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Diffstat (limited to 'src/quick/handlers/qquickmultipointhandler.cpp')
| -rw-r--r-- | src/quick/handlers/qquickmultipointhandler.cpp | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/src/quick/handlers/qquickmultipointhandler.cpp b/src/quick/handlers/qquickmultipointhandler.cpp new file mode 100644 index 0000000000..b126b93211 --- /dev/null +++ b/src/quick/handlers/qquickmultipointhandler.cpp @@ -0,0 +1,315 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtQuick module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** 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 Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** 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-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qquickmultipointhandler_p.h" +#include <private/qquickitem_p.h> +#include <QLineF> +#include <QMouseEvent> +#include <QDebug> + +QT_BEGIN_NAMESPACE + +/*! + \qmltype MultiPointHandler + \since 5.10 + \preliminary + \instantiates QQuickMultiPointHandler + \inherits PointerDeviceHandler + \inqmlmodule Qt.labs.handlers + \ingroup qtquick-handlers + \brief Abstract handler for multi-point Pointer Events. + + An intermediate class (not registered as a QML type) + for any type of handler which requires and acts upon a specific number + of multiple touchpoints. +*/ +QQuickMultiPointHandler::QQuickMultiPointHandler(QObject *parent, int minimumPointCount) + : QQuickPointerDeviceHandler(parent) + , m_minimumPointCount(minimumPointCount) + , m_maximumPointCount(-1) + , m_pointDistanceThreshold(0) +{ +} + +QQuickMultiPointHandler::~QQuickMultiPointHandler() +{ +} + +bool QQuickMultiPointHandler::wantsPointerEvent(QQuickPointerEvent *event) +{ + if (!QQuickPointerDeviceHandler::wantsPointerEvent(event)) + return false; + + if (event->asPointerNativeGestureEvent()) + return true; + + if (sameAsCurrentPoints(event)) + return true; + + const QVector<QQuickEventPoint *> candidatePoints = eligiblePoints(event); + const bool ret = (candidatePoints.size() >= minimumPointCount() && candidatePoints.size() <= maximumPointCount()); + if (ret) + m_currentPoints = candidatePoints; + return ret; +} + +QVector<QQuickEventPoint *> QQuickMultiPointHandler::eligiblePoints(QQuickPointerEvent *event) +{ + QVector<QQuickEventPoint *> ret; + int c = event->pointCount(); + QRectF parentBounds = parentItem()->mapRectToScene(parentItem()->boundingRect()) + .marginsAdded(QMarginsF(m_pointDistanceThreshold, m_pointDistanceThreshold, m_pointDistanceThreshold, m_pointDistanceThreshold)); + // If one or more points are newly pressed or released, all non-released points are candidates for this handler. + // In other cases however, do not steal the grab: that is, if a point has a grabber, + // it's not a candidate for this handler. + bool stealingAllowed = event->isPressEvent() || event->isReleaseEvent(); + for (int i = 0; i < c; ++i) { + QQuickEventPoint *p = event->point(i); + if (!stealingAllowed) { + QObject *exclusiveGrabber = p->exclusiveGrabber(); + if (exclusiveGrabber && exclusiveGrabber != this) + continue; + } + if (p->state() != QQuickEventPoint::Released && parentBounds.contains(p->scenePosition())) + ret << p; + } + return ret; +} + +/*! + \qmlproperty int MultiPointHandler::minimumPointCount + + The minimum number of touchpoints required to activate this handler. + + If a smaller number of touchpoints are in contact with the + \l {PointerHandler::parent}{parent}, they will be ignored. + + Any ignored points are eligible to activate other Pointer Handlers that + have different constraints, on the same Item or on other Items. + + The default value is 2. +*/ +void QQuickMultiPointHandler::setMinimumPointCount(int c) +{ + if (m_minimumPointCount == c) + return; + + m_minimumPointCount = c; + emit minimumPointCountChanged(); + if (m_maximumPointCount < 0) + emit maximumPointCountChanged(); +} + +/*! + \qmlproperty int MultiPointHandler::maximumPointCount + + The maximum number of touchpoints this handler can utilize. + + If a larger number of touchpoints are in contact with the + \l {PointerHandler::parent}{parent}, the required number of points will be + chosen in the order that they are pressed, and the remaining points will + be ignored. + + Any ignored points are eligible to activate other Pointer Handlers that + have different constraints, on the same Item or on other Items. + + The default value is the same as \l minimumPointCount. +*/ +void QQuickMultiPointHandler::setMaximumPointCount(int maximumPointCount) +{ + if (m_maximumPointCount == maximumPointCount) + return; + + m_maximumPointCount = maximumPointCount; + emit maximumPointCountChanged(); +} + +/*! + \qmlproperty real