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QVariantAnimation Class Reference

\inmodule QtCore More...

#include <qvariantanimation.h>

+ Inheritance diagram for QVariantAnimation:
+ Collaboration diagram for QVariantAnimation:

Public Types

using KeyValue = std::pair<qreal, QVariant>
 This is a typedef for std::pair<qreal, QVariant>.
 
typedef QList< KeyValueKeyValues
 This is a typedef for QList<KeyValue>
 
typedef QVariant(*) Interpolator(const void *from, const void *to, qreal progress)
 
- Public Types inherited from QAbstractAnimation
enum  Direction { Forward , Backward }
 This enum describes the direction of the animation when in \l Running state. More...
 
enum  State { Stopped , Paused , Running }
 This enum describes the state of the animation. More...
 
enum  DeletionPolicy { KeepWhenStopped = 0 , DeleteWhenStopped }
 \value KeepWhenStopped The animation will not be deleted when stopped. More...
 

Signals

void valueChanged (const QVariant &value)
 QVariantAnimation emits this signal whenever the current value changes.
 
- Signals inherited from QAbstractAnimation
void finished ()
 QAbstractAnimation emits this signal after the animation has stopped and has reached the end.
 
void stateChanged (QAbstractAnimation::State newState, QAbstractAnimation::State oldState)
 QAbstractAnimation emits this signal whenever the state of the animation has changed from oldState to newState.
 
void currentLoopChanged (int currentLoop)
 QAbstractAnimation emits this signal whenever the current loop changes.
 
void directionChanged (QAbstractAnimation::Direction)
 QAbstractAnimation emits this signal whenever the direction has been changed.
 
- Signals inherited from QObject
void destroyed (QObject *=nullptr)
 This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
 
void objectNameChanged (const QString &objectName, QPrivateSignal)
 This signal is emitted after the object's name has been changed.
 

Public Member Functions

 QVariantAnimation (QObject *parent=nullptr)
 Construct a QVariantAnimation object.
 
 ~QVariantAnimation ()
 Destroys the animation.
 
QVariant startValue () const
 
void setStartValue (const QVariant &value)
 
QVariant endValue () const
 
void setEndValue (const QVariant &value)
 
QVariant keyValueAt (qreal step) const
 Returns the key frame value for the given step.
 
void setKeyValueAt (qreal step, const QVariant &value)
 Creates a key frame at the given step with the given value.
 
KeyValues keyValues () const
 Returns the key frames of this animation.
 
void setKeyValues (const KeyValues &values)
 Replaces the current set of key frames with the given keyValues.
 
QVariant currentValue () const
 
int duration () const override
 This pure virtual function returns the duration of the animation, and defines for how long QAbstractAnimation should update the current time.
 
void setDuration (int msecs)
 
QBindable< int > bindableDuration ()
 
QEasingCurve easingCurve () const
 
void setEasingCurve (const QEasingCurve &easing)
 
QBindable< QEasingCurvebindableEasingCurve ()
 
- Public Member Functions inherited from QAbstractAnimation
 QAbstractAnimation (QObject *parent=nullptr)
 Constructs the QAbstractAnimation base class, and passes parent to QObject's constructor.
 
virtual ~QAbstractAnimation ()
 Stops the animation if it's running, then destroys the QAbstractAnimation.
 
State state () const
 
QBindable< QAbstractAnimation::StatebindableState () const
 
QAnimationGroupgroup () const
 If this animation is part of a QAnimationGroup, this function returns a pointer to the group; otherwise, it returns \nullptr.
 
Direction direction () const
 
void setDirection (Direction direction)
 
QBindable< DirectionbindableDirection ()
 
int currentTime () const
 
QBindable< int > bindableCurrentTime ()
 
int currentLoopTime () const
 Returns the current time inside the current loop.
 
int loopCount () const
 
void setLoopCount (int loopCount)
 
QBindable< int > bindableLoopCount ()
 
int currentLoop () const
 
QBindable< int > bindableCurrentLoop () const
 
int totalDuration () const
 Returns the total and effective duration of the animation, including the loop count.
 
- Public Member Functions inherited from QObject
Q_INVOKABLE QObject (QObject *parent=nullptr)
 Constructs an object with parent object parent.
 
virtual ~QObject ()
 Destroys the object, deleting all its child objects.
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 Filters events if this object has been installed as an event filter for the watched object.
 
