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<?php
/*=======================================================================
// File: JPGRAPH_LOG.PHP
// Description: Log scale plot extension for JpGraph
// Created: 2001-01-08
// Author: Johan Persson (johanp@aditus.nu)
// Ver: $Id: jpgraph_log.php 56 2005-06-06 20:14:44Z ljp $
//
// Copyright (c) Aditus Consulting. All rights reserved.
//========================================================================
*/
DEFINE('LOGLABELS_PLAIN',0);
DEFINE('LOGLABELS_MAGNITUDE',1);
//===================================================
// CLASS LogScale
// Description: Logarithmic scale between world and screen
//===================================================
class LogScale extends LinearScale {
//---------------
// CONSTRUCTOR
// Log scale is specified using the log of min and max
function LogScale($min,$max,$type="y") {
$this->LinearScale($min,$max,$type);
$this->ticks = new LogTicks();
$this->name = 'log';
}
//----------------
// PUBLIC METHODS
// Translate between world and screen
function Translate($a) {
if( !is_numeric($a) ) {
if( $a != '' && $a != '-' && $a != 'x' )
JpGraphError::Raise('Your data contains non-numeric values.');
return 1;
}
if( $a < 0 ) {
JpGraphError::Raise("Negative data values can not be used in a log scale.");
exit(1);
}
if( $a==0 ) $a=1;
$a=log10($a);
return ceil($this->off + ($a*1.0 - $this->scale[0]) * $this->scale_factor);
}
// Relative translate (don't include offset) usefull when we just want
// to know the relative position (in pixels) on the axis
function RelTranslate($a) {
if( !is_numeric($a) ) {
if( $a != '' && $a != '-' && $a != 'x' )
JpGraphError::Raise('Your data contains non-numeric values.');
return 1;
}
if( $a==0 ) $a=1;
$a=log10($a);
return round(($a*1.0 - $this->scale[0]) * $this->scale_factor);
}
// Use bcpow() for increased precision
function GetMinVal() {
if( function_exists("bcpow") )
return round(bcpow(10,$this->scale[0],15),14);
else
return round(pow(10,$this->scale[0]),14);
}
function GetMaxVal() {
if( function_exists("bcpow") )
return round(bcpow(10,$this->scale[1],15),14);
else
return round(pow(10,$this->scale[1]),14);
}
// Logarithmic autoscaling is much simplier since we just
// set the min and max to logs of the min and max values.
// Note that for log autoscale the "maxstep" the fourth argument
// isn't used. This is just included to give the method the same
// signature as the linear counterpart.
function AutoScale(&$img,$min,$max,$dummy) {
if( $min==0 ) $min=1;
if( $max <= 0 ) {
JpGraphError::Raise('Scale error for logarithmic scale. You have a problem with your data values. The max value must be greater than 0. It is mathematically impossible to have 0 in a logarithmic scale.');
}
$smin = floor(log10($min));
$smax = ceil(log10($max));
$this->Update($img,$smin,$smax);
}
//---------------
// PRIVATE METHODS
} // Class
//===================================================
// CLASS LogTicks
// Description:
//===================================================
class LogTicks extends Ticks{
var $label_logtype=LOGLABELS_MAGNITUDE;
//---------------
// CONSTRUCTOR
function LogTicks() {
}
//---------------
// PUBLIC METHODS
function IsSpecified() {
return true;
}
function SetLabelLogType($aType) {
$this->label_logtype = $aType;
}
// For log scale it's meaningless to speak about a major step
// We just return -1 to make the framework happy (specifically
// StrokeLabels() )
function GetMajor() {
return -1;
}
function SetTextLabelStart($aStart) {
JpGraphError::Raise('Specifying tick interval for a logarithmic scale is undefined. Remove any calls to SetTextLabelStart() or SetTextTickInterval() on the logarithmic scale.');
}
function SetXLabelOffset($dummy) {
// For log scales we dont care about XLabel offset
}
// Draw ticks on image "img" using scale "scale". The axis absolute
// position in the image is specified in pos, i.e. for an x-axis
// it specifies the absolute y-coord and for Y-ticks it specified the
// absolute x-position.
function Stroke(&$img,&$scale,$pos) {
$start = $scale->GetMinVal();
$limit = $scale->GetMaxVal();
$nextMajor = 10*$start;
$step = $nextMajor / 10.0;
$img->SetLineWeight($this->weight);
if( $scale->type == "y" ) {
// member direction specified if the ticks should be on
// left or right side.
