60542da091
"Set" the wallpaper during startup only sometimes Since commit 4f5e0e7, i3 would take a screenshot and set that as the background pixmap of the root window during startup. This is the easy part of setting a proper X11 wallpaper. The code in question was added because something either set the background pixmap of the root window to NONE or the X11 server was started with "-background none". This is apparently done by default by e.g. gdm to avoid some flickering while the X11 server starts up. This commit makes this code conditional: Only when no wallpaper is detected is a screenshot taken. Since I could not find any way to query the background of a window, a more direct approach is taken to detect this situation: First, we find some part of the root window that is not currently covered. Then we open a white window there, close it again and grab a screenshot. If a wallpaper is set, the X11 server will draw this wallpaper after the window is closed and something else will be visible in the screenshot. However, the wallpaper could have a white pixel at the tested position. Thus, this procedure is repeated with a black window. Only when this procedure produces two different pixel values is a screenshot taken and set as the wallpaper. Fixes: https://github.com/i3/i3/issues/4371 Fixes: https://github.com/i3/i3/issues/2869 Signed-off-by: Uli Schlachter <psychon@znc.in>
i3: A tiling window manager
i3 is a tiling window manager for X11.
For more information about i3, please see the project's website and online documentation.
For information about contributing to i3, please see CONTRIBUTING.md.