ID:               38764
 User updated by:  markg852 at hotmail dot com
 Reported By:      markg852 at hotmail dot com
 Status:           Bogus
 Bug Type:         GD related
 Operating System: Windows XP, linux
 PHP Version:      5.1.6
 Assigned To:      pajoye
 New Comment:

@ [EMAIL PROTECTED]
i even tested the 6.0.0-dev snapshot and it still has the exact same
issue.

@ [EMAIL PROTECTED]
tested your suggestion and the result is still exactly the same.

and just to be sore.. i`m talking about the QUALITY!!! that`s just
different.. just look at the image i supplied in the first image.

Could this be a bug in GD itself (so not php`s fault) or in php_gd.dll
?


Previous Comments:
------------------------------------------------------------------------

[2006-09-09 22:16:22] [EMAIL PROTECTED]

doh, submit too quickly

all you have to do:
imagecolortransparent($thumb, 0);
imagealphablending($thumb, false);

the fist to set the bgd color, the second function to keep the alpha
information while copying (no blend ops).

------------------------------------------------------------------------

[2006-09-09 22:13:18] [EMAIL PROTECTED]

There is no bug.

You copy an image to a another image. The destination image has no
transparent color defined. True color images are "filled" with black by
default, that's why you see black instead of the transparent color.

short version: all you need to do is:
ImageColorTransparent($thumb, 0);





------------------------------------------------------------------------

[2006-09-09 21:51:58] [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



------------------------------------------------------------------------

[2006-09-09 21:47:45] markg852 at hotmail dot com

The bug is in imagecopyresampled() AND imagecopyresized()!!

------------------------------------------------------------------------

[2006-09-09 21:45:27] markg852 at hotmail dot com

Description:
------------
This bug can be found when trying to make a thumbnail from a url
(example: http://promote.opera.com/logos/Opera5_t.png) the png isn`t
even transperant anymore unless these 3 lines of code are also added: 

$background = imagecolorallocate($thumb, 0, 0, 0);
ImageColorTransparent($thumb, $background); // make the new temp image
all transparent
imagealphablending($thumb, false); // turn off the alpha blending to
keep the alpha channel

i tried everything i could thing of but the quality stays different..

What the code below does is the following:
1. It downloaded the opera logo png image and makes a thumbnail of the
URL!!
2. (after hitting F5) the code will make another thumbnail from the
downloaded full scale image.
3. (after hitting F5 2nd time) the code will show both thumbnails and
look at the quality difference!! and without the 3 lines posted above
the "ugly" image has a black background!!

Reproduce code:
---------------
<?php
// Error Reporting
error_reporting(E_ALL);

// File and new size
if (file_exists('thumb_van_url.png') AND
file_exists('thumb_van_path.png'))
{
    echo '<img src="./thumb_van_url.png"></img>';
    echo "Thumbnail made from URL";
    echo '<img src="./thumb_van_path.png"></img>';
    echo "This one is made from a PATH";
    exit;
}
elseif (file_exists('./Opera5_t.png'))
{
    $filename = 'Opera5_t.png';
    $mid = 'van_path';
}
else
{
    $filename = 'http://promote.opera.com/logos/Opera5_t.png';
    $mid = 'van_url';
   
imagepng(imagecreatefrompng('http://promote.opera.com/logos/Opera5_t.png'),
'Opera5_t.png');
}

$percent = 0.1;

// Get new sizes
list($width, $height) = getimagesize($filename);
$newwidth = $width * $percent;
$newheight = $height * $percent;

// Load
$thumb = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefrompng($filename);

$background = imagecolorallocate($thumb, 0, 0, 0);
ImageColorTransparent($thumb, $background); // make the new temp image
all transparent
imagealphablending($thumb, false); // turn off the alpha blending to
keep the alpha channel

// Resize
imagecopyresampled($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight,
$width, $height);

// Output
imagepng($thumb, 'thumb_' . $mid . '.png');
echo '<img src="./thumb_' . $mid . '.png"></img>';


// Content type
// header('Content-type: image/png');
// readfile('thumb_' . $mid . '.png');
?>



Expected result:
----------------
http://img393.imageshack.us/img393/2796/uitkomstvc4.png



------------------------------------------------------------------------


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