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Diffstat (limited to 'src/declarative/util/qdeclarativespringanimation.cpp')
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diff --git a/src/declarative/util/qdeclarativespringanimation.cpp b/src/declarative/util/qdeclarativespringanimation.cpp new file mode 100644 index 00000000..034c54b2 --- /dev/null +++ b/src/declarative/util/qdeclarativespringanimation.cpp @@ -0,0 +1,462 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtDeclarative module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** GNU Lesser General Public License Usage +** This file may be used under the terms of the GNU Lesser General Public +** License version 2.1 as published by the Free Software Foundation and +** appearing in the file LICENSE.LGPL included in the packaging of this +** file. Please review the following information to ensure the GNU Lesser +** General Public License version 2.1 requirements will be met: +** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU General +** Public License version 3.0 as published by the Free Software Foundation +** and appearing in the file LICENSE.GPL included in the packaging of this +** file. Please review the following information to ensure the GNU General +** Public License version 3.0 requirements will be met: +** http://www.gnu.org/copyleft/gpl.html. +** +** Other Usage +** Alternatively, this file may be used in accordance with the terms and +** conditions contained in a signed written agreement between you and Nokia. +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "private/qdeclarativespringanimation_p.h" + +#include "private/qdeclarativeanimation_p_p.h" +#include <qdeclarativeproperty_p.h> + +#include <QtCore/qdebug.h> + +#include <private/qobject_p.h> + +#include <limits.h> +#include <math.h> + +QT_BEGIN_NAMESPACE + + +class QDeclarativeSpringAnimationPrivate : public QDeclarativePropertyAnimationPrivate +{ + Q_DECLARE_PUBLIC(QDeclarativeSpringAnimation) +public: + + + struct SpringAnimation { + SpringAnimation() + : currentValue(0), to(0), velocity(0), start(0), duration(0) {} + qreal currentValue; + qreal to; + qreal velocity; + int start; + int duration; + }; + QHash<QDeclarativeProperty, SpringAnimation> activeAnimations; + + qreal maxVelocity; + qreal velocityms; + int lastTime; + qreal mass; + qreal spring; + qreal damping; + qreal epsilon; + qreal modulus; + + bool useMass : 1; + bool haveModulus : 1; + + enum Mode { + Track, + Velocity, + Spring + }; + Mode mode; + + QDeclarativeSpringAnimationPrivate() + : maxVelocity(0), velocityms(0), lastTime(0) + , mass(1.0), spring(0.), damping(0.), epsilon(0.01) + , modulus(0.0), useMass(false), haveModulus(false) + , mode(Track), clock(0) + { } + + void tick(int time); + bool animate(const QDeclarativeProperty &property, SpringAnimation &animation, int elapsed); + void updateMode(); + + typedef QTickAnimationProxy<QDeclarativeSpringAnimationPrivate, &QDeclarativeSpringAnimationPrivate::tick> Clock; + Clock *clock; +}; + +void QDeclarativeSpringAnimationPrivate::tick(int time) +{ + if (mode == Track) { + clock->stop(); + return; + } + int elapsed = time - lastTime; + if (!elapsed) + return; + + if (mode == Spring) { + if (elapsed < 16) // capped at 62fps. + return; + int count = elapsed / 16; + lastTime = time - (elapsed - count * 16); + } else { + lastTime = time; + } + + QMutableHashIterator<QDeclarativeProperty, SpringAnimation> it(activeAnimations); + while (it.hasNext()) { + it.next(); + if (animate(it.key(), it.value(), elapsed)) + it.remove(); + } + + if (activeAnimations.isEmpty()) + clock->stop(); +} + +bool QDeclarativeSpringAnimationPrivate::animate(const QDeclarativeProperty &property, SpringAnimation &animation, int elapsed) +{ + qreal srcVal = animation.to; + + bool stop = false; + + if (haveModulus) { + animation.currentValue = fmod(animation.currentValue, modulus); + srcVal = fmod(srcVal, modulus); + } + if (mode == Spring) { + // Real men solve the spring DEs using RK4. + // We'll do something much simpler which gives a result that looks fine. + int count = elapsed / 16; + for (int i = 0; i < count; ++i) { + qreal diff = srcVal - animation.currentValue; + if (haveModulus && qAbs(diff) > modulus / 2) { + if (diff < 0) + diff += modulus; + else + diff -= modulus; + } + if (useMass) + animation.velocity = animation.velocity + (spring * diff - damping * animation.velocity) / mass; + else + animation.velocity = animation.velocity + spring * diff - damping * animation.velocity; + if (maxVelocity > qreal(0.)) { + // limit velocity + if (animation.velocity > maxVelocity) + animation.velocity = maxVelocity; + else if (animation.velocity < -maxVelocity) + animation.velocity = -maxVelocity; + } + animation.currentValue += animation.velocity * qreal(16.0) / qreal(1000.0); + if (haveModulus) { + animation.currentValue = fmod(animation.currentValue, modulus); + if (animation.currentValue < qreal(0.0)) + animation.currentValue += modulus; + } + } + if (qAbs(animation.velocity) < epsilon && qAbs(srcVal - animation.currentValue) < epsilon) { + animation.velocity = 0.0; + animation.currentValue = srcVal; + stop = true; + } + } else { + qreal moveBy = elapsed * velocityms; + qreal diff = srcVal - animation.currentValue; + if (haveModulus && qAbs(diff) > modulus / 2) { + if (diff < 0) + diff += modulus; + else + diff -= modulus; + } + if (diff > 0) { + animation.currentValue += moveBy; + if (haveModulus) + animation.currentValue = fmod(animation.currentValue, modulus); + } else { + animation.currentValue -= moveBy; + if (haveModulus && animation.currentValue < qreal(0.0)) + animation.currentValue = fmod(animation.currentValue, modulus) + modulus; + } + if (lastTime - animation.start >= animation.duration) { + animation.currentValue = animation.to; + stop = true; + } + } + + qreal old_to = animation.to; + + QDeclarativePropertyPrivate::write(property, animation.currentValue, + QDeclarativePropertyPrivate::BypassInterceptor | + QDeclarativePropertyPrivate::DontRemoveBinding); + + return (stop && old_to == animation.to); // do not stop if we got restarted +} + +void QDeclarativeSpringAnimationPrivate::updateMode() +{ + if (spring == 0. && maxVelocity == 0.) + mode = Track; + else if (spring > 0.) + mode = Spring; + else { + mode = Velocity; + QHash<QDeclarativeProperty, SpringAnimation>::iterator it; + for (it = activeAnimations.begin(); it != activeAnimations.end(); ++it) { + SpringAnimation &animation = *it; + animation.start = lastTime; + qreal dist = qAbs(animation.currentValue - animation.to); + if (haveModulus && dist > modulus / 2) + dist = modulus - fmod(dist, modulus); + animation.duration = dist / velocityms; + } + } +} + +/*! + \qmlclass SpringAnimation QDeclarativeSpringAnimation + \ingroup qml-animation-transition + \inherits NumberAnimation + \since 4.7 + + \brief The SpringAnimation element allows a property to track a value in a spring-like motion. + + SpringAnimation mimics the oscillatory behavior of a spring, with the appropriate \l spring constant to + control the acceleration and the \l damping to control how quickly the effect dies away. + + You can also limit the maximum \l velocity of the animation. + + The following \l Rectangle moves to the position of the mouse using a + SpringAnimation when the mouse is clicked. The use of the \l Behavior + on the \c x and \c y values indicates that whenever these values are + changed, a SpringAnimation should be applied. + + \snippet doc/src/snippets/declarative/springanimation.qml 0 + + Like any other animation element, a SpringAnimation can be applied in a + number of ways, including transitions, behaviors and property value + sources. The \l {QML Animation and Transitions} documentation shows a + variety of methods for creating animations. + + \sa SmoothedAnimation, {QML Animation and Transitions}, {declarative/animation/basics}{Animation basics example}, {declarative/toys/clocks}{Clocks example} +*/ + +QDeclarativeSpringAnimation::QDeclarativeSpringAnimation(QObject *parent) +: QDeclarativeNumberAnimation(*(new QDeclarativeSpringAnimationPrivate),parent) +{ + Q_D(QDeclarativeSpringAnimation); + d->clock = new QDeclarativeSpringAnimationPrivate::Clock(d, this); +} + +QDeclarativeSpringAnimation::~QDeclarativeSpringAnimation() +{ +} + +/*! + \qmlproperty real SpringAnimation::velocity + + This property holds the maximum velocity allowed when tracking the source. + + The default value is 0 (no maximum velocity). +*/ + +qreal QDeclarativeSpringAnimation::velocity() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->maxVelocity; +} + +void QDeclarativeSpringAnimation::setVelocity(qreal velocity) +{ + Q_D(QDeclarativeSpringAnimation); + d->maxVelocity = velocity; + d->velocityms = velocity / 1000.0; + d->updateMode(); +} + +/*! + \qmlproperty