<?php
/*=======================================================================
// File:	JPGRAPH_GRADIENT.PHP
// Description:	Create a color gradient
// Created: 	2003-02-01
// Ver:		$Id: jpgraph_gradient.php 947 2007-10-19 22:14:19Z ljp $
//
// Copyright (c) Aditus Consulting. All rights reserved.
//========================================================================
*/

// Styles for gradient color fill
DEFINE("GRAD_VER", 1);
DEFINE("GRAD_VERT", 1);
DEFINE("GRAD_HOR", 2);
DEFINE("GRAD_MIDHOR", 3);
DEFINE("GRAD_MIDVER", 4);
DEFINE("GRAD_CENTER", 5);
DEFINE("GRAD_WIDE_MIDVER", 6);
DEFINE("GRAD_WIDE_MIDHOR", 7);
DEFINE("GRAD_LEFT_REFLECTION", 8);
DEFINE("GRAD_RIGHT_REFLECTION", 9);
DEFINE("GRAD_RAISED_PANEL", 10);
DEFINE("GRAD_DIAGONAL", 11);
  
//===================================================
// CLASS Gradient
// Description: Handles gradient fills. This is to be
// considered a "friend" class of Class Image.
//===================================================
class Gradient
{
    private $img=null;
    private $numcolors=100;
    //---------------
    // CONSTRUCTOR
    public function Gradient(&$img)
    {
        $this->img = $img;
    }


    public function SetNumColors($aNum)
    {
        $this->numcolors=$aNum;
    }
    //---------------
    // 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
    // $style		Which way is the gradient oriented?
    public function FilledRectangle($xl, $yt, $xr, $yb, $from_color, $to_color, $style=1)
    {
        switch ($style) {
        case GRAD_VER:
        $steps = ceil(abs($xr-$xl));
        $delta = $xr>=$xl ? 1 : -1;
        $this->GetColArray($from_color, $to_color, $steps, $colors, $this->numcolors);
        for ($i=0, $x=$xl; $i < $steps; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yt, $x, $yb);
            $x += $delta;
        }
        break;

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

        case GRAD_MIDHOR:
        $steps = ceil(abs($yb-$yt)/2);
        $delta = $yb >= $yt ? 1 : -1;
        $this->GetColArray($from_color, $to_color, $steps, $colors, $this->numcolors);
        for ($y=$yt, $i=0; $i < $steps;  ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($xl, $y, $xr, $y);
            $y += $delta;
        }
        --$i;
        if (abs($yb-$yt) % 2 == 1) {
            --$steps;
        }
        for ($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 GRAD_MIDVER:
        $steps = ceil(abs($xr-$xl)/2);
        $delta = $xr>=$xl ? 1 : -1;
        $this->GetColArray($from_color, $to_color, $steps, $colors, $this->numcolors);
        for ($x=$xl, $i=0; $i < $steps; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        --$i;
        if (abs($xr-$xl) % 2 == 1) {
            --$steps;
        }
        for ($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 GRAD_WIDE_MIDVER:
        $diff = ceil(abs($xr-$xl));
        $steps = floor(abs($diff)/3);
        $firststep = $diff - 2*$steps ;
        $delta = $xr >= $xl ? 1 : -1;
        $this->GetColArray($from_color, $to_color, $firststep, $colors, $this->numcolors);
        for ($x=$xl, $i=0; $i < $firststep; ++$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 GRAD_WIDE_MIDHOR:
        $diff = ceil(abs($yb-$yt));
        $steps = floor(abs($diff)/3);
        $firststep = $diff - 2*$steps ;
        $delta = $yb >= $yt? 1 : -1;
        $this->GetColArray($from_color, $to_color, $firststep, $colors, $this->numcolors);
        for ($y=$yt, $i=0; $i < $firststep;  ++$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 GRAD_LEFT_REFLECTION:
        $steps1 = ceil(0.3*abs($xr-$xl));
        $delta = $xr>=$xl ? 1 : -1;

        $from_color = $this->img->rgb->Color($from_color);
        $adj = 1.4;
        $m = ($adj-1.0)*(255-min(255, min($from_color[0], min($from_color[1], $from_color[2]))));
        $from_color2 = array(min(255, $from_color[0]+$m),
                    min(255, $from_color[1]+$m), min(255, $from_color[2]+$m));

