image_filter_keyword

image_filter_keyword($value, $current_pixels, $new_pixels)

function image_filter_keyword($value, $current_pixels, $new_pixels) {
  switch ($value) {
    case 'top':
    case 'left':
      return 0;

    case 'bottom':
    case 'right':
      return $current_pixels - $new_pixels;

    case 'center':
      return $current_pixels / 2 - $new_pixels / 2;
  }
  return $value;
}