#39353 [Bgs]: more imagecopyresized() alpha problems

ID: 39353 User updated by: seth at pricepages dot org Reported By: seth at pricepages dot org Status: Bogus Bug Type: GD related Operating System: Mac 10.4 PHP Version: 5CVS-2006-11-02 (snap) Assigned To: pajoye New Comment: > For example? gdImageCopyResized() in our example (palette -> true color, no alpha blending) requires 11+ branches and 3 function calls per input pixel. There is another function call and 4+ branches per output pixel. I'm skipping a good number of branches created by the short-circuiting in each of those 15 if statements. Those create bubbles in your processor pipeline which are going to kill your performance much faster than initializing each pixel 3 times. It's a good thing we are working with small images on fast computers. :) No reply requested. Previous Comments: ------------------------------------------------------------------------ [2006-11-04 19:32:15] pajoye@php.net A last comment is this free support session, you certainly do not know that the default contents of an image create by imagecreatetruecolor is black and not transparent/NULL. ------------------------------------------------------------------------ [2006-11-04 19:21:46] pajoye@php.net "That is a workaround. imagecopyresized() isn't working as defined in the manual, so you've changed the destination image to compensate." Now you've reached my patience limit. http://blog.thepimp.net/misc/bug39353_with_alpha.png is exactly what you expect. Now if you do not understand the different between the TRANSPARENT COLOR and the alpha channel of each independent pixel, I cannot help you further. But you keep considering other apps behaviors as what should happen in gd. It is not the case for various reasons (backward compatibility is one of them). "But I've seen worse code in the GD library..." For example? ------------------------------------------------------------------------ [2006-11-04 19:16:05] seth at pricepages dot org That is a workaround. imagecopyresized() isn't working as defined in the manual, so you've changed the destination image to compensate. I suppose it's fine if you don't want to fix it, I think I can use this workaround for now. There is a waste of pixel processing, though. You need to process the entire final image twice. But I've seen worse code in the GD library... ------------------------------------------------------------------------ [2006-11-04 18:59:26] pajoye@php.net $img = imagecreatetruecolor($width, $height); $bgdalpha = imagecolorallocatealpha($img,0,0,0, 127); imagefill($img, 0,0, $bgdalpha); imagecopyresized($img, $small, 0,0, 0,0, $width, $height, $srcW,$srcH); imagesavealpha($img, 1); imagepng($img, 'a.png'); ------------------------------------------------------------------------ [2006-11-04 18:10:10] seth at pricepages dot org But I *still* can't produce the image that I want. I simply want to enlarge $small. How can I do this? ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/39353 -- Edit this bug report at http://bugs.php.net/?id=39353&edit=1