imagegestures example: scaleFactor is relative; get values directly

QPinchGesture::scaleFactor is relative to the previous zoom factor,
so either we need to multiply the total zoom by scaleFactor,
or set it based on totalScaleFactor, which is simpler. Pinch-zoom is
now working in this example.
There's also no reason to use getProperty() when the accessors are
directly accessible in QPinchGesture.

Task-number: QTBUG-6010
Change-Id: I150dc0b18b4b871a08ec55c0f77463509ab26afe
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/examples/widgets/gestures/imagegestures/imagewidget.cpp b/examples/widgets/gestures/imagegestures/imagewidget.cpp
index 876930fab8..38319a9dbe 100644
--- a/examples/widgets/gestures/imagegestures/imagewidget.cpp
+++ b/examples/widgets/gestures/imagegestures/imagewidget.cpp
@@ -142,16 +142,12 @@ void ImageWidget::pinchTriggered(QPinchGesture *gesture)
 {
     QPinchGesture::ChangeFlags changeFlags = gesture->changeFlags();
     if (changeFlags & QPinchGesture::RotationAngleChanged) {
-        const qreal value = gesture->property("rotationAngle").toReal();
-        const qreal lastValue = gesture->property("lastRotationAngle").toReal();
-        const qreal rotationAngleDelta = value - lastValue;
-        rotationAngle += rotationAngleDelta;
-        qCDebug(lcExample) << "pinchTriggered(): rotation by" << rotationAngleDelta << rotationAngle;
+        rotationAngle += gesture->rotationAngle() - gesture->lastRotationAngle();
+        qCDebug(lcExample) << "pinchTriggered(): rotate to" << rotationAngle;
     }
     if (changeFlags & QPinchGesture::ScaleFactorChanged) {
-        qreal value = gesture->property("scaleFactor").toReal();
-        currentStepScaleFactor = value;
-        qCDebug(lcExample) << "pinchTriggered(): " << currentStepScaleFactor;
+        currentStepScaleFactor = gesture->totalScaleFactor();
+        qCDebug(lcExample) << "pinchTriggered(): zoom by" << gesture->scaleFactor() << "->" << currentStepScaleFactor;
     }
     if (gesture->state() == Qt::GestureFinished) {
         scaleFactor *= currentStepScaleFactor;