Re: Transparent Windows, WindowMaker and [NSWindow backgroundColor]

[Austin Clow]

I can't seem to get the transparency to happen. 

I installed cairo, and xcompmgr, rebuilt the latest back, and then set defaults write NSGlobalDomain GSBackend libgnustep-cairo

The application launches fine, and I do notice some *better* drawing, and a few things that draw strangely (I'll report them when I figure out what is going on), but setting the window's backgroundColor with an alpha value (0.5 or otherwise) the window does not become transparent. 

I will try the [NSWindow setAlpha:] that was mentioned by Fred, but on a Mac this makes the window as well as its content transparent, so perhaps this is different on  GNUstep? We'll see. 

If there is anything hat I might be missing, please let me know. 

- Austin

On Jun 2, 2011, at 2:31 PM, Fred Kiefer wrote:

On 02.06.2011 20:55, David Chisnall wrote:

On 2 Jun 2011, at 19:44, Austin Clow wrote:

Are transparent windows supported in WindowMaker?

Wrong question.  WindowMaker is a window manager, it has nothing to do with whether transparent windows work, it just controls their positioning and their decorations.

Transparent windows are supported in X11 by a combination of the composite and render extensions.  Applications draw RGBA windows, which are directed off screen.  A compositing manager then draws them onto the display.  GNUstep will draw RGBA windows (with the Cairo back end definitely, I think with libart, and I think not with xlib), but for these to be transparent / translucent you must be running a compositing manager.  X.org comes with a simple compositing manager, xcompmgr, which should work (it can also draw shadows, but little else).  Alternatively, you can run a more complex one, like Compiz, which adds other effects.

You may have to set the alpha value of the window as well. But I haven't tested that feature recently. When we added support to RGBA windows in the cairo backend this was needed.