Re: Multiple GdkScreens?

[Havoc Pennington <hp redhat com>]

Hi,

Pascal Schoenhardt wrote:
> As far as I know, the number
> of screens in X is hard coded to 1, and always will be (hence
> xinerama, and now RandR 1.2).

It isn't hardcoded to 1 in X, there can be multiple.

There's no real reason to have multiple and few people do it anymore, 
but in the days before Xinerama people used to do multiple monitors by 
having multiple screens. There are probably still people running various 
kinds of legacy apps or hardware that use multiple screens.

> Are there other platforms on which Gdk may have more than one screen?
> Or if multiple X servers are running, with multiple copies of Gnome,
> do they still share the same gdk?

Multiple X servers would show up as multiple GdkDisplay.

The way to think of a screen is that it's a root window (a window with 
no parent). Xinerama spreads a root window across multiple monitors, but 
with multiple screens you have multiple root windows.

Back in the day one reason for multiple screens was to use a different 
visual (color depth, etc.) on each screen. Since each window has a fixed 
visual, if you have two root windows one could be say 256-color for 
email and stuff, and one could be your 3D graphics.

Nowadays almost nobody cares what the visual is, they just always use a 
24-bit color depth for everything.

Havoc