QEasingCurve Class▲
-
Header: QEasingCurve
-
CMake:
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
-
qmake: QT += core
-
Group: QEasingCurve is part of Animation Framework
Detailed Description▲
Easing curves describe a function that controls how the speed of the interpolation between 0 and 1 should be. Easing curves allow transitions from one value to another to appear more natural than a simple constant speed would allow. The QEasingCurve class is usually used in conjunction with the QVariantAnimation and QPropertyAnimation classes but can be used on its own. It is usually used to accelerate the interpolation from zero velocity (ease in) or decelerate to zero velocity (ease out). Ease in and ease out can also be combined in the same easing curve.
To calculate the speed of the interpolation, the easing curve provides the function valueForProgress(), where the progress argument specifies the progress of the interpolation: 0 is the start value of the interpolation, 1 is the end value of the interpolation. The returned value is the effective progress of the interpolation. If the returned value is the same as the input value for all input values the easing curve is a linear curve. This is the default behaviour.
For example,
QEasingCurve easing(QEasingCurve::InOutQuad);
for (qreal t = 0.0; t < 1.0; t += 0.1)
qWarning() << "Effective progress" << t << "is"
<< easing.valueForProgress(t);will print the effective progress of the interpolation between 0 and 1.
When using a QPropertyAnimation, the associated easing curve will be used to control the progress of the interpolation between startValue and endValue:
QPropertyAnimation animation;
animation.setStartValue(0);
animation.setEndValue(1000);
animation.setDuration(1000);
animation.setEasingCurve(QEasingCurve::InOutQuad);The ability to set an amplitude, overshoot, or period depends on the QEasingCurve type. Amplitude access is available to curves that behave as springs such as elastic and bounce curves. Changing the amplitude changes the height of the curve. Period access is only available to elastic curves and setting a higher period slows the rate of bounce. Only curves that have "boomerang" behaviors such as the InBack, OutBack, InOutBack, and OutInBack have overshoot settings. These curves will interpolate beyond the end points and return to the end point, acting similar to a boomerang.
The Easing Curves Example contains samples of QEasingCurve types and lets you change the curve settings.
Member Type Documentation▲
QEasingCurve::EasingFunction▲
This is a typedef for a pointer to a function with the following signature:
qreal myEasingFunction(qreal progress);enum QEasingCurve::Type▲
The type of easing curve.
|
Constant |
|
|---|---|
|
QEasingCurve::Linear |
0 |
|
Constant |
|
|---|---|
|
QEasingCurve::InQuad |
1 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutQuad |
2 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutQuad |
3 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInQuad |
4 |
|
Constant |
|
|---|---|
|
QEasingCurve::InCubic |
5 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutCubic |
6 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutCubic |
7 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInCubic |
8 |
|
Constant |
|
|---|---|
|
QEasingCurve::InQuart |
9 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutQuart |
10 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutQuart |
11 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInQuart |
12 |
|
Constant |
|
|---|---|
|
QEasingCurve::InQuint |
13 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutQuint |
14 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutQuint |
15 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInQuint |
16 |
|
Constant |
|
|---|---|
|
QEasingCurve::InSine |
17 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutSine |
18 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutSine |
19 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInSine |
20 |
|
Constant |
|
|---|---|
|
QEasingCurve::InExpo |
21 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutExpo |
22 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutExpo |
23 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInExpo |
24 |
|
Constant |
|
|---|---|
|
QEasingCurve::InCirc |
25 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutCirc |
26 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutCirc |
27 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInCirc |
28 |
|
Constant |
|
|---|---|
|
QEasingCurve::InElastic |
29 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutElastic |
30 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutElastic |
31 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInElastic |
32 |
|
Constant |
|
|---|---|
|
QEasingCurve::InBack |
33 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutBack |
34 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutBack |
35 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInBack |
36 |
|
Constant |
|
|---|---|
|
QEasingCurve::InBounce |
37 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutBounce |
38 |
|
Constant |
|
|---|---|
|
QEasingCurve::InOutBounce |
39 |
|
Constant |
|
|---|---|
|
QEasingCurve::OutInBounce |
40 |
|
Constant |
Value |
Description |
|---|---|---|
|
QEasingCurve::BezierSpline |
45 |
Allows defining a custom easing curve using a cubic bezier spline |
|
QEasingCurve::TCBSpline |
46 |
Allows defining a custom easing curve using a TCB spline |
|
QEasingCurve::Custom |
47 |
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. |
See Also▲
See also addCubicBezierSegment(), addTCBSegment()
Member Function Documentation▲
QEasingCurve::QEasingCurve(QEasingCurve::Type type = Linear)▲
Constructs an easing curve of the given type.
QEasingCurve::QEasingCurve(const QEasingCurve &other)▲
Construct a copy of other.
[since 5.2] QEasingCurve::QEasingCurve(QEasingCurve &&other)▲
Move-constructs a QEasingCurve instance, making it point at the same object that other was pointing to.
