\omitvalue OutCurve
\omitvalue SineCurve
\omitvalue CosineCurve
+ \value BezierSpline Allows defining a custom easing curve using a cubic bezier spline
+ \sa addCubicBezierSegment()
+ \value TCBSpline Allows defining a custom easing curve using a TCB spline
+ \sa addTCBSegment
\value Custom This is returned if the user specified a custom curve type with
setCustomType(). Note that you cannot call setType() with this value,
but type() can return it.
*/
#include "qeasingcurve.h"
+#include <cmath>
#ifndef QT_NO_DEBUG_STREAM
#include <QtCore/qdebug.h>
#include <QtCore/qdatastream.h>
#endif
+#include <QtCore/qpoint.h>
+#include <QtCore/qvector.h>
+
QT_BEGIN_NAMESPACE
static bool isConfigFunction(QEasingCurve::Type type)
{
- return type >= QEasingCurve::InElastic
- && type <= QEasingCurve::OutInBounce;
+ return (type >= QEasingCurve::InElastic
+ && type <= QEasingCurve::OutInBounce) ||
+ type == QEasingCurve::BezierSpline ||
+ type == QEasingCurve::TCBSpline;
}
+struct TCBPoint {
+ QPointF _point;
+ qreal _t;
+ qreal _c;
+ qreal _b;
+
+ TCBPoint() {}
+ TCBPoint(QPointF point, qreal t, qreal c, qreal b) : _point(point), _t(t), _c(c), _b(b) {}
+
+ bool operator==(const TCBPoint& other)
+ {
+ return _point == other._point &&
+ qFuzzyCompare(_t, other._t) &&
+ qFuzzyCompare(_c, other._c) &&
+ qFuzzyCompare(_b, other._b);
+ }
+};
+
+
+typedef QVector<TCBPoint> TCBPoints;
+
class QEasingCurveFunction
{
public:
qreal _p;
qreal _a;
qreal _o;
+ QVector<QPointF> _bezierCurves;
+ TCBPoints _tcbPoints;
+
};
qreal QEasingCurveFunction::value(qreal t)
QEasingCurveFunction *QEasingCurveFunction::copy() const
{
- return new QEasingCurveFunction(_t, _p, _a, _o);
+ QEasingCurveFunction *rv = new QEasingCurveFunction(_t, _p, _a, _o);
+ rv->_bezierCurves = _bezierCurves;
+ rv->_tcbPoints = _tcbPoints;
+ return rv;
}
bool QEasingCurveFunction::operator==(const QEasingCurveFunction& other)
return _t == other._t &&
qFuzzyCompare(_p, other._p) &&
qFuzzyCompare(_a, other._a) &&
- qFuzzyCompare(_o, other._o);
+ qFuzzyCompare(_o, other._o) &&
+ _bezierCurves == other._bezierCurves &&
+ _tcbPoints == other._tcbPoints;
}
QT_BEGIN_INCLUDE_NAMESPACE
QEasingCurve::EasingFunction func;
};
+struct BezierEase : public QEasingCurveFunction
+{
+ struct SingleCubicBezier {
+ qreal p0x, p0y;
+ qreal p1x, p1y;
+ qreal p2x, p2y;
+ qreal p3x, p3y;
+ };
+
+ bool _init;
+ bool _valid;
+ QVector<SingleCubicBezier> _curves;
+ int _curveCount;
+ QVector<qreal> _intervals;
+
+ BezierEase()
+ : QEasingCurveFunction(InOut), _init(false), _valid(false), _curves(10), _intervals(10)
+ { }
+
+ void init()
+ {
+ if (_bezierCurves.last() == QPointF(1.0, 1.0)) {
+ _init = true;
+ _curveCount = _bezierCurves.count() / 3;
+
+ for (int i=0; i < _curveCount; i++) {
+ _intervals[i] = _bezierCurves.at(i * 3 + 2).x();
+
+ if (i == 0) {
+ _curves[0].p0x = 0.0;
+ _curves[0].p0y = 0.0;
+
+ _curves[0].p1x = _bezierCurves.at(0).x();
+ _curves[0].p1y = _bezierCurves.at(0).y();
