QEasingCurve ¶

概要 ¶

详细描述 ¶

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.

例如，

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.

当使用 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 ，和 OutInBack have overshoot settings. These curves will interpolate beyond the end points and return to the end point, acting similar to a boomerang.

缓和曲线范例 contains samples of QEasingCurve types and lets you change the curve settings.

class QEasingCurve ( [ type=Linear ] ) ¶

QEasingCurve(other)

param type

Type

param other

QEasingCurve

Constructs an easing curve of the given type .

PySide2.QtCore.QEasingCurve. Type ¶

The type of easing curve.

常量	描述
QEasingCurve.Linear

常量	描述
QEasingCurve.InQuad

常量	描述
QEasingCurve.OutQuad

常量	描述
QEasingCurve.InOutQuad

常量	描述
QEasingCurve.OutInQuad

常量	描述
QEasingCurve.InCubic

常量	描述
QEasingCurve.OutCubic

常量	描述
QEasingCurve.InOutCubic

常量	描述
QEasingCurve.OutInCubic

常量	描述
QEasingCurve.InQuart

常量	描述
QEasingCurve.OutQuart

常量	描述
QEasingCurve.InOutQuart

常量	描述
QEasingCurve.OutInQuart

常量	描述
QEasingCurve.InQuint

常量	描述
QEasingCurve.OutQuint

常量	描述
QEasingCurve.InOutQuint

常量	描述
QEasingCurve.OutInQuint

常量	描述
QEasingCurve.InSine

常量	描述
QEasingCurve.OutSine

常量	描述
QEasingCurve.InOutSine

常量	描述
QEasingCurve.OutInSine

常量	描述
QEasingCurve.InExpo

常量	描述
QEasingCurve.OutExpo

常量	描述
QEasingCurve.InOutExpo

常量	描述
QEasingCurve.OutInExpo

常量	描述
QEasingCurve.InCirc

常量	描述
QEasingCurve.OutCirc

常量	描述
QEasingCurve.InOutCirc

常量	描述
QEasingCurve.OutInCirc

常量	描述
QEasingCurve.InElastic

amplitude**period

常量	描述
QEasingCurve.OutElastic

amplitude**period

常量	描述
QEasingCurve.InOutElastic

常量	描述
QEasingCurve.OutInElastic

常量	描述
QEasingCurve.InBack

常量	描述
QEasingCurve.OutBack

常量	描述
QEasingCurve.InOutBack

常量	描述
QEasingCurve.OutInBack

常量	描述
QEasingCurve.InBounce

常量	描述
QEasingCurve.OutBounce

常量	描述
QEasingCurve.InOutBounce

常量	描述
QEasingCurve.OutInBounce

常量	描述
QEasingCurve.BezierSpline	Allows defining a custom easing curve using a cubic bezier spline
QEasingCurve.TCBSpline	Allows defining a custom easing curve using a TCB spline
QEasingCurve.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.

另请参阅

addCubicBezierSegment() addTCBSegment()

PySide2.QtCore.QEasingCurve. addCubicBezierSegment ( c1 , c2 , endPoint ) ¶

参数

• c1 – QPointF

• c2 – QPointF

• endPoint – QPointF

Adds a segment of a cubic bezier spline to define a custom easing curve. It is only applicable if type() is 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.

PySide2.QtCore.QEasingCurve. addTCBSegment ( nextPoint , t , c , b ) ¶

参数

• nextPoint – QPointF

• t – qreal

• c – qreal

• b – qreal

Adds a segment of a TCB bezier spline to define a custom easing curve. It is only applicable if type() is 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 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.

PySide2.QtCore.QEasingCurve. amplitude ( ) ¶

返回类型

qreal

Returns the amplitude. This is not applicable for all curve types. It is only applicable for bounce and elastic curves (curves of type() InBounce , OutBounce , InOutBounce , OutInBounce , InElastic , OutElastic , InOutElastic or OutInElastic ).

另请参阅

setAmplitude()

PySide2.QtCore.QEasingCurve. customType ( ) ¶

返回类型

PyObject

PySide2.QtCore.QEasingCurve. __ne__ ( other ) ¶

参数

other – QEasingCurve

返回类型

bool

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

另请参阅

operator==()

PySide2.QtCore.QEasingCurve. __eq__ ( other ) ¶

参数

other – QEasingCurve

返回类型

bool

Compare this easing curve with other 并返回 true if they are equal. It will also compare the properties of a curve.

PySide2.QtCore.QEasingCurve. overshoot ( ) ¶

返回类型

qreal

Returns the overshoot. This is not applicable for all curve types. It is only applicable if type() is InBack , OutBack , InOutBack or OutInBack .

另请参阅

setOvershoot()

PySide2.QtCore.QEasingCurve. period ( ) ¶

返回类型

qreal

Returns the period. This is not applicable for all curve types. It is only applicable if type() is InElastic , OutElastic , InOutElastic or OutInElastic .

另请参阅

setPeriod()

PySide2.QtCore.QEasingCurve. setAmplitude ( amplitude ) ¶

参数

amplitude – qreal

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.

另请参阅

amplitude()

PySide2.QtCore.QEasingCurve. setCustomType ( arg__1 ) ¶

参数

arg__1 – PyObject

PySide2.QtCore.QEasingCurve. setOvershoot ( overshoot ) ¶

参数

overshoot – qreal

Sets the overshoot to overshoot .

0 produces no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent.

另请参阅

overshoot()

PySide2.QtCore.QEasingCurve. setPeriod ( period ) ¶

参数

period – qreal

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.

另请参阅

period()

PySide2.QtCore.QEasingCurve. setType ( type ) ¶

参数

type – Type

Sets the type of the easing curve to type .

另请参阅

type()

PySide2.QtCore.QEasingCurve. swap ( other ) ¶

参数

other – QEasingCurve

Swaps curve other with this curve. This operation is very fast and never fails.

PySide2.QtCore.QEasingCurve. toCubicSpline ( ) ¶

返回类型

返回 cubicBezierSpline that defines a custom easing curve. If the easing curve does not have a custom bezier easing curve the list is empty.

PySide2.QtCore.QEasingCurve. type ( ) ¶

返回类型

Type

Returns the type of the easing curve.

另请参阅

setType()

PySide2.QtCore.QEasingCurve. valueForProgress ( progress ) ¶

参数

progress – qreal

返回类型

qreal

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, InBack will return negative values in the beginning of the function.