From: [EMAIL PROTECTED]
Operating system: All
PHP version: 4.3.0
PHP Bug Type: Feature/Change Request
Bug description: Add imagesavealpha so that imagepng can output alpha channel
(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
--
Edit bug report at http://bugs.php.net/?id=21524&edit=1
--
Try a CVS snapshot: http://bugs.php.net/fix.php?id=21524&r=trysnapshot
Fixed in CVS: http://bugs.php.net/fix.php?id=21524&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=21524&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=21524&r=needtrace
Try newer version: http://bugs.php.net/fix.php?id=21524&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=21524&r=support
Expected behavior: http://bugs.php.net/fix.php?id=21524&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=21524&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=21524&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=21524&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=21524&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=21524&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=21524&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=21524&r=gnused
