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List:       kde-devel
Subject:    Re: [PATCH] Transparency support and bugfixes
From:       Roberto Alsina <ralsina () unl ! edu ! ar>
Date:       1999-02-22 19:17:25
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On Mon, 22 Feb 1999, Timothy Whitfield wrote:

> Thank you for the correction. I learned something.
> 
> Does anyone know how eterm does it?

As far as I know, it captures the root window when it moves, and puts it 
behind the text.

At least I have not seen screenshots of it showing other windows behind 
itself. This can be easily checked by someone who actually has the beast 
installed :-)

> Timothy
> 
> On Mon, 22 Feb 1999, Jo Dillon wrote:
> 
> > Timothy Whitfield (timothy@datasync.com) spake thusly:
> > 
> > > Why do we need letters? They don't look cool. ;-)
> > > 
> > > Ok we are about to find out exactly how much I don't know about X.
> > > 
> > > <IMHO>
> > > It seems as if we are saying that X uses the reverse-painters algorythm as
> > > far as sending rect updates, only in this case we want to use the painters
> > > algorythm.  So in order to do this we have to use a non-transparent widget
> > > like currently implemented in order for kwmbgnd not to paint over our
> > > letters.
> > > 
> > > But is there any reason why we can't force kwmbknd to update before we do,
> > > by sending a rect update to applications behind the window
> > > with the transparency and then put the letters on?
> > > 
> > > Note: I did not volunteer as I am not even sure whether what I am saying
> > > is possible, or just shows my ignorance about X message processing.
> > >  </IMHO>
> > 
> >   X quite simply doesn't work this way. X has a hierarchical group of
> > windows (so a button is a window inside a top-level app window) and you
> > draw into those windows. If another window is over the top, it doesn't
> > get drawn over. So kwmbknd /cannot/ overwrite what's in the application
> > windows, since it's painting on the root window. It can't happen. No way.
> > (at least, not with normal X commands - you could muck around with
> > XFree's DGA extension or something, but X doesn't really provide the
> > support you'd need).
> > 
> > -- 
> > 	Jo
> > 
> > 
> 
> 

 ("\''/").__..-''"`-. .         Roberto Alsina
 `9_ 9  )   `-. (    ).`-._.`)  ralsina@unl.edu.ar
 (_Y_.)' ._   ) `._`.  " -.-'   Centro de Telematica
  _..`-'_..-_/ /-'_.'           Universidad Nacional del Litoral
(l)-'' ((i).' ((!.'             Santa Fe - Argentina
                                KDE Developer (MFCH)
Life isn't short. It's just that death is longer.

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