| 1 |
<?php
|
| 2 |
// $ID $
|
| 3 |
/**
|
| 4 |
* @file routine for image layering
|
| 5 |
*
|
| 6 |
*/
|
| 7 |
|
| 8 |
|
| 9 |
/****************************************************************************************************************************************/
|
| 10 |
/**
|
| 11 |
* Note that the below code is laboriously slow - it takes and compares every pixel of the two inputs
|
| 12 |
* and calculates a new valus for each of them. this is only a fallback because reliable image toolkit
|
| 13 |
* transparencies was buggy on certain platforms :(
|
| 14 |
*/
|
| 15 |
|
| 16 |
//Niko (http://www.codeguru.com.ua)
|
| 17 |
class watermark {
|
| 18 |
function create_watermark($main_img_obj, $watermark_img_obj, $x_ins, $y_ins, $alpha_level = 100) {
|
| 19 |
$alpha_level /= 100;
|
| 20 |
# Should this change to match both images?
|
| 21 |
#$main_img_obj_w = max(imagesx($main_img_obj), imagesx($watermark_img_obj));
|
| 22 |
#$main_img_obj_h = max(imagesy($main_img_obj), imagesy($watermark_img_obj));
|
| 23 |
$main_img_obj_w = imagesx($main_img_obj);
|
| 24 |
$main_img_obj_h = imagesy($main_img_obj);
|
| 25 |
$watermark_img_obj_w = imagesx($watermark_img_obj);
|
| 26 |
$watermark_img_obj_h = imagesy($watermark_img_obj);
|
| 27 |
|
| 28 |
$main_img_obj_min_x = $x_ins;
|
| 29 |
$main_img_obj_min_y = $y_ins;
|
| 30 |
|
| 31 |
$return_img = imagecreatetruecolor($main_img_obj_w, $main_img_obj_h);
|
| 32 |
imagesavealpha($return_img, true);
|
| 33 |
imagealphablending($return_img, false);
|
| 34 |
|
| 35 |
|
| 36 |
for ($y = 0; $y < $main_img_obj_h; $y++) {
|
| 37 |
for ($x = 0; $x < $main_img_obj_w; $x++) {
|
| 38 |
|
| 39 |
$return_color = NULL;
|
| 40 |
|
| 41 |
$watermark_x = $x - $main_img_obj_min_x;
|
| 42 |
$watermark_y = $y - $main_img_obj_min_y;
|
| 43 |
|
| 44 |
$main_rgb = imagecolorsforindex($main_img_obj, imagecolorat($main_img_obj, $x, $y));
|
| 45 |
|
| 46 |
if ($watermark_x >= 0 && $watermark_x < $watermark_img_obj_w && $watermark_y >= 0 && $watermark_y < $watermark_img_obj_h) {
|
| 47 |
$watermark_rbg = imagecolorsforindex($watermark_img_obj, imagecolorat($watermark_img_obj, $watermark_x, $watermark_y));
|
| 48 |
|
| 49 |
$watermark_alpha = round(((127 - $watermark_rbg['alpha']) / 127), 2);
|
| 50 |
$watermark_alpha = $watermark_alpha * $alpha_level;
|
| 51 |
|
| 52 |
$avg_red = $this->_get_ave_color($main_rgb['red'], $watermark_rbg['red'], $watermark_alpha);
|
| 53 |
$avg_green = $this->_get_ave_color($main_rgb['green'], $watermark_rbg['green'], $watermark_alpha);
|
| 54 |
$avg_blue = $this->_get_ave_color($main_rgb['blue'], $watermark_rbg['blue'], $watermark_alpha);
|
| 55 |
|
| 56 |
// TODO figure out the maths for merging two transparent images
|
| 57 |
$new_alpha = min($watermark_rbg['alpha'], $main_rgb['alpha']);
|
| 58 |
#$new_alpha = $main_rgb['alpha'];
|
| 59 |
#$new_alpha = 0;
|
| 60 |
|
| 61 |
$return_color = $this->_get_image_color($return_img, $avg_red, $avg_green, $avg_blue, $new_alpha);
|
| 62 |
}
|
| 63 |
else {
|
| 64 |
$return_color = imagecolorat($main_img_obj, $x, $y);
|
| 65 |
}
|
| 66 |
imagesetpixel($return_img, $x, $y, $return_color);
|
| 67 |
}
|
| 68 |
}
|
| 69 |
return $return_img;
|
| 70 |
}
|
| 71 |
|
| 72 |
function _get_ave_color($color_a, $color_b, $alpha_level) {
|
| 73 |
return round((($color_a * (1 - $alpha_level)) + ($color_b * $alpha_level)));
|
| 74 |
}
|
| 75 |
|
| 76 |
function _get_image_color($im, $r, $g, $b, $alpha) {
|
| 77 |
$c = imagecolorexactalpha($im, $r, $g, $b, $alpha);
|
| 78 |
if ($c != -1)
|
| 79 |
return $c;
|
| 80 |
$c = imagecolorallocate($im, $r, $g, $b, $alpha);
|
| 81 |
if ($c != -1)
|
| 82 |
return $c;
|
| 83 |
return imagecolorclosest($im, $r, $g, $b, $alpha);
|
| 84 |
}
|
| 85 |
}
|
| 86 |
/****************************************************************************************************************************************/
|
Parent Directory
| 
Revision Log
| 
Revision Graph