intercept all keys before the desktop

[totaam]

From this mailing list discussion: https://xpra.org/list/2016-March/001497.html, it would be nice if we could catch the special keys like the windows key and forward them to the server.

The Virtual-Key Codes shows VK_LWIN as 0x5B and VK_RWIN as 0x5c.

Looks like we will need SetWindowsHookEx as per this answer: Python and SetWindowsHookExA.
Alternatively we could use pyhook or pyhk. (meh)

This is for win32, not sure what we can do for X11 without grabbing the keyboard..

[totaam]

Mostly done in r12226, still TODO:

• send the key event to the server (Super_L and Super_R?)
• maybe generalize the code so we can catch AltGr and have a better workaround? (altgr workaround causes spurious ctrl key events to be sent #1119)
• make it an option (some users may not want their windows key intercepted), and maybe a tray option for it too

[totaam]

• r12228 sends the key event to the server (and should deal with most modifier keys - but not all, this will have to do)
• r12229 makes this behaviour off by default, enable it with the env var: XPRA_FORWARD_WINDOWS_KEY=1 (I don't have time to make a command line option and do all the man page updates that go with it)

Tested using xev to see the Super_R event server side, I cannot test with the left hand side windows key because my virtualbox VM does not pass it through to the guest.

@afarr: mostly a FYI, I don't think you want to capture the windows key in your setup. New beta build uploaded. Feel free to test or just close it.

[totaam]

@johnss1221: there are windows beta builds including this change - does this work for you? (see comment:2 for enabling it)

[totaam]

Not heard back, so I'll assume that this works as expected.

@afarr: feel free to test or just close.

[totaam]

Tried to test a little, but I'm not sure what windows keyboard commands I can expect a fedora server to know what to do with.

Maybe maxmylyn will test with a shadow server... in any case though, I'll close this.

[totaam]

This is now enabled by default when grabs are active, see #1195#comment:1