On Sat, 20 Oct 2001 16:40:20 +0800 Maxim Koshelev <[EMAIL PROTECTED]> babbled
profusely:

> Carsten Haitzler (The Rasterman) wrote:
> 
> >you can't always do both. and you want 8bits for alpha.. not 24 :). xrender
> is
> >
> Why can't? Explain deeply please. 8 bits per color for alpha mask is 24 
> bits for full color RGB.
> Of course if we want to realize limited alpha mask we can do 8 bits for 
> one pixel without
> partitioning on RedAlpha, GreenAlpha and BlueAlpha. (of course one can 
> change
> image on window to achieve the same result but we need powerfull api)

err. we only need 1 alpha value - not one per red, gree and blue. ? what are you
talking about here? u need r,g and b info and then alpha for the pixel. only 1
alpha value per pixel.

> >alreayd done.. also u dont always want 8bits per color. there is a lot of
> >hardware that will only do 4 bits per channel.
> >
> Already done?! and alpha masks for windows?! I need to update my sources 
> of Xfree86 to play with it....

no - but multiple depth pixmap support is.

> I repeat again: this is only API call. You can change 24 bits to 8bit or 
> any number of bits in the render's core.
> For first release we can just write in docs: "Limited support, 
> translated into 8 bit depth"
> 
> >anyway... 1 call - fine.. "set the mask to hispixmap).. what if i change some
> >parts of the pixmap and want to update only those bits of the window mask?
> i'd
> >need to now be abel to set a pixmap as a portion of the mask of a window. now
> >our call has more parameters... i can go on... the more powerful.. the more
> >complex.
> >
> Ok add  more parameters  :-) e.g:
> 
> XWindowSetAlphaMask(Window,void *maskdata,x,y,width,height,mode);
> where x,y point to pixel of Window where left upper corner of the mask
> will be placed :)
> mode is a mode of joining with previous setted mask 
> (ALPHA_MASK_OR,_XOR,_REPLACE etc)
> If window has no alpha mask is set then assumed that it have non 
> transparent mask :-) (pointer to alpha mask is NULL for default windows)

yes. but the more powerful.. the more complex the api call becomes.. or u start
needing multilple api calls. i the end programmers will figure it out - if you
can't figure it out - you shoudlnt be playing with code at this level and so
wait for a higher level api/widget set ect. to wrap it for you.

> >32bits for an alpha mask is just overkill and a waste of bandwidth.
> >
> ok, ok 24 bits :-)
> 
> >theres nothing wrong with adding system calls to expand the functionality as
> the
> >need grows. u cannot design an api that will forever not change ANd have it
> be
> >sane to impliment and efficient. the solution is to come up with a clean api
> >that can be extended over time - and we have that.
> >
> But we can try to do such API :-)
> 
> 
> 
> 
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-- 
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