+
+ _curves[0].p2x = _bezierCurves.at(1).x();
+ _curves[0].p2y = _bezierCurves.at(1).y();
+
+ _curves[0].p3x = _bezierCurves.at(2).x();
+ _curves[0].p3y = _bezierCurves.at(2).y();
+
+ } else if (i == (_curveCount - 1)) {
+ _curves[i].p0x = _bezierCurves.at(_bezierCurves.count() - 4).x();
+ _curves[i].p0y = _bezierCurves.at(_bezierCurves.count() - 4).y();
+
+ _curves[i].p1x = _bezierCurves.at(_bezierCurves.count() - 3).x();
+ _curves[i].p1y = _bezierCurves.at(_bezierCurves.count() - 3).y();
+
+ _curves[i].p2x = _bezierCurves.at(_bezierCurves.count() - 2).x();
+ _curves[i].p2y = _bezierCurves.at(_bezierCurves.count() - 2).y();
+
+ _curves[i].p3x = _bezierCurves.at(_bezierCurves.count() - 1).x();
+ _curves[i].p3y = _bezierCurves.at(_bezierCurves.count() - 1).y();
+ } else {
+ _curves[i].p0x = _bezierCurves.at(i * 3 - 1).x();
+ _curves[i].p0y = _bezierCurves.at(i * 3 - 1).y();
+
+ _curves[i].p1x = _bezierCurves.at(i * 3).x();
+ _curves[i].p1y = _bezierCurves.at(i * 3).y();
+
+ _curves[i].p2x = _bezierCurves.at(i * 3 + 1).x();
+ _curves[i].p2y = _bezierCurves.at(i * 3 + 1).y();
+
+ _curves[i].p3x = _bezierCurves.at(i * 3 + 2).x();
+ _curves[i].p3y = _bezierCurves.at(i * 3 + 2).y();
+ }
+ }
+ _valid = true;
+ } else {
+ _valid = false;
+ }
+ }
+
+ QEasingCurveFunction *copy() const
+ {
+ BezierEase *rv = new BezierEase();
+ rv->_t = _t;
+ rv->_p = _p;
+ rv->_a = _a;
+ rv->_o = _o;
+ rv->_bezierCurves = _bezierCurves;
+ rv->_tcbPoints = _tcbPoints;
+ return rv;
+ }
+
+ void getBezierSegment(SingleCubicBezier * &singleCubicBezier, qreal x)
+ {
+
+ int currentSegment = 0;
+
+ while (currentSegment < _curveCount) {
+ if (x <= _intervals.data()[currentSegment])
+ break;
+ currentSegment++;
+ }
+
+ singleCubicBezier = &_curves.data()[currentSegment];
+ }
+
+
+ qreal static inline newtonIteration(const SingleCubicBezier &singleCubicBezier, qreal t, qreal x)
+ {
+ qreal currentXValue = evaluateForX(singleCubicBezier, t);
+
+ const qreal newT = t - (currentXValue - x) / evaluateDerivateForX(singleCubicBezier, t);
+
+ return newT;
+ }
+
+ qreal value(qreal x)
+ {
+ Q_ASSERT(_bezierCurves.count() % 3 == 0);
+
+ if (_bezierCurves.isEmpty()) {
+ return x;
+ }
+
+ if (!_init)
+ init();
+
+ if (!_valid) {
+ qWarning("QEasingCurve: Invalid bezier curve");
+ return x;
+ }
+ SingleCubicBezier *singleCubicBezier = 0;
+ getBezierSegment(singleCubicBezier, x);
+
+ return evaluateSegmentForY(*singleCubicBezier, findTForX(*singleCubicBezier, x));
+ }
+
+ qreal static inline evaluateSegmentForY(const SingleCubicBezier &singleCubicBezier, qreal t)
+ {
+ const qreal p0 = singleCubicBezier.p0y;
+ const qreal p1 = singleCubicBezier.p1y;
+ const qreal p2 = singleCubicBezier.p2y;
+ const qreal p3 = singleCubicBezier.p3y;
+
+ const qreal s = 1 - t;
+
+ const qreal s_squared = s*s;
+ const qreal t_squared = t*t;
+
+ const qreal s_cubic = s_squared * s;
+ const qreal t_cubic = t_squared * t;
+
