QQuickFlickable: fix flicking when item is rotated

QEventPoint::velocity() is in screen coordinates, as documented; it needs
to be transformed to local coordinates in case the Flickable is rotated
and/or scaled. windowToItemTransform() gives us a composite transform
matrix; we remove the translation components to get only the rotation
and scaling.

Also fix the press position calculation in handleReleaseEvent().

With the manual test one can pinch to scale and rotate a Flickable, then
verify that with a single finger, the Flickable gets scrolled by an
appropriate distance in spite of that.

Done-with: Ivan Solovev
Fixes: QTBUG-99639
Pick-to: 6.3 6.2
Change-Id: I60af1dd932835d358baa1422523cc24b2ab046a0
Reviewed-by: Ivan Solovev <[email protected]>
Reviewed-by: Paul Olav Tvete <[email protected]>

1 files changed, 84 insertions, 0 deletions

diff --git a/tests/manual/pointer/pinchFlickable.qml b/tests/manual/pointer/pinchFlickable.qml
new file mode 100644
index 0000000000..48a00b4b1b
--- /dev/null
+++ b/tests/manual/pointer/pinchFlickable.qml
@@ -0,0 +1,84 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the manual tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick
+
+Item {
+    width: 300
+    height: 300
+
+    Flickable {
+        id: flickable
+        anchors.fill: parent
+        contentHeight: column.height
+
+        Column {
+            id: column
+            width: parent.width
+
+            Repeater {
+                model: 255
+
+                delegate: Rectangle {
+                    width: column.width
+                    height: 50
+                    color: flickable.dragging ? "steelblue" : "gray"
+                    Text {
+                        anchors.centerIn: parent
+                        text: index
+                    }
+                }
+            }
+        }
+    }
+    PinchHandler {
+        target: flickable
+    }
+}