PinchArea: fix pinches being stolen when in PathView

Keep the mouse grab in addition to touch, as PathView
apparently doesn't deal with touch events yet.

Fixes: QTBUG-105058
Change-Id: Id94768aec847138cccdeccfa92e4bc72a19810fe
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 10800723ab6dacf1203986a6b0815dec45528ef4)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 137 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickpincharea/data/pinchAreaInPathView.qml b/tests/auto/quick/qquickpincharea/data/pinchAreaInPathView.qml
new file mode 100644
index 0000000000..dc909c2c7c
--- /dev/null
+++ b/tests/auto/quick/qquickpincharea/data/pinchAreaInPathView.qml
@@ -0,0 +1,48 @@
+import QtQuick
+
+PathView {
+    width: 600
+    height: 200
+
+    model: 3
+    delegate: Rectangle {
+        width: 200
+        height: 200
+        color: "salmon"
+        opacity: PathView.isCurrentItem ? 1 : 0.5
+
+        property alias pinchArea: pinchArea
+
+        Text {
+            text: "Test"
+            font.pixelSize: 100
+            anchors.fill: parent
+            fontSizeMode: Text.Fit
+            horizontalAlignment: Text.AlignHCenter
+            verticalAlignment: Text.AlignVCenter
+        }
+
+        PinchArea {
+            id: pinchArea
+            anchors.fill: parent
+            pinch.target: parent
+            pinch.dragAxis: Pinch.XAndYAxis
+            pinch.minimumScale: 1.0
+            pinch.maximumScale: 5.0
+
+            onPinchFinished: (pinch) => {
+                parent.scale = 1
+                parent.x = 0
+                parent.y = 0
+            }
+        }
+    }
+    path: Path {
+        startX: 100
+        startY: 100
+        PathLine {
+            x: 700
+            y: 100
+        }
+    }
+}
diff --git a/tests/auto/quick/qquickpincharea/tst_qquickpincharea.cpp b/tests/auto/quick/qquickpincharea/tst_qquickpincharea.cpp
index d23f804690..c5e07ac7b5 100644
--- a/tests/auto/quick/qquickpincharea/tst_qquickpincharea.cpp
+++ b/tests/auto/quick/qquickpincharea/tst_qquickpincharea.cpp
@@ -1,6 +1,7 @@
 // Copyright (C) 2020 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
+#include <QtCore/private/qvariantanimation_p.h>
 #include <QtTest/QtTest>
 #include <QtTest/QSignalSpy>
 #include <QtGui/QStyleHints>
@@ -8,6 +9,7 @@
 #include <QtGui/private/qeventpoint_p.h>
 #include <qpa/qwindowsysteminterface.h>
 #include <private/qquickpincharea_p.h>
+#include <QtQuick/private/qquickpathview_p.h>
 #include <QtQuick/private/qquickrectangle_p.h>
 #include <QtQuick/qquickview.h>
 #include <QtQml/qqmlcontext.h>
@@ -30,6 +32,7 @@ private slots:
     void transformedPinchArea();
     void dragTransformedPinchArea_data();
     void dragTransformedPinchArea();
+    void pinchAreaKeepsDragInView();
 
 private:
     QQuickView *createView();
@@ -618,6 +621,92 @@ void tst_QQuickPinchArea::dragTransformedPinchArea() // QTBUG-63673
     QCOMPARE(pinchArea->pinch()->active(), false);
 }
 
+template<typename F>
+void forEachLerpStep(int steps, F &&func)
+{
+    for (int i = 0; i < steps; ++i) {
+        const qreal t = qreal(i) / steps;
+        func(t);
+    }
+}
+
+QPoint lerpPoints(const QPoint &point1, const QPoint &point2, qreal t)
+{
+    return QPoint(_q_interpolate(point1.x(), point2.x(), t), _q_interpolate(point1.y(), point2.y(), t));
+};
+
+// QTBUG-105058
+void tst_QQuickPinchArea::pinchAreaKeepsDragInView()
+{
+    QQuickView view;
+    view.setSource(testFileUrl("pinchAreaInPathView.qml"));
+    QVERIFY(view.rootObject());
+    view.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
+
+    QQuickPathView *pathView = qobject_cast<QQuickPathView*>(view.rootObject());
+    QVERIFY(pathView);
+    QCOMPARE(pathView->count(), 3);
+
+    const QQuickItem *pinchDelegateItem = pathView->itemAtIndex(0);
+    QQuickPinchArea *pinchArea = pinchDelegateItem->property("pinchArea").value<QQuickPinchArea*>();
+    QVERIFY(pinchArea);
+
+    // Press.
+    QTest::QTouchEventSequence pinchSequence = QTest::touchEvent(&view, device);
+    QPoint point1Start = { 80, 120 };
+    QPoint point2Start = { 120, 80 };
+    const int dragThreshold = qApp->styleHints()->startDragDistance();
+    pinchSequence.press(1, pinchArea->mapToScene(point1Start).toPoint(), &view)
+                 .press(2, pinchArea->mapToScene(point2Start).toPoint(), &view).commit();
+    QQuickTouchUtils::flush(&view);
+
+    // Move past the drag threshold to begin the pinch.
+    const int steps = 30;
+    QPoint point1End = point1Start + QPoint(-dragThreshold, dragThreshold);
+    QPoint point2End = point2Start + QPoint(dragThreshold, -dragThreshold);
+    forEachLerpStep(steps, [&](qreal t) {
+        pinchSequence.move(1, lerpPoints(point1Start, point1End, t), &view)
+                     .move(2, lerpPoints(point2Start, point2End, t), &view).commit();
+        QQuickTouchUtils::flush(&view);
+        QTest::qWait(5);
+    });
+    QCOMPARE(pinchArea->pinch()->active(), true);
+    QVERIFY2(pinchDelegateItem->scale() > 1.0, qPrintable(QString::number(pinchDelegateItem->scale())));
+    // The PathView contents shouldn't have moved.
+    QCOMPARE(pathView->offset(), 0);
+
+    // Release a touch point.
+    pinchSequence.stationary(1).release(2, point2End, &view).commit();
+    QQuickTouchUtils::flush(&view);
+
+    // Press it again.
+    pinchSequence.stationary(1).press(2, point2End, &view).commit();
+    QQuickTouchUtils::flush(&view);
+    QCOMPARE(pinchArea->pinch()->active(), true);
+
+    // Drag to the right; the PathView still shouldn't move.
+    point1Start = point1End;
+    point2Start = point2End;
+    point1End = point1Start + QPoint(100, 0);
+    point2End = point2Start + QPoint(100, 0);
+    forEachLerpStep(steps, [&](qreal t) {
+        pinchSequence.move(1, lerpPoints(point1Start, point1End, t), &view)
+                     .move(2, lerpPoints(point2Start, point2End, t), &view).commit();
+        QQuickTouchUtils::flush(&view);
+        QTest::qWait(5);
+    });
+    QCOMPARE(pinchArea->pinch()->active(), true);
+    QVERIFY2(pinchDelegateItem->scale() > 1.0, qPrintable(QString::number(pinchDelegateItem->scale())));
+    QCOMPARE(pathView->offset(), 0);
+
+    // Release pinch.
+    pinchSequence.release(1, point1End, &view).release(2, point2End, &view).commit();
+    QQuickTouchUtils::flush(&view);
+    QCOMPARE(pinchArea->pinch()->active(), false);
+    QCOMPARE(pathView->offset(), 0);
+}
+
 QQuickView *tst_QQuickPinchArea::createView()
 {
     QQuickView *window = new QQuickView(nullptr);