Forums / Developer / PNG image resize loose transparency

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PNG image resize loose transparency

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Olivier Versanne

Monday 06 July 2009 4:39:35 am

Hi,

I'm using eZ Image filters to resize my PNG pictures.

Here my image.ini.append.php :

<?php /* #?ini charset="iso-8859-1"?

[AliasSettings]
AliasList[]=alternate_view

[alternate_view]
Reference=reference
Filters[]=geometry/scaledownonly=45;45
*/

And, when I try to view the resized picture, I get a black background instead of transparency background.
I think this problem comes from the grafical module that eZ is using. How could I know which extension eZ uses, and how could I change it? (Imagick / GD... or another that works with eZ).

Thanks,

Olivier.

André R.

Monday 06 July 2009 5:24:25 am

This is controlled by image.ini settings, and if ImageMagic is not used (as in GD is used instead), you can see that in settings/override/image.ini.append.php with content like this:

[ImageMagick]
IsEnabled=false

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Olivier Versanne

Monday 13 July 2009 4:24:23 am

Thanks!

Vytautas Germanavičius

Thursday 08 October 2009 4:52:09 am

after i switched to gd i lost transparency on all png images.

Has anyone solution for this?

i filled issue:
http://issues.ez.no/IssueView.php?Id=15640&activeItem=1

{set-block scope=root variable=cache_ttl}0{/set-block}

Vytautas Germanavičius

Friday 17 June 2011 8:22:21 am

This message gave me idea
http://stackoverflow.com/questions/32243/can-png-image-transparency-be-preserved-when-using-phps-gdlib-imagecopyresampled

And i made small changes in ezimagegdhandler.php:
i added

    imagealphablending( $temporaryImageObject, false );    imagesavealpha( $temporaryImageObject, true );

after

       $temporaryImageObject = eZImageGDHandler::imageCreate( $destinationWidth, $destinationHeight, eZImageGDHandler::isImageTrueColor( $imageObject, $sourceMimeData ) );

It saves PNG transparency before resizing.

I made patch, if someone is interested. http://issues.ez.no/IssueView.php?Id=15640&activeItem=1

{set-block scope=root variable=cache_ttl}0{/set-block}