QString objectName () const
 
Q_WEAK_OVERLOAD void setObjectName (const QString &name)
 Sets the object's name to name.
 
void setObjectName (QAnyStringView name)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
QBindable< QStringbindableObjectName ()
 
bool isWidgetType () const
 Returns true if the object is a widget; otherwise returns false.
 
bool isWindowType () const
 Returns true if the object is a window; otherwise returns false.
 
bool isQuickItemType () const
 Returns true if the object is a QQuickItem; otherwise returns false.
 
bool signalsBlocked () const noexcept
 Returns true if signals are blocked; otherwise returns false.
 
bool blockSignals (bool b) noexcept
 If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
 
QThreadthread () const
 Returns the thread in which the object lives.
 
bool moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
 Changes the thread affinity for this object and its children and returns true on success.
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
 
int startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
 
void killTimer (int id)
 Kills the timer with timer identifier, id.
 
void killTimer (Qt::TimerId id)
 
template<typename T >
findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
 
template<typename T >
QList< T > findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
 
template<typename T >
findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
template<typename T >
QList< T > findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QObjectListchildren () const
 Returns a list of child objects.
 
void setParent (QObject *parent)
 Makes the object a child of parent.
 
void installEventFilter (QObject *filterObj)
 Installs an event filter filterObj on this object.
 
void removeEventFilter (QObject *obj)
 Removes an event filter object obj from this object.
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
 
bool disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
 
bool disconnect (const QObject *receiver, const char *member=nullptr) const
 
void dumpObjectTree () const
 Dumps a tree of children to the debug output.
 
void dumpObjectInfo () const
 Dumps information about signal connections, etc.
 
bool setProperty (const char *name, const QVariant &value)
 Sets the value of the object's name property to value.
 
bool setProperty (const char *name, QVariant &&value)
 
QVariant property (const char *name) const
 Returns the value of the object's name property.
 
QList< QByteArraydynamicPropertyNames () const
 
QBindingStoragebindingStorage ()
 
const QBindingStoragebindingStorage () const
 
QObjectparent () const
 Returns a pointer to the parent object.
 
bool inherits (const char *classname) const
 Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.
 

Protected Member Functions

 QVariantAnimation (QVariantAnimationPrivate &dd, QObject *parent=nullptr)
 
bool event (QEvent *event) override
 \reimp
 
void updateCurrentTime (int) override
 \reimp
 
void updateState (QAbstractAnimation::State newState, QAbstractAnimation::State oldState) override
 \reimp
 
virtual void updateCurrentValue (const QVariant &value)
 This virtual function is called every time the animation's current value changes.
 
virtual QVariant interpolated (const QVariant &from, const QVariant &to, qreal progress) const
 This virtual function returns the linear interpolation between variants from and to, at progress, usually a value between 0 and 1.
 
- Protected Member Functions inherited from QAbstractAnimation
 QAbstractAnimation (QAbstractAnimationPrivate &dd, QObject *parent=nullptr)
 
virtual void updateDirection (QAbstractAnimation::Direction direction)
 This virtual function is called by QAbstractAnimation when the direction of the animation is changed.
 
- Protected Member Functions inherited from QObject
QObjectsender () const
 Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
 
int senderSignalIndex () const
 
int receivers (const char *signal) const
 Returns the number of receivers connected to the signal.
 
bool isSignalConnected (const QMetaMethod &signal) const
 
virtual void timerEvent (QTimerEvent *event)
 This event handler can be reimplemented in a subclass to receive timer events for the object.
 
virtual void childEvent (QChildEvent *event)
 This event handler can be reimplemented in a subclass to receive child events.
 
virtual void customEvent (QEvent *event)
 This event handler can be reimplemented in a subclass to receive custom events.
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
 QObject (QObjectPrivate &dd, QObject *parent=nullptr)
 

Properties

QVariant startValue
 the optional start value of the animation
 
QVariant endValue
 the end value of the animation
 
QVariant currentValue
 the current value of the animation.
 
int duration
 the duration of the animation
 
QEasingCurve easingCurve
 the easing curve of the animation
 
- Properties inherited from QAbstractAnimation
State state
 state of the animation.
 
int loopCount
 the loop count of the animation
 
int currentTime
 the current time and progress of the animation
 
int currentLoop
 the current loop of the animation
 
Direction direction
 the direction of the animation when it is in \l Running state.
 
int duration
 the duration of the animation.
 
