summaryrefslogtreecommitdiffstats
path: root/src/declarative/util/qdeclarativespringanimation.cpp
blob: b5babadda0690168bc26eb072c5aac8d542bfbee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
/****************************************************************************
**
** Copyright (C) 2011 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.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#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 > 0.) {
                // limit velocity
                if (animation.velocity > maxVelocity)
                    animation.velocity = maxVelocity;
                else if (animation.velocity < -maxVelocity)
                    animation.velocity = -maxVelocity;
            }
            animation.currentValue += animation.velocity * 16.0 / 1000.0;
            if (haveModulus) {
                animation.currentValue = fmod(animation.currentValue, modulus);
                if (animation.currentValue < 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 < 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 Animation
    \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