imagefilter.inc in ImageAPI 6

File

imagefilter.inc

<?php

//Made by Chao Xu(Mgccl) 3/1/07

//www.webdevlogs.com

//V 1.0

// Drupal code style and some restructuring by dopry. http://www.darrelopry.com
define('IMG_FILTER_NEGATE', 0);
define('IMG_FILTER_GRAYSCALE', 1);
define('IMG_FILTER_BRIGHTNESS', 2);
define('IMG_FILTER_CONTRAST', 3);
define('IMG_FILTER_COLORIZE', 4);
define('IMG_FILTER_EDGEDETECT', 5);
define('IMG_FILTER_EMBOSS', 6);
define('IMG_FILTER_GAUSSIAN_BLUR', 7);
define('IMG_FILTER_SELECTIVE_BLUR', 8);
define('IMG_FILTER_MEAN_REMOVAL', 9);
define('IMG_FILTER_SMOOTH', 10);
define('IMAGEAPI_IMAGEFILTER_PHP', 1);

/**
 * walk each pixel in an image applying $callback to it.
 */
function _imageapi_gd_pixel_color_walk(&$im, $callback, $arg1 = NULL, $arg2 = NULL, $arg3 = NULL, $arg4 = NULL) {
  $max_y = imagesy($im);
  $max_x = imagesx($im);
  for ($y = 0; $y < $max_y; ++$y) {
    for ($x = 0; $x < $max_x; ++$x) {
      $rgb = imagecolorat($im, $x, $y);
      $r = $rgb >> 16 & 0xff;
      $g = $rgb >> 8 & 0xff;
      $b = $rgb & 0xff;
      $a = $rgb >> 24;
      $callback($r, $g, $b, $a, $arg1, $arg2, $arg3, $arg4);

      // sanitize rgb values.
      $r = $r > 255 ? 255 : ($r < 0 ? 0 : $r);
      $g = $g > 255 ? 255 : ($g < 0 ? 0 : $g);
      $b = $b > 255 ? 255 : ($b < 0 ? 0 : $b);
      $a = $a > 127 ? 127 : ($a < 0 ? 0 : $a);
      if (!($color = imagecolorallocatealpha($im, $r, $g, $b, $a))) {
        $color = imagecolorclosestalpha($im, $r, $g, $b, $a);
      }
      imagesetpixel($im, $x, $y, $color);
    }
  }
}
function _imageapi_gd_pixel_negate(&$r, &$g, &$b, &$a) {
  $r = 255 - $r;
  $g = 255 - $g;
  $b = 255 - $b;
}
function _imageapi_gd_pixel_grayscale(&$r, &$g, &$b, &$a) {
  $r = round($r * 0.299 + $g * 0.587 + $b * 0.114);
  $g = $r;
  $b = $r;
}
function _imageapi_gd_pixel_brightness(&$r, &$g, &$b, &$a, $arg1) {
  $r += $arg1;
  $g += $arg1;
  $b += $arg1;
}
function _imageapi_gd_pixel_contrast(&$r, &$g, &$b, &$a, $contrast) {

  // normalize color value between -0.5 - 0.5
  // multiply by contrast value to accentuate positive/negative value.
  // denormalize to 0-255 range.
  $r = (($r / 255 - 0.5) * $contrast + 0.5) * 255;
  $g = (($g / 255 - 0.5) * $contrast + 0.5) * 255;
  $b = (($b / 255 - 0.5) * $contrast + 0.5) * 255;
}
function _imageapi_gd_pixel_colorize(&$r, &$g, &$b, &$a, $arg1, $arg2, $arg3, $arg4) {
  $r += $arg1;
  $g += $arg2;
  $b += $arg3;
}
function imagefilter(&$im, $var, $arg1 = NULL, $arg2 = NULL, $arg3 = NULL, $arg4 = NULL) {
  switch ($var) {
    case IMG_FILTER_NEGATE:
      _imageapi_gd_pixel_color_walk($im, '_imageapi_gd_pixel_negate');
      return TRUE;
    case IMG_FILTER_GRAYSCALE:
      _imageapi_gd_pixel_color_walk($im, '_imageapi_gd_pixel_grayscale');
      return TRUE;
    case IMG_FILTER_BRIGHTNESS:
      _imageapi_gd_pixel_color_walk($im, '_imageapi_gd_pixel_brightness', $arg1);
      return TRUE;
    case IMG_FILTER_CONTRAST:

      // normalize between 0-1, square to keep positive.
      $contrast = pow((100 - $arg1) / 100, 2);
      _imageapi_gd_pixel_color_walk($im, '_imageapi_gd_pixel_contrast', $contrast);
      return TRUE;
    case IMG_FILTER_COLORIZE:
      $arg1 = is_null($arg1) ? 0 : $arg1;
      $arg2 = is_null($arg2) ? 0 : $arg2;
      $arg3 = is_null($arg3) ? 0 : $arg3;
      $arg4 = is_null($arg4) ? 0 : $arg4;
      _imageapi_gd_pixel_color_walk($im, '_imageapi_gd_pixel_colorize', $arg1, $arg2, $arg3, $arg4);
      return TRUE;
    case IMG_FILTER_EDGEDETECT:
      return imageconvolution($im, array(
        array(
          -1,
          0,
          -1,
        ),
        array(
          0,
          4,
          0,
        ),
        array(
          -1,
          0,
          -1,
        ),
      ), 1, 127);
    case IMG_FILTER_EMBOSS:
      return imageconvolution($im, array(
        array(
          1.5,
          0,
          0,
        ),
        array(
          0,
          0,
          0,
        ),
        array(
          0,
          0,
          -1.5,
        ),
      ), 1, 127);
    case IMG_FILTER_GAUSSIAN_BLUR:
      return imageconvolution($im, array(
        array(
          1,
          2,
          1,
        ),
        array(
          2,
          4,
          2,
        ),
        array(
          1,
          2,
          1,
        ),
      ), 16, 0);
    case IMG_FILTER_SELECTIVE_BLUR:
      for ($y = 0; $y < $max_y; ++$y) {
        for ($x = 0; $x < $max_x; ++$x) {
          $flt_r_sum = $flt_g_sum = $flt_b_sum = 0;
          $cpxl = imagecolorat($im, $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 {
                $pxl = imagecolorat($im, $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) {
                  $pxl = imagecolorat($im, $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);
              $new_pxl = imagecolorallocatealpha($im, (int) $new_r, (int) $new_g, (int) $new_b, $new_a);
              if ($new_pxl == FALSE) {
                $new_pxl = imagecolorclosestalpha($im, (int) $new_r, (int) $new_g, (int) $new_b, $new_a);
              }
              imagesetpixel($im, $x, $y, $new_pxl);
            }
          }
        }
      }
      return TRUE;
    case IMG_FILTER_MEAN_REMOVAL:
      return imageconvolution($im, array(
        array(
          -1,
          -1,
          -1,
        ),
        array(
          -1,
          9,
          -1,
        ),
        array(
          -1,
          -1,
          -1,
        ),
      ), 1, 0);
    case IMG_FILTER_SMOOTH:
      return imageconvolution($im, array(
        array(
          1,
          1,
          1,
        ),
        array(
          1,
          $arg1,
          1,
        ),
        array(
          1,
          1,
          1,
        ),
      ), $arg1 + 8, 0);
  }
}

Functions

Name	Description
imagefilter
_imageapi_gd_pixel_brightness
_imageapi_gd_pixel_colorize
_imageapi_gd_pixel_color_walk	walk each pixel in an image applying $callback to it.
_imageapi_gd_pixel_contrast
_imageapi_gd_pixel_grayscale
_imageapi_gd_pixel_negate

Constants

Name	Description
IMAGEAPI_IMAGEFILTER_PHP
IMG_FILTER_BRIGHTNESS
IMG_FILTER_COLORIZE
IMG_FILTER_CONTRAST
IMG_FILTER_EDGEDETECT
IMG_FILTER_EMBOSS
IMG_FILTER_GAUSSIAN_BLUR
IMG_FILTER_GRAYSCALE
IMG_FILTER_MEAN_REMOVAL
IMG_FILTER_NEGATE
IMG_FILTER_SELECTIVE_BLUR
IMG_FILTER_SMOOTH