QVariantAnimation¶
The QVariantAnimation
class provides a base class for animations. More…

Inherited by: QPropertyAnimation
New in version 4.6.
Synopsis¶
Functions¶
def
currentValue
()def
easingCurve
()def
endValue
()def
keyValueAt
(step)def
setDuration
(msecs)def
setEasingCurve
(easing)def
setEndValue
(value)def
setKeyValueAt
(step, value)def
setStartValue
(value)def
startValue
()def
valueChanged
(value)
Virtual functions¶
def
interpolated
(from, to, progress)def
updateCurrentValue
(value)
Detailed Description¶
This class is part of The Animation Framework . It serves as a base class for property and item animations, with functions for shared functionality.
The class performs interpolation over QVariant s, but leaves using the interpolated values to its subclasses. Currently, Qt provides QPropertyAnimation
, which animates Qt properties . See the QPropertyAnimation
class description if you wish to animate such properties.
You can then set start and end values for the property by calling setStartValue()
and setEndValue()
, and finally call start()
to start the animation. QVariantAnimation
will interpolate the property of the target object and emit valueChanged()
. To react to a change in the current value you have to reimplement the updateCurrentValue()
virtual function or connect to said signal.
It is also possible to set values at specified steps situated between the start and end value. The interpolation will then touch these points at the specified steps. Note that the start and end values are defined as the key values at 0.0 and 1.0.
There are two ways to affect how QVariantAnimation
interpolates the values. You can set an easing curve by calling setEasingCurve()
, and configure the duration by calling setDuration()
. You can change how the QVariant s are interpolated by creating a subclass of QVariantAnimation
, and reimplementing the virtual interpolated()
function.
Subclassing QVariantAnimation
can be an alternative if you have QVariant s that you do not wish to declare as Qt properties. Note, however, that you in most cases will be better off declaring your QVariant as a property.
Not all QVariant types are supported. Below is a list of currently supported QVariant types:
Int
UInt
Double
Float
QLine
QLineF
QPoint
QPointF
QSize
QSizeF
QRect
QRectF
QColor
If you need to interpolate other variant types, including custom types, you have to implement interpolation for these yourself. To do this, you can register an interpolator function for a given type. This function takes 3 parameters: the start value, the end value, and the current progress.
Example:
QVariant myColorInterpolator(const QColor &start, const QColor &end, qreal progress) { ... return QColor(...); } ... qRegisterAnimationInterpolator<QColor>(myColorInterpolator);
Another option is to reimplement interpolated()
, which returns interpolation values for the value being interpolated.
-
class
PySide6.QtCore.
QVariantAnimation
([parent=None])¶ - Parameters
parent –
PySide6.QtCore.QObject
Construct a QVariantAnimation
object. parent
is passed to QAbstractAnimation
‘s constructor.
-
PySide6.QtCore.QVariantAnimation.
currentValue
()¶ - Return type
object
-
PySide6.QtCore.QVariantAnimation.
easingCurve
()¶ - Return type
See also
-
PySide6.QtCore.QVariantAnimation.
endValue
()¶ - Return type
object
See also
-
PySide6.QtCore.QVariantAnimation.
interpolated
(from, to, progress)¶ - Parameters
from – object
to – object
progress – float
- Return type
object
This virtual function returns the linear interpolation between variants from
and to
, at progress
, usually a value between 0 and 1. You can reimplement this function in a subclass of QVariantAnimation
to provide your own interpolation algorithm.
Note that in order for the interpolation to work with a QEasingCurve
that return a value smaller than 0 or larger than 1 (such as InBack
) you should make sure that it can extrapolate. If the semantic of the datatype does not allow extrapolation this function should handle that gracefully.
You should call the QVariantAnimation
implementation of this function if you want your class to handle the types already supported by Qt (see class QVariantAnimation
description for a list of supported types).
See also
-
PySide6.QtCore.QVariantAnimation.
keyValueAt
(step)¶ - Parameters
step – float
- Return type
object
Returns the key frame value for the given step
. The given step
must be in the range 0 to 1. If there is no KeyValue
for step
, it returns an invalid QVariant .
See also
keyValues()
setKeyValueAt()
-
PySide6.QtCore.QVariantAnimation.
setDuration
(msecs)¶ - Parameters
msecs – int
See also
duration()
-
PySide6.QtCore.QVariantAnimation.
setEasingCurve
(easing)¶ - Parameters
easing –
PySide6.QtCore.QEasingCurve
See also
-
PySide6.QtCore.QVariantAnimation.
setEndValue
(value)¶ - Parameters
value – object
See also
-
PySide6.QtCore.QVariantAnimation.
setKeyValueAt
(step, value)¶ - Parameters
step – float
value – object
Creates a key frame at the given step
with the given value
. The given step
must be in the range 0 to 1.
See also
setKeyValues()
keyValueAt()
-
PySide6.QtCore.QVariantAnimation.
setStartValue
(value)¶ - Parameters
value – object
See also
-
PySide6.QtCore.QVariantAnimation.
startValue
()¶ - Return type
object
See also
-
PySide6.QtCore.QVariantAnimation.
updateCurrentValue
(value)¶ - Parameters
value – object
This virtual function is called every time the animation’s current value changes. The value
argument is the new current value.
The base class implementation does nothing.
See also
-
PySide6.QtCore.QVariantAnimation.
valueChanged
(value)¶ - Parameters
value – object
QVariantAnimation
emits this signal whenever the current value
changes.
See also
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