[TYPO3] TS: BgrndColor of partially transparent GIFs whenscalingwith IMG_RESOURCE

Peter Klein peter at umloud.dk
Tue Mar 14 16:20:02 CET 2006

Hi Joerg . Have you tried the "transparentColor" and/or the 
"transparentBackground" properties?


Peter Klein/Umloud Untd

"Joerg Wagner - DigiLog multimedia" <usenet at digilog.de> skrev i en 
news:mailman.1.1142325366.11339.typo3-english at lists.netfielders.de...
> Hi Paul,
> thanks for your answer, but you missed the point.
> I am aware that GIF only offers 1bit transparency. With "partially 
> transparent GIF" I meant that parts of the GIF are transparent, others are 
> not, and the problem arises at the edge between those areas when the GIFs 
> are scaled down and the IMG_RESOURCE scaling mechanism introduces 
> antialiasing at the edge. The antialiasing itself is not the problem, but 
> I need to control the color to be AAed against.
> --
> Jörg Wagner
> DigiLog multimedia
> "P H Vetch" <paul at qedstudio.com> schrieb im Newsbeitrag 
> news:mailman.11739.1142323551.3122.typo3-english at lists.netfielders.de...
>> 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:
>> http://www.pixy.cz/blogg/clanky/rubberheaders/
>> There are plugins in TYPO3 which address the PNG support in IE, have a
>> search around.
>> Best
>> Paul
>>> -----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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