Backported jump fix to Flickable

Avoid Flickable view jumping when drag threashold is exceeded.
(d630c627ed1dfbcfb48f907d2d37048b049830a5)

2 files changed, 9 insertions, 2 deletions

diff --git a/src/graphicsitems/qxflickable.cpp b/src/graphicsitems/qxflickable.cpp
index 78c0e7a..0287205 100644
--- a/src/graphicsitems/qxflickable.cpp
+++ b/src/graphicsitems/qxflickable.cpp
@@ -642,6 +642,8 @@ void QxFlickablePrivate::handleMousePressEvent(QGraphicsSceneMouseEvent *event)
     timeline.clear();
     hData.velocity = 0;
     vData.velocity = 0;
+    hData.dragStartOffset = 0;
+    vData.dragStartOffset = 0;
     lastPos = QPoint();
     lastPosTime.start();
     pressPos = event->pos();
@@ -664,7 +666,9 @@ void QxFlickablePrivate::handleMouseMoveEvent(QGraphicsSceneMouseEvent *event)
     if (q->yflick()) {
         int dy = int(event->pos().y() - pressPos.y());
         if (qAbs(dy) > QApplication::startDragDistance() || pressTime.elapsed() > 200) {
-            qreal newY = dy + vData.pressPos;
+            if (!vMoved)
+                vData.dragStartOffset = dy;
+            qreal newY = dy + vData.pressPos - vData.dragStartOffset;
             const qreal minY = q->minYExtent();
             const qreal maxY = q->maxYExtent();
             if (newY > minY)
@@ -691,7 +695,9 @@ void QxFlickablePrivate::handleMouseMoveEvent(QGraphicsSceneMouseEvent *event)
     if (q->xflick()) {
         int dx = int(event->pos().x() - pressPos.x());
         if (qAbs(dx) > QApplication::startDragDistance() || pressTime.elapsed() > 200) {
-            qreal newX = dx + hData.pressPos;
+            if (!hMoved)
+                hData.dragStartOffset = dx;
+            qreal newX = dx + hData.pressPos - hData.dragStartOffset;
             const qreal minX = q->minXExtent();
             const qreal maxX = q->maxXExtent();
             if (newX > minX)
diff --git a/src/graphicsitems/qxflickable_p_p.h b/src/graphicsitems/qxflickable_p_p.h
index fa28be4..264bddc 100644
--- a/src/graphicsitems/qxflickable_p_p.h
+++ b/src/graphicsitems/qxflickable_p_p.h
@@ -94,6 +94,7 @@ public:
         QDeclarativeTimeLineValueProxy<QxFlickablePrivate> move;
         qreal viewSize;
         qreal pressPos;
+        qreal dragStartOffset;
         qreal velocity;
         qreal flickTarget;
         QxFlickablePrivate::Velocity smoothVelocity;