Re: Transparent Windows, WindowMaker and [NSWindow backgroundColor]

[David Chisnall]

On 2 Jun 2011, at 20:26, Austin Clow wrote:

> If I install cairo, and set 
> 
> defaults write NSGlobalDomain GSBackend libgnustep-cairo
> 
> will transparent windows 'just work'?

They will 'just work' from a toolkit perspective, but you must be running a 
compositing manager for them to just work from a user perspective.  X11 was 
originally intended to give different programs shared access to a common frame 
buffer.  It doesn't support transparency by default, because windows do not 
draw the parts that are covered.  To make this work, a compositing manager 
redirects windows' drawing off screen (so they draw in their entirety) and then 
composites the result.

As I said originally, GNUstep with the (default) cairo back end will show you 
transparent[1] and translucent windows IF you are running a compositing 
manager.  You should have xcompmgr installed, if you have a complete install of 
X.org.  It will provide you with a simple default compositing manager.

David

[1] You can actually emulate transparent windows with the XSHAPE extension, but 
I don't think GNUstep does.  Translucent windows are more interesting anyway.