function canvasactions_mask in ImageCache Actions 5.2

Same name and namespace in other branches

1. 5.3 canvasactions.inc \canvasactions_mask()

Given a mask image resource object in the $action, use the alpha values from it to set transparency on the source image.

Note that the returned image has transparency set BUT if it's a jpeg it may not remember that channel. Need to switch formats or flatten before saving, or the transparency will be lost.

1 call to canvasactions_mask()

canvasactions_roundedcorners_image in ./canvasactions.inc

Create a rounded corner mask and alpha-merge it with the image.

File

./canvasactions.inc, line 605

Code

function canvasactions_mask(&$image, $mask) {

  // I do not believe there is a func for this, so I'll do it pixel-by-pixel
  // Slow, I know.
  $info = $image->info;
  if (!$info) {
    return FALSE;
  }
  $img =& $image->resource;
  $msk =& $mask->resource;
  imagesavealpha($image->resource, TRUE);
  imagealphablending($image->resource, FALSE);

  // Support indexed color (gif) if I have to
  $transparent_ix = imagecolortransparent($image->resource);
  $width = imagesx($img);

  // Use the actual, not claimed image size.
  $height = imagesy($img);
  for ($i = 0; $i < $height; $i++) {

    //this loop traverses each row in the image
    for ($j = 0; $j < $width; $j++) {

      //this loop traverses each pixel of each row

      // Get the color & alpha info of the current pixel
      $color_ix = imagecolorat($img, $j, $i);

      // an index
      $rgba_array = imagecolorsforindex($img, $color_ix);

      // support indexed trans
      if ($color_ix == $transparent_ix) {
        $rgba_array['alpha'] = 127;
      }

      // Get the alpha of the corresponding mask pixel
      $mask_color_ix = imagecolorat($msk, $j, $i);

      // an index
      $msk_rgba_array = imagecolorsforindex($msk, $mask_color_ix);

      // Calculate the total alpha value of this pixel
      $rgba_array['alpha'] = max($msk_rgba_array['alpha'], $rgba_array['alpha']);

      //paint the pixel
      if ($image->info['mime_type'] == 'image/gif') {

        // indexed color - re-use existing pallette
        $color_to_paint = imagecolorclosestalpha($image->resource, $rgba_array['red'], $rgba_array['green'], $rgba_array['blue'], $rgba_array['alpha']);
      }
      else {
        $color_to_paint = imagecolorallocatealpha($image->resource, $rgba_array['red'], $rgba_array['green'], $rgba_array['blue'], $rgba_array['alpha']);
      }
      imagesetpixel($image->resource, $j, $i, $color_to_paint);
    }
  }
  return TRUE;
}