Composit manager question

Soeren Sandmann sandmann at
Sat Aug 12 08:15:59 EEST 2006

"Oleg Sukhodolsky" <son.two at> writes:

> EWMH defines a _NET_WM_WINDOW_OPACITY hint to tell a composite manager to make
> the window translucent.

No it doesn't, and it would be a mistake to add it in my opinion. 

> Modern application require an alpha-mask to be set to make some
> areas of the window fully transparent, others to be semi-transparent
> and the rest to be fully opaque.  So the questions: 1. Is or will be
> there a standard way to set the opacity-mask by means of a hint?
> 2. If there's no a composite manager running, or the composite
> manager doesn't support the feature (like old and sweet xcompmgr :)
> ), what is the right way to set such a mask?

As Daniel said, the answer is to use an ARGB32 visual, which means
requesting that the pixels in the window are 32 bits deep, with 8 of
those bit being interpreted as an alpha value. Hence the name
"ARGB32". Alpha, Red, Green, Blue - 32 bits.


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