In ec27b99c2a the filtering mode is
changed from Linear to Nearest since users encountered obscure cases,
in particular when multisampling with large sample counts got enabled,
where the different filtering mode becomes noticeable. (Qt 5 and Qt 6
up until 6.4 uses Nearest, whereas the OpenGL -> QRhi migration
introduced using Linear in 6.4)
Meanwhile, the as of now undocumented high DPI downscaling feature
got introduced, and that prefers linear filtering. (since that's
definitely not a 1:1 mapping when it comes to texture size and the
on-screen quad) To reconcile the differences, add support for both
kind of samplers, and choose based on the sizes.
This should have no effect when not running with the env.var.
QT_WIDGETS_RHI=1 QT_WIDGETS_HIGHDPI_DOWNSCALE=1 set, but should
restore the pre-6.5.2 look when they are set.
Pick-to: 6.6 6.5
Fixes: QTBUG-115461
Change-Id: I42eb8526cb7f74236b5550e26c4570771d2fbfb4
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
9505305c40