/**
* PNG ALPHA CHANNEL SUPPORT for imagecopymerge();
* by Sina Salek
*
* Bugfix by Ralph Voigt (bug which causes it
* to work only for $src_x = $src_y = 0.
* Also, inverting opacity is not necessary.)
* 08-JAN-2011
*
**/
function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct, $dst_im_ext)
{
if ($dst_im_ext == 'jpg' && $pct == 100) {
imagealphablending($dst_im, true);
imagealphablending($src_im, true);
imagecopy($dst_im, $src_im, $dst_x, $dst_y, 0, 0, $src_w, $src_h);
} else {
$transparent_index = imagecolortransparent($dst_im);
$colors_total = imagecolorstotal($dst_im);
$cut = imagecreatetruecolor($src_w, $src_h);
if ($transparent_index >= 0) {
$transparent_color = imagecolorsforindex($dst_im, $transparent_index);
$transparent_index = imagecolorallocatealpha($cut, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue'], 127);
imagefill($cut, 0, 0, $transparent_index);
imagecolortransparent($cut, $transparent_index);
} else {
$color = imagecolorallocatealpha($cut, 0, 0, 0, 127);
imagefill($cut, 0, 0, $color);
}
if ($dst_im_ext == 'png') {
imagealphablending($dst_im, false);
imagesavealpha($dst_im, true);
} else {
if ($dst_im_ext !== 'jpg') {
imagetruecolortopalette($dst_im, true, 255);
imagesavealpha($dst_im, false);
}
}
if ($dst_im_ext == 'png' && $colors_total == 0) {
if ($pct < 100) {
filter_opacity($src_im, $pct);
}
imagealphablending($dst_im, true);
imagesavealpha($dst_im, true);
imagecopy($dst_im, $src_im, $dst_x, $dst_y, 0, 0, $src_w, $src_h);
imagealphablending($dst_im, false);
} else {
imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);
imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);
imagecopymerge($dst_im, $cut, $dst_x, $dst_y, 0, 0, $src_w, $src_h, $pct);
}
}
imagedestroy($cut);
imagedestroy($src_im);
}
function create_watermark($source_file_path, $output_file_path)
{
list(, , $source_type) = getimagesize($source_file_path);
if ($source_type === NULL) {
return false;
}
switch ($source_type) {
case IMAGETYPE_GIF:
$source_gd_image = imagecreatefromgif($source_file_path);
break;
case IMAGETYPE_JPEG:
$source_gd_image = imagecreatefromjpeg($source_file_path);
break;
case IMAGETYPE_PNG:
$source_gd_image = imagecreatefrompng($source_file_path);
break;
default:
return false;
}
list(, , $output_type) = getimagesize(WATERMARK_OVERLAY_IMAGE);
if ($output_type === NULL) {
return false;
}
switch ($output_type) {
case IMAGETYPE_GIF:
$overlay_gd_image = imagecreatefromgif(WATERMARK_OVERLAY_IMAGE);
break;
case IMAGETYPE_JPEG:
$overlay_gd_image = imagecreatefromjpeg(WATERMARK_OVERLAY_IMAGE);
break;
case IMAGETYPE_PNG:
$overlay_gd_image = imagecreatefrompng(WATERMARK_OVERLAY_IMAGE);
imagealphablending($overlay_gd_image, true);
break;
default:
return false;
}
filter_opacity($overlay_gd_image, WATERMARK_OVERLAY_OPACITY);
$overlay_width = imagesx($overlay_gd_image);
$overlay_height = imagesy($overlay_gd_image);
$coordinates = explode(',', WATERMARK_OUTPUT_COORDINATES);
$length = count($coordinates);
for ($i = 0; $i < $length; $i = $i + 2) {
imagecopy($source_gd_image, $overlay_gd_image, $coordinates[$i], $coordinates[$i + 1], 0, 0, $overlay_width, $overlay_height);
}
if ($source_type['mime'] == 'image/png') {
imagepng($source_gd_image, $output_file_path);
} else {
imagejpeg($source_gd_image, $output_file_path, WATERMARK_OUTPUT_QUALITY);
}
imagedestroy($source_gd_image);
imagedestroy($overlay_gd_image);
}
