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<?php
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/*=======================================================================
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// File:	JPGRAPH_GRADIENT.PHP
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// Description:	Create a color gradient
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// Created: 	2003-02-01
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// Author:	Johan Persson (johanp@aditus.nu)
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// Ver:		$Id: jpgraph_gradient.php,v 1.1 2004/06/15 10:13:19 jpm Exp $
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//
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// License:	This code is released under QPL
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// Copyright (C) 2003 Johan Persson
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//========================================================================
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*/
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//===================================================
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// CLASS Gradient
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// Description: Handles gradient fills. This is to be
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// considered a "friend" class of Class Image.
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//===================================================
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class Gradient {
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    var $img=null;
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//---------------
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// CONSTRUCTOR
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    function Gradient(&$img) {
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	$this->img = $img;
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    }
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//---------------
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// PUBLIC METHODS
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    // Produce a gradient filled rectangle with a smooth transition between
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    // two colors.
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    // ($xl,$yt) 	Top left corner
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    // ($xr,$yb)	Bottom right
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    // $from_color	Starting color in gradient
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    // $to_color	End color in the gradient
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    // $style		Which way is the gradient oriented?
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    function FilledRectangle($xl,$yt,$xr,$yb,$from_color,$to_color,$style=1) {
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	switch( $style ) {
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	    case 1:  // HORIZONTAL
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		$steps = abs($xr-$xl);
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		$delta = $xr>=$xl ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for( $i=0, $x=$xl; $i<$steps; ++$i ) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yt,$x,$yb);
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		    $x += $delta;
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		}
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		break;
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	    case 2: // VERTICAL
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		$steps = abs($yb-$yt);
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		$delta = $yb>=$yt ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for($i=0,$y=$yt; $i<$steps; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		break;
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	    case 3: // VERTICAL FROM MIDDLE
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		$steps = abs($yb-$yt)/2;
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		$delta = $yb>=$yt ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for($y=$yt, $i=0; $i < $steps;  ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		--$i;
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		for($j=0; $j < $steps; ++$j, --$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		$this->img->Line($xl,$y,$xr,$y);
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		break;
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	    case 4: // HORIZONTAL FROM MIDDLE
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		$steps = abs($xr-$xl)/2;
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		$delta = $xr>=$xl ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for($x=$xl, $i=0; $i<$steps; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		--$i;
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		for($j=0; $j<$steps; ++$j, --$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		$this->img->Line($x,$yb,$x,$yt);
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		break;
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	    case 6: // HORIZONTAL WIDER MIDDLE
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		$steps = abs($xr-$xl)/3;
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		$delta = $xr>=$xl ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for($x=$xl, $i=0; $i < $steps; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		--$i;
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		$this->img->current_color = $colors[$i];
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		for($j=0; $j< $steps; ++$j) {
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		for($j=0; $j<$steps; ++$j, --$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		break;
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	    case 8:  // LEFT REFLECTION
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		$steps1 = round(0.3*abs($xr-$xl));
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		$delta = $xr>=$xl ? 1 : -1;
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		$this->GetColArray($from_color.':1.3',$to_color,$steps1,$colors);
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		for($x=$xl, $i=0; $i < $steps1; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		$steps2 = max(1,round(0.08*abs($xr-$xl)));
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		$this->img->SetColor($to_color);
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		for($j=0; $j< $steps2; ++$j) {
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		$steps = abs($xr-$xl)-$steps1-$steps2;
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		$this->GetColArray($to_color,$from_color,$steps,$colors);
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		for($i=0; $i < $steps; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		break;
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	    case 9:  // RIGHT REFLECTION
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		$steps1 = round(0.7*abs($xr-$xl));
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		$delta = $xr>=$xl ? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps1,$colors);
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		for($x=$xl, $i=0; $i < $steps1; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		$steps2 = max(1,round(0.08*abs($xr-$xl)));
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		$this->img->SetColor($to_color);
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		for($j=0; $j< $steps2; ++$j) {
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		$steps = abs($xr-$xl)-$steps1-$steps2;
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		$this->GetColArray($to_color,$from_color.':1.3',$steps,$colors);
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		for($i=0; $i < $steps; ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($x,$yb,$x,$yt);
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		    $x += $delta;
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		}
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		break;
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172
 
173
	    case 7: // VERTICAL WIDER MIDDLE
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		$steps = abs($yb-$yt)/3;
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		$delta = $yb>=$yt? 1 : -1;
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		for($y=$yt, $i=0; $i<$steps;  ++$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		--$i;
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		$this->img->current_color = $colors[$i];
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		for($j=0; $j< $steps; ++$j) {
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		for($j=0; $j<$steps; ++$j, --$i) {
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Line($xl,$y,$xr,$y);
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		    $y += $delta;
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		}
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		break;
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195
	    case 5: // Rectangle
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		$steps = floor(min(($yb-$yt)+1,($xr-$xl)+1)/2);
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		$this->GetColArray($from_color,$to_color,$steps,$colors);
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		$dx = ($xr-$xl)/2;
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		$dy = ($yb-$yt)/2;
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		$x=$xl;$y=$yt;$x2=$xr;$y2=$yb;
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		for($x=$xl, $i=0; $x<$xl+$dx && $y<$yt+$dy ; ++$x, ++$y, --$x2, --$y2, ++$i) {
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		    assert($i<count($colors));
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		    $this->img->current_color = $colors[$i];
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		    $this->img->Rectangle($x,$y,$x2,$y2);
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		}
206
		$this->img->Line($x,$y,$x2,$y2);
207
		break;
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209
	    default:
210
		die("JpGraph Error: Unknown gradient style (=$style).");
211
		break;
212
	}
213
    }
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215
//---------------
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// PRIVATE METHODS
217
    // Add to the image color map the necessary colors to do the transition
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    // between the two colors using $numcolors intermediate colors
219
    function GetColArray($from_color,$to_color,$arr_size,&$colors,$numcols=100) {
220
	if( $arr_size==0 ) return;
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	// If color is given as text get it's corresponding r,g,b values
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	$from_color = $this->img->rgb->Color($from_color);
223
	$to_color = $this->img->rgb->Color($to_color);
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225
	$rdelta=($to_color[0]-$from_color[0])/$numcols;
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	$gdelta=($to_color[1]-$from_color[1])/$numcols;
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	$bdelta=($to_color[2]-$from_color[2])/$numcols;
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	$colorsperstep	= $numcols/$arr_size;
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	$prevcolnum	= -1;
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	for ($i=0; $i<$arr_size; ++$i) {
231
	    $colnum	= floor($colorsperstep*$i);
232
	    if ( $colnum == $prevcolnum )
233
		$colors[$i]	= $colidx;
234
	    else {
235
		$r = floor($from_color[0] + $colnum*$rdelta);
236
		$g = floor($from_color[1] + $colnum*$gdelta);
237
		$b = floor($from_color[2] + $colnum*$bdelta);
238
		$colidx = $this->img->rgb->Allocate(sprintf("#%02x%02x%02x",$r,$g,$b));
239
		$colors[$i]	= $colidx;
240
	    }
241
	    $prevcolnum = $colnum;
242
	}
243
    }
244
} // Class
245
 
246
?>