Fix drawTiledPixmap() and texture-brush painting with high-DPR images

Although QPainter::drawImage()/drawPixmap() would render images scaled
according to their devicePixelRatio(), that would not happen for
drawTiledPixmap() and when using a textured brush. Implemented here,
in combination with the pending "High-dpi drawTiledPixmap (raster
paint engine)" commit.

[ChangeLog][QtGui] Fix drawTiledPixmap() and texture-brush painting with high-DPR images

Task-number: QTBUG-67248
Change-Id: I037e3f897fa708038a0222d3b0c61c7842d87961
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

3 files changed, 17 insertions, 0 deletions

diff --git a/src/gui/painting/qemulationpaintengine.cpp b/src/gui/painting/qemulationpaintengine.cpp
index e6686e3721..49ecd3b318 100644
--- a/src/gui/painting/qemulationpaintengine.cpp
+++ b/src/gui/painting/qemulationpaintengine.cpp
@@ -101,6 +101,14 @@ void QEmulationPaintEngine::fill(const QVectorPath &path, const QBrush &brush)
             real_engine->fill(path, copy);
             return;
         }
+    } else if (style == Qt::TexturePattern) {
+        qreal dpr = qHasPixmapTexture(brush) ? brush.texture().devicePixelRatioF() : brush.textureImage().devicePixelRatioF();
+        if (!qFuzzyCompare(dpr, 1.0)) {
+            QBrush copy = brush;
+            combineXForm(&copy, QRectF(0, 0, 1.0/dpr, 1.0/dpr));
+            real_engine->fill(path, copy);
+            return;
+        }
     }
 
     real_engine->fill(path, brush);
diff --git a/src/gui/painting/qpaintengineex.cpp b/src/gui/painting/qpaintengineex.cpp
index 0643a7cbb6..9f07af92e4 100644
--- a/src/gui/painting/qpaintengineex.cpp
+++ b/src/gui/painting/qpaintengineex.cpp
@@ -948,6 +948,8 @@ void QPaintEngineEx::drawTiledPixmap(const QRectF &r, const QPixmap &pixmap, con
 {
     QBrush brush(state()->pen.color(), pixmap);
     QTransform xform = QTransform::fromTranslate(r.x() - s.x(), r.y() - s.y());
+    if (!qFuzzyCompare(pixmap.devicePixelRatioF(), 1.0))
+        xform.scale(1.0/pixmap.devicePixelRatioF(), 1.0/pixmap.devicePixelRatioF());
     brush.setTransform(xform);
 
     qreal pts[] = { r.x(), r.y(),
diff --git a/src/gui/painting/qpainter.cpp b/src/gui/painting/qpainter.cpp
index b992e8f55d..a0a58cc157 100644
--- a/src/gui/painting/qpainter.cpp
+++ b/src/gui/painting/qpainter.cpp
@@ -190,6 +190,13 @@ void QPainterPrivate::checkEmulation()
     if (pg && pg->coordinateMode() > QGradient::LogicalMode)
         doEmulation = true;
 
+    if (state->brush.style() == Qt::TexturePattern) {
+        if (qHasPixmapTexture(state->brush))
+            doEmulation |= !qFuzzyCompare(state->brush.texture().devicePixelRatioF(), 1.0);
+        else
+            doEmulation |= !qFuzzyCompare(state->brush.textureImage().devicePixelRatioF(), 1.0);
+    }
+
     if (doEmulation && extended->flags() & QPaintEngineEx::DoNotEmulate)
         return;