2 files changed, 44 insertions, 5 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 6622e55..18d39c5 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -597,19 +597,28 @@ void QGL2PaintEngineExPrivate::updateMatrix()
 
     const GLfloat wfactor = 2.0f / width;
     const GLfloat hfactor = -2.0f / height;
+    GLfloat dx = transform.dx();
+    GLfloat dy = transform.dy();
+
+    // Non-integer translates can have strange effects for some rendering operations such as
+    // anti-aliased text rendering. In such cases, we snap the translate to the pixel grid.
+    if (snapToPixelGrid && transform.type() == QTransform::TxTranslate) {
+        // 0.50 needs to rounded down to 0.0 for consistency with raster engine:
+        dx = ceilf(dx - 0.5f);
+        dy = ceilf(dy - 0.5f);
+    }
 
     if (addOffset) {
-        pmvMatrix[2][0] = (wfactor * (transform.dx() + 0.49f)) - transform.m33();
-        pmvMatrix[2][1] = (hfactor * (transform.dy() + 0.49f)) + transform.m33();
-    } else {
-        pmvMatrix[2][0] = (wfactor * transform.dx()) - transform.m33();
-        pmvMatrix[2][1] = (hfactor * transform.dy()) + transform.m33();
+        dx += 0.49f;
+        dy += 0.49f;
     }
 
     pmvMatrix[0][0] = (wfactor * transform.m11())  - transform.m13();
     pmvMatrix[1][0] = (wfactor * transform.m21())  - transform.m23();
+    pmvMatrix[2][0] = (wfactor * dx) - transform.m33();
     pmvMatrix[0][1] = (hfactor * transform.m12())  + transform.m13();
     pmvMatrix[1][1] = (hfactor * transform.m22())  + transform.m23();
+    pmvMatrix[2][1] = (hfactor * dy) + transform.m33();
     pmvMatrix[0][2] = transform.m13();
     pmvMatrix[1][2] = transform.m23();
     pmvMatrix[2][2] = transform.m33();
@@ -707,6 +716,11 @@ void QGL2PaintEngineExPrivate::drawTexture(const QGLRect& dest, const QGLRect& s
         matrixDirty = true;
     }
 
+    if (snapToPixelGrid) {
+        snapToPixelGrid = false;
+        matrixDirty = true;
+    }
+
     if (prepareForDraw(opaque))
         shaderManager->currentProgram()->setUniformValue(location(QGLEngineShaderManager::ImageTexture), QT_IMAGE_TEXTURE_UNIT);
 
@@ -874,6 +888,11 @@ void QGL2PaintEngineExPrivate::fill(const QVectorPath& path)
         matrixDirty = true;
     }
 
+    if (snapToPixelGrid) {
+        snapToPixelGrid = false;
+        matrixDirty = true;
+    }
+
     // Might need to call updateMatrix to re-calculate inverseScale
     if (matrixDirty)
         updateMatrix();
@@ -1278,6 +1297,11 @@ void QGL2PaintEngineExPrivate::stroke(const QVectorPath &path, const QPen &pen)
         matrixDirty = true;
     }
 
+    if (snapToPixelGrid) {
+        snapToPixelGrid = false;
+        matrixDirty = true;
+    }
+
     const Qt::PenStyle penStyle = qpen_style(pen);
     const QBrush &penBrush = qpen_brush(pen);
     const bool opaque = penBrush.isOpaque() && s->opacity > 0.99;
@@ -1551,6 +1575,10 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(const QPointF &p, QFontEngineGly
         addOffset = false;
         matrixDirty = true;
     }
+    if (!snapToPixelGrid) {
+        snapToPixelGrid = true;
+        matrixDirty = true;
+    }
 
     QBrush pensBrush = q->state()->pen.brush();
     setBrush(pensBrush);
@@ -1669,6 +1697,11 @@ void QGL2PaintEngineExPrivate::drawPixmaps(const QDrawPixmaps::Data *drawingData
         matrixDirty = true;
     }
 
+    if (snapToPixelGrid) {
+        snapToPixelGrid = false;
+        matrixDirty = true;
+    }
+
     bool allOpaque = true;
 
     for (int i = 0; i < dataCount; ++i) {
@@ -1949,6 +1982,10 @@ void QGL2PaintEngineExPrivate::writeClip(const QVectorPath &path, uint value)
         addOffset = false;
         matrixDirty = true;
     }
+    if (snapToPixelGrid) {
+        snapToPixelGrid = false;
+        matrixDirty = true;
+    }
 
     if (matrixDirty)
         updateMatrix();
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
index 8562678..5ba1d31 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
@@ -167,6 +167,7 @@ public:
             width(0), height(0),
             ctx(0),
             useSystemClip(true),
+            snapToPixelGrid(false),
             addOffset(false),
             inverseScale(1)
     { }
@@ -260,6 +261,7 @@ public:
     GLfloat staticVertexCoordinateArray[8];
     GLfloat staticTextureCoordinateArray[8];
 
+    bool snapToPixelGrid;
     bool addOffset; // When enabled, adds a 0.49,0.49 offset to matrix in updateMatrix
     GLfloat pmvMatrix[3][3];
     GLfloat inverseScale;