[TYPO3-english] Alpha transparent PNG with GIFBUILDER and masks

[Bernhard Kraft]

Rudy Gnodde schrieb:

> This outputs a 24-bit PNG with transparency, but no alpha transparency.
> The color set at pixel 0,0 is set as transparent. This is what
> transparentBackground does according to the manual, so no surprise there
> really, but not the result I want.

Hello !

I am not absolutely sure. Back in 2005 I did a lot of changes to the
GIFBUILDER / t3lib_stdGraphic, (I introduced the png_truecolor flag) But
AFAIR it is not possible to create alpha-layer images using the GIFBUILDER.

There is only 0/1 transparency.

I guess what you would like to achieve, is to add the mask-image as
alpha channel for the specified "file". But in face the "mask option
works different:

When you have an image in your gifbuilder-object. probably defined by
5 = IMAGE
in your case, then the GIFBUILDER file/mask options "overlays" the
specified file over the "current" one, using the "mask" file as
overlay-information.

so this is rather only useful for overlaying one image over another
using a specified mask - and not for setting the alpha-layer of a png file.

I guess best solution to accomplish this, would be to create your own
little extension, using imageMagick to accomplish this task.



greets,
Bernhard