Fix QGraphicsItem::deviceTransform() to also work with normal items.

QGraphicsItem::deviceTransform() returns the item-to-device transform,
provided with the device-to-scene transform, and combining it with the
item's scene transform. This function is meant to handle items that
enable ItemIgnoresTransformations, but it happened to not work properly
for items that _don't_ enable that flag. Unfortunately this bug is
hard to work around for users from the outside, as it requires you to
check if the item or any ancestor enables ItemIgnoresTransformations.

The fix also removes unnecessary branchs inside QGV so that we use the
same function for all items.

Reviewed-by: bnilsen

1 files changed, 110 insertions, 0 deletions

diff --git a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
index 6d150cb..58a17ea 100644
--- a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -215,6 +215,8 @@ private slots:
     void tabChangesFocus_data();
     void cacheMode();
     void updateCachedItemAfterMove();
+    void deviceTransform_data();
+    void deviceTransform();
 
     // task specific tests below me
     void task141694_textItemEnsureVisible();
@@ -6200,5 +6202,113 @@ void tst_QGraphicsItem::updateCachedItemAfterMove()
     QCOMPARE(tester->repaints, 1);
 }
 
+class Track : public QGraphicsRectItem
+{
+public:
+    Track(const QRectF &rect)
+        : QGraphicsRectItem(rect)
+    {
+        setAcceptHoverEvents(true);
+    }
+
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0)
+    {
+        QGraphicsRectItem::paint(painter, option, widget);
+        painter->drawText(boundingRect(), Qt::AlignCenter, QString("%1x%2\n%3x%4").arg(p.x()).arg(p.y()).arg(sp.x()).arg(sp.y()));
+    }
+    
+protected:
+    void hoverMoveEvent(QGraphicsSceneHoverEvent *event)
+    {
+        p = event->pos();
+        sp = event->widget()->mapFromGlobal(event->screenPos());
+        update();
+    }
+private:
+    QPointF p;
+    QPoint sp;
+};
+
+void tst_QGraphicsItem::deviceTransform_data()
+{
+    QTest::addColumn<bool>("untransformable1");
+    QTest::addColumn<bool>("untransformable2");
+    QTest::addColumn<bool>("untransformable3");
+    QTest::addColumn<qreal>("rotation1");
+    QTest::addColumn<qreal>("rotation2");
+    QTest::addColumn<qreal>("rotation3");
+    QTest::addColumn<QTransform>("deviceX");
+    QTest::addColumn<QPointF>("mapResult1");
+    QTest::addColumn<QPointF>("mapResult2");
+    QTest::addColumn<QPointF>("mapResult3");
+
+    QTest::newRow("nil") << false << false << false
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform()
+                         << QPointF(150, 150) << QPointF(250, 250) << QPointF(350, 350);
+    QTest::newRow("deviceX rot 90") << false << false << false
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-150, 150) << QPointF(-250, 250) << QPointF(-350, 350);
+    QTest::newRow("deviceX rot 90 100") << true << false << false
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-50, 150) << QPointF(50, 250) << QPointF(150, 350);
+    QTest::newRow("deviceX rot 90 010") << false << true << false
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-150, 150) << QPointF(-150, 250) << QPointF(-50, 350);
+    QTest::newRow("deviceX rot 90 001") << false << false << true
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-150, 150) << QPointF(-250, 250) << QPointF(-250, 350);
+    QTest::newRow("deviceX rot 90 111") << true << true << true
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-50, 150) << QPointF(50, 250) << QPointF(150, 350);
+    QTest::newRow("deviceX rot 90 101") << true << false << true
+                         << qreal(0.0) << qreal(0.0) << qreal(0.0)
+                         << QTransform().rotate(90)
+                         << QPointF(-50, 150) << QPointF(50, 250) << QPointF(150, 350);
+}
+
+void tst_QGraphicsItem::deviceTransform()
+{
+    QFETCH(bool, untransformable1);
+    QFETCH(bool, untransformable2);
+    QFETCH(bool, untransformable3);
+    QFETCH(qreal, rotation1);
+    QFETCH(qreal, rotation2);
+    QFETCH(qreal, rotation3);
+    QFETCH(QTransform, deviceX);
+    QFETCH(QPointF, mapResult1);
+    QFETCH(QPointF, mapResult2);
+    QFETCH(QPointF, mapResult3);
+
+    QGraphicsScene scene;
+    Track *rect1 = new Track(QRectF(0, 0, 100, 100));
+    Track *rect2 = new Track(QRectF(0, 0, 100, 100));
+    Track *rect3 = new Track(QRectF(0, 0, 100, 100));
+    rect2->setParentItem(rect1);
+    rect3->setParentItem(rect2);
+    rect1->setPos(100, 100);
+    rect2->setPos(100, 100);
+    rect3->setPos(100, 100);
+    rect1->rotate(rotation1);
+    rect2->rotate(rotation2);
+    rect3->rotate(rotation3);
+    rect1->setFlag(QGraphicsItem::ItemIgnoresTransformations, untransformable1);
+    rect2->setFlag(QGraphicsItem::ItemIgnoresTransformations, untransformable2);
+    rect3->setFlag(QGraphicsItem::ItemIgnoresTransformations, untransformable3);
+    rect1->setBrush(Qt::red);
+    rect2->setBrush(Qt::green);
+    rect3->setBrush(Qt::blue);
+    scene.addItem(rect1);
+
+    QCOMPARE(rect1->deviceTransform(deviceX).map(QPointF(50, 50)), mapResult1);
+    QCOMPARE(rect2->deviceTransform(deviceX).map(QPointF(50, 50)), mapResult2);
+    QCOMPARE(rect3->deviceTransform(deviceX).map(QPointF(50, 50)), mapResult3);
+}
+
 QTEST_MAIN(tst_QGraphicsItem)
 #include "tst_qgraphicsitem.moc"