[Gllug] Screen capture [again ;)]

[Tom Gilbert]

* ChrisJS at aol.com (ChrisJS at aol.com) wrote:
> In a message dated 30/07/2001 08:01:01 GMT Daylight Time, tom at linuxbrit.co.uk 
> writes:
> 
> > You couldn't do that at a window manager level - window managers are
> >  simply meant to draw borders around windows and have very little to do
> >  with them actually being drawn. No, if you wanted a 3D environment you'd
> >  have to do this at the X level, intercepting applications' operations on
> >  pixmaps and displaying them in a different way.
> >  
> >  Tom.
> 
> Damn... Thanks. I think I'll have to think it out again, as old Fagin would 
> doubtless say... You don't think it would be possible to work around it, 
> doing something like drawing the apps outside the visible area, reading the 
> relevant section of the display and then drawing what I wanted on the visible 
> bit ?

Horrendous performance-wise and X doesn't support what you need. It only
draws stuff that's visible, if you place a window outside the visible
area, X (quite rightly) won't render it. Even if it did, you'd have to
grab and copy the area you wanted to do stuff with and that would be so
slow and awful I can't even think about it :)

No, you actually have to intercept window draws, probably best done by
giving the app pseudo-pixmaps to draw on that you do something different
with yourself.

But good luck calculating which expose events to send to an application
based on where it's window is in 3D space :) It's hard enough in 2D.

Tom.
-- 
   .^.    .-------------------------------------------------------.
   /V\    | Tom Gilbert, London, England | http://linuxbrit.co.uk |
 /(   )\  | Open Source/UNIX consultant  | tom at linuxbrit.co.uk    |
  ^^-^^   `-------------------------------------------------------'

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