- Properties inherited from QObject
QString objectName
 the name of this object
 

Friends

template<typename T >
void qRegisterAnimationInterpolator (QVariant(*func)(const T &, const T &, qreal))
 \threadsafe
 

Additional Inherited Members

- Public Slots inherited from QAbstractAnimation
void start (QAbstractAnimation::DeletionPolicy policy=KeepWhenStopped)
 Starts the animation.
 
void pause ()
 Pauses the animation.
 
void resume ()
 Resumes the animation after it was paused.
 
void setPaused (bool)
 If paused is true, the animation is paused.
 
void stop ()
 Stops the animation.
 
void setCurrentTime (int msecs)
 
- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 
- Static Public Member Functions inherited from QObject
static QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
 \threadsafe
 
static QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
 
static bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
 \threadsafe
 
static bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
 
static bool disconnect (const QMetaObject::Connection &)
 Disconnect a connection.
 
template<typename Func1 , typename Func2 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
 
template<typename Func1 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)
 
- Protected Attributes inherited from QObject
QScopedPointer< QObjectDatad_ptr
 

Detailed Description

\inmodule QtCore

The QVariantAnimation class provides a base class for animations.

Since
4.6

This class is part of \l{The Animation Framework}. It serves as a base class for property and item animations, with functions for shared functionality.

The class performs interpolation over \l{QVariant}s, but leaves using the interpolated values to its subclasses. Currently, Qt provides QPropertyAnimation, which animates Qt \l{Qt's Property System}{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 \l{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 \l{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:

\list

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:

Another option is to reimplement interpolated(), which returns interpolation values for the value being interpolated.

\omit We need some snippets around here. \endomit

See also
QPropertyAnimation, QAbstractAnimation, {The Animation Framework}

Definition at line 18 of file qvariantanimation.h.

Member Typedef Documentation

◆ Interpolator

QVariant(*) QVariantAnimation::Interpolator(const void *from, const void *to, qreal progress)

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

QVariant myInterpolator(const QVariant &from, const QVariant &to, qreal progress);
GLuint start
qRegisterAnimationInterpolator< QColor >(myColorInterpolator)
QVariant myInterpolator(const QVariant &from, const QVariant &to, qreal progress)
[0]
QVariant myColorInterpolator(const QColor &start, const QColor &end, qreal progress)
[0]

Definition at line 57 of file qvariantanimation.h.

◆ KeyValue

This is a typedef for std::pair<qreal, QVariant>.

Definition at line 29 of file qvariantanimation.h.

◆ KeyValues

This is a typedef for QList<KeyValue>

Definition at line 30 of file qvariantanimation.h.

Constructor & Destructor Documentation

◆ QVariantAnimation() [1/2]

QVariantAnimation::QVariantAnimation ( QObject * parent = nullptr)

Construct a QVariantAnimation object.

parent is passed to QAbstractAnimation's constructor.

Definition at line 311 of file qvariantanimation.cpp.

◆ ~QVariantAnimation()

QVariantAnimation::~QVariantAnimation ( )

Destroys the animation.

Definition at line 325 of file qvariantanimation.cpp.

◆ QVariantAnimation() [2/2]

QVariantAnimation::QVariantAnimation ( QVariantAnimationPrivate & dd,
QObject * parent = nullptr )
protected

Definition at line 318 of file qvariantanimation.cpp.

Member Function Documentation

◆ bindableDuration()

QBindable< int > QVariantAnimation::bindableDuration ( )

Definition at line 498 of file qvariantanimation.cpp.

◆ bindableEasingCurve()

QBindable< QEasingCurve > QVariantAnimation::bindableEasingCurve ( )

Definition at line 368 of file qvariantanimation.cpp.

◆ currentValue()

QVariant QVariantAnimation::currentValue ( ) const

Definition at line 620 of file qvariantanimation.cpp.

◆ duration()

int QVariantAnimation::duration ( ) const
overridevirtual

This pure virtual function returns the duration of the animation, and defines for how long QAbstractAnimation should update the current time.

This duration is local, and does not include the loop count.

A return value of -1 indicates that the animation has no defined duration; the animation should run forever until stopped. This is useful for