回复： 回复： 回复： transparent background of XLib window

[Thomas Lübking]

On Mittwoch, 16. April 2014 05:26:57 CEST, LIDE wrote:
> Now, I can run xcompmgr without any effect. Here is my 32bit window exapmle:

The code is ok (you forgot "XFree(gc);"), but it's not checked whether a matching visual was found.
XMatchVisualInfo returns a http://tronche.com/gui/x/xlib/introduction/errors.html#Status

if (!XMatchVisualInfo(display, DefaultScreen(display), 32, TrueColor, &vinfo)) {
    printf("Something's fishy here!");
    return 1;
}


> But the background is still black? Does xcompmgr need any settings? 

A black window would be the expected result w/o compositing.
xcompmgr does not require further switches, but the server needs the COMPOSITE and DAMAGE extensions loaded ("xdpyinfo | grep -iA40 extensions").

Iirc you should get warnings if xcompmgr fails for any reason.

Cheers,
Thomas