Bug #72913 [NEW]: imagecopy() loses single-color transparency on palette images

From: cmb Operating system: * PHP version: 7.0.10 Package: GD related Bug Type: Bug Bug description:imagecopy() loses single-color transparency on palette images Description: ------------ When copying a single-color transparency true-color image onto a palette image with imagecopy(), the transparency is lost, if compiled against the bundled libgd. With external libgd it works fine. That bug affects all currently supported PHP versions. Test script: --------------- <?php $base64 = 'iVBORw0KGgoAAAANSUhEUgAAADIAAAAyCAIAAACRXR/mAAAABnRSTlMAAAAAAABu' . 'pgeRAAAAVklEQVRYw+3UQQqAMBAEwf3/p9eTBxEPiWAmWMU8oGFJqgAAuOpzWTX3' . 'xQUti+uRJTZ9V5aY1bOTFZLV7yZr9zt6ibv/qPXfrMpsGipbIy7oqQ8AYJED1plD' . 'y5PCu2sAAAAASUVORK5CYII='; $src = imagecreatefromstring(base64_decode($base64)); $dst = imagecreate(50, 50); $transparent = imagecolorallocatealpha($dst, 255, 255, 255, 127); imagealphablending($dst, false); imagesavealpha($dst, true); imagecopy($dst, $src, 0,0, 0,0, 50,50); imagepng($dst, __DIR__ . '/test.png'); Expected result: ---------------- An image with red circle on a _transparent_ background. Actual result: -------------- An image with red circle on a _black_ background. -- Edit bug report at https://bugs.php.net/bug.php?id=72913&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=72913&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=72913&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=72913&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=72913&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=72913&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=72913&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=72913&r=needscript Try newer version: https://bugs.php.net/fix.php?id=72913&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=72913&r=support Expected behavior: https://bugs.php.net/fix.php?id=72913&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=72913&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=72913&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=72913&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=72913&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=72913&r=dst IIS Stability: https://bugs.php.net/fix.php?id=72913&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=72913&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=72913&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=72913&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=72913&r=mysqlcfg