About ImageMagick not because I don’t know very well this software (that’s why it’s wonderfull for me to have CI’s driver for it!) But this is one library for watermarking with GD that work perfectly:
<?php
class waterMarker
{
function watermark($sourcefile, $watermarkfile) {
#
# $sourcefile = Filename of the picture to be watermarked.
# $watermarkfile = Filename of the 24-bit PNG watermark file.
#
//Get the resource ids of the pictures
$watermarkfile_id = imagecreatefrompng($watermarkfile);
imageAlphaBlending($watermarkfile_id, false);
imageSaveAlpha($watermarkfile_id, true);
$fileType = strtolower(substr($sourcefile, strlen($sourcefile)-3));
switch($fileType) {
case('gif'):
$sourcefile_id = imagecreatefromgif($sourcefile);
break;
case('png'):
$sourcefile_id = imagecreatefrompng($sourcefile);
break;
default:
$sourcefile_id = imagecreatefromjpeg($sourcefile);
}
//Get the sizes of both pix
$sourcefile_width=imageSX($sourcefile_id);
$sourcefile_height=imageSY($sourcefile_id);
$watermarkfile_width=imageSX($watermarkfile_id);
$watermarkfile_height=imageSY($watermarkfile_id);
$dest_x = $sourcefile_width - $watermarkfile_width;
$dest_y = $sourcefile_height - $watermarkfile_height;
// if a gif, we have to upsample it to a truecolor image
if($fileType == 'gif') {
// create an empty truecolor container
$tempimage = imagecreatetruecolor($sourcefile_width,
$sourcefile_height);
// copy the 8-bit gif into the truecolor image
imagecopy($tempimage, $sourcefile_id, 0, 0, 0, 0,
$sourcefile_width, $sourcefile_height);
// copy the source_id int
$sourcefile_id = $tempimage;
}
imagecopy($sourcefile_id, $watermarkfile_id, $dest_x, $dest_y, 0, 0,
$watermarkfile_width, $watermarkfile_height);
//Create a jpeg out of the modified picture
switch($fileType) {
// remember we don't need gif any more, so we use only png or jpeg.
// See the upsaple code immediately above to see how we handle gifs
case('png'):
imagepng ($sourcefile_id, $sourcefile);
break;
default:
imagejpeg ($sourcefile_id, $sourcefile);
}
imagedestroy($sourcefile_id);
imagedestroy($watermarkfile_id);
}
}
?>
Also, not to say you have to take it or make spy on them, but you may look at Kohana image lib, there is some good code to look at there.