        $this->GetColArray($from_color2, $to_color, $steps1, $colors, $this->numcolors);
        $n = count($colors);
        for ($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        $steps2 = max(1, ceil(0.08*abs($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, $this->numcolors);
        $n = count($colors);
        for ($i=0; $i < $steps && $i < $n; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        break;

        case GRAD_RIGHT_REFLECTION:
        $steps1 = ceil(0.7*abs($xr-$xl));
        $delta = $xr>=$xl ? 1 : -1;

        $this->GetColArray($from_color, $to_color, $steps1, $colors, $this->numcolors);
        $n = count($colors);
        for ($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        $steps2 = max(1, ceil(0.08*abs($xr-$xl)));
        $this->img->SetColor($to_color);
        for ($j=0; $j< $steps2; ++$j) {
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }

        $from_color = $this->img->rgb->Color($from_color);
        $adj = 1.4;
        $m = ($adj-1.0)*(255-min(255, min($from_color[0], min($from_color[1], $from_color[2]))));
        $from_color = array(min(255, $from_color[0]+$m),
                    min(255, $from_color[1]+$m), min(255, $from_color[2]+$m));

        $steps = abs($xr-$xl)-$steps1-$steps2;
        $this->GetColArray($to_color, $from_color, $steps, $colors, $this->numcolors);
        $n = count($colors);
        for ($i=0; $i < $steps && $i < $n; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        break;

        case GRAD_CENTER:
        $steps = ceil(min(($yb-$yt)+1, ($xr-$xl)+1)/2);
        $this->GetColArray($from_color, $to_color, $steps, $colors, $this->numcolors);
        $dx = ($xr-$xl)/2;
        $dy = ($yb-$yt)/2;
        $x=$xl;$y=$yt;$x2=$xr;$y2=$yb;
        $n = count($colors);
        for ($x=$xl, $i=0; $x < $xl+$dx && $y < $yt+$dy && $i < $n; ++$x, ++$y, --$x2, --$y2, ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Rectangle($x, $y, $x2, $y2);
        }
        $this->img->Line($x, $y, $x2, $y2);
        break;
        
        case GRAD_RAISED_PANEL:
        // right to left
        $steps1 = $xr-$xl;
        $delta = $xr>=$xl ? 1 : -1;
        $this->GetColArray($to_color, $from_color, $steps1, $colors, $this->numcolors);
        $n = count($colors);
        for ($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
            $this->img->current_color = $colors[$i];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        
        // left to right
        $xr -= 3;
        $xl += 3;
        $yb -= 3;
        $yt += 3;
        $steps2 = $xr-$xl;
        $delta = $xr>=$xl ? 1 : -1;
        for ($x=$xl, $j=$steps2; $j >= 0; --$j) {
            $this->img->current_color = $colors[$j];
            $this->img->Line($x, $yb, $x, $yt);
            $x += $delta;
        }
        break;

        case GRAD_DIAGONAL:
        // use the longer dimension to determine the required number of steps.
        // first loop draws from one corner to the mid-diagonal and the second
        // loop draws from the mid-diagonal to the opposing corner.
        if ($xr-$xl > $yb - $yt) {
            // width is greater than height -> use x-dimension for steps
            $steps = $xr-$xl;
            $delta = $xr>=$xl ? 1 : -1;
            $this->GetColArray($from_color, $to_color, $steps*2, $colors, $this->numcolors);
            $n = count($colors);

            for ($x=$xl, $i=0; $i < $steps && $i < $n; ++$i) {
                $this->img->current_color = $colors[$i];
                $y = $yt+($i/$steps)*($yb-$yt)*$delta;
                $this->img->Line($x, $yt, $xl, $y);
                $x += $delta;
            }

