[mythtv-commits] [MythTV/mythtv] e537ea: Wayland: Fix alpha blending

[Mark Kendall]

  Branch: refs/heads/fixes/31
  Home:   https://github.com/MythTV/mythtv
  Commit: e537ea801af3a1d69c6fd0dbf8060ff22ba34cf2
      https://github.com/MythTV/mythtv/commit/e537ea801af3a1d69c6fd0dbf8060ff22ba34cf2
  Author: Mark Kendall <mark.kendall at gmail.com>
  Date:   2020-08-03 (Mon, 03 Aug 2020)

  Changed paths:
    M mythtv/libs/libmythui/mythdisplay.cpp

  Log Message:
  -----------
  Wayland: Fix alpha blending

- each window in wayland has its own buffer/texture and these are always
composited with alpha blending
- as a result any alpha blended areas of our UI will allow the
underlying window to be visible if the window/surface buffer has a
buffer with alpha
- usually the default surface format does not request a buffer with
alpha but when wayland decorations are enabled, Qt overrides the alpha
depth
- so as a workaround, disable Qt wayland decorations, which we don't
need anyway
- note - this may not be the best solution. Using
wl_surface_set_opaque_region on our surface would allow the compositor
to optimise rendering as it knows it does not need to show anything
hidden by the window. In testing this works but requires linking to
libwayland-client and including Qt private headers (which is far from
ideal)

- Fixes #13483

(cherry picked from commit b6e7e18a4c209a0dd246c4624db918af0d5152ff)