function imageapi_imagemagick_image_overlay in ImageCache Actions 6

Improvements on this are welcomed!

Please be aware of the limitations of imagemagick libraries out there - the versions distributed on hosted servers (if any) are often several years behind. Using the latest imagemagick release features will make this function unusable in real deployments.

File

./imagecache_canvasactions.module, line 214

A collection of canvas (layer) type manipulations for imagecache - including "Watermark"

Code

function imageapi_imagemagick_image_overlay(&$image, &$layer, $x = 0, $y = 0, $alpha = 100, $reverse = FALSE) {
  $layer_filepath = $layer->source;

  # TODO - alpha channels

  # I spent ages on the docs, but it appears my version of convert does not support -merge, -watermark or -dissolve

  // Bloody libraries - I tried  [6.2.8 06/11/08] because that's what I could get for my distro.
  // Set its offset. Offset arguments require a sign in front.
  if ($x >= 0) {
    $x = "+{$x}";
  }
  if ($y >= 0) {
    $y = "+{$y}";
  }

  # This just drops the image on, no alpha:
  if ($alpha == 100) {
    $image->ops[] = " \"{$layer_filepath}\" -geometry {$x}{$y} -composite ";
  }
  else {
    $compose_arg = "  ";

    # $compose_arg = " -compose dissolve ";

    // -compose dissolve is supposed to work, but doesn't in available imagemagick versions
    $geometry_arg = "-geometry {$x}{$y}";
    $alpha_arg = "-set \"option:compose:args\" {$alpha}";
    $image->ops[] = " \"{$layer_filepath}\" {$compose_arg} {$geometry_arg} {$alpha_arg} -composite ";
  }

  #  watchdog('imagecache_canvas', print_r($image->ops, 1) );

  # This also worked

  #  $image->ops[] = ' -draw "image over {$x},{$y} 0,0 \'{$layer_filepath}\'"'  ;

  // TODO - I may end up with a different sized image from doing this?
  return TRUE;
}