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>

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();
 
@@ -2714,17 +2717,21 @@ 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);
     }
 
+    if (!isCosmetic)
         matrix = brush.transform() * matrix;
 
     if ((!brush.isOpaque() && brush.style() < Qt::LinearGradientPattern) || opacity != 1.0)

src/opengl/qopenglpaintengine.cpp

@@ -304,6 +304,7 @@ void QOpenGL2PaintEngineExPrivate::updateBrushUniforms()
         return;
 
     QTransform brushQTransform = currentBrush.transform();
+    bool isCosmetic = false;
 
     if (style == Qt::SolidPattern) {
         QColor col = qt_premultiplyColor(currentBrush.color(), (GLfloat)q->state()->opacity);
@@ -320,6 +321,8 @@ void QOpenGL2PaintEngineExPrivate::updateBrushUniforms()
 
             QVector2D halfViewportSize(width*0.5, height*0.5);
             shaderManager->currentProgram()->setUniformValue(location(QOpenGLEngineShaderManager::HalfViewportSize), halfViewportSize);
+
+            isCosmetic = !q->painter()->testRenderHint(QPainter::NonCosmeticBrushPatterns);
         }
         else if (style == Qt::LinearGradientPattern) {
             const QLinearGradient *g = static_cast<const QLinearGradient *>(currentBrush.gradient());
@@ -394,8 +397,12 @@ void QOpenGL2PaintEngineExPrivate::updateBrushUniforms()
             qWarning("QOpenGL2PaintEngineEx: Unimplemented fill style");
 
         const QPointF &brushOrigin = q->state()->brushOrigin;
-        QTransform matrix = q->state()->matrix;
+        QTransform matrix;
+        if (!isCosmetic)
+            matrix = q->state()->matrix;
         matrix.translate(brushOrigin.x(), brushOrigin.y());
+        if (!isCosmetic)
+            matrix = brushQTransform * matrix;
 
         QTransform translate(1, 0, 0, 1, -translationPoint.x(), -translationPoint.y());
         qreal m22 = -1;
@@ -405,7 +412,7 @@ void QOpenGL2PaintEngineExPrivate::updateBrushUniforms()
             dy = 0;
         }
         QTransform gl_to_qt(1, 0, 0, m22, 0, dy);
-        QTransform inv_matrix = gl_to_qt * (brushQTransform * matrix).inverted() * translate;
+        QTransform inv_matrix = gl_to_qt * matrix.inverted() * translate;
 
         shaderManager->currentProgram()->setUniformValue(location(QOpenGLEngineShaderManager::BrushTransform), inv_matrix);
         shaderManager->currentProgram()->setUniformValue(location(QOpenGLEngineShaderManager::BrushTexture), QT_BRUSH_TEXTURE_UNIT);
@@ -818,8 +825,11 @@ void QOpenGL2PaintEngineExPrivate::fill(const QVectorPath& path)
     }
 
     // Might need to call updateMatrix to re-calculate inverseScale
-    if (matrixDirty)
+    if (matrixDirty) {
         updateMatrix();
+        if (currentBrush.style() > Qt::SolidPattern)
+            brushUniformsDirty = true;
+    }
 
     const bool supportsElementIndexUint = funcs.hasOpenGLExtension(QOpenGLExtensions::ElementIndexUint);
 
@@ -1419,7 +1429,12 @@ void QOpenGL2PaintEngineExPrivate::stroke(const QVectorPath &path, const QPen &p
 
 void QOpenGL2PaintEngineEx::penChanged() { }
 void QOpenGL2PaintEngineEx::brushChanged() { }
-void QOpenGL2PaintEngineEx::brushOriginChanged() { }
+
+void QOpenGL2PaintEngineEx::brushOriginChanged()
+{
+    Q_D(QOpenGL2PaintEngineEx);
+    d->brushUniformsDirty = true;
+}
 
 void QOpenGL2PaintEngineEx::opacityChanged()
 {
@@ -1462,7 +1477,7 @@ void QOpenGL2PaintEngineEx::renderHintsChanged()
     d->lastTextureUsed = GLuint(-1);
 
     d->brushTextureDirty = true;
-//    qDebug("QOpenGL2PaintEngineEx::renderHintsChanged() not implemented!");
+    d->brushUniformsDirty = true;
 }
 
 void QOpenGL2PaintEngineEx::transformChanged()

tests/baseline/painting/scripts/pattern_xform.qps

@@ -9,13 +9,14 @@ setBrush green Dense4Pattern
 drawRect 0 0 40 40
 setBrush green DiagCrossPattern
 drawRect 40 0 40 40
-setBrush green VerPattern
+setBrush green HorPattern
 brushRotate 30
 drawRect 80 0 40 40
+fillRect 120 0 40 40
 save
 setPen brush 40 SolidLine FlatCap
 setBrush NoBrush
-drawLine 120 20 160 20
+drawLine 160 20 200 20
 restore
 end_block
 restore

tests/baseline/painting/scripts/pattern_xform2.qps

@@ -0,0 +1,81 @@
+# Version: 1
+# CheckVsReference: 5%
+
+# 1: Check brush origin vs (non)cosmetic brush patterns
+
+setBrush blue CrossPattern
+begin_block blockName
+save
+setBrushOrigin 0 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 1 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 2 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 3 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 4 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 5 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 6 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 7 0
+fillRect 0 0 32 32
+translate 0 32
+setBrushOrigin 8 0
+fillRect 0 0 32 32
+restore
+end_block blockName
+
+save
+setBrush red CrossPattern
+scale 2 1
+repeat_block blockName
+restore
+
+save
+translate 0 300
+setRenderHint NonCosmeticBrushPatterns true
+setBrush blue CrossPattern
+repeat_block blockName
+setBrush red CrossPattern
+scale 2 1
+repeat_block blockName
+restore
+
+# 2: Check brush update after only xform or hint change
+translate 100 0
+
+save
+setPen NoPen
+setBrush blue DiagCrossPattern
+setRenderHint NonCosmeticBrushPatterns true
+drawRect 10 10 200 100
+scale 10 10
+drawRect 22 1 20 10
+drawRect 22 12 20 10
+setRenderHint NonCosmeticBrushPatterns false
+drawRect 1 12 20 10
+restore
+
+setBrush green DiagCrossPattern
+setPen brush 100 SolidLine FlatCap
+pen_setCosmetic true
+setBrush NoBrush
+translate 0 250
+setRenderHint NonCosmeticBrushPatterns true
+drawLine 10 60 210 60
+scale 10 10
+drawLine 22 6 42 6
+drawLine 22 17 42 17
+setRenderHint NonCosmeticBrushPatterns false
+drawLine 1 17 21 17
+

tests/manual/lance/main.cpp

@@ -191,6 +191,7 @@ int main(int argc, char **argv)
 
     DeviceType type = WidgetType;
     QSurfaceFormat contextFormat;
+    contextFormat.setStencilBufferSize(8);
     bool checkers_background = true;
 
     QImage::Format imageFormat = QImage::Format_ARGB32_Premultiplied;