ID: 39273
Updated by: [EMAIL PROTECTED]
Reported By: seth at pricepages dot org
-Status: Feedback
+Status: Bogus
Bug Type: GD related
Operating System: Mac 10.4
PHP Version: 5.1.6
-Assigned To:
+Assigned To: pajoye
New Comment:
There is nothing wrong in imagecopyresize (or imagecopy).
The problem you have is the misunderstanding of what is the background
color, the alpha channel and alpha blending.
Your original image has many black colors, one is transparent (what you
consider as background), and the other with various transparency
levels.
Try the code below, it will explain you what is your image and how it
works.
<?php
$small = imagecreatefrompng('39273.png');
print_r(imagecolortransparent($small));
$width = 300;
$height = 300;
$srcW = imagesx($small);
$srcH = imagesy($small);
print_r(imagecolorsforindex($small, imagecolorat($small, 0,0)));
// one of the ""black"" pixel
print_r(imagecolorsforindex($small, imagecolorat($small, 37,1)));
imagecolortransparent($small, 1);
$img = imagecreatetruecolor($width, $height);
$trans = imagecolorresolve($img,255,255,255);
imagefill($img, 0,0, $trans);
imagecolortransparent($img, $trans);
imagecopyresized($img, $small, 0,0, 0,0, $width, $height, $srcW,
$srcH);
imagepng($img, '1.png');
Previous Comments:
------------------------------------------------------------------------
[2006-10-27 07:42:40] [EMAIL PROTECTED]
Please try using this CVS snapshot:
http://snaps.php.net/php5.2-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5.2-win32-latest.zip
------------------------------------------------------------------------
[2006-10-27 04:17:23] seth at pricepages dot org
Description:
------------
imagecopyresampled() should be copying the alpha channel, but
it doesn't seem to be doing so. This is a palette based source
image being copied to a true color image.
If you use imagecopy() instead, the image copies as expected
(mostly).
Reproduce code:
---------------
<?php
$small = imagecreatefrompng('http://leopold.sage.wisc.edu/test.png');
$width = 300;
$height = 300;
$srcW = imagesx($small);
$srcH = imagesy($small);
$img = imagecreatetruecolor($width, $height);
//Make a transparent canvas
$trans = imagecolorresolve($img,255,255,255);
imagecolortransparent($img, $trans);
imagealphablending($img, false);
imagefilledrectangle( $img,
0, 0,
$width, $height,
$trans);
//This shouldn't *need* to be on, but it does
imagealphablending($img, true);
//One of these works, the other doesn't
//imagecopy($img, $small, 0,0, 0,0, $srcW, $srcH);
imagecopyresized($img, $small, 0,0, 0,0, $width, $height, $srcW,
$srcH);
header('Content-Type: image/png');
imagepng($img);
?>
Expected result:
----------------
An enlarged, pixellated, mostly transparent, image.
Actual result:
--------------
A black, opaque, image.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=39273&edit=1
