Xpra: Ticket #1570: transparent windows

Transparency aka "alpha channel" tracker ticket.

Original tickets and important changesets:

#77 tray icons
#262 disappearing tooltips
#279 32-bit visuals and transparent windows
#280 Systray icon transparency broken
#385 opengl transparency (and more)
#487 webp artifacts with transparency
#500 small tooltip windows have transparency issues
#577 detect lack of transparency support and disable it to save bandwidth
#892 transparency forwarding is broken
#961 transparency support is broken with pixmap backing
#1145 pixbuf backend does not support transparency with desktop scaling enabled
#1682 transparency with the native opengl backend on win32
#1794 transparency with the native opengl backend on macos

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

status changed from new to assigned
description modified (diff)

Fixes in r16262:

skip compositing check with opengl backend on macos (though transparency still doesn't work..)
enable transparency by default on macos as this seems to work with both cairo and pixmap backends
remove override in pixmap backing, use the superclass default (ie: enabled on macos)
add better error logging when initializing / enabling transparency, especially failures

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

attachment set to win32-opengl-alpha.patch

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

description modified (diff)

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

milestone changed from 3.0 to 4.0

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

status changed from assigned to closed
resolution set to fixed

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