CopperSpice API  1.8.1
QEasingCurve Class Reference

The QEasingCurve class provides easing curves for controlling animation. More...

## Public Typedefs

typedef qreal (* EasingFunction) (qreal progress)

enum  Type

## Public Methods

QEasingCurve (const QEasingCurve &other)

QEasingCurve (Type type=Linear)

~QEasingCurve ()

qreal amplitude () const

EasingFunction customType () const

bool operator!= (const QEasingCurve &other) const

QEasingCurve & operator= (const QEasingCurve &other)

bool operator== (const QEasingCurve &other) const

qreal overshoot () const

qreal period () const

void setAmplitude (qreal amplitude)

void setCustomType (EasingFunction func)

void setOvershoot (qreal overshoot)

void setPeriod (qreal period)

void setType (Type type)

Type type () const

qreal valueForProgress (qreal progress) const

## Friends

QDataStreamoperator<< (QDataStream &stream, const QEasingCurve &easing)

## Related Functions

These are not member functions

QDataStreamoperator>> (QDataStream &stream, const QEasingCurve &easing)

## Detailed Description

The QEasingCurve class provides easing curves for controlling animation.

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 behavior.

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:

animation.setStartValue(0);
animation.setEndValue(1000);
animation.setDuration(1000);

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.

setAmplitude()

## Member Typedef Documentation

 QEasingCurve::EasingFunction

This is a typedef for a pointer to a function with the following signature:

qreal myEasingFunction(qreal progress);

## Member Enumeration Documentation

 enum QEasingCurve::Type

The type of easing curve.

ConstantValueDescription
QEasingCurve::Linear 0
Easing curve for a linear (t) function: velocity is constant.
QEasingCurve::InQuad 1
Easing curve for a quadratic (t^2) function: accelerating from zero velocity.
QEasingCurve::OutQuad 2
Easing curve for a quadratic (t^2) function: decelerating to zero velocity.
QEasingCurve::InOutQuad 3
Easing curve for a quadratic (t^2) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInQuad 4
Easing curve for a quadratic (t^2) function: deceleration until halfway, then acceleration.
QEasingCurve::InCubic 5
Easing curve for a cubic (t^3) function: accelerating from zero velocity.
QEasingCurve::OutCubic 6
Easing curve for a cubic (t^3) function: decelerating to zero velocity.
QEasingCurve::InOutCubic 7
Easing curve for a cubic (t^3) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInCubic 8
Easing curve for a cubic (t^3) function: deceleration until halfway, then acceleration.
QEasingCurve::InQuart 9
Easing curve for a quartic (t^4) function: accelerating from zero velocity.
QEasingCurve::OutQuart 10
Easing curve for a quartic (t^4) function: decelerating to zero velocity.
QEasingCurve::InOutQuart 11
Easing curve for a quartic (t^4) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInQuart 12
Easing curve for a quartic (t^4) function: deceleration until halfway, then acceleration.
QEasingCurve::InQuint 13
Easing curve for a quintic (t^5) easing in: accelerating from zero velocity.
QEasingCurve::OutQuint 14
Easing curve for a quintic (t^5) function: decelerating to zero velocity.
QEasingCurve::InOutQuint 15
Easing curve for a quintic (t^5) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInQuint 16
Easing curve for a quintic (t^5) function: deceleration until halfway, then acceleration.
QEasingCurve::InSine 17
Easing curve for a sinusoidal (sin(t)) function: accelerating from zero velocity.
QEasingCurve::OutSine 18
Easing curve for a sinusoidal (sin(t)) function: decelerating from zero velocity.
QEasingCurve::InOutSine 19
Easing curve for a sinusoidal (sin(t)) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInSine 20
Easing curve for a sinusoidal (sin(t)) function: deceleration until halfway, then acceleration.
QEasingCurve::InExpo 21
Easing curve for an exponential (2^t) function: accelerating from zero velocity.
QEasingCurve::OutExpo 22
Easing curve for an exponential (2^t) function: decelerating from zero velocity.
QEasingCurve::InOutExpo 23
Easing curve for an exponential (2^t) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInExpo 24
Easing curve for an exponential (2^t) function: deceleration until halfway, then acceleration.
QEasingCurve::InCirc 25
Easing curve for a circular (sqrt(1-t^2)) function: accelerating from zero velocity.
QEasingCurve::OutCirc 26
Easing curve for a circular (sqrt(1-t^2)) function: decelerating from zero velocity.
QEasingCurve::InOutCirc 27
Easing curve for a circular (sqrt(1-t^2)) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInCirc 28
Easing curve for a circular (sqrt(1-t^2)) function: deceleration until halfway, then acceleration.
QEasingCurve::InElastic 29
Easing curve for an elastic (exponentially decaying sine wave) function: accelerating from zero velocity. The peak amplitude can be set with the amplitude parameter, and the period of decay by the period parameter.
QEasingCurve::OutElastic 30
Easing curve for an elastic (exponentially decaying sine wave) function: decelerating from zero velocity. The peak amplitude can be set with the amplitude parameter, and the period of decay by the period parameter.
QEasingCurve::InOutElastic 31
Easing curve for an elastic (exponentially decaying sine wave) function: acceleration until halfway, then deceleration.
QEasingCurve::OutInElastic 32
Easing curve for an elastic (exponentially decaying sine wave) function: deceleration until halfway, then acceleration.
QEasingCurve::InBack 33
Easing curve for a back (overshooting cubic function: (s+1)*t^3 - s*t^2) easing in: accelerating from zero velocity.
QEasingCurve::OutBack 34
Easing curve for a back (overshooting cubic function: (s+1)*t^3 - s*t^2) easing out: decelerating to zero velocity.
QEasingCurve::InOutBack 35
Easing curve for a back (overshooting cubic function: (s+1)*t^3 - s*t^2) easing in/out: acceleration until halfway, then deceleration.
QEasingCurve::OutInBack 36
Easing curve for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing out/in: deceleration until halfway, then acceleration.
QEasingCurve::InBounce 37
Easing curve for a bounce (exponentially decaying parabolic bounce) function: accelerating from zero velocity.
QEasingCurve::OutBounce 38
Easing curve for a bounce (exponentially decaying parabolic bounce) function: decelerating from zero velocity.
QEasingCurve::InOutBounce 39
Easing curve for a bounce (exponentially decaying parabolic bounce) function easing in/out: acceleration until halfway, then deceleration.
QEasingCurve::OutInBounce 40
Easing curve for a bounce (exponentially decaying parabolic bounce) function easing out/in: deceleration until halfway, then acceleration.
QEasingCurve::Custom 45 This is returned if the user specified a custom curve type with setCustomType(). You can not call setType() with this value, but type() can return it.

