Enable touch-pad navigation

For the curve-editor, transition-editor and timeline
Renamed ruler-scaling-factor to zoom in order to not confuse it with
ruler-scale-factor

Change-Id: I099e8e9a1e6092c9abb0a1a935fb8510aa90d5e4
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

3 files changed, 160 insertions, 0 deletions

diff --git a/src/plugins/qmldesigner/components/componentcore/componentcore.pri b/src/plugins/qmldesigner/components/componentcore/componentcore.pri
index 14337508ec..decf24a5a8 100644
--- a/src/plugins/qmldesigner/components/componentcore/componentcore.pri
+++ b/src/plugins/qmldesigner/components/componentcore/componentcore.pri
@@ -14,6 +14,7 @@ SOURCES += modelnodecontextmenu_helper.cpp
 SOURCES += selectioncontext.cpp
 SOURCES += designeractionmanager.cpp
 SOURCES += modelnodeoperations.cpp
+SOURCES += navigation2d.cpp
 SOURCES += crumblebar.cpp
 SOURCES += qmldesignericonprovider.cpp
 SOURCES += zoomaction.cpp
@@ -33,6 +34,7 @@ HEADERS += selectioncontext.h
 HEADERS += componentcore_constants.h
 HEADERS += designeractionmanager.h
 HEADERS += modelnodeoperations.h
+HEADERS += navigation2d.h
 HEADERS += actioninterface.h
 HEADERS += crumblebar.h
 HEADERS += qmldesignericonprovider.h
diff --git a/src/plugins/qmldesigner/components/componentcore/navigation2d.cpp b/src/plugins/qmldesigner/components/componentcore/navigation2d.cpp
new file mode 100644
index 0000000000..94d6b5ad38
--- /dev/null
+++ b/src/plugins/qmldesigner/components/componentcore/navigation2d.cpp
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+#include "navigation2d.h"
+
+#include <QGestureEvent>
+#include <QWheelEvent>
+
+namespace QmlDesigner {
+
+Navigation2dScrollBar::Navigation2dScrollBar(QWidget *parent)
+    : QScrollBar(parent)
+{}
+
+bool Navigation2dScrollBar::postEvent(QEvent *event)
+{
+    if (event->type() == QEvent::Wheel) {
+        wheelEvent(static_cast<QWheelEvent *>(event));
+        return true;
+    }
+    return false;
+}
+
+void Navigation2dScrollBar::wheelEvent(QWheelEvent *event)
+{
+    if (!event->angleDelta().isNull())
+        QScrollBar::wheelEvent(event);
+}
+
+
+Navigation2dFilter::Navigation2dFilter(QWidget *parent, Navigation2dScrollBar *scrollbar)
+    : QObject(parent)
+    , m_scrollbar(scrollbar)
+{
+    if (parent)
+        parent->grabGesture(Qt::PinchGesture);
+}
+
+bool Navigation2dFilter::eventFilter(QObject *, QEvent *event)
+{
+    if (event->type() == QEvent::Gesture)
+        return gestureEvent(static_cast<QGestureEvent *>(event));
+    else if (event->type() == QEvent::Wheel && m_scrollbar)
+        return wheelEvent(static_cast<QWheelEvent *>(event));
+
+    return QObject::event(event);
+}
+
+bool Navigation2dFilter::gestureEvent(QGestureEvent *event)
+{
+    if (QPinchGesture *pinch = static_cast<QPinchGesture *>(event->gesture(Qt::PinchGesture))) {
+        QPinchGesture::ChangeFlags changeFlags = pinch->changeFlags();
+        if (changeFlags & QPinchGesture::ScaleFactorChanged) {
+            emit zoomChanged(-(1.0 - pinch->scaleFactor()), pinch->startCenterPoint());
+            event->accept();
+            return true;
+        }
+    }
+    return false;
+}
+
+bool Navigation2dFilter::wheelEvent(QWheelEvent *event)
+{
+    if (m_scrollbar->postEvent(event))
+        event->ignore();
+
+    return false;
+}
+
+} // End namespace QmlDesigner.
diff --git a/src/plugins/qmldesigner/components/componentcore/navigation2d.h b/src/plugins/qmldesigner/components/componentcore/navigation2d.h
new file mode 100644
index 0000000000..434b59055c
--- /dev/null
+++ b/src/plugins/qmldesigner/components/componentcore/navigation2d.h
@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+#pragma once
+
+#include <QScrollBar>
+
+QT_FORWARD_DECLARE_CLASS(QGestureEvent)
+QT_FORWARD_DECLARE_CLASS(QWheelEvent)
+
+namespace QmlDesigner {
+
+class Navigation2dScrollBar : public QScrollBar
+{
+    Q_OBJECT
+
+public:
+    Navigation2dScrollBar(QWidget *parent = nullptr);
+
+    bool postEvent(QEvent *event);
+
+protected:
+    void wheelEvent(QWheelEvent *event) override;
+};
+
+
+class Navigation2dFilter : public QObject
+{
+    Q_OBJECT
+
+signals:
+    void zoomChanged(double scale, const QPointF &pos);
+
+public:
+    Navigation2dFilter(QWidget *parent = nullptr, Navigation2dScrollBar *scrollbar = nullptr);
+
+protected:
+    bool eventFilter(QObject *obj, QEvent *event) override;
+
+private:
+    bool gestureEvent(QGestureEvent *event);
+    bool wheelEvent(QWheelEvent *event);
+    Navigation2dScrollBar *m_scrollbar = nullptr;
+};
+
+} // namespace QmlDesigner