+ return s_cubic * p0 + 3 * s_squared * t * p1 + 3 * s * t_squared * p2 + t_cubic * p3;
+ }
+
+ qreal static inline evaluateForX(const SingleCubicBezier &singleCubicBezier, qreal t)
+ {
+ const qreal p0 = singleCubicBezier.p0x;
+ const qreal p1 = singleCubicBezier.p1x;
+ const qreal p2 = singleCubicBezier.p2x;
+ const qreal p3 = singleCubicBezier.p3x;
+
+ const qreal s = 1 - t;
+
+ const qreal s_squared = s*s;
+ const qreal t_squared = t*t;
+
+ const qreal s_cubic = s_squared * s;
+ const qreal t_cubic = t_squared * t;
+
+ return s_cubic * p0 + 3 * s_squared * t * p1 + 3 * s * t_squared * p2 + t_cubic * p3;
+ }
+
+ qreal static inline evaluateDerivateForX(const SingleCubicBezier &singleCubicBezier, qreal t)
+ {
+ const qreal p0 = singleCubicBezier.p0x;
+ const qreal p1 = singleCubicBezier.p1x;
+ const qreal p2 = singleCubicBezier.p2x;
+ const qreal p3 = singleCubicBezier.p3x;
+
+ const qreal t_squared = t*t;
+
+ return -3*p0 + 3*p1 + 6*p0*t - 12*p1*t + 6*p2*t + 3*p3*t_squared - 3*p0*t_squared + 9*p1*t_squared - 9*p2*t_squared;
+ }
+
+ qreal static inline _cbrt(qreal d)
+ {
+ qreal sign = 1;
+ if (d < 0)
+ sign = -1;
+ d = d * sign;
+
+ qreal t_i = _fast_cbrt(d);
+
+ //one step of Halley's Method to get a better approximation
+ const qreal t_i_cubic = t_i * t_i * t_i;
+ qreal t = t_i * (t_i_cubic + d + d) / (t_i_cubic + t_i_cubic + d);
+
+ //another step
+ /*t_i = t;
+ t_i_cubic = pow(t_i, 3);
+ t = t_i * (t_i_cubic + d + d) / (t_i_cubic + t_i_cubic + d);*/
+
+ return t * sign;
+ }
+
+ float static inline _fast_cbrt(float x)
+ {
+ int& i = (int&) x;
+ i = (i - (127<<23)) / 3 + (127<<23);
+ return x;
+ }
+
+ double static inline _fast_cbrt(double d)
+ {
+ const unsigned int B1 = 715094163;
+ double t = 0.0;
+ unsigned int* pt = (unsigned int*) &t;
+ unsigned int* px = (unsigned int*) &d;
+ pt[1]=px[1]/3+B1;
+ return t;
+ }
+
+ qreal static inline _acos(qreal x)
+ {
+ return sqrt(1-x)*(1.5707963267948966192313216916398f + x*(-0.213300989f + x*(0.077980478f + x*-0.02164095f)));
+ }
+
+ qreal static inline _cos(qreal x) //super fast _cos
+ {
+ const qreal pi_times2 = 2 * M_PI;
+ const qreal pi_neg = -1 * M_PI;
+ const qreal pi_by2 = M_PI / 2.0;
+
+ x += pi_by2; //the polynom is for sin
+
+ if (x < pi_neg)
+ x += pi_times2;
+ else if (x > M_PI)
+ x -= pi_times2;
+
+ const qreal a = 0.405284735;
+ const qreal b = 1.27323954;
+
+ const qreal x_squared = x * x;
+
+ if (x < 0) {
+ qreal cos = b * x + a * x_squared;
+
+ if (cos < 0)
+ return 0.225 * (cos * -1 * cos - cos) + cos;
+ return 0.225 * (cos * cos - cos) + cos;
+ } //else
+
+ qreal cos = b * x - a * x_squared;
+
+ if (cos < 0)
+ return 0.225 * (cos * 1 *-cos - cos) + cos;
+ return 0.225 * (cos * cos - cos) + cos;
+ }
+
+ bool static inline inRange(qreal f)
+ {
+ return (f >= -0.01 && f <= 1.01);
+ }
+
+ void static inline cosacos(qreal x, qreal &s1, qreal &s2, qreal &s3 )
+ {
+ //This function has no proper algebraic representation in real numbers.