MultiPointHandler::pointDistanceThreshold + + The margin beyond the bounds of the \l {PointerHandler::parent}{parent} + item within which a touch point can activate this handler. For example, on + a PinchHandler where the \l {PointerHandler::target}{target} is also the + \c parent, it's useful to set this to a distance at least half the width + of a typical user's finger, so that if the \c parent has been scaled down + to a very small size, the pinch gesture is still possible. + + The default value is 0. + + \image pointDistanceThreshold.png +*/ +void QQuickMultiPointHandler::setPointDistanceThreshold(qreal pointDistanceThreshold) +{ + if (m_pointDistanceThreshold == pointDistanceThreshold) + return; + + m_pointDistanceThreshold = pointDistanceThreshold; + emit pointDistanceThresholdChanged(); +} + +bool QQuickMultiPointHandler::sameAsCurrentPoints(QQuickPointerEvent *event) +{ + bool ret = true; + int c = event->pointCount(); + if (c != m_currentPoints.size()) + return false; + // TODO optimize: either ensure the points are sorted, + // or use std::equal with a predicate + for (int i = 0; ret && i < c; ++i) { + if (event->point(i)->state() == QQuickEventPoint::Released) + return false; + bool found = false; + int pointId = event->point(i)->pointId(); + for (QQuickEventPoint *o : qAsConst(m_currentPoints)) + if (o && pointId == o->pointId()) + found = true; + if (!found) + ret = false; + } + return ret; +} + +// TODO make templates for these functions somehow? +QPointF QQuickMultiPointHandler::touchPointCentroid() +{ + QPointF ret; + if (Q_UNLIKELY(m_currentPoints.size() == 0)) + return ret; + for (QQuickEventPoint *point : qAsConst(m_currentPoints)) + ret += point->scenePosition(); + return ret / m_currentPoints.size(); +} + +QVector2D QQuickMultiPointHandler::touchPointCentroidVelocity() +{ + QVector2D ret; + if (Q_UNLIKELY(m_currentPoints.size() == 0)) + return ret; + for (QQuickEventPoint *point : qAsConst(m_currentPoints)) + ret += point->velocity(); + return ret / m_currentPoints.size(); +} + +qreal QQuickMultiPointHandler::averageTouchPointDistance(const QPointF &ref) +{ + qreal ret = 0; + if (Q_UNLIKELY(m_currentPoints.size() == 0)) + return ret; + for (QQuickEventPoint *point : qAsConst(m_currentPoints)) + ret += QVector2D(point->scenePosition() - ref).length(); + return ret / m_currentPoints.size(); +} + +qreal QQuickMultiPointHandler::averageStartingDistance(const QPointF &ref) +{ + // TODO cache it in setActive()? + qreal ret = 0; + if (Q_UNLIKELY(m_currentPoints.size() == 0)) + return ret; + for (QQuickEventPoint *point : qAsConst(m_currentPoints)) + ret += QVector2D(point->sceneGrabPosition() - ref).length(); + return ret / m_currentPoints.size(); +} + +QVector<QQuickMultiPointHandler::PointData> QQuickMultiPointHandler::angles(const QPointF &ref) const +{ + QVector<PointData> angles; + angles.reserve(m_currentPoints.count()); + for (QQuickEventPoint *point : qAsConst(m_currentPoints)) { + qreal angle = QLineF(ref, point->scenePosition()).angle(); + angles.append(PointData(point->pointId(), -angle)); // convert to clockwise, to be consistent with QQuickItem::rotation + } + return angles; +} + +qreal QQuickMultiPointHandler::averageAngleDelta(const QVector<PointData> &old, const QVector<PointData> &newAngles) +{ + qreal avgAngleDelta = 0; + int numSamples = 0; + + auto oldBegin = old.constBegin(); + + for (PointData newData : newAngles) { + quint64 id = newData.id; + auto it = std::find_if(oldBegin, old.constEnd(), [id] (PointData pd) { return pd.id == id; }); + qreal angleD = 0; + if (it != old.constEnd()) { + PointData oldData = *it; + // We might rotate from 359 degrees to 1 degree. However, this + // should be interpreted as a rotation of +2 degrees instead of + // -358 degrees. Therefore, we call remainder() to translate the angle + // to be in the range [-180, 180] (-350 to +10 etc) + angleD = remainder(newData.angle - oldData.angle, qreal(360)); + // optimization: narrow down the O(n^2) search to optimally O(n) + // if both vectors have the same points and they are in the same order + if (it == oldBegin) + ++oldBegin; + numSamples++; + } + avgAngleDelta += angleD; + } + if (numSamples > 1) + avgAngleDelta /= numSamples; + + return avgAngleDelta; +} + +void QQuickMultiPointHandler::acceptPoints(const QVector<QQuickEventPoint *> &points) +{ + for (QQuickEventPoint* point : points) + point->setAccepted(); +} + +bool QQuickMultiPointHandler::grabPoints(QVector<QQuickEventPoint *> points) +{ + bool allowed = true; + for (QQuickEventPoint* point : points) { + if (!canGrab(point)) { + allowed = false; + break; + } + } + if (allowed) { + for (QQuickEventPoint* point : points) + setExclusiveGrab(point); + } + return allowed; +} + +QT_END_NAMESPACE |