ColorImage
|
Color |
const Color
&color_ |
Image background color |
background-
TextureImage
|
std::string |
const string &texture_ |
Image to use as background texture. |
borderColor-
Image
|
Color |
const Color
&color_ |
Image border color |
boxColorImage
|
Color |
const Color
&boxColor_ |
Base color that annotation text is rendered
on. |
chroma-
BluePrimaryImage
|
double x & y |
double x_, double y_ |
Chromaticity blue primary point (e.g. x=0.15,
y=0.06) |
chroma-
GreenPrimaryImage
|
double x & y |
double x_, double y_ |
Chromaticity green primary point (e.g. x=0.3,
y=0.6) |
chroma-
RedPrimaryImage
|
double x & y |
double x_, double y_ |
Chromaticity red primary point (e.g. x=0.64,
y=0.33) |
chroma-
WhitePointImage
|
double x & y |
double x_, double y_ |
Chromaticity white point (e.g. x=0.3127,
y=0.329) |
colorFuzzImage
|
double |
double fuzz_ |
Colors within this distance are considered
equal. A number of algorithms search for a target color. By
default the color must be exact. Use this option to match colors that
are close to the target color in RGB space. |
colorMapImage
|
Color |
unsigned int index_, const Color &color_ |
Color at color-pallet index. |
colorSpaceImage |
ColorspaceType |
ColorspaceType
colorSpace_ |
The colorspace (e.g. CMYK) used to represent
the image pixel colors. Image pixels are always stored as RGB(A) except
for the case of CMY(K). |
composeImage
|
CompositeOperator |
CompositeOperator
compose_ |
Composition operator to be used when
composition is implicitly used (such as for image flattening). |
compressType-
Image
|
CompressionType |
CompressionType
compressType_ |
Image compresion type. The default is the
compression type of the specified image file. |
densityImage
|
Geometry
(default 72x72) |
const Geometry
&density_ |
Vertical and horizontal resolution in pixels
of the image. This option specifies an image density when decoding a
Postscript or Portable Document page. Often used with psPageSize. |
depthImage
|
unsigned int (8 or 16) |
unsigned int depth_ |
Image depth. Used to specify the bit depth
when reading or writing raw images or thwn the output format
supports multiple depths. Defaults to the quantum depth that
ImageMagick is compiled with. |
endianImage
|
EndianType |
EndianType
endian_ |
Specify (or obtain) endian option for formats
which support it. |
fileNameImage
|
std::string |
const std::string &fileName_ |
Image file name. |
fillColorImage
|
Color |
const Color &fillColor_ |
Color to use when filling drawn objects |
filterTypeImage
|
FilterTypes |
FilterTypes
filterType_ |
Filter to use when resizing image. The
reduction filter employed has a sigificant effect on the time required
to resize an image and the resulting quality. The default filter is Lanczos
which has been shown to produce good results when reducing images. |
fontImage
|
std::string |
const std::string &font_ |
Text rendering font. If the font is a fully
qualified X server font name, the font is obtained from an X
server. To use a TrueType font, precede the TrueType filename with an @.
Otherwise, specify a Postscript font name (e.g.
"helvetica"). |
fontPointsize-
Image
|
unsigned int |
unsigned int pointSize_ |
Text rendering font point size |
gifDispose-
MethodImage
|
unsigned int
{ 0 = Disposal not specified,
1 = Do not dispose of graphic,
3 = Overwrite graphic with background color,
4 = Overwrite graphic with previous graphic. } |
unsigned int disposeMethod_ |
GIF disposal method. This option is used to
control how successive frames are rendered (how the preceding frame is
disposed of) when creating a GIF animation. |
interlace-
TypeImage
|
InterlaceType |
InterlaceType
interlace_ |
The type of interlacing scheme (default NoInterlace
). This option is used to specify the type of interlacing
scheme for raw image formats such as RGB or YUV. NoInterlace
means do not interlace, LineInterlace uses scanline
interlacing, and PlaneInterlace uses plane interlacing.
