imagerotate preserve alpha channel only if degree less then 45
| Bug #39366 | imagerotate preserve alpha channel only if degree less then 45 | ||||
|---|---|---|---|---|---|
| Submitted: | 2006-11-03 22:16 UTC | Modified: | 2006-11-04 03:24 UTC | ||
| From: | ciakana at gmail dot com | Assigned: | pajoye (profile) | ||
| Status: | Closed | Package: | GD related | ||
| PHP Version: | 5.2.0 | OS: | Windows XP | ||
| Private report: | No | CVE-ID: | None | ||
[2006-11-03 22:16 UTC] ciakana at gmail dot com
Description:
------------
If I run the allegated script, where shade.png is a png image with a transparent background (full alpha channel), all works if the degrees are less then 45. If I set the degrees to 300, for example, the background become black.
Reproduce code:
---------------
<?php
$filename="shade.png";
$degrees =300;
header('Content-type: image/png');
$source = imagecreatefrompng($filename);
$rotate = imagerotate($source, $degrees, -1);
imagealphablending($rotate, true);
imagesavealpha($rotate, true);
imagepng($rotate);
?>
Expected result:
----------------
An image with a black bakground
Actual result:
--------------
A rotated copy of the original image with the alpha channel preserved
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[2006-11-03 22:18 UTC] ciakana at gmail dot com
Description: ------------ If I run the allegated script, where shade.png is a png image with a transparent background (full alpha channel), all works if the degrees are less then 45. If I set the degrees to 300, for example, the background become black. Reproduce code: --------------- <?php $filename="shade.png"; $degrees =300; header('Content-type: image/png'); $source = imagecreatefrompng($filename); $rotate = imagerotate($source, $degrees, -1); imagealphablending($rotate, true); imagesavealpha($rotate, true); imagepng($rotate); ?> Expected result: ---------------- A rotated copy of the original image with the alpha channel preserved Actual result: -------------- An image with a black bakground[2006-11-04 03:24 UTC] pajoye@php.net