Bug #53580 [Sus->Opn]: During resize gdImageCopyResampled cause colors change

Edit report at https://bugs.php.net/bug.php?id=53580&edit=1 ID: 53580 Updated by: cmb@php.net Reported by: chupakabr at gmail dot com Summary: During resize gdImageCopyResampled cause colors change -Status: Suspended +Status: Open Type: Bug Package: GD related Operating System: Windows, Ubuntu, CentOS, any? PHP Version: 5.2.16 Block user comment: N Private report: N New Comment: The issue has been fixed upstream (not yet released, though), so it may be ported. Previous Comments: ------------------------------------------------------------------------ [2016-08-21 19:33:18] cmb@php.net This bug has already been reported as <https://github.com/libgd/libgd/issues/99>, so I'm suspending this ticket. ------------------------------------------------------------------------ [2015-07-20 14:02:46] cmb@php.net IMHO it makes sense to apply rounding (instead of truncation) in this case, but we might need a fallback for lround() for older compilers. And interestingly, some quick tests (script from bug #41820) on Win7/VC14 cause all pixels to be rounded to 0x636363. Still better than having two colors, but weird. ------------------------------------------------------------------------ [2010-12-20 09:45:26] chupakabr at gmail dot com Description: ------------ Reproduce: To test resize image containing solid white background. After resize pixels with color different from #FFFFFF will appear. Probable cause: gdImageSetPixel parameters (red, green, blue, alpha) are casted to int in gdImageCopyResampled which cause them to floor so 254.9999999 became 254 instead of 255. Issues seem to be related: http://bugs.php.net/bug.php?id=30591 http://bugs.php.net/bug.php?id=41820 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=53580&edit=1