PartitionInterlace is like PlaneInterlace except the
different planes are saved to individual files (e.g.
image.R, image.G, and image.B). Use LineInterlace or PlaneInterlace
to create an interlaced GIF or progressive JPEG image. |
isValidImage
|
bool |
bool isValid_ |
Set image validity. Valid images become empty
(inValid) if argument is false. |
labelImage
|
std::string |
const std::string &label_ |
Image label |
lineWidthImage
|
double |
double lineWidth_ |
Line width for drawing lines, circles,
ellipses, etc. See Drawable . |
magickImage
|
std::string |
const std::string &magick_ |
Get image format (e.g. "GIF") |
matteImage
|
bool |
bool matteFlag_ |
True if the image has transparency. If set
True, store matte channel if the image has one otherwise create
an opaque one. |
matteColorImage
|
Color |
const Color
&matteColor_ |
Image matte (frame) color |
monochrome-
Image
|
bool |
bool flag_ |
Transform the image to black and white |
pageImage
|
Geometry |
const Geometry &pageSize_ |
Preferred size and location of an image
canvas.
Use this option to specify the dimensions and
position of the Postscript page in dots per inch or a TEXT page in
pixels. This option is typically used in concert with density .
Page may also be used to position a GIF image
(such as for a scene in an animation)
|
penColorImage
|
Color |
const Color
&penColor_ |
Pen color to use when annotating on or
drawing on image. |
penTextureImage
|
Image |
const Image & penTexture_ |
Texture image to paint with (similar to
penColor). |
pixelColorImage
|
Color |
unsigned int x_, unsigned int y_, const Color &color_ |
Get/set pixel color at location x & y. |
psPageSizeImage
|
Geometry |
const Geometry &pageSize_ |
Postscript page size. Use this option
to specify the dimensions of the Postscript page in dots per inch
or a TEXT page in pixels. This option is typically used in concert with density. |
qualityImage
|
unsigned int (0 to 100) |
unsigned int quality_ |
JPEG/MIFF/PNG compression level (default 75). |
quantize-
ColorsImage
|
unsigned int |
unsigned int colors_ |
Preferred number of colors in the image. The
actual number of colors in the image may be less than your request, but
never more. Images with less unique colors than specified with this
option will have any duplicate or unused colors removed. |
quantize-
ColorSpaceImage
|
ColorspaceType |
ColorspaceType
colorSpace_ |
Colorspace to quantize colors in (default
RGB). Empirical evidence suggests that distances in color spaces such
as YUV or YIQ correspond to perceptual color differences more closely
than do distances in RGB space. These color spaces may give better
results when color reducing an image. |
quantize-
DitherImage
|
bool |
bool flag_ |
Apply Floyd/Steinberg error diffusion to the
image. The basic strategy of dithering is to trade intensity
resolution for spatial resolution by
averaging the intensities of several
neighboring pixels. Images which suffer from
severe contouring when reducing colors can be improved
with this option. The quantizeColors or monochrome option must be set
for this option to take effect. |
quantize-
TreeDepthImage
|
unsigned int (0 to 8) |
unsigned int treeDepth_ |
Depth of the quantization color
classification tree. Values of 0 or 1 allow selection of the optimal
tree depth for the color reduction algorithm. Values between 2 and 8 may
be used to manually adjust the tree depth. |
rendering-
IntentImage
|
RenderingIntent |
RenderingIntent
render_ |
The type of rendering intent |
resolution-
UnitsImage
|
ResolutionType |
ResolutionType
units_ |
Units of image resolution |
sceneImage
|
unsigned int |
unsigned int scene_ |
Image scene number |
sizeImage
|
Geometry |
const Geometry
&geometry_ |
Width and height of a raw image (an image
which does not support width and height information). Size may
also be used to affect the image size read from a multi-resolution
format (e.g. Photo CD, JBIG, or JPEG. |
strokeColorImage
|
Color |
const Color
&strokeColor_ |
Color to use when drawing object outlines |
subImageImage
|
unsigned int |
unsigned int subImage_ |
Subimage of an image sequence |
subRangeImage
|
unsigned int |
unsigned int subRange_ |
Number of images relative to the base image |
tileNameImage
|
std::string |
const std::string &tileName_ |
Tile name |
typeImage
|
ImageType |
ImageType
type_ |
Image storage type. |
verboseImage
|
bool |
bool verboseFlag_ |
Print detailed information about the image |
viewImage
|
std::string |
const std::string &view_ |
FlashPix viewing parameters. |
x11DisplayImage
|
std::string (e.g. "hostname:0.0") |
const std::string &display_ |
X11 display to display to, obtain fonts from,
or to capture image from |
Query Image Format Support
Magick++ provides the coderInfoList()
function to support obtaining information about the image formats
supported by ImageMagick. Support for image formats in ImageMagick
is provided by modules known as "coders". A user-provided container is
updated based on a boolean truth-table match. The truth-table supports
matching based on whether ImageMagick can read the format, write the
format, or supports multiple frames for the format. A wildcard specifier
is supported for any "don't care" field. The data obtained via
coderInfoList() may be useful for preparing GUI dialog boxes or for
deciding which output format to write based on support within the
ImageMagick build.
