I only get VisibilityNotify events at window mapping

[Carsten Haitzler]

On Sat, 17 Sep 2022 11:30:39 -0300 Lucas de Sena <lucas at seninha.org> said:

> Hi,
> 
> I'm trying to get VisibilityNotify events to check whether a given
> window is obscured.
> 
> However, I only get VisibilityNotify events after mapping the window.
> Obscuring it with any other window (be it a sibling or not) does not
> trigger a VisibilityNotify event, nor when I unobscure it.
> 
> And when I get such event, the value of `ev.xvisibility.state` is always
> `VisibilityUnobscured`, even when mapping the window below others.
> 
> Here's a sample program:
> 
> 	#include <stdio.h>
> 	#include <X11/Xlib.h>
> 	
> 	int
> 	main(void)
> 	{
> 		Display *dpy;
> 		Window win;
> 		XEvent ev;
> 	
> 		if ((dpy = XOpenDisplay(NULL)) == NULL)
> 			return 1;
> 		win = XCreateWindow(
> 			dpy,
> 			XDefaultRootWindow(dpy),
> 			0, 0,
> 			100, 100,
> 			0,
> 			CopyFromParent, InputOutput, CopyFromParent,
> 			CWEventMask | CWBackPixel,
> 			&(XSetWindowAttributes){
> 				.event_mask = VisibilityChangeMask,
> 				.background_pixel = BlackPixel(dpy,
> DefaultScreen(dpy)), }
> 		);
> 		XMapWindow(dpy, win);
> 		while (!XNextEvent(dpy, &ev))
> 			if (ev.type == VisibilityNotify)
> 				printf("visibility: %d\n",
> ev.xvisibility.state); return 0;
> 	}
> 
> Is that how VisibilityNotify is supposed to work?

should i assume you're running in a composited environment? (i.e. a compositor
is running redirecting your window rendering to a pixmap)?



-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
Carsten Haitzler - raster at rasterman.com