[TYPO3] TS: BgrndColor of partially transparent GIFs when scalingwith IMG_RESOURCE

P H Vetch paul at qedstudio.com
Tue Mar 14 09:05:43 CET 2006

Hi there,

The problem you're having has to do with a limitation of the GIF format -
you can't have partial transparency (only 1 bit alpha supported, so a pixel
is either 100% transparent or 100% opaque).  The only format which will help
you is 24bit PNG, though this has it's own drawbacks (namely than the
transparency isn't supported by IE without some additional work).

For a handy illstrated explanation of the issue see the bottom of this page:


There are plugins in TYPO3 which address the PNG support in IE, have a
search around.




> -----Original Message-----
> From: typo3-english-bounces at lists.netfielders.de 
> [mailto:typo3-english-bounces at lists.netfielders.de] On Behalf 
> Of Joerg Wagner - DigiLog multimedia
> Sent: 14 March 2006 07:50
> To: typo3-english at lists.netfielders.de
> Subject: [TYPO3] TS: BgrndColor of partially transparent GIFs 
> when scalingwith IMG_RESOURCE
> Hi all !
> I am trying to use partially transparent GIFs as backgrounds 
> for <div> tags. 
> Where the GIFs are transparent the CSS background-color of 
> the div can be seen as expected. I use hard edges between GIF 
> foreground and transparent background (no antialiasing) so 
> this works fine.
> The user can select the GIFs in a TemplaVoila FCE and I also 
> have provide for the possibility to scale the GIFs as needed.
> Now, when I scale the IMG_RESOURCE that renders the GIF as 
> needed (by setting the width or height prop of the 
> IMG_RESOURCE), the edges to the transparent background get 
> antialiased against white color(!) which is not the 
> background-color of my divs, so the edges produce a visible 
> jaggy white glow.
> Is there any way to define the background color that the 
> IMG_RESOURCE object uses to antialias against when scaling 
> transparent GIFs? TSref shows now such property for IMG_RESOURCE.
> Thanks for your help.
> --
> Jvrg Wagner
> DigiLog multimedia 

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