169 lines
6.1 KiB
C++
169 lines
6.1 KiB
C++
/*
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Gwenview: an image viewer
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Copyright 2019 Steffen Hartleib <steffenhartleib@t-online.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Cambridge, MA 02110-1301, USA.
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*/
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// Self
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#include "twofingerpan.h"
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// Qt
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#include <QGraphicsWidget>
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#include <QTouchEvent>
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#include <QVector2D>
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// KF
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// Local
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#include "gwenview_lib_debug.h"
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#include "lib/touch/touch_helper.h"
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namespace Gwenview
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{
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struct TwoFingerPanRecognizerPrivate {
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TwoFingerPanRecognizer *q = nullptr;
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bool mTargetIsGrapicsWidget = false;
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qint64 mTouchBeginnTimestamp;
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bool mGestureTriggered;
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qint64 mLastTouchTimestamp;
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};
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TwoFingerPanRecognizer::TwoFingerPanRecognizer()
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: QGestureRecognizer()
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, d(new TwoFingerPanRecognizerPrivate)
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{
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d->q = this;
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}
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TwoFingerPanRecognizer::~TwoFingerPanRecognizer()
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{
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delete d;
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}
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QGesture *TwoFingerPanRecognizer::create(QObject *)
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{
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return static_cast<QGesture *>(new TwoFingerPan());
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}
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QGestureRecognizer::Result TwoFingerPanRecognizer::recognize(QGesture *state, QObject *watched, QEvent *event)
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{
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// Because of a bug in Qt in a gesture event in a graphicsview, all gestures are trigger twice
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// https://bugreports.qt.io/browse/QTBUG-13103
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if (qobject_cast<QGraphicsWidget *>(watched))
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d->mTargetIsGrapicsWidget = true;
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if (d->mTargetIsGrapicsWidget && watched->isWidgetType())
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return Ignore;
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switch (event->type()) {
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case QEvent::TouchBegin: {
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auto touchEvent = static_cast<QTouchEvent *>(event);
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d->mTouchBeginnTimestamp = touchEvent->timestamp();
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d->mLastTouchTimestamp = touchEvent->timestamp();
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d->mGestureTriggered = false;
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state->setProperty("delayActive", true);
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state->setHotSpot(touchEvent->touchPoints().first().screenPos());
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return TriggerGesture;
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}
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case QEvent::TouchUpdate: {
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auto touchEvent = static_cast<QTouchEvent *>(event);
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const qint64 now = touchEvent->timestamp();
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const QPointF pos = touchEvent->touchPoints().first().pos();
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state->setHotSpot(touchEvent->touchPoints().first().screenPos());
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if (touchEvent->touchPoints().size() >> 2) {
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if (d->mGestureTriggered) {
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d->mGestureTriggered = false;
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}
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return CancelGesture;
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}
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if (touchEvent->touchPoints().size() == 2) {
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if (touchEvent->touchPointStates() & Qt::TouchPointReleased) {
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if (d->mGestureTriggered) {
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d->mGestureTriggered = false;
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return FinishGesture;
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}
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}
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if (now - d->mTouchBeginnTimestamp >= Touch_Helper::Touch::gestureDelay) {
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state->setProperty("delayActive", false);
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// Check if both touch points moving in the same direction
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const QVector2D vectorTouchPoint1 = QVector2D(touchEvent->touchPoints().at(0).startPos() - touchEvent->touchPoints().at(0).pos());
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const QVector2D vectorTouchPoint2 = QVector2D(touchEvent->touchPoints().at(1).startPos() - touchEvent->touchPoints().at(1).pos());
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QVector2D dotProduct = vectorTouchPoint1 * vectorTouchPoint2;
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// The dot product is greater than zero if both touch points moving in the same direction
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// special case if the touch point moving exact or almost exact in x or y axis
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// one value of the dot product is zero or a little bit less than zero and
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// the other value is bigger than zero
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if (dotProduct.x() >= -500 && dotProduct.x() <= 0 && dotProduct.y() > 0)
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dotProduct.setX(1);
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if (dotProduct.y() >= -500 && dotProduct.y() <= 0 && dotProduct.x() > 0)
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dotProduct.setY(1);
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if (dotProduct.x() > 0 && dotProduct.y() > 0) {
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const QPointF diff = (touchEvent->touchPoints().first().lastPos() - pos);
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state->setProperty("delta", diff);
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d->mGestureTriggered = true;
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return TriggerGesture;
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} else {
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// special case if the user makes a very slow pan gesture, the vectors a very short. Sometimes the
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// dot product is then zero, so we only want to cancel the gesture if the user makes a bigger wrong gesture
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if (vectorTouchPoint1.toPoint().manhattanLength() > 50 || vectorTouchPoint2.toPoint().manhattanLength() > 50) {
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d->mGestureTriggered = false;
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return CancelGesture;
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} else {
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const QPointF diff = (touchEvent->touchPoints().first().lastPos() - pos);
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state->setProperty("delta", diff);
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d->mGestureTriggered = true;
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return TriggerGesture;
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}
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}
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} else {
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state->setProperty("delta", QPointF(0, 0));
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state->setProperty("delayActive", true);
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d->mGestureTriggered = false;
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return TriggerGesture;
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}
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}
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break;
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}
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case QEvent::TouchEnd: {
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auto touchEvent = static_cast<QTouchEvent *>(event);
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if (d->mGestureTriggered) {
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d->mGestureTriggered = false;
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state->setHotSpot(touchEvent->touchPoints().first().screenPos());
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return FinishGesture;
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}
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break;
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}
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default:
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return Ignore;
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}
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return Ignore;
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}
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TwoFingerPan::TwoFingerPan(QObject *parent)
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: QGesture(parent)
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{
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}
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} // namespace
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