ID: 33914
User updated by: me at thomaskeller dot biz
Reported By: me at thomaskeller dot biz
Status: Bogus
Bug Type: GD related
Operating System: Linux 2.4 shared hosting
PHP Version: 4.3.11
Assigned To: pajoye
New Comment:
> Again it's not a bug.
> You have to set the transparent color correctly
> in the destination image.
So what means "correctly" here? I've tried several
dozens of combination to get the desired result
but failed with each. I copied palettes over, tried to
copy into a 32bit target image while later shrinking
it back via imagetruecolortopalette, and more.
I'll promise I'll shut up if you just give me a few
lines of CORRECT code. The docs don't help me on my
problem.
I've also noticed that a list($r, $g, $b) =
imagecolorsforindex(...) doesn't work as suspected,
because all three variables are unset. This is my
current code:
<?php
$im_source = imagecreatefromgif($somefile);
$im_target = imagecreate($width, $height);
$idx = imagecolortransparent($im_source);
$rgba = imagecolorsforindex($im_source, $idx);
imagecopyresampled($im_target,$im_source, 0, 0, 0, 0,
$new_width, $new_height, $orig_width, $orig_height);
$transColor = imagecolorallocate($im_target,
$rgba['red'], $rgba['green'], $rgba['blue']);
imagecolortransparent($im_target, $transColor);
header("Content-type: image/gif");
imagegif($im_target);
exit;
?>
imagecolortransparent on $im_target afterwards returns
the index for the transparent color (white), but still the
background of the image has another color (rgb 128,64,88).
If I set this color to be transparent, nothing happens
(its still there).
Previous Comments:
------------------------------------------------------------------------
[2005-07-29 18:19:57] [EMAIL PROTECTED]
Again it's not a bug.
You have to set the transparent color correctly in the destination
image.
--Pierre
------------------------------------------------------------------------
[2005-07-29 18:12:15] [EMAIL PROTECTED]
RTFM: http://www.php.net/imagecolortransparent
------------------------------------------------------------------------
[2005-07-29 17:36:48] me at thomaskeller dot biz
I have already provided a sample script, which is available on
http://thomaskeller.biz/work/php/PHP_GIF/image.php, the source for this
file is http://thomaskeller.biz/work/php/PHP_GIF/image.phps [0].
The test image which fails to be scaled is
http://thomaskeller.biz/work/php/PHP_GIF/rose.gif
As you can see here [0] the problematic code seems to be (shortened):
<?php
$idx = imagecolortransparent($im_src);
if ($idx > -1) // transparent color found?
{
list($r, $g, $b) = imagecolorsforindex($im_src,$idx);
$transColor = imagecolorexact($im_target, $r, $g, $b);
imagecolortransparent($im_target, $transColor);
}
?>
where I try to receive the index of the transparent color
of the original image, then find the rgb value of this color and
finally create a new color on the target image using the rgb value and
set it as transparent color.
------------------------------------------------------------------------
[2005-07-29 17:19:21] [EMAIL PROTECTED]
Provide a sample (and little) script and the images causing your
problem may help.
For what you said, the "random" color may in fact be the background.
You have to set the transparent color yourself to the dest image.
Short version, it's not a bug as far as I can tell now.
I keep this bug to bogus, if you have a reproducable script with one
image, turn it back to open.
------------------------------------------------------------------------
[2005-07-29 02:37:12] me at thomaskeller dot biz
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.
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=33914&edit=1