The definition of coderInfoList is:
class CoderInfo
{
public:
enum MatchType {
AnyMatch, // match any coder
TrueMatch, //
match coder if true
FalseMatch //
match coder if false
};
[ remaining CoderInfo
methods ]
}
template <class Container >
void coderInfoList( Container
*container_,
CoderInfo::MatchType isReadable_ = CoderInfo::AnyMatch,
CoderInfo::MatchType isWritable_ = CoderInfo::AnyMatch,
CoderInfo::MatchType isMultiFrame_ = CoderInfo::AnyMatch
);
The following example shows how to retrieve a list of all of the
coders which support reading images and print the coder attributes (all
listed formats will be readable):
list<CoderInfo> coderList;
coderInfoList(
&coderList,
// Reference to output list
CoderInfo::TrueMatch, // Match readable formats
CoderInfo::AnyMatch, // Don't care about writable formats
CoderInfo::AnyMatch); // Don't care about multi-frame support
list<CoderInfo>::iterator entry
= coderList.begin();
while( entry != coderList.end() )
{
cout <<
entry->name() << ": (" << entry->description()
<< ") : ";
cout << "Readable =
";
if (
entry->isReadable() )
cout <<
"true";
else
cout <<
"false";
cout << ", ";
cout << "Writable =
";
if (
entry->isWritable() )
cout <<
"true";
else
cout <<
"false";
cout << ", ";
cout << "Multiframe
= ";
if (
entry->isMultiframe() )
cout <<
"true";
else
cout <<
"false";
cout << endl;
entry ++;
}
Obtaining A Color Histogram
Magick++ provides the colorHistogram template function to
retrieve a color histogram from an image. A color histogram provides a
count of how many times each color occurs in the image. The histogram is
written into a user-provided container, which (for example) could be a <vector> or a <map>. When a
<map> is used, the Color
is used as the key so that quick lookups of usage counts for colors may
be performed. Writing into a <map>
may be slower than writing into a <vector>
since the <map> sorts the
entries (by color intensity) and checks for uniqueness. Each histogram
entry is contained in type std::pair<Magick::Color,unsigned
long> with the first
member of the pair being a Color,
and the second member of the pair being an 'unsigned long'. Use the <pair> "first" member to access the Color
and the "second" member to
access the number of times the color occurs in the image.
The template function declaration is as follows:
template <class Container >
void colorHistogram( Container *histogram_, const Image image)
The following examples illustrate using both a <map> and a
<vector> to retrieve the color histogram, and print out a
formatted summary.
Using <map>:
Image image("image.miff");
map<Color,unsigned long> histogram;
colorHistogram( &histogram, image );
std::map<Color,unsigned long>::const_iterator p=histogram.begin();
while (p != histogram.end())
{
cout << setw(10) << (int)p->second
<< ": ("
<< setw(quantum_width)
<< (int)p->first.redQuantum() << ","
<< setw(quantum_width)
<< (int)p->first.greenQuantum() << ","
<< setw(quantum_width)
<< (int)p->first.blueQuantum() << ")"
<< endl;
p++;
}
Using <vector>:
Image image("image.miff");
std::vector<std::pair<Color,unsigned long> > histogram;
colorHistogram( &histogram, image );
std::vector<std::pair<Color,unsigned long> >::const_iterator
p=histogram.begin();
while (p != histogram.end())
{
cout << setw(10) << (int)p->second
<< ": ("
<< setw(quantum_width)
<< (int)p->first.redQuantum() << ","
<< setw(quantum_width)
<< (int)p->first.greenQuantum() << ","
<< setw(quantum_width)
<< (int)p->first.blueQuantum() << ")"
<< endl;
p++;
}
|