Xpra: Ticket #1570: transparent windows

Transparency aka "alpha channel" tracker ticket.

Original tickets and important changesets:

Mon, 10 Jul 2017 06:35:41 GMT - Antoine Martin: status, description changed

Fixes in r16262:

This reverts an earlier changeset: r4934 "transparency does not work on OSX" - as it works with cairo and pixmap, the opengl case may be fixable. If not, we should disable it in the backend - which will save some bandwidth.

Mon, 06 Nov 2017 09:00:02 GMT - Antoine Martin:

Hopefully this can be dealt with as part of #1569.

Sat, 11 Nov 2017 15:16:04 GMT - Antoine Martin:

r17373 enables transparency with GTK3, which works for the cairo backend (with opengl=off).

For opengl, r17375 passes the flag to the glcontext class so it can choose an appropriate visual. Unfortunately, despite using the https://stackoverflow.com/a/4055059), the window remains opaque on win32. See patch attached.

Sat, 11 Nov 2017 15:16:30 GMT - Antoine Martin: attachment set

try to enable transparency with opengl

Sun, 12 Nov 2017 07:17:39 GMT - Antoine Martin:

r17385 uses non-opengl rendering if the window requires transparency, will follow up in #1682 for win32.

macos support is blocked by #1575

Wed, 28 Mar 2018 14:14:47 GMT - Antoine Martin: description changed

r18900 does the same as r17373 on macos: the cairo backend does handle transparency already just fine so let's use it, for opengl: #1794.

Mon, 08 Jul 2019 16:27:08 GMT - Antoine Martin: milestone changed

Sat, 21 Sep 2019 12:16:09 GMT - Antoine Martin: status changed; resolution set

Closing as this is now supported on all platforms, with all the backends, except for win32 + opengl: #1682

Sat, 23 Jan 2021 05:27:59 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1570