From:             me at thomaskeller dot biz
Operating system: Linux 2.4 shared hosting
PHP version:      4.3.11
PHP Bug Type:     GD related
Bug description:  Resizing palette based images with transparency bit loose 
transparency

Description:
------------
Following use case:
Uploaded images should be shrinked to a certain size according to our
guidelines.

Works with jpeg/ png (not palette based) images without a problem,
problems arise when used palette based (8bit) images. Resizing via
imagecopyresampled/ imagecopyresize works only for images WITHOUT a
transparency color set properly. If a transparency color is set in the
image, the value of this color is just ignored and a random background
color is applied to the "transparent" area. It makes no difference if the
image is outputted as gif or 8bit png.

If imagecopyresampled/imagecopyresized is called with the same
width/height for the source and the target image, the transparency keeps
intact.



Reproduce code:
---------------
I've setuped a few things on a test server:

PHPInfo:
 http://thomaskeller.biz/work/php/PHP_GIF/info.php
Testfile:
 http://thomaskeller.biz/work/php/PHP_GIF/image.php
Testfile (Source):
 http://thomaskeller.biz/work/php/PHP_GIF/image.phps

image.php loads http://thomaskeller.biz/work/php/PHP_GIF/rose.gif by
default, but you can load an own gif file via URL like

image.php?filename=http://your.server.com/file.gif

The loaded image is per default resized to its double width/ height.


-- 
Edit bug report at http://bugs.php.net/?id=33914&edit=1
-- 
Try a CVS snapshot (php4):   http://bugs.php.net/fix.php?id=33914&r=trysnapshot4
Try a CVS snapshot (php5.0): 
http://bugs.php.net/fix.php?id=33914&r=trysnapshot50
Try a CVS snapshot (php5.1): 
http://bugs.php.net/fix.php?id=33914&r=trysnapshot51
Fixed in CVS:                http://bugs.php.net/fix.php?id=33914&r=fixedcvs
Fixed in release:            http://bugs.php.net/fix.php?id=33914&r=alreadyfixed
Need backtrace:              http://bugs.php.net/fix.php?id=33914&r=needtrace
Need Reproduce Script:       http://bugs.php.net/fix.php?id=33914&r=needscript
Try newer version:           http://bugs.php.net/fix.php?id=33914&r=oldversion
Not developer issue:         http://bugs.php.net/fix.php?id=33914&r=support
Expected behavior:           http://bugs.php.net/fix.php?id=33914&r=notwrong
Not enough info:             
http://bugs.php.net/fix.php?id=33914&r=notenoughinfo
Submitted twice:             
http://bugs.php.net/fix.php?id=33914&r=submittedtwice
register_globals:            http://bugs.php.net/fix.php?id=33914&r=globals
PHP 3 support discontinued:  http://bugs.php.net/fix.php?id=33914&r=php3
Daylight Savings:            http://bugs.php.net/fix.php?id=33914&r=dst
IIS Stability:               http://bugs.php.net/fix.php?id=33914&r=isapi
Install GNU Sed:             http://bugs.php.net/fix.php?id=33914&r=gnused
Floating point limitations:  http://bugs.php.net/fix.php?id=33914&r=float
No Zend Extensions:          http://bugs.php.net/fix.php?id=33914&r=nozend
MySQL Configuration Error:   http://bugs.php.net/fix.php?id=33914&r=mysqlcfg

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