Improve Touch support

With this patch dolphin now supports the following touch gestures:

* Tap gesture to interact/open with directories, files and so on
* TapAndHold and release gesture for access to the context menu (main window, panel folder, places and information)
* TapAndHold and moving gesture for drag and drop action (main windows, panel folder and places)
* pinch gesture for zoom in main window
* kinetic scrolling (QScroller) for main window, panel folder, panel places, panel information, setting preview and service
* two fingers swipe gesture to left, right and up as shortcut to navigate back, forward and up
* two finger tap gesture to toggle item selection, similar to Ctrl and left mouse click

FEATURE: 385066
FIXED-IN: 20.11.80

 You are currently rebasing branch 'touch' on '85241a924'.

1 files changed, 139 insertions, 0 deletions

diff --git a/src/kitemviews/private/ktwofingerswipe.cpp b/src/kitemviews/private/ktwofingerswipe.cpp
new file mode 100644
index 000000000..6d0e18e65
--- /dev/null
+++ b/src/kitemviews/private/ktwofingerswipe.cpp
@@ -0,0 +1,139 @@
+/*
+ * SPDX-FileCopyrightText: 2020 Steffen Hartleib <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+// Self
+#include "ktwofingerswipe.h"
+
+// Qt
+#include <QTouchEvent>
+#include <QLineF>
+
+KTwoFingerSwipeRecognizer::KTwoFingerSwipeRecognizer() :
+    QGestureRecognizer(),
+    m_touchBeginnTimestamp(0),
+    m_gestureAlreadyTriggered(false)
+{
+}
+
+KTwoFingerSwipeRecognizer::~KTwoFingerSwipeRecognizer()
+{
+}
+
+QGesture* KTwoFingerSwipeRecognizer::create(QObject*)
+{
+    return static_cast<QGesture*>(new KTwoFingerSwipe());
+}
+
+QGestureRecognizer::Result KTwoFingerSwipeRecognizer::recognize(QGesture* gesture, QObject* watched, QEvent* event)
+{
+    Q_UNUSED(watched)
+
+    KTwoFingerSwipe* const kTwoFingerSwipe = static_cast<KTwoFingerSwipe*>(gesture);
+    const QTouchEvent* touchEvent = static_cast<const QTouchEvent*>(event);
+
+    const int maxTimeFrameForSwipe = 90;
+    const int minDistanceForSwipe = 30;
+
+    switch (event->type()) {
+    case QEvent::TouchBegin: {
+        m_touchBeginnTimestamp = touchEvent->timestamp();
+        m_gestureAlreadyTriggered = false;
+        kTwoFingerSwipe->setHotSpot(touchEvent->touchPoints().first().startScreenPos());
+        kTwoFingerSwipe->setPos(touchEvent->touchPoints().first().startPos());
+        kTwoFingerSwipe->setScreenPos(touchEvent->touchPoints().first().startScreenPos());
+        kTwoFingerSwipe->setScenePos(touchEvent->touchPoints().first().startScenePos());
+        return MayBeGesture;
+    }
+
+    case QEvent::TouchUpdate: {
+        const qint64 now = touchEvent->timestamp();
+        const qint64 elapsedTime = now - m_touchBeginnTimestamp;
+        const QPointF distance = touchEvent->touchPoints().first().startPos() - touchEvent->touchPoints().first().pos();
+        kTwoFingerSwipe->setHotSpot(touchEvent->touchPoints().first().startScreenPos());
+        kTwoFingerSwipe->setPos(touchEvent->touchPoints().first().startPos());
+        kTwoFingerSwipe->setScreenPos(touchEvent->touchPoints().first().startScreenPos());
+        kTwoFingerSwipe->setScenePos(touchEvent->touchPoints().first().startScenePos());
+        const QLineF ql = QLineF(touchEvent->touchPoints().first().startPos(), touchEvent->touchPoints().first().pos());
+        kTwoFingerSwipe->setSwipeAngle(ql.angle());
+
+        if (touchEvent->touchPoints().size() > 2) {
+            return CancelGesture;
+        }
+
+        if (touchEvent->touchPoints().size() == 2) {
+            if ((elapsedTime) > maxTimeFrameForSwipe) {
+                return CancelGesture;
+            }
+
+            if (distance.manhattanLength() >= minDistanceForSwipe &&
+                    (elapsedTime) <= maxTimeFrameForSwipe && !m_gestureAlreadyTriggered) {
+                m_gestureAlreadyTriggered = true;
+                return FinishGesture;
+            } else if ((elapsedTime) <= maxTimeFrameForSwipe && !m_gestureAlreadyTriggered) {
+                return TriggerGesture;
+            }
+        }
+        break;
+    }
+
+    default:
+        return Ignore;
+    }
+    return Ignore;
+}
+
+KTwoFingerSwipe::KTwoFingerSwipe(QObject* parent) :
+    QGesture(parent),
+    m_pos(QPointF(-1, -1)),
+    m_screenPos(QPointF(-1, -1)),
+    m_scenePos(QPointF(-1, -1)),
+    m_swipeAngle(0.0)
+{
+}
+
+KTwoFingerSwipe::~KTwoFingerSwipe()
+{
+}
+
+QPointF KTwoFingerSwipe::pos() const
+{
+    return m_pos;
+}
+
+void KTwoFingerSwipe::setPos(QPointF _pos)
+{
+    m_pos = _pos;
+}
+
+QPointF KTwoFingerSwipe::screenPos() const
+{
+    return m_screenPos;
+}
+
+void KTwoFingerSwipe::setScreenPos(QPointF _screenPos)
+{
+    m_screenPos = _screenPos;
+}
+
+QPointF KTwoFingerSwipe::scenePos() const
+{
+    return m_scenePos;
+}
+
+void KTwoFingerSwipe::setScenePos(QPointF _scenePos)
+{
+    m_scenePos = _scenePos;
+}
+
+qreal KTwoFingerSwipe::swipeAngle() const
+{
+    return m_swipeAngle;
+}
+ void KTwoFingerSwipe::setSwipeAngle(qreal _swipeAngle)
+{
+    m_swipeAngle = _swipeAngle;
+}
+