<?php

//include this file whenever you have to use imageconvolution…
//you can use in your project, but keep the comment below
//great for any image manipulation library
//Made by Chao Xu(Mgccl) 3/1/07
//www.webdevlogs.com
//V 1.0
if (!function_exists('imagefilter')) {
    function imagefilter($source, $var, $arg1 = null, $arg2 = null, $arg3 = null) {
        #define(’IMAGE_FILTER_NEGATE’, 0);
        #define(’IMAGE_FILTER_GRAYSCALE’, 1);
        #define(’IMAGE_FILTER_BRIGHTNESS’, 2);
        #define(’IMAGE_FILTER_CONTRAST’, 3);
        #define(’IMAGE_FILTER_COLORIZE’, 4);
        #define(’IMAGE_FILTER_EDGEDETECT’, 5);
        #define(’IMAGE_FILTER_EMBOSS’, 6);
        #define(’IMAGE_FILTER_GAUSSIAN_BLUR’, 7);
        #define(’IMAGE_FILTER_SELECTIVE_BLUR’, 8);
        #define(’IMAGE_FILTER_MEAN_REMOVAL’, 9);
        #define(’IMAGE_FILTER_SMOOTH’, 10);
        $max_y = imagesy($source);
        $max_x = imagesx($source);
       switch ($var) {
           case 0:
               $y = 0;
               while ($y<$max_y) {
                   $x = 0;
                   while ($x<$max_x) {
                       $rgb = imagecolorat($source, $x, $y);
                       $r = 255 - (($rgb >> 16) & 0xFF);
                       $g = 255 - (($rgb >> 8) & 0xFF);
                       $b = 255 - ($rgb & 0xFF);
                       $a = $rgb >> 24;
                       $new_pxl = imagecolorallocatealpha($source, $r, $g, $b, $a);
                       if ($new_pxl == false) {
                           $new_pxl = imagecolorclosestalpha($source, $r, $g, $b, $a);
                       }
                       imagesetpixel($source, $x, $y, $new_pxl);
                       ++$x;
                   }
                   ++$y;
               }
               return true;
           break;
           case 1:
               $y = 0;
               while ($y<$max_y) {
                   $x = 0;
                   while ($x<$max_x) {
                       $rgb = imagecolorat($source, $x, $y);
                       $a = $rgb >> 24;
                       $r = ((($rgb >> 16) & 0xFF)*0.299)+((($rgb >> 8) & 0xFF)*0.587)+(($rgb & 0xFF)*0.114);
                       $new_pxl = imagecolorallocatealpha($source, $r, $r, $r, $a);
                       if ($new_pxl == false) {
                           $new_pxl = imagecolorclosestalpha($source, $r, $r, $r, $a);
                       }
                       imagesetpixel($source, $x, $y, $new_pxl);
                       ++$x;
                   }
                   ++$y;
               }
               return true;
           break;
           case 2:
               $y = 0;
               while ($y<$max_y) {
                   $x = 0;
                   while ($x<$max_x) {
                       $rgb = imagecolorat($source, $x, $y);
                       $r = (($rgb >> 16) & 0xFF) + $arg1;
                       $g = (($rgb >> 8) & 0xFF) + $arg1;
                       $b = ($rgb & 0xFF) + $arg1;
                       $a = $rgb >> 24;
                         $r = ($r > 255)? 255 : (($r < 0)? 0:$r);
                       $g = ($g > 255)? 255 : (($g < 0)? 0:$g);
                       $b = ($b > 255)? 255 : (($b < 0)? 0:$b);
                       $new_pxl = imagecolorallocatealpha($source, $r, $g, $b, $a);
                       if ($new_pxl == false) {
                           $new_pxl = imagecolorclosestalpha($source, $r, $g, $b, $a);
                       }
                       imagesetpixel($source, $x, $y, $new_pxl);
                       ++$x;
                   }
                   ++$y;
               }
               return true;
           break;
           case 3:
               $contrast = pow((100-$arg1)/100, 2);
               $y = 0;
               while ($y<$max_y) {
                   $x = 0;
                   while ($x<$max_x) {
                       $rgb = imagecolorat($source, $x, $y);
                       $a = $rgb >> 24;
                       $r = (((((($rgb >> 16) & 0xFF)/255)-0.5)*$contrast)+0.5)*255;
                       $g = (((((($rgb >> 8) & 0xFF)/255)-0.5)*$contrast)+0.5)*255;
                       $b = ((((($rgb & 0xFF)/255)-0.5)*$contrast)+0.5)*255;
                       $r = ($r > 255)? 255 : (($r < 0)? 0:$r);
                       $g = ($g > 255)? 255 : (($g < 0)? 0:$g);
                       $b = ($b > 255)? 255 : (($b < 0)? 0:$b);
                       $new_pxl = imagecolorallocatealpha($source, $r, $g, $b, $a);
                       if ($new_pxl == false) {
                           $new_pxl = imagecolorclosestalpha($source, $r, $g, $b, $a);
                       }
                       imagesetpixel($source, $x, $y, $new_pxl);
                       ++$x;
                   }
                   ++$y;
               }
               return true;
           break;
           case 4:
               $x = 0;
               while ($x<$max_x) {
                   $y = 0;
                   while ($y<$max_y) {
                       $rgb = imagecolorat($source, $x, $y);
                       $r = (($rgb >> 16) & 0xFF) + $arg1;
                       $g = (($rgb >> 8) & 0xFF) + $arg2;
                       $b = ($rgb & 0xFF) + $arg3;
                       $a = $rgb >> 24;
                       $r = ($r > 255)? 255 : (($r < 0)? 0:$r);
                       $g = ($g > 255)? 255 : (($g < 0)? 0:$g);
                       $b = ($b > 255)? 255 : (($b < 0)? 0:$b);
                       $new_pxl = imagecolorallocatealpha($source, $r, $g, $b, $a);
                       if ($new_pxl == false) {
                           $new_pxl = imagecolorclosestalpha($source, $r, $g, $b, $a);
                       }
                       imagesetpixel($source, $x, $y, $new_pxl);
                       ++$y;
                       }
                   ++$x;
               }
               return true;
           break;
           case 5:
               return imageconvolution($source, array(array(-1, 0, -1), array(0, 4, 0), array(-1, 0, -1)), 1, 127);
           break;
           case 6:
               return imageconvolution($source, array(array(1.5, 0, 0), array(0, 0, 0), array(0, 0, -1.5)), 1, 127);
           break;
           case 7:
               return imageconvolution($source, array(array(1, 2, 1), array(2, 4, 2), array(1, 2, 1)), 16, 0);
           break;
           case 8:
       for ($y = 0; $y<$max_y; $y++) {
           for ($x = 0; $x<$max_x; $x++) {
                 $flt_r_sum = $flt_g_sum = $flt_b_sum = 0;
               $cpxl = imagecolorat($source, $x, $y);
               for ($j=0; $j<3; $j++) {
                   for ($i=0; $i<3; $i++) {
                       if (($j == 1) && ($i == 1)) {
                           $flt_r[1][1] = $flt_g[1][1] = $flt_b[1][1] = 0.5;
                       } 
                       else {
                           $pxl = imagecolorat($source, $x-(3>>1)+$i, $y-(3>>1)+$j);
         
