WebSVN – Sites.tela-botanica.org – //branches/v4.0/api/jpgraph_1.12.2/jpgraph_gradient.php

<?php
/*=======================================================================
// File:        JPGRAPH_GRADIENT.PHP
// Description: Create a color gradient
// Created:     2003-02-01
// Author:      Johan Persson (johanp@aditus.nu)
// Ver:         $Id: jpgraph_gradient.php,v 1.1 2004/06/15 10:13:19 jpm Exp $
//
// License:     This code is released under QPL
// Copyright (C) 2003 Johan Persson
//========================================================================
*/

  
//===================================================
// CLASS Gradient
// Description: Handles gradient fills. This is to be
// considered a "friend" class of Class Image.
//===================================================
class Gradient {
    var $img=null;
//---------------
// CONSTRUCTOR
    function Gradient(&$img) {
        $this->img = $img;
    }

//---------------
// PUBLIC METHODS       
    // Produce a gradient filled rectangle with a smooth transition between
    // two colors.
    // ($xl,$yt)        Top left corner
    // ($xr,$yb)        Bottom right
    // $from_color      Starting color in gradient
    // $to_color        End color in the gradient
    // $style           Which way is the gradient oriented?
    function FilledRectangle($xl,$yt,$xr,$yb,$from_color,$to_color,$style=1) {
        switch( $style ) {      
            case 1:  // HORIZONTAL
                $steps = abs($xr-$xl);
                $delta = $xr>=$xl ? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for( $i=0, $x=$xl; $i<$steps; ++$i ) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yt,$x,$yb);
                    $x += $delta;
                }
                break;

            case 2: // VERTICAL
                $steps = abs($yb-$yt);
                $delta = $yb>=$yt ? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for($i=0,$y=$yt; $i<$steps; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }
                break;

            case 3: // VERTICAL FROM MIDDLE
                $steps = abs($yb-$yt)/2;
                $delta = $yb>=$yt ? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for($y=$yt, $i=0; $i < $steps;  ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }
                --$i;
                for($j=0; $j < $steps; ++$j, --$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }
                $this->img->Line($xl,$y,$xr,$y);
                break;

            case 4: // HORIZONTAL FROM MIDDLE
                $steps = abs($xr-$xl)/2;
                $delta = $xr>=$xl ? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for($x=$xl, $i=0; $i<$steps; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                --$i;
                for($j=0; $j<$steps; ++$j, --$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                $this->img->Line($x,$yb,$x,$yt);                
                break;

            case 6: // HORIZONTAL WIDER MIDDLE
                $steps = abs($xr-$xl)/3;
                $delta = $xr>=$xl ? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for($x=$xl, $i=0; $i < $steps; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                --$i;
                $this->img->current_color = $colors[$i];
                for($j=0; $j< $steps; ++$j) {
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                
                for($j=0; $j<$steps; ++$j, --$i) {
                    $this->img->current_color = $colors[$i];                            
                    $this->img->Line($x,$yb,$x,$yt);    
                    $x += $delta;
                }                               
                break;
            

            case 8:  // LEFT REFLECTION
                $steps1 = round(0.3*abs($xr-$xl));
                $delta = $xr>=$xl ? 1 : -1;             

                $this->GetColArray($from_color.':1.3',$to_color,$steps1,$colors);
                for($x=$xl, $i=0; $i < $steps1; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                $steps2 = max(1,round(0.08*abs($xr-$xl)));
                $this->img->SetColor($to_color);
                for($j=0; $j< $steps2; ++$j) {
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                $steps = abs($xr-$xl)-$steps1-$steps2;
                $this->GetColArray($to_color,$from_color,$steps,$colors);   
                for($i=0; $i < $steps; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                break;

            case 9:  // RIGHT REFLECTION
                $steps1 = round(0.7*abs($xr-$xl));
                $delta = $xr>=$xl ? 1 : -1;             

                $this->GetColArray($from_color,$to_color,$steps1,$colors);
                for($x=$xl, $i=0; $i < $steps1; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                $steps2 = max(1,round(0.08*abs($xr-$xl)));
                $this->img->SetColor($to_color);
                for($j=0; $j< $steps2; ++$j) {
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                $steps = abs($xr-$xl)-$steps1-$steps2;
                $this->GetColArray($to_color,$from_color.':1.3',$steps,$colors);   
                for($i=0; $i < $steps; ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($x,$yb,$x,$yt);
                    $x += $delta;
                }
                break;



            case 7: // VERTICAL WIDER MIDDLE
                $steps = abs($yb-$yt)/3;
                $delta = $yb>=$yt? 1 : -1;
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                for($y=$yt, $i=0; $i<$steps;  ++$i) {
                    $this->img->current_color = $colors[$i];
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }
                --$i;
                $this->img->current_color = $colors[$i];
                for($j=0; $j< $steps; ++$j) {
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }
                for($j=0; $j<$steps; ++$j, --$i) {
                    $this->img->current_color = $colors[$i];                            
                    $this->img->Line($xl,$y,$xr,$y);
                    $y += $delta;
                }                               
                break;

            case 5: // Rectangle
                $steps = floor(min(($yb-$yt)+1,($xr-$xl)+1)/2); 
                $this->GetColArray($from_color,$to_color,$steps,$colors);
                $dx = ($xr-$xl)/2;
                $dy = ($yb-$yt)/2;
                $x=$xl;$y=$yt;$x2=$xr;$y2=$yb;
                for($x=$xl, $i=0; $x<$xl+$dx && $y<$yt+$dy ; ++$x, ++$y, --$x2, --$y2, ++$i) {
                    assert($i<count($colors));
                    $this->img->current_color = $colors[$i];                    
                    $this->img->Rectangle($x,$y,$x2,$y2);
                }
                $this->img->Line($x,$y,$x2,$y2);
                break;

            default:
                die("JpGraph Error: Unknown gradient style (=$style).");
                break;
        }
    }

//---------------
// PRIVATE METHODS      
    // Add to the image color map the necessary colors to do the transition
    // between the two colors using $numcolors intermediate colors
    function GetColArray($from_color,$to_color,$arr_size,&$colors,$numcols=100) {
        if( $arr_size==0 ) return;
        // If color is given as text get it's corresponding r,g,b values
        $from_color = $this->img->rgb->Color($from_color);
        $to_color = $this->img->rgb->Color($to_color);
                
        $rdelta=($to_color[0]-$from_color[0])/$numcols;
        $gdelta=($to_color[1]-$from_color[1])/$numcols;
        $bdelta=($to_color[2]-$from_color[2])/$numcols;
        $colorsperstep  = $numcols/$arr_size;
        $prevcolnum     = -1;
        for ($i=0; $i<$arr_size; ++$i) {
            $colnum     = floor($colorsperstep*$i);
            if ( $colnum == $prevcolnum ) 
                $colors[$i]     = $colidx;
            else {
                $r = floor($from_color[0] + $colnum*$rdelta);
                $g = floor($from_color[1] + $colnum*$gdelta);
                $b = floor($from_color[2] + $colnum*$bdelta);
                $colidx = $this->img->rgb->Allocate(sprintf("#%02x%02x%02x",$r,$g,$b));
                $colors[$i]     = $colidx;
            }
            $prevcolnum = $colnum;
        }
    }   
} // Class

?>
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