            for ($x=$xl, $i = 0; $i < $steps && $i < $n; ++$i) {
                $this->img->current_color = $colors[$steps+$i];
                $y = $yt+($i/$steps)*($yb-$yt)*$delta;
                $this->img->Line($x, $yb, $xr, $y);
                $x += $delta;
            }
        } else {
            // height is greater than width -> use y-dimension for steps
            $steps = $yb-$yt;
            $delta = $yb>=$yt ? 1 : -1;
            $this->GetColArray($from_color, $to_color, $steps*2, $colors, $this->numcolors);
            $n = count($colors);
            
            for ($y=$yt, $i=0; $i < $steps && $i < $n; ++$i) {
                $this->img->current_color = $colors[$i];
                $x = $xl+($i/$steps)*($xr-$xl)*$delta;
                $this->img->Line($x, $yt, $xl, $y);
                $y += $delta;
            }

            for ($y=$yt, $i = 0; $i < $steps && $i < $n; ++$i) {
                $this->img->current_color = $colors[$steps+$i];
                $x = $xl+($i/$steps)*($xr-$xl)*$delta;
                $this->img->Line($x, $yb, $xr, $y);
                $x += $delta;
            }
        }
        break;

        default:
        JpGraphError::RaiseL(7001, $style);
//("Unknown gradient style (=$style).");
        break;
    }
    }

    // Fill a special case of a polygon with a flat bottom
    // with a gradient. Can be used for filled line plots.
    // Please note that this is NOT a generic gradient polygon fill
    // routine. It assumes that the bottom is flat (like a drawing
    // of a mountain)
    public function FilledFlatPolygon($pts, $from_color, $to_color)
    {
        if (count($pts) == 0) {
            return;
        }
    
        $maxy=$pts[1];
        $miny=$pts[1];
        $n = count($pts) ;
        for ($i=0, $idx=0; $i < $n; $i += 2) {
            $x = round($pts[$i]);
            $y = round($pts[$i+1]);
            $miny = min($miny, $y);
            $maxy = max($maxy, $y);
        }
        
        $colors = array();
        $this->GetColArray($from_color, $to_color, abs($maxy-$miny)+1, $colors, $this->numcolors);
        for ($i=$miny, $idx=0; $i <= $maxy; ++$i) {
            $colmap[$i] = $colors[$idx++];
        }

        $n = count($pts)/2 ;
        $idx = 0 ;
        while ($idx < $n-1) {
            $p1 = array(round($pts[$idx*2]),round($pts[$idx*2+1]));
            $p2 = array(round($pts[++$idx*2]),round($pts[$idx*2+1]));
        
            // Find the largest rectangle we can fill
            $y = max($p1[1], $p2[1]) ;
            for ($yy=$maxy; $yy > $y; --$yy) {
                $this->img->current_color = $colmap[$yy];
                $this->img->Line($p1[0], $yy, $p2[0]-1, $yy);
            }
        
            if ($p1[1] == $p2[1]) {
                continue;
            }

            // Fill the rest using lines (slow...)
            $slope = ($p2[0]-$p1[0])/($p1[1]-$p2[1]);
            $x1 = $p1[0];
            $x2 = $p2[0]-1;
            $start = $y;
            if ($p1[1] > $p2[1]) {
                while ($y >= $p2[1]) {
                    $x1=$slope*($start-$y)+$p1[0];
                    $this->img->current_color = $colmap[$y];
                    $this->img->Line($x1, $y, $x2, $y);
                    --$y;
                }
            } else {
                while ($y >= $p1[1]) {
                    $x2=$p2[0]+$slope*($start-$y);
                    $this->img->current_color = $colmap[$y];
                    $this->img->Line($x1, $y, $x2, $y);
                    --$y;
                }
            }
        }
    }

    //---------------
    // PRIVATE METHODS
    // Add to the image color map the necessary colors to do the transition
    // between the two colors using $numcolors intermediate colors
    public function GetColArray($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;
        $from_alpha = $from_color[3];
        $to_alpha = $to_color[3];
        $adelta = ($to_alpha - $from_alpha) / $numcols ;
        for ($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);
                $alpha = $from_alpha + $colnum*$adelta;
                $colidx = $this->img->rgb->Allocate(sprintf("#%02x%02x%02x", $r, $g, $b), $alpha);
                $colors[$i] = $colidx;
            }
            $prevcolnum = $colnum;
        }
    }
} // Class