Fix potential use of incorrect bounds in delegate tracking.

Using GridView.SnapToRow and GridView.ApplyRange with a top margin
could lead to the view jumping (rather than smoothly transitioning)
when changing the currentIndex.

Change-Id: I6936b378220f59e8d416f7531cf8b6906c723cb2
Task-number: QTBUG-45640
Reviewed-by: Martin Jones <martin.jones@qinetic.com.au>

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickgridview/data/qtbug45640.qml b/tests/auto/quick/qquickgridview/data/qtbug45640.qml
new file mode 100644
index 0000000000..6973773432
--- /dev/null
+++ b/tests/auto/quick/qquickgridview/data/qtbug45640.qml
@@ -0,0 +1,24 @@
+import QtQuick 2.0
+
+GridView {
+    id: gridView
+    width: 400; height: 400
+    cellHeight: 100
+    cellWidth: 100
+    model: 32
+
+    topMargin: 50
+    snapMode: GridView.SnapToRow
+    preferredHighlightBegin: 50
+    preferredHighlightEnd: 50
+    highlightRangeMode: GridView.ApplyRange
+
+    delegate: Rectangle {
+        width: 100
+        height: 100
+        color: index % 2 == 0 ? "#FFFF00" : "#0000FF"
+    }
+
+    highlight: Rectangle { color: "red"; z: 2 }
+    highlightMoveDuration: 1000
+}