Make QAccessibleQuickView::childAt() work properly with overlapping items

The previous code did not consider items that were overlapped due to
having different z coordinates.

The approach used is now the same as found in
QQuickCanvas::mousePressEvent().

Strictly speaking, this is a violation of childAt (since it will
disregard the implementation of childAt of all the descendants along
the path down to the item actually returned.)

However, I don't see any good reason for that the implementation for
childAt() would be different than how mousePressEvent behaves.
It should also perform better than any other solution I managed to
think of.

Change-Id: I2d3fa2282437c7b5533c6149c62fc456ccf2ccfa
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@nokia.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/src/plugins/accessible/shared/qdeclarativeaccessible.cpp b/src/plugins/accessible/shared/qdeclarativeaccessible.cpp
index 7db5f07cbe..1b35594e74 100644
--- a/src/plugins/accessible/shared/qdeclarativeaccessible.cpp
+++ b/src/plugins/accessible/shared/qdeclarativeaccessible.cpp
@@ -70,9 +70,8 @@ QFlags<QAccessible::RelationFlag> QDeclarativeAccessible::relationTo(const QAcce
 
 QAccessibleInterface *QDeclarativeAccessible::childAt(int x, int y) const
 {
-    // Look for children first.
-    // Start with the last child first, because children are ordered in paint order
-    // (which is opposite of hit test order)
+    // Note that this function will disregard stacking order.
+    // (QAccessibleQuickView::childAt() does this correctly and more efficient)
 
     // If the item clips its children, we can return early if the coordinate is outside its rect
     if (clipsChildren()) {