#21524 [Opn->Asn]: Add imagesavealpha so that imagepng can output alpha channel
ID: 21524
Updated by: pajoye@php.net
Reported By: phpbugs@koimo.net
-Status: Open
+Status: Assigned
Bug Type: Feature/Change Request
Operating System: All
PHP Version: 4.3.0
-Assigned To:
+Assigned To: pajoye
New Comment:
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php
Hello,
This feature will be present in futur version of php (means not any
upcoming bugfixes releases) using the bundled GD.
Thank's for your report,
pierre
Previous Comments:
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[2003-01-08 13:22:36] phpbugs@koimo.net
(Not sure whether this should be here or under GD related)
It would be useful if PHP had access to the gdSaveAlpha function in the
GD library.
Using PHP 4.3.0 with bundled GD, there is currently no way I can see to
prevent imagepng stripping the alpha channel of a truecolor image. The
following script produces a white circle on a black background, rather
than a semi-transparent circular 'hole':
<?php
$image = imagecreatetruecolor(200, 200);
imagealphablending($image, false);
imagefilledellipse($image, 100, 100, 150, 150, 0x3fffffff);
header('Content-type: image/png');
imagepng($image);
?>
According to the GD change list at
http://www.boutell.com/gd/manual2.0.9.html#whatsnew2.0.2
this is the correct default behaviour since version 2.0.2 - there is a
function gdSaveAlpha to turn on and off alpha output which appears to
be present in the bundled GD in CVS but at the moment without any PHP
wrapper. A PHP function imagesavealpha(resource image, bool savealpha)
would allow alpha output when required without breaking any existing
scripts.
-S. Haydon
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Edit this bug report at http://bugs.php.net/?id=21524&edit=1
Thread (3 messages)