Support cosmetic brush patterns in the pdf and opengl paint engines

This implements the recent functionality extension of painting
cosmetic (untransformed) brush patterns, and the corresponding
NonCosmeticBrushPatterns render hint, in the pdf and opengl paint
engines.

As part of the implementation it also fixes a couple of pre-existing
bugs in the opengl engine, relating to updating the brush after
changes in transformation or brush origin.

As a driveby, it also includes a minor fix for the lance testing tool:
request stencil buffer, as that is needed and not always provided by
default. This echoes a recent fix done to tst_baseline_painting.

Change-Id: Ia8811477e015eebeb40ed138bca96643ce1ab0dc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 11 insertions, 4 deletions

diff --git a/src/gui/painting/qpdf.cpp b/src/gui/painting/qpdf.cpp
index ddfec47c6f..cfb9481ab3 100644
--- a/src/gui/painting/qpdf.cpp
+++ b/src/gui/painting/qpdf.cpp
@@ -1081,6 +1081,9 @@ void QPdfEngine::updateState(const QPaintEngineState &state)
 
     QPaintEngine::DirtyFlags flags = state.state();
 
+    if (flags & DirtyHints)
+        flags |= DirtyBrush;
+
     if (flags & DirtyTransform)
         d->stroker.matrix = state.transform();
 
@@ -2714,18 +2717,22 @@ int QPdfEnginePrivate::addBrushPattern(const QTransform &m, bool *specifyColor,
     *specifyColor = true;
     *gStateObject = 0;
 
-    QTransform matrix = m;
+    const Qt::BrushStyle style = brush.style();
+    const bool isCosmetic = style >= Qt::Dense1Pattern && style <= Qt::DiagCrossPattern
+                            && !q->painter()->testRenderHint(QPainter::NonCosmeticBrushPatterns);
+    QTransform matrix;
+    if (!isCosmetic)
+        matrix = m;
     matrix.translate(brushOrigin.x(), brushOrigin.y());
     matrix = matrix * pageMatrix();
-    //qDebug() << brushOrigin << matrix;
 
-    Qt::BrushStyle style = brush.style();
     if (style == Qt::LinearGradientPattern || style == Qt::RadialGradientPattern) {// && style <= Qt::ConicalGradientPattern) {
         *specifyColor = false;
         return gradientBrush(brush, matrix, gStateObject);
     }
 
-    matrix = brush.transform() * matrix;
+    if (!isCosmetic)
+        matrix = brush.transform() * matrix;
 
     if ((!brush.isOpaque() && brush.style() < Qt::LinearGradientPattern) || opacity != 1.0)
         *gStateObject = addConstantAlphaObject(qRound(brush.color().alpha() * opacity),