Add painter render hint for brush pattern transformation

[ChangeLog][QtGui][QPainter] In Qt 5, the predefined brush patterns
would always be transformed along with the object being painted. In Qt
6.0 onwards, they would or would not, depending on the
SmoothPixmapTransformation render hint. Instead of this somewhat
surprising behavior, make the default be untransformed
(i.e. cosmetic), which makes sense when it comes to dpr scaling. For
the cases where one wants scaling, a new render hint is introduced to
enable that: NonCosmeticPatternBrushes.

Change-Id: I2208c7a28af9056d7ab97a529b66bf2d502c3c4f
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gui/painting/qpainter.cpp b/src/gui/painting/qpainter.cpp
index a38d42c504..6995f7d180 100644
--- a/src/gui/painting/qpainter.cpp
+++ b/src/gui/painting/qpainter.cpp
@@ -1412,6 +1412,12 @@ void QPainterPrivate::updateState(QPainterState *newState)
     JPEG compression.
     This value was added in Qt 5.13.
 
+    \value NonCosmeticBrushPatterns When painting with a brush with one of the predefined pattern
+    styles, transform the pattern too, along with the object being painted. The default is to treat
+    the pattern as cosmetic, so that the pattern pixels will map directly to device pixels,
+    independently of any active transformations.
+    This value was added in Qt 6.4.
+
     \sa renderHints(), setRenderHint(), {QPainter#Rendering
     Quality}{Rendering Quality}, {Concentric Circles Example}