#41820 [Opn->Asn]: Color noise in resized image when using IMAGECOPYRESAMPLED

ID: 41820 Updated by: sniper@php.net Reported By: richard dot gavenda at rksting dot cz -Status: Open +Status: Assigned Bug Type: GD related Operating System: Windows XP PHP Version: 5.2.3 Assigned To: pajoye Previous Comments: ------------------------------------------------------------------------ [2007-06-28 10:14:26] richard dot gavenda at rksting dot cz Ok, so let's close whis thread. I will wait for future versions :-) ------------------------------------------------------------------------ [2007-06-28 10:12:15] richard dot gavenda at rksting dot cz So there must be some sort of bug in resampling algorithm. When i resizing bitmap filled with solid color in any bitmap editor, using any aproximation (linear, bicubic, etc.) I get an image filled with exactly same solid color. With this issue I'm unable to reach one bit transparency of resized image. ------------------------------------------------------------------------ [2007-06-28 10:08:08] pajoye@php.net "Position of horizontal and vertical stripes is different on different machines." Yes, it is the problem with floating points value when we need a constant and precise result on different architecture. See; http://docs.sun.com/source/806-3568/ncg_goldberg.html for a good explanation about this problem. For example, your images has variation between 126 and 127 for a given channel. It may be only something like 126.49999 and 126.50000. I don't think I can fix it easily for this implementation (bicubic interpolation using floating points implementation). Future versions will have more filters and using less volatile precisions. ------------------------------------------------------------------------ [2007-06-28 10:00:33] richard dot gavenda at rksting dot cz Position of horizontal and vertical stripes is different on different machines. ------------------------------------------------------------------------ [2007-06-28 09:58:20] pajoye@php.net It is what I said, a rounding issue. I'm not sure yet how to make it more portable. ------------------------------------------------------------------------ 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/41820 -- Edit this bug report at http://bugs.php.net/?id=41820&edit=1