                           $new_a = $pxl >> 24;
                           //$r = (($pxl >> 16) & 0xFF);
                           //$g = (($pxl >> 8) & 0xFF);
                           //$b = ($pxl & 0xFF);
                           $new_r = abs((($cpxl >> 16) & 0xFF) - (($pxl >> 16) & 0xFF));
                           if ($new_r != 0) {
                               $flt_r[$j][$i] = 1/$new_r;
                           } 
                           else {
                               $flt_r[$j][$i] = 1;
                           }

                           $new_g = abs((($cpxl >> 8) & 0xFF) - (($pxl >> 8) & 0xFF));
                           if ($new_g != 0) {
                               $flt_g[$j][$i] = 1/$new_g;
                           } 
                           else {
                               $flt_g[$j][$i] = 1;
                           }

                           $new_b = abs(($cpxl & 0xFF) - ($pxl & 0xFF));
                           if ($new_b != 0) {
                               $flt_b[$j][$i] = 1/$new_b;
                           } 
                           else {
                               $flt_b[$j][$i] = 1;
                           }
                       }

                       $flt_r_sum += $flt_r[$j][$i];
                       $flt_g_sum += $flt_g[$j][$i];
                       $flt_b_sum += $flt_b[$j][$i];
                   }
               }

               for ($j=0; $j<3; $j++) {
                   for ($i=0; $i<3; $i++) {
                       if ($flt_r_sum != 0) {
                           $flt_r[$j][$i] /= $flt_r_sum;
                       }
                       if ($flt_g_sum != 0) {
                           $flt_g[$j][$i] /= $flt_g_sum;
                       }
                       if ($flt_b_sum != 0) {
                           $flt_b[$j][$i] /= $flt_b_sum;
                       }
                   }
               }

               $new_r = $new_g = $new_b = 0;

               for ($j=0; $j<3; $j++) {
                   for ($i=0; $i<3; $i++) {
                       $pxl = imagecolorat($source, $x-(3>>1)+$i, $y-(3>>1)+$j);
                       $new_r += (($pxl >> 16) & 0xFF) * $flt_r[$j][$i];
                       $new_g += (($pxl >> 8) & 0xFF) * $flt_g[$j][$i];
                       $new_b += ($pxl & 0xFF) * $flt_b[$j][$i];
                   }
               }

               $new_r = ($new_r > 255)? 255 : (($new_r < 0)? 0:$new_r);
               $new_g = ($new_g > 255)? 255 : (($new_g < 0)? 0:$new_g);
               $new_b = ($new_b > 255)? 255 : (($new_b < 0)? 0:$new_b);
               $new_pxl = imagecolorallocatealpha($source, (int)$new_r, (int)$new_g, (int)$new_b, $new_a);
               if ($new_pxl == false) {
                   $new_pxl = imagecolorclosestalpha($source, (int)$new_r, (int)$new_g, (int)$new_b, $new_a);
               }
               imagesetpixel($source, $x, $y, $new_pxl);
           }
       }
       return true;
           break;
           case 9:
               return imageconvolution($source, array(array(-1, -1, -1), array(-1, 9, -1), array(-1, -1, -1)), 1, 0);
           break;
           case 10:
               return imageconvolution($source, array(array(1, 1, 1), array(1, $arg1, 1), array(1, 1, 1)), $arg1+8, 0);
           break;
       }
    }
}
