MouseArea: fix bug preventing dragging from start

The same bounded dragPos values were used for
- moving the target item to new position; and
- if dragging didn’t start yet, determining whether cursor moved over
the threshold distance.

It is right for moving the target item, but in the second case it led to
that dragging did not start if the distance between item's left border
and minimumX (right border and maximumX, top border and minimumY,
bottom border and maximumY accordingly) was less than drag.threshold.

Task-number: QTBUG-58347
Change-Id: If61a98bf734739323ef19dee6709560b754b2456
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

2 files changed, 54 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickmousearea/data/availableDistanceLessThanDragThreshold.qml b/tests/auto/quick/qquickmousearea/data/availableDistanceLessThanDragThreshold.qml
new file mode 100644
index 0000000000..2b45a19340
--- /dev/null
+++ b/tests/auto/quick/qquickmousearea/data/availableDistanceLessThanDragThreshold.qml
@@ -0,0 +1,24 @@
+import QtQuick 2.0
+
+Rectangle {
+    width: 400
+    height: 200
+
+    MouseArea {
+        id: mouseArea
+        objectName: "mouseArea"
+        width: 200
+        height: 200
+
+        drag.target: mouseArea
+        drag.axis: Drag.XAxis
+        drag.minimumX: 0
+        drag.maximumX: 200
+        drag.threshold: 200
+
+        Rectangle {
+            anchors.fill: parent
+            color: "red"
+        }
+    }
+}
diff --git a/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp b/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
index e1f903123b..c2a2118598 100644
--- a/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
+++ b/tests/auto/quick/qquickmousearea/tst_qquickmousearea.cpp
@@ -88,6 +88,7 @@ private slots:
     void invalidDrag_data() { rejectedButton_data(); }
     void invalidDrag();
     void cancelDragging();
+    void availableDistanceLessThanDragThreshold();
     void setDragOnPressed();
     void updateMouseAreaPosOnClick();
     void updateMouseAreaPosOnResize();
@@ -583,6 +584,35 @@ void tst_QQuickMouseArea::cancelDragging()
     QTest::mouseRelease(&window, Qt::LeftButton, 0, QPoint(122,122));
 }
 
+// QTBUG-58347
+void tst_QQuickMouseArea::availableDistanceLessThanDragThreshold()
+{
+    QQuickView view;
+    QByteArray errorMessage;
+    QVERIFY2(initView(view, testFileUrl("availableDistanceLessThanDragThreshold.qml"), true, &errorMessage),
+             errorMessage.constData());
+    view.show();
+    view.requestActivate();
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
+    QVERIFY(view.rootObject());
+
+    QQuickMouseArea *mouseArea = view.rootObject()->findChild<QQuickMouseArea*>("mouseArea");
+    QVERIFY(mouseArea);
+
+    QPoint position(100, 100);
+    QTest::mousePress(&view, Qt::LeftButton, 0, position);
+    QTest::qWait(10);
+    position.setX(301);
+    QTest::mouseMove(&view, position);
+    position.setX(501);
+    QTest::mouseMove(&view, position);
+    QVERIFY(mouseArea->drag()->active());
+    QTest::mouseRelease(&view, Qt::LeftButton, 0, position);
+
+    QVERIFY(!mouseArea->drag()->active());
+    QCOMPARE(mouseArea->x(), 200.0);
+}
+
 void tst_QQuickMouseArea::setDragOnPressed()
 {
     QQuickView window;