Use QTransform more efficiently.

Reviewed-by: Samuel

3 files changed, 15 insertions, 19 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 555f7b0..b2c04ca 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -989,7 +989,8 @@ void QGraphicsItemPrivate::childrenBoundingRectHelper(QTransform *x, QRectF *rec
         bool hasPos = !childd->pos.isNull();
         if (hasPos || childd->transformData) {
             // COMBINE
-            QTransform matrix = childd->transformToParent() * *x;
+            QTransform matrix = childd->transformToParent();
+            matrix *= *x;
             *rect |= matrix.mapRect(child->boundingRect());
             if (!childd->children.isEmpty())
                 childd->childrenBoundingRectHelper(&matrix, rect);
@@ -3204,8 +3205,7 @@ QTransform QGraphicsItem::deviceTransform(const QTransform &viewportTransform) c
     QPointF mappedPoint = (untransformedAncestor->sceneTransform() * viewportTransform).map(QPointF(0, 0));
 
     // COMBINE
-    QTransform matrix;
-    matrix.translate(mappedPoint.x(), mappedPoint.y());
+    QTransform matrix = QTransform::fromTranslate(mappedPoint.x(), mappedPoint.y());
     if (untransformedAncestor->d_ptr->transformData)
         matrix = untransformedAncestor->d_ptr->transformData->computedFullTransform(&matrix);
 
@@ -3303,9 +3303,8 @@ QTransform QGraphicsItem::itemTransform(const QGraphicsItem *other, bool *ok) co
     bool cousins = other != commonAncestor && this != commonAncestor;
     if (cousins) {
         bool good = false;
-        QTransform thisToScene;
-        QTransform otherToScene;
-        thisToScene = itemTransform(commonAncestor, &good);
+        QTransform thisToScene = itemTransform(commonAncestor, &good);
+        QTransform otherToScene(Qt::Uninitialized);
         if (good)
             otherToScene = other->itemTransform(commonAncestor, &good);
         if (!good) {
@@ -4150,8 +4149,7 @@ QRegion QGraphicsItem::boundingRegion(const QTransform &itemToDeviceTransform) c
     p.end();
 
     // Transform QRegion back to device space
-    QTransform unscale;
-    unscale.scale(1 / granularity, 1 / granularity);
+    QTransform unscale = QTransform::fromScale(1 / granularity, 1 / granularity);
     QRegion r;
     QBitmap colorMask = QBitmap::fromImage(mask.createMaskFromColor(0));
     foreach (const QRect &rect, QRegion( colorMask ).rects()) {
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index d9d31ef..4d4c3b4 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -5073,7 +5073,7 @@ void QGraphicsScenePrivate::drawSubtreeRecursive(QGraphicsItem *item, QPainter *
     // Calculate the full transform for this item.
     bool wasDirtyParentSceneTransform = false;
     bool dontDrawItem = true;
-    QTransform transform;
+    QTransform transform(Qt::Uninitialized);
     if (item) {
         if (item->d_ptr->itemIsUntransformable()) {
             transform = item->deviceTransform(viewTransform);
diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index fb1a822..553d71c 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -1940,8 +1940,7 @@ void QGraphicsView::render(QPainter *painter, const QRectF &target, const QRect
     itemList.clear();
 
     // Setup painter matrix.
-    QTransform moveMatrix;
-    moveMatrix.translate(-d->horizontalScroll(), -d->verticalScroll());
+    QTransform moveMatrix = QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
     QTransform painterMatrix = d->matrix * moveMatrix;
     painterMatrix *= QTransform()
                      .translate(targetRect.left(), targetRect.top())
@@ -2292,9 +2291,9 @@ QPolygonF QGraphicsView::mapToScene(const QPolygon &polygon) const
 QPainterPath QGraphicsView::mapToScene(const QPainterPath &path) const
 {
     Q_D(const QGraphicsView);
-    QTransform moveMatrix;
-    moveMatrix.translate(d->horizontalScroll(), d->verticalScroll());
-    return (moveMatrix * d->matrix.inverted()).map(path);
+    QTransform matrix = QTransform::fromTranslate(d->horizontalScroll(), d->verticalScroll());
+    matrix *= d->matrix.inverted();
+    return matrix.map(path);
 }
 
 /*!
@@ -2388,9 +2387,9 @@ QPolygon QGraphicsView::mapFromScene(const QPolygonF &polygon) const
 QPainterPath QGraphicsView::mapFromScene(const QPainterPath &path) const
 {
     Q_D(const QGraphicsView);
-    QTransform moveMatrix;
-    moveMatrix.translate(-d->horizontalScroll(), -d->verticalScroll());
-    return (d->matrix * moveMatrix).map(path);
+    QTransform matrix = d->matrix;
+    matrix *= QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
+    return matrix.map(path);
 }
 
 /*!
@@ -3553,8 +3552,7 @@ QTransform QGraphicsView::transform() const
 QTransform QGraphicsView::viewportTransform() const
 {
     Q_D(const QGraphicsView);
-    QTransform moveMatrix;
-    moveMatrix.translate(-d->horizontalScroll(), -d->verticalScroll());
+    QTransform moveMatrix = QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
     return d->identityMatrix ? moveMatrix : d->matrix * moveMatrix;
 }