Is there a chance to set an alpha-mask using XOrg?

[Glynn Clements]

Leif Bergerhoff wrote:

> > It depends on your toolkit. If you're not using any particular toolkit,
> > the easiest way is to set _NET_WM_WINDOW_OPACITY on your window. See
> > http://webcvs.freedesktop.org/xapps/transset/transSet.c?view=markup for
> > an example.
> >
> > Make sure a composite manager is running (many desktops run one by
> > default these days).
> 
> No, I don't want to make use of a toolkit if possible.
> 
> As I can see I would have to make use of the composite extension.
> If I remember correctly, I read about this extension supporting max. 2 output 
> devices. Right?
> This would mean, I'll need another way for setting an image as an alpha-mask, 
> since I want to make use of 6 output devices.

If you just want rendering functions which support translucency, use
Cairo (you can use XRender directly, but there's unlikely to be any
advantage to doing so).

The core X protocol doesn't support alpha blending; apart from
anything else, it's only meaningful with StaticGray and TrueColor
visuals.

-- 
Glynn Clements <glynn at gclements.plus.com>