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, 20 insertions, 5 deletions

diff --git a/src/opengl/qopenglpaintengine.cpp b/src/opengl/qopenglpaintengine.cpp
index 01241f19f0..1d9afc5191 100644
--- a/src/opengl/qopenglpaintengine.cpp
+++ b/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()