real SpringAnimation::spring + + This property describes how strongly the target is pulled towards the + source. The default value is 0 (that is, the spring-like motion is disabled). + + The useful value range is 0 - 5.0. + + When this property is set and the \l velocity value is greater than 0, + the \l velocity limits the maximum speed. +*/ +qreal QDeclarativeSpringAnimation::spring() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->spring; +} + +void QDeclarativeSpringAnimation::setSpring(qreal spring) +{ + Q_D(QDeclarativeSpringAnimation); + d->spring = spring; + d->updateMode(); +} + +/*! + \qmlproperty real SpringAnimation::damping + This property holds the spring damping value. + + This value describes how quickly the spring-like motion comes to rest. + The default value is 0. + + The useful value range is 0 - 1.0. The lower the value, the faster it + comes to rest. +*/ +qreal QDeclarativeSpringAnimation::damping() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->damping; +} + +void QDeclarativeSpringAnimation::setDamping(qreal damping) +{ + Q_D(QDeclarativeSpringAnimation); + if (damping > 1.) + damping = 1.; + + d->damping = damping; +} + + +/*! + \qmlproperty real SpringAnimation::epsilon + This property holds the spring epsilon. + + The epsilon is the rate and amount of change in the value which is close enough + to 0 to be considered equal to zero. This will depend on the usage of the value. + For pixel positions, 0.25 would suffice. For scale, 0.005 will suffice. + + The default is 0.01. Tuning this value can provide small performance improvements. +*/ +qreal QDeclarativeSpringAnimation::epsilon() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->epsilon; +} + +void QDeclarativeSpringAnimation::setEpsilon(qreal epsilon) +{ + Q_D(QDeclarativeSpringAnimation); + d->epsilon = epsilon; +} + +/*! + \qmlproperty real SpringAnimation::modulus + This property holds the modulus value. The default value is 0. + + Setting a \a modulus forces the target value to "wrap around" at the modulus. + For example, setting the modulus to 360 will cause a value of 370 to wrap around to 10. +*/ +qreal QDeclarativeSpringAnimation::modulus() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->modulus; +} + +void QDeclarativeSpringAnimation::setModulus(qreal modulus) +{ + Q_D(QDeclarativeSpringAnimation); + if (d->modulus != modulus) { + d->haveModulus = modulus != 0.0; + d->modulus = modulus; + d->updateMode(); + emit modulusChanged(); + } +} + +/*! + \qmlproperty real SpringAnimation::mass + This property holds the "mass" of the property being moved. + + The value is 1.0 by default. + + A greater mass causes slower movement and a greater spring-like + motion when an item comes to rest. +*/ +qreal QDeclarativeSpringAnimation::mass() const +{ + Q_D(const QDeclarativeSpringAnimation); + return d->mass; +} + +void QDeclarativeSpringAnimation::setMass(qreal mass) +{ + Q_D(QDeclarativeSpringAnimation); + if (d->mass != mass && mass > 0.0) { + d->useMass = mass != 1.0; + d->mass = mass; + emit massChanged(); + } +} + +void QDeclarativeSpringAnimation::transition(QDeclarativeStateActions &actions, + QDeclarativeProperties &modified, + TransitionDirection direction) +{ + Q_D(QDeclarativeSpringAnimation); + Q_UNUSED(direction); + + if (d->clock->state() != QAbstractAnimation::Running) { + d->lastTime = 0; + } + + QDeclarativeNumberAnimation::transition(actions, modified, direction); + + if (!d->actions) + return; + + if (!d->actions->isEmpty()) { + for (int i = 0; i < d->actions->size(); ++i) { + const QDeclarativeProperty &property = d->actions->at(i).property; + QDeclarativeSpringAnimationPrivate::SpringAnimation &animation + = d->activeAnimations[property]; + animation.to = d->actions->at(i).toValue.toReal(); + animation.start = d->lastTime; + if (d->fromIsDefined) + animation.currentValue = d->actions->at(i).fromValue.toReal(); + else + animation.currentValue = property.read().toReal(); + if (d->mode == QDeclarativeSpringAnimationPrivate::Velocity) { + qreal dist = qAbs(animation.currentValue - animation.to); + if (d->haveModulus && dist > d->modulus / 2) + dist = d->modulus - fmod(dist, d->modulus); + animation.duration = dist / d->velocityms; + } + } + } +} + + +QAbstractAnimation *QDeclarativeSpringAnimation::qtAnimation() +{ + Q_D(QDeclarativeSpringAnimation); + return d->clock; +} + +QT_END_NAMESPACE |