class watermark in ImageCache Actions 8
Same name and namespace in other branches
- 5.3 watermark.inc \watermark
- 5.2 watermark.inc \watermark
- 6.2 watermark.inc \watermark
- 6 watermark.inc \watermark
- 7 watermark.inc \watermark
@file Routine for image layering.
Note that the below code is laboriously slow - it takes and compares every pixel of the two inputs and calculates a new values for each of them. this is only a fallback because reliable image toolkit transparencies was buggy on certain platforms :(
Code from: Niko (http://www.codeguru.com.ua).
Hierarchy
- class \watermark
Expanded class hierarchy of watermark
1 string reference to 'watermark'
- image_gd_overlay in ./
image_overlay.inc - GD toolkit specific implementation of the image overlay effect.
File
- ./
watermark.inc, line 13 - Routine for image layering.
View source
class watermark {
/**
* TODO
*
* @param resource $main_img_obj
* @param resource $watermark_img_obj
* @param int $x_ins
* @param int $y_ins
* @param int $alpha_level
*
* @return resource
*
*/
function create_watermark($main_img_obj, $watermark_img_obj, $x_ins, $y_ins, $alpha_level = 100) {
$alpha_level /= 100;
// Should this change to match both images?
//$main_img_obj_w = max(imagesx($main_img_obj), imagesx($watermark_img_obj));
//$main_img_obj_h = max(imagesy($main_img_obj), imagesy($watermark_img_obj));
$main_img_obj_w = imagesx($main_img_obj);
$main_img_obj_h = imagesy($main_img_obj);
$watermark_img_obj_w = imagesx($watermark_img_obj);
$watermark_img_obj_h = imagesy($watermark_img_obj);
$main_img_obj_min_x = $x_ins;
$main_img_obj_min_y = $y_ins;
$return_img = imagecreatetruecolor($main_img_obj_w, $main_img_obj_h);
imagesavealpha($return_img, TRUE);
imagealphablending($return_img, FALSE);
for ($y = 0; $y < $main_img_obj_h; $y++) {
for ($x = 0; $x < $main_img_obj_w; $x++) {
$return_color = NULL;
$watermark_x = $x - $main_img_obj_min_x;
$watermark_y = $y - $main_img_obj_min_y;
$main_rgb = imagecolorsforindex($main_img_obj, imagecolorat($main_img_obj, $x, $y));
if ($watermark_x >= 0 && $watermark_x < $watermark_img_obj_w && $watermark_y >= 0 && $watermark_y < $watermark_img_obj_h) {
$watermark_rbg = imagecolorsforindex($watermark_img_obj, imagecolorat($watermark_img_obj, $watermark_x, $watermark_y));
$watermark_alpha = round((127 - $watermark_rbg['alpha']) / 127, 2);
$watermark_alpha = $watermark_alpha * $alpha_level;
$avg_red = $this
->_get_ave_color($main_rgb['red'], $watermark_rbg['red'], $watermark_alpha);
$avg_green = $this
->_get_ave_color($main_rgb['green'], $watermark_rbg['green'], $watermark_alpha);
$avg_blue = $this
->_get_ave_color($main_rgb['blue'], $watermark_rbg['blue'], $watermark_alpha);
// TODO figure out the maths for merging two transparent images.
$new_alpha = min($watermark_rbg['alpha'], $main_rgb['alpha']);
//$new_alpha = $main_rgb['alpha'];
//$new_alpha = 0;
$return_color = $this
->_get_image_color($return_img, $avg_red, $avg_green, $avg_blue, $new_alpha);
}
else {
$return_color = imagecolorat($main_img_obj, $x, $y);
}
imagesetpixel($return_img, $x, $y, $return_color);
}
}
return $return_img;
}
/**
* Get an average color.
*
* @param int $color_a
* @param int $color_b
* @param float $alpha_level
*
* @return float
*
*/
function _get_ave_color($color_a, $color_b, $alpha_level) {
return round($color_a * (1 - $alpha_level) + $color_b * $alpha_level);
}
/**
* TODO
*
* @param resource $image
* @param int $r
* @param int $g
* @param int $b
* @param int $alpha
*
* @return int
*/
function _get_image_color($image, $r, $g, $b, $alpha) {
$c = imagecolorexactalpha($image, $r, $g, $b, $alpha);
if ($c != -1) {
return $c;
}
// @todo: this now uses imagecolorallocatealpha(): test
$c = imagecolorallocatealpha($image, $r, $g, $b, $alpha);
if ($c != -1) {
return $c;
}
// @todo: this now uses imagecolorclosestalpha(): test
return imagecolorclosestalpha($image, $r, $g, $b, $alpha);
}
}
Members
Name | Modifiers | Type | Description | Overrides |
---|---|---|---|---|
watermark:: |
function | TODO | ||
watermark:: |
function | Get an average color. | ||
watermark:: |
function | TODO |