$a=$pos + $this->direction*$this->GetMinTickAbsSize();
$a2=$pos + $this->direction*$this->GetMajTickAbsSize();
$count=1;
$this->maj_ticks_pos[0]=$scale->Translate($start);
$this->maj_ticklabels_pos[0]=$scale->Translate($start);
if( $this->supress_first )
$this->maj_ticks_label[0]="";
else {
if( $this->label_formfunc != '' ) {
$f = $this->label_formfunc;
$this->maj_ticks_label[0]=call_user_func($f,$start);
}
elseif( $this->label_logtype == LOGLABELS_PLAIN )
$this->maj_ticks_label[0]=$start;
else
$this->maj_ticks_label[0]='10^'.round(log10($start));
}
$i=1;
for($y=$start; $y<=$limit; $y+=$step,++$count ) {
$ys=$scale->Translate($y);
$this->ticks_pos[]=$ys;
$this->ticklabels_pos[]=$ys;
if( $count % 10 == 0 ) {
if( !$this->supress_tickmarks ) {
if( $this->majcolor!="" ) {
$img->PushColor($this->majcolor);
$img->Line($pos,$ys,$a2,$ys);
$img->PopColor();
}
else
$img->Line($pos,$ys,$a2,$ys);
}
$this->maj_ticks_pos[$i]=$ys;
$this->maj_ticklabels_pos[$i]=$ys;
if( $this->label_formfunc != '' ) {
$f = $this->label_formfunc;
$this->maj_ticks_label[$i]=call_user_func($f,$nextMajor);
}
elseif( $this->label_logtype == 0 )
$this->maj_ticks_label[$i]=$nextMajor;
else
$this->maj_ticks_label[$i]='10^'.round(log10($nextMajor));
++$i;
$nextMajor *= 10;
$step *= 10;
$count=1;
}
else {
if( !$this->supress_tickmarks && !$this->supress_minor_tickmarks) {
if( $this->mincolor!="" ) $img->PushColor($this->mincolor);
$img->Line($pos,$ys,$a,$ys);
if( $this->mincolor!="" ) $img->PopColor();
}
}
}
}
else {
$a=$pos - $this->direction*$this->GetMinTickAbsSize();
$a2=$pos - $this->direction*$this->GetMajTickAbsSize();
$count=1;
$this->maj_ticks_pos[0]=$scale->Translate($start);
$this->maj_ticklabels_pos[0]=$scale->Translate($start);
if( $this->supress_first )
$this->maj_ticks_label[0]="";
else {
if( $this->label_formfunc != '' ) {
$f = $this->label_formfunc;
$this->maj_ticks_label[0]=call_user_func($f,$start);
}
elseif( $this->label_logtype == 0 )
$this->maj_ticks_label[0]=$start;
else
$this->maj_ticks_label[0]='10^'.round(log10($start));
}
$i=1;
for($x=$start; $x<=$limit; $x+=$step,++$count ) {
$xs=$scale->Translate($x);
$this->ticks_pos[]=$xs;
$this->ticklabels_pos[]=$xs;
if( $count % 10 == 0 ) {
if( !$this->supress_tickmarks ) {
$img->Line($xs,$pos,$xs,$a2);
}
$this->maj_ticks_pos[$i]=$xs;
$this->maj_ticklabels_pos[$i]=$xs;
if( $this->label_formfunc != '' ) {
$f = $this->label_formfunc;
$this->maj_ticks_label[$i]=call_user_func($f,$nextMajor);
}
elseif( $this->label_logtype == 0 )
$this->maj_ticks_label[$i]=$nextMajor;
else
$this->maj_ticks_label[$i]='10^'.round(log10($nextMajor));
++$i;
$nextMajor *= 10;
$step *= 10;
$count=1;
}
else {
if( !$this->supress_tickmarks && !$this->supress_minor_tickmarks) {
$img->Line($xs,$pos,$xs,$a);
}
}
}
}
return true;
}
} // Class
/* EOF */
?>
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