Bug #66714 [NEW]: imageconvolution processing output inconsistent with previous versions

From: drew dot mclellan at gmail dot com Operating system: Linux PHP version: 5.5.9 Package: GD related Bug Type: Bug Bug description:imageconvolution processing output inconsistent with previous versions Description: ------------ The behaviour of imageconvolution() appears to have changed in PHP 5.5.9. The results are visual, so hard to describe, but the behaviour is significantly different from earlier versions. The test script is boilerplate code for basic image sharpening, as found all over the web. In PHP 5.5.9 the result is a loss of brightness in the resulting image. Test script: --------------- $image = imagecreatefromjpeg('/path/to/picture.jpg'); $matrix = array(array(-1, -1, -1), array(-1, 20, -1), array(-1, -1, -1)); $divisor = array_sum(array_map('array_sum', $matrix)); imageconvolution($image, $matrix, $divisor, 0); echo imagecolorat($image, 0, 0); Expected result: ---------------- The echo'd output (colour reference number at 0,0) should be the same in PHP 5.5.8 and 5.5.9 for the same input image. Actual result: -------------- The output number is much lower in 5.5.9 than 5.5.8, indicating a darker colour and a loss of brightness. The issue is that the behaviour has changed. -- Edit bug report at https://bugs.php.net/bug.php?id=66714&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=66714&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=66714&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=66714&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=66714&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=66714&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=66714&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=66714&r=needscript Try newer version: https://bugs.php.net/fix.php?id=66714&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=66714&r=support Expected behavior: https://bugs.php.net/fix.php?id=66714&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=66714&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=66714&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=66714&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=66714&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=66714&r=dst IIS Stability: https://bugs.php.net/fix.php?id=66714&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=66714&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=66714&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=66714&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=66714&r=mysqlcfg