Req #66887 [Fbk]: imagescale - poor quality of scaled image

Edit report at https://bugs.php.net/bug.php?id=66887&edit=1 ID: 66887 Updated by: pajoye@php.net Reported by: mruz at poczta dot onet dot pl Summary: imagescale - poor quality of scaled image Status: Feedback Type: Feature/Change Request Package: GD related Operating System: openSUSE 13.1 PHP Version: 5.5.10 Block user comment: N Private report: N New Comment: Looks like a bug. Which gd do you use? Bundled or system? See phpinfo I also need to know which architecture you use (cpu) Previous Comments: ------------------------------------------------------------------------ [2014-03-12 11:02:25] mruz at poczta dot onet dot pl Sorry, http://mruz.pl/test/tmp0.jpg , available file names: tmp[0-20].jpg ------------------------------------------------------------------------ [2014-03-12 10:55:56] pajoye@php.net and which result do you get? link pls ------------------------------------------------------------------------ [2014-03-12 10:37:20] mruz at poczta dot onet dot pl $algs = [ IMG_BELL, IMG_BESSEL, IMG_BICUBIC, IMG_BICUBIC_FIXED, IMG_BILINEAR_FIXED, IMG_BLACKMAN, IMG_BOX, IMG_BSPLINE, IMG_CATMULLROM, IMG_GAUSSIAN, IMG_GENERALIZED_CUBIC, IMG_HERMITE, IMG_HAMMING, IMG_HANNING, IMG_MITCHELL, IMG_POWER, IMG_QUADRATIC, IMG_SINC, IMG_NEAREST_NEIGHBOUR, IMG_WEIGHTED4, IMG_TRIANGLE, ]; foreach ($algs as $key => $alg) { $img = imagescale($oryginal, 600, 400, $alg); imagejpeg($img, 'tmp'.$key.'.jpg', 90); echo '<img src="tmp'.$key.'.jpg" /><br />'; } All images are the same... ------------------------------------------------------------------------ [2014-03-12 10:20:24] pajoye@php.net Please ignore the background call. It is totally unrelated to this problem. JPEG does not have alpha, so could you please using only the scale function and compare the results? See http://www.php.net/imagesetinterpolation for the different algorithms available. ------------------------------------------------------------------------ [2014-03-12 10:02:36] mruz at poczta dot onet dot pl I resized to 600x400: http://mruz.pl/test/test1.jpg (imagecopyresized) http://mruz.pl/test/test2.jpg (imagescale) http://mruz.pl/test/test.jpg (oryginal) If I apply white background after imagescale(): imagecolorallocatealpha($background, r, g, b, $opacity); imagealphablending($background, true); imagecopy($background, $img, 0, 0, 0, 0, $width, $height) is much worse.. http://mruz.pl/test/test3.jpg (background after imagescale) ------------------------------------------------------------------------ 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 https://bugs.php.net/bug.php?id=66887 -- Edit this bug report at https://bugs.php.net/bug.php?id=66887&edit=1