ID: 47946 Updated by: il...@php.net Reported By: jcolby at acsol dot net -Status: Open +Status: Closed Bug Type: GD related Operating System: openSuse, CentOS, FreeBSD PHP Version: 5.2.9 New Comment:
This bug has been fixed in CVS. Snapshots of the sources are packaged every three hours; this change will be in the next snapshot. You can grab the snapshot at http://snaps.php.net/. Thank you for the report, and for helping us make PHP better. Previous Comments: ------------------------------------------------------------------------ [2009-04-10 16:31:46] jcolby at acsol dot net Missing function from test case: function array_flatten($array) { (array)$tempArray = array(); foreach ( $array as $value ) { if ( is_array($value) ) { $tempArray = array_merge($tempArray, array_flatten($value)); } else { $tempArray[] = $value; } } return $tempArray; } ------------------------------------------------------------------------ [2009-04-10 16:26:01] jcolby at acsol dot net Description: ------------ When using imageconvolution on an image containing alpha, the background color on the resource image will be replaced with opaque black regardless of any alpha or background settings. This is because of the gdimagecopy internal to the function without the proper savealpha flags being set & no transparent image fill after gdimagecreatetruecolor is used inside the function. This is similar to bug #34992 but I've had a chance to break it open and actually fix it. This affects all versions of php 5, up to the latest 5.2.9 stable build, and I wouldn't doubt it currently affects 6 as well. Now, I managed to fix it in my own build, but I don't know how to get it advanced from there. This is not my realm of experience, I just had to repair it. Patch: php-5.2.9\ext\gd\libgd\gd.c Add in var initialization: /* patch */ gdImagePtr srctrans; /* patch */ Add after "srcback = gdImageCreateTrueColor..." /* patch */ srcback->saveAlphaFlag = 1; srctrans = gdImageColorAllocateAlpha(srcback, 0, 0, 0, 127); gdImageFill(srcback, 0, 0, srctrans); /* end patch */ Thats all it requires. Reproduce code: --------------- <?php function makeFilter($resource, $matrix, $offset=1.0) { global $$resource; (float)$divisor = array_sum(array_flatten($matrix)); if ($divisor == 0) { $divisor = .01; } return imageconvolution($resource, $matrix, $divisor, $offset) ? true : false; } $edgeMatrix = array(array(1, 0, 1), array(0, 5, 0), array(1, 0, 1)); $file = "images/anypngwithalpha.png"; // path to png image $im = imagecreatefrompng($file); // open image imagesavealpha($im, true); makeFilter($im, $edgeMatrix); header('Content-type: image/png'); imagepng($im); imagedestroy($im); ?> Expected result: ---------------- Convolutionmatrix should apply to all opaque or semi opaque pixels, and background should remain unchanged. Actual result: -------------- Convolutionmatrix applies to all opaque and semi opaque pixels, background reverts to solid opaque black regardless of any external settings. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=47946&edit=1
