Comments on: PHP-GD: Resize Transparent Image PNG & GIF

By: Adam Šorfa

Adam Šorfa — Thu, 26 Jan 2012 14:56:09 +0000

This example works only with PNG images. Background of my transparent GIF images are still black. can someone help me please?

By: Andrew

Andrew — Mon, 16 Jan 2012 03:53:50 +0000

Oh man! I’ve been trying to find a fix for this for months and months for our WordPress blog.
The fix offered at the top didn’t do it, Benjamin’s fix did the trick. I think the problem is that GIF and PNG8 have different pallette numbers for the transparent, which wasn’t being considered by earlier fixes?
Sooo pleased to see this problem dealt with once and for all.

By: Lu Cila

Lu Cila — Tue, 06 Dec 2011 16:03:40 +0000

Bien vos! thanks

By: Olivier Pons

Olivier Pons — Sat, 12 Nov 2011 11:14:23 +0000

You saved my day!

By: Timension » Fix GIF images’ black background in Wordpress

Timension » Fix GIF images’ black background in Wordpress — Tue, 08 Nov 2011 06:16:46 +0000

[...] http://www.akemapa.com/2008/07/10/php-gd-resize-transparent-image-png-gif/ [...]

By: Benjamin

Benjamin — Fri, 21 Oct 2011 13:40:21 +0000

I don’t know if all problems are solved, but here are my changes based on the initial script, to make everything (PNG, GIF) work well:

$new_image = imagecreatetruecolor($width, $height);

// Preserve transparency
$transparent_index = imagecolortransparent($this->image);
if ($transparent_index >= 0) { // GIF
imagepalettecopy($this->image, $new_image);
imagefill($new_image, 0, 0, $transparent_index);
imagecolortransparent($new_image, $transparent_index);
imagetruecolortopalette($new_image, true, 256);
}
else // PNG
{
imagealphablending($new_image, false);
imagesavealpha($new_image,true);
$transparent = imagecolorallocatealpha($new_image, 255, 255, 255, 127);
imagefilledrectangle($new_image, 0, 0, $width,$height, $transparent);
}

imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());

By: nkos

nkos — Thu, 02 Jun 2011 12:17:17 +0000

Perfect !
Thank you !!

nico

By: Jure Sah

Jure Sah — Thu, 21 Apr 2011 21:14:56 +0000

Thanks. Used here: http://www.rockettheme.com/forum/index.php?f=214&t=130087&p=647850&rb_v=viewtopic#p647850

By: bacc

bacc — Tue, 05 Apr 2011 01:10:32 +0000

Excelent!! I found some errors in the script (resizeimage.php is imageresize.php)

The only code working on the network!

—

Excelente!! Encontre un par de errores en el script (resizeimage.php se llama imageresize.php)

El unico codigo que funciona en la red!!

Saludos!!!

By: Mohamed El Allali

Mohamed El Allali — Mon, 21 Feb 2011 18:34:20 +0000

Hello, nice script thanks for sharing, just a small error in the usage script

$image = “some/dir/image.png”; // File image location
should be
$img = “some/dir/image.png”; // File image location

i need it to keep the same ratio as the original image, i’ll try to modify it later, but any suggestion is welcome ^_^

By: James Saunderson

James Saunderson — Tue, 15 Feb 2011 12:39:06 +0000

Thanks! that fixed it.

while trying to find the problem i noticed the actual image was transparent, the php created image was transparent then i resized imagecopyresampled() to be smaller than my full image and it is that function that is losing the transparency of the copied image:

[php]
$bgImageURL = ‘blue-bg.gif’;
$bgImage = imagecreatetruecolor(156,40);
imagealphablending($bgImage, false);//needed
//imagesavealpha($bgImage,true); //not needed
$transparent = imagecolorallocatealpha($bgImage, 255, 255, 255,127);//needed
//imagecolortransparent($bgImage,$transparent); //not needed
imagefilledrectangle($bgImage, 0, 0, 156, 40, $transparent);//needed
$srcimage = @imagecreatefromgif($bgImageURL);
imagecopyresized($bgImage, $srcimage, 0, 0, 0, 0, 146, 30, 1000, 250);
//imagecopyresampled($bgImage,$srcimage,0,0,0,0, 146,30,1000,250);//loses transparency
header(‘content-type: image/gif’);
imagegif($bgImage);
[/php]

likely sounds like a bug in later versions
i am running PHP Version 5.2.6 & GD Version: bundled (2.0.34 compatible)

By: Navi

Navi — Thu, 10 Feb 2011 13:21:59 +0000

Not working for transparent GIF’s – PHP 5 / GD 2 / Linux

By: Extract And Display A Re-sized Image From A WordPress Post In Archives And Searches | Bharat Karavadra

Sat, 22 Jan 2011 14:58:00 +0000

[...] You can extract and resize JPEG, GIF and PNG images from your posts. (PNG and GIF transparency is in development. PNG transparency on resize is working thanks to soem code by Miaz Mauzka). [...]

By: Bharat Karavadra

Bharat Karavadra — Sat, 22 Jan 2011 14:54:59 +0000

Thank you Miaz,

I am creating an image resize feature for WordPress and I had ssiues with PNG’s always having a balck background when resized.

I use a part of you code and resized PNG images now appear as they should. I have not yet tested it for GIF’s but I’m sure your code will work as it works for PNG’s.

You can take a look a look at a WordPress post that has a transparent PNG here:
http://www.karavadra.net/wordpress/contact-form-for-wordpress
and if you finf this post in the arhcives or search results then you will see a resized transparent version.

Thank you again.

By: banderon

banderon — Wed, 12 Jan 2011 19:49:28 +0000

I tried this with no luck as well. I could not use imagecopyresampled, and had to use the following instead:
imagecolortransparent($newImg, $transparent);
imagecopyresized($newImg, $im, 0, 0, 0, 0, $nWidth, $nHeight, $imgInfo[0], $imgInfo[1]);

This works for the transparency, but the image quality is poor (resize is worse than resample). Any ideas why I can’t use resample?