When PLASMA_USE_QT_SCALING=1 is set, Plasma uses native Qt scaling. This works fine for integer scale factors, and fixes a lot of bugs (see Bug 356446) but it introduces a new one: with non-integer scale factors, text becomes blurry and pixellated because of a bug in Text.NativeRendering: https://bugreports.qt.io/browse/QTBUG-67007
QQC2-desktop-style forces the use of Text.QtRendering rendering for non-integer scale factors, successfully working around the problem. But PlasmaComponents QML objects don't implement the same workaround, so we see the issue in Plasma. This patch fixes that, and gets us one step closer to being able to use Qt scaling in Plasmashell.
There is no effect when PLASMA_USE_QT_SCALING=1 is not being used.
FIXED-IN 5.13
BUG: 391691
BUG: 384031
CCBUG: 386216
CCBUG: 391695
CCBUG: 391694
CCBUG: 385547
CCBUG: 391692
CCBUG: 356446