This function was introduced in Qt 5.2.
QEasingCurve::~QEasingCurve()▲
Destructor.
void QEasingCurve::addCubicBezierSegment(const QPointF &c1, const QPointF &c2, const QPointF &endPoint)▲
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. c1 and c2 are the control points used for drawing the curve. endPoint is the endpoint of the curve.
void QEasingCurve::addTCBSegment(const QPointF &nextPoint, qreal t, qreal c, qreal b)▲
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 explicitly at (0.0, 0.0) and has to end at (1.0, 1.0) to be a valid easing curve. The tension t changes the length of the tangent vector. The continuity c changes the sharpness in change between the tangents. The bias b changes the direction of the tangent vector. nextPoint is the sample position. 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.
qreal QEasingCurve::amplitude() const▲
Returns the amplitude. This is not applicable for all curve types. It is only applicable for bounce and elastic curves (curves of type() QEasingCurve::InBounce, QEasingCurve::OutBounce, QEasingCurve::InOutBounce, QEasingCurve::OutInBounce, QEasingCurve::InElastic, QEasingCurve::OutElastic, QEasingCurve::InOutElastic or QEasingCurve::OutInElastic).
See Also▲
See also setAmplitude()
QEasingCurve::EasingFunction QEasingCurve::customType() const▲
Returns the function pointer to the custom easing curve. If type() does not return QEasingCurve::Custom, this function will return 0.
See Also▲
See also setCustomType()
qreal QEasingCurve::overshoot() const▲
Returns the overshoot. This is not applicable for all curve types. It is only applicable if type() is QEasingCurve::InBack, QEasingCurve::OutBack, QEasingCurve::InOutBack or QEasingCurve::OutInBack.
See Also▲
See also setOvershoot()
qreal QEasingCurve::period() const▲
Returns the period. This is not applicable for all curve types. It is only applicable if type() is QEasingCurve::InElastic, QEasingCurve::OutElastic, QEasingCurve::InOutElastic or QEasingCurve::OutInElastic.
See Also▲
See also setPeriod()
void QEasingCurve::setAmplitude(qreal amplitude)▲
Sets the amplitude to amplitude.
This will set the amplitude of the bounce or the amplitude of the elastic "spring" effect. The higher the number, the higher the amplitude.
See Also▲
See also amplitude()
void QEasingCurve::setCustomType(QEasingCurve::EasingFunction func)▲
Sets a custom easing curve that is defined by the user in the function func. The signature of the function is qreal myEasingFunction(qreal progress), where progress and the return value are considered to be normalized between 0 and 1. (In some cases the return value can be outside that range) After calling this function type() will return QEasingCurve::Custom. func cannot be zero.
See Also▲
See also customType(), valueForProgress()
void QEasingCurve::setOvershoot(qreal overshoot)▲
Sets the overshoot to overshoot.
0 produces no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent.
See Also▲
See also overshoot()
void QEasingCurve::setPeriod(qreal period)▲
Sets the period to period. Setting a small period value will give a high frequency of the curve. A large period will give it a small frequency.
See Also▲
See also period()
void QEasingCurve::setType(QEasingCurve::Type type)▲
[since 5.0] void QEasingCurve::swap(QEasingCurve &other)▲
Swaps curve other with this curve. This operation is very fast and never fails.
This function was introduced in Qt 5.0.
[since 5.0] QList<QPointF> QEasingCurve::toCubicSpline() const▲
Returns the cubicBezierSpline that defines a custom easing curve. If the easing curve does not have a custom bezier easing curve the list is empty.
This function was introduced in Qt 5.0.
QEasingCurve::Type QEasingCurve::type() const▲
qreal QEasingCurve::valueForProgress(qreal progress) const▲
Return the effective progress for the easing curve at progress. Whereas progress must be between 0 and 1, the returned effective progress can be outside those bounds. For example, QEasingCurve::InBack will return negative values in the beginning of the function.
bool QEasingCurve::operator!=(const QEasingCurve &other) const▲
Compare this easing curve with other and returns true if they are not equal. It will also compare the properties of a curve.
See Also▲
See also operator==()
QEasingCurve &QEasingCurve::operator=(const QEasingCurve &other)▲
Copy other.
[since 5.2] QEasingCurve &QEasingCurve::operator=(QEasingCurve &&other)▲
Move-assigns other to this QEasingCurve instance.
This function was introduced in Qt 5.2.
bool QEasingCurve::operator==(const QEasingCurve &other) const▲
Compare this easing curve with other and returns true if they are equal. It will also compare the properties of a curve.
Related Non-Members▲
QDataStream &operator<<(QDataStream &stream, const QEasingCurve &easing)▲
Writes the given easing curve to the given stream and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types
QDataStream &operator>>(QDataStream &stream, QEasingCurve &easing)▲
Reads an easing curve from the given stream into the given easing curve and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types