DragHandler: override wantsEventPoint to retain interest out of bounds

In any use case where the movement is constrained, as in a slider or
scrollbar, it's possible to keep dragging even when the eventpoint
is out of bounds. QQuickPointerSingleHandler::wantsEventPoint() returns
false when the point is out of bounds, so we have to override it.

Change-Id: Id80f614d6c38f28e6520ee8eacf7649f7317a5ef
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/quick/handlers/qquickdraghandler.cpp b/src/quick/handlers/qquickdraghandler.cpp
index 0b77bb46c6..dadf8bba04 100644
--- a/src/quick/handlers/qquickdraghandler.cpp
+++ b/src/quick/handlers/qquickdraghandler.cpp
@@ -67,6 +67,13 @@ QQuickDragHandler::~QQuickDragHandler()
 {
 }
 
+bool QQuickDragHandler::wantsEventPoint(QQuickEventPoint *point)
+{
+    // If we've already been interested in a point, stay interested, even if it has strayed outside bounds.
+    return ((point->state() != QQuickEventPoint::Pressed && currentPointId() == point->pointId())
+            || QQuickPointerSingleHandler::wantsEventPoint(point));
+}
+
 void QQuickDragHandler::handleEventPoint(QQuickEventPoint *point)
 {
     // If there's no target or the target has no parent, we shouldn't be dragging