## Constructor & Destructor Documentation

 QEasingCurve::QEasingCurve ( Type type = Linear )

Constructs an easing curve of the given type.

 QEasingCurve::QEasingCurve ( const QEasingCurve & other )

Construct a copy of other.

 QEasingCurve::~QEasingCurve ( )

Destroys the current QEasingCurve object.

## Method Documentation

 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).

setAmplitude()
 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.

setCustomType()
 bool QEasingCurve::operator!= ( const QEasingCurve & other ) const
inline

Compare this easing curve with other and returns true if they are not equal. It will also compare the properties of a curve.

operator==()
 QEasingCurve & QEasingCurve::operator= ( const QEasingCurve & other )

Copy other.

 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.

 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.

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.

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.

amplitude()
 void QEasingCurve::setCustomType ( 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 is 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 can not be zero.

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.

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.

period()
 void QEasingCurve::setType ( Type type )

Sets the type of the easing curve to type.

type()
 Type QEasingCurve::type ( ) const

Returns the type of the easing curve.

setType()
 qreal QEasingCurve::valueForProgress ( qreal progress ) const

Return the effective progress for the easing curve at progress. While progress must be between 0 and 1, the returned effective progress can be outside those bounds. For instance, QEasingCurve::InBack will return negative values in the beginning of the function.

## Friends And Related Function Documentation

 QDataStream & operator<< ( QDataStream & stream, const QEasingCurve & easing )
friend

Writes the given easing to the stream. Returns a reference to the stream.

Refer to Serializing Data Types for additional information.

 QDataStream & operator>> ( QDataStream & stream, const QEasingCurve & easing )
related

Reads from the stream into the given easing. Returns a reference to the stream.

Refer to Serializing Data Types for additional information.