+ //We use approximations instead
+
+ const qreal x_squared = x * x;
+ const qreal x_plus_one_sqrt = sqrt(1.0 + x);
+ const qreal one_minus_x_sqrt = sqrt(1.0 - x);
+
+ //cos(acos(x) / 3)
+ //s1 = _cos(_acos(x) / 3);
+ s1 = 0.463614 - 0.0347815 * x + 0.00218245 * x_squared + 0.402421 * x_plus_one_sqrt;
+
+ //cos(acos((x) - M_PI) / 3)
+ //s3 = _cos((_acos(x) - M_PI) / 3);
+ s3 = 0.463614 + 0.402421 * one_minus_x_sqrt + 0.0347815 * x + 0.00218245 * x_squared;
+
+ //cos((acos(x) + M_PI) / 3)
+ //s2 = _cos((_acos(x) + M_PI) / 3);
+ s2 = -0.401644 * one_minus_x_sqrt - 0.0686804 * x + 0.401644 * x_plus_one_sqrt;
+ }
+
+ qreal static inline singleRealSolutionForCubic(qreal a, qreal b, qreal c)
+ {
+ //returns the real solutiuon in [0..1]
+ //We use the Cardano formula
+
+ //substituiton: x = z - a/3
+ // z^3+pz+q=0
+
+ if (c < 0.000001 && c > -0.000001)
+ return 0;
+
+ const qreal a_by3 = a / 3.0;
+
+ const qreal a_cubic = a * a * a;
+
+ const qreal p = b - a * a_by3;
+ const qreal q = 2.0 * a_cubic / 27.0 - a * b / 3.0 + c;
+
+ const qreal q_squared = q * q;
+ const qreal p_cubic = p * p * p;
+ const qreal D = 0.25 * q_squared + p_cubic / 27.0;
+
+ if (D >= 0) {
+ const qreal D_sqrt = sqrt(D);
+ qreal u = _cbrt( -q * 0.5 + D_sqrt);
+ qreal v = _cbrt( -q * 0.5 - D_sqrt);
+ qreal z1 = u + v;
+
+ qreal t1 = z1 - a_by3;
+
+ if (inRange(t1))
+ return t1;
+ qreal z2 = -1 *u;
+ qreal t2 = z2 - a_by3;
+ return t2;
+ }
+
+ //casus irreducibilis
+ const qreal p_minus_sqrt = sqrt(-p);
+
+ //const qreal f = sqrt(4.0 / 3.0 * -p);
+ const qreal f = sqrt(4.0 / 3.0) * p_minus_sqrt;
+
+ //const qreal sqrtP = sqrt(27.0 / -p_cubic);
+ const qreal sqrtP = -3.0*sqrt(3.0) / (p_minus_sqrt * p);
+
+
+ const qreal g = -q * 0.5 * sqrtP;
+
+ qreal s1;
+ qreal s2;
+ qreal s3;
+
+ cosacos(g, s1, s2, s3);
+
+ qreal z1 = -1* f * s2;
+ qreal t1 = z1 - a_by3;
+ if (inRange(t1))
+ return t1;
+
+ qreal z2 = f * s1;
+ qreal t2 = z2 - a_by3;
+ if (inRange(t2))
+ return t2;
+
+ qreal z3 = -1 * f * s3;
+ qreal t3 = z3 - a_by3;
+ return t3;
+ }
+
+ qreal static inline findTForX(const SingleCubicBezier &singleCubicBezier, qreal x)
+ {
+ const qreal p0 = singleCubicBezier.p0x;
+ const qreal p1 = singleCubicBezier.p1x;
+ const qreal p2 = singleCubicBezier.p2x;
+ const qreal p3 = singleCubicBezier.p3x;
+
+ const qreal factorT3 = p3 - p0 + 3 * p1 - 3 * p2;
+ const qreal factorT2 = 3 * p0 - 6 * p1 + 3 * p2;
+ const qreal factorT1 = -3 * p0 + 3 * p1;
+ const qreal factorT0 = p0 - x;
+
+ const qreal a = factorT2 / factorT3;
+ const qreal b = factorT1 / factorT3;
+ const qreal c = factorT0 / factorT3;
+
+ return singleRealSolutionForCubic(a, b, c);
