Follow up from #1206.
Instead of starting Xephyr nested in a mostly unused Xvfb display, we should be able to start the Xvfb and watch the root window directly for damage events.
This should work without having to enable the Composite extension, without redirecting any windows, which would be more compatible with some rendering mechanisms which are not currently supported, notably some multi display native graphics card modes. We would not need to run as window manager on the vfb display at all, simplifying the code greatly (no need for focus management, etc - just direct mouse and keyboard events).
poc patch showing the root window as a managed window
much better approach using a dedicated model and server class
Some preparatory refactoring which also helps in more clearly separating the gtk code and pure x11 code: r12970 (cursor, clobber flag), r12971 (windows vs cursors), r12973 (bell, motion, cursors).
Things left to do:
More preparatory work in r12974 (randr cleanup), r12975 + r12976 (mouse pointer adjustments: re-use shadow code), r12977 (window model class refactoring), r12978 (split damage from composite), r12979 (fix undedirect), r12980 (logging tweak), r12982 (unnecessary import fixup)
Full "start-desktop" support added in r12981 + r12983, see commit message for details.
Turns out that the corrupted window with resizing may well be an Intel opengl issue (#1233), and it should work well enough as of r12986, will need to re-test on non-intel chipsets.
For reference, here's how you can easily start a non-composited vfb:
xpra start-desktop \ --xvfb='Xvfb -extension Composite -nolisten tcp -noreset -auth $XAUTHORITY -screen 0 1920x1080x24+32'
Another option is to use an existing display server with
xpra start-desktop --use-display.
This mode may be useful for adding support for deep colour modes (#909).
Some minor updates:
xpra start-desktop :20 --start=xterm \ --xvfb='Xvfb -extension Composite -nolisten tcp -noreset -auth $XAUTHORITY \ -screen 0 1920x1080x24+32 \ -screen 1 1920x1080x24+32'
Unfortunately, there is an Xorg bug which sends all events to the first screen: XTestFakeMotionEvent no longer works on multiple screen displays
@afarr: just a FYI, please close.
Noted... to the best of my ability.
Added wiki page: wiki/Desktop.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1247