ID:               45030
 Updated by:       [EMAIL PROTECTED]
 Reported By:      lieyang at yahoo dot com
-Status:           Assigned
+Status:           Feedback
 Bug Type:         GD related
 Operating System: x86_64 GNU/Linux Kernel 2.6.9-4
 PHP Version:      5.2.6
 Assigned To:      pajoye
 New Comment:

In fact yes, I need the source image (what you have in $imageData).
Sorry for the double posts.


Previous Comments:
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[2008-05-17 22:48:55] [EMAIL PROTECTED]

no need for src images :-)

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[2008-05-17 22:43:05] [EMAIL PROTECTED]

Please provide me the source image and the result you get. You can use
http://bugs.libgd.org as well as you can add attachments to your report.

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[2008-05-17 21:43:31] lieyang at yahoo dot com

Description:
------------
When resizing a 24 bit png image with imagecopyresampled, the
destination image alpha channel contains noise where it should be
completely transparent. When the re-sized image is displayed on Motorola
phones with only 4 levels of transparency, 
the image shows many dark dots.

If we replace imagecopyresampled with imagecopyresized in the following
sample reproduce code, the problem goes away.

Reproduce code:
---------------
 
$imageSrc = imagecreatefromstring($imageData);

$imageDst = imagecreatetruecolor($width, $height);
imagealphablending($imageDst, false);
$color = imagecolorallocatealpha($imageDst, 0, 0, 0, 127);
imagefill($imageDst, 0, 0, $color);
imagesavealpha($imageDst, true);

imagecopyresampled($imageDst,$imageSrc, $dst_x, $dst_y, $src_x,
$src_y, $dst_w, $dst_h, $src_w, $src_h);

Expected result:
----------------
Completely transparent regions should still be completely transparent
in destination image.

Actual result:
--------------
Destination image alpha channel noise (some pixel values that should be
fully transparent have different value "2").
You can see the noise all over the transparent regions with any
graphics tools (for example, color selection with gimp).



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