+
+ //one new iteration to increase numeric stability
+ //return newtonIteration(singleCubicBezier, t, x);
+ }
+};
+
+struct TCBEase : public BezierEase
+{
+ qreal value(qreal x)
+ {
+ Q_ASSERT(_bezierCurves.count() % 3 == 0);
+
+ if (_bezierCurves.isEmpty()) {
+ qWarning("QEasingCurve: Invalid tcb curve");
+ return x;
+ }
+
+ return BezierEase::value(x);
+ }
+
+};
+
struct ElasticEase : public QEasingCurveFunction
{
ElasticEase(Type type)
ElasticEase *rv = new ElasticEase(_t);
rv->_p = _p;
rv->_a = _a;
+ rv->_bezierCurves = _bezierCurves;
+ rv->_tcbPoints = _tcbPoints;
return rv;
}
{
BounceEase *rv = new BounceEase(_t);
rv->_a = _a;
+ rv->_bezierCurves = _bezierCurves;
+ rv->_tcbPoints = _tcbPoints;
return rv;
}
{
BackEase *rv = new BackEase(_t);
rv->_o = _o;
+ rv->_bezierCurves = _bezierCurves;
+ rv->_tcbPoints = _tcbPoints;
return rv;
}
case QEasingCurve::OutInBack:
curveFunc = new BackEase(BackEase::OutIn);
break;
+ case QEasingCurve::BezierSpline:
+ curveFunc = new BezierEase();
+ break;
+ case QEasingCurve::TCBSpline:
+ curveFunc = new TCBEase();
+ break;
default:
curveFunc = new QEasingCurveFunction(QEasingCurveFunction::In, qreal(0.3), qreal(1.0), qreal(1.70158));
}
}
/*!
+ Adds a segment of a cubic bezier spline to define a custom easing curve.
+ It is only applicable if type() is QEasingCurve::BezierSpline.
+ Note that the spline implicitly starts at (0.0, 0.0) and has to end at (1.0, 1.0) to
+ be a valid easing curve.
+ */
+void QEasingCurve::addCubicBezierSegment(const QPointF & c1, const QPointF & c2, const QPointF & endPoint)
+{
+ if (!d_ptr->config)
+ d_ptr->config = curveToFunctionObject(d_ptr->type);
+ d_ptr->config->_bezierCurves << c1 << c2 << endPoint;
+}
+
+QVector<QPointF> static inline tcbToBezier(const TCBPoints &tcbPoints)
+{
+ const int count = tcbPoints.count();
+ QVector<QPointF> bezierPoints;
+
+ for (int i = 1; i < count; i++) {
+ const qreal t_0 = tcbPoints.at(i - 1)._t;
+ const qreal c_0 = tcbPoints.at(i - 1)._c;
+ qreal b_0 = -1;
+
+ qreal const t_1 = tcbPoints.at(i)._t;
+ qreal const c_1 = tcbPoints.at(i)._c;
+ qreal b_1 = 1;
+
+ QPointF c_minusOne; //P1 last segment - not available for the first point
+ const QPointF c0(tcbPoints.at(i - 1)._point); //P0 Hermite/TBC
+ const QPointF c3(tcbPoints.at(i)._point); //P1 Hermite/TBC
+ QPointF c4; //P0 next segment - not available for the last point
+
+ if (i > 1) { //first point no left tangent
+ c_minusOne = tcbPoints.at(i - 2)._point;
+ b_0 = tcbPoints.at(i - 1)._b;
+ }
+
+ if (i < (count - 1)) { //last point no right tangent
+ c4 = tcbPoints.at(i + 1)._point;
+ b_1 = tcbPoints.at(i)._b;
+ }
+
+ const qreal dx_0 = 0.5 * (1-t_0) * ((1 + b_0) * (1 + c_0) * (c0.x() - c_minusOne.x()) + (1- b_0) * (1 - c_0) * (c3.x() - c0.x()));
+ const qreal dy_0 = 0.5 * (1-t_0) * ((1 + b_0) * (1 + c_0) * (c0.y() - c_minusOne.y()) + (1- b_0) * (1 - c_0) * (c3.y() - c0.y()));
+
+ const qreal dx_1 = 0.5 * (1-t_1) * ((1 + b_1) * (1 - c_1) * (c3.x() - c0.x()) + (1 - b_1) * (1 + c_1) * (c4.x() - c3.x()));
+ const qreal dy_1 = 0.5 * (1-t_1) * ((1 + b_1) * (1 - c_1) * (c3.y() - c0.y()) + (1 - b_1) * (1 + c_1) * (c4.y() - c3.y()));
+
+ const QPointF d_0 = QPointF(dx_0, dy_0);
+ const QPointF d_1 = QPointF(dx_1, dy_1);
+
+ QPointF c1 = (3 * c0 + d_0) / 3;
+ QPointF c2 = (3 * c3 - d_1) / 3;
+ bezierPoints << c1 << c2 << c3;
+ }
+ return bezierPoints;
+}
+
+/*!
+ Adds a segment of a TCB bezier spline to define a custom easing curve.
+ It is only applicable if type() is QEasingCurve::TCBSpline.
+ The spline has to start explitly at (0.0, 0.0) and has to end at (1.0, 1.0) to
+ be a valid easing curve.
+ The three parameters are called tension, continuity and bias. All three parameters are
+ valid between -1 and 1 and define the tangent of the control point.
+ If all three parameters are 0 the resulting spline is a Catmull-Rom spline.
+ The begin and endpoint always have a bias of -1 and 1, since the outer tangent is not defined.
+ */
+void QEasingCurve::addTCBSegment(const QPointF &nextPoint, qreal t, qreal c, qreal b)
+{
+ if (!d_ptr->config)
+ d_ptr->config = curveToFunctionObject(d_ptr->type);
+
+ d_ptr->config->_tcbPoints.append(TCBPoint(nextPoint, t, c ,b));
+
+ if (nextPoint == QPointF(1.0, 1.0)) {
+ d_ptr->config->_bezierCurves = tcbToBezier(d_ptr->config->_tcbPoints);
+ d_ptr->config->_tcbPoints.clear();
+ }
+
+}
+
+/*!
Returns the type of the easing curve.
*/
QEasingCurve::Type QEasingCurve::type() const
qreal amp = -1.0;
qreal period = -1.0;
qreal overshoot = -1.0;
+ QVector<QPointF> bezierCurves;
+ QVector<TCBPoint> tcbPoints;
if (config) {
amp = config->_a;
period = config->_p;
overshoot = config->_o;
+ bezierCurves = config->_bezierCurves;
+ tcbPoints = config->_tcbPoints;
+
delete config;
config = 0;
}
- if (isConfigFunction(newType) || (amp != -1.0) || (period != -1.0) || (overshoot != -1.0)) {
+ if (isConfigFunction(newType) || (amp != -1.0) || (period != -1.0) || (overshoot != -1.0) ||
+ !bezierCurves.isEmpty()) {
config = curveToFunctionObject(newType);
if (amp != -1.0)
config->_a = amp;
config->_p = period;
if (overshoot != -1.0)
config->_o = overshoot;
+ config->_bezierCurves = bezierCurves;
+ config->_tcbPoints = tcbPoints;
func = 0;
} else if (newType != QEasingCurve::Custom) {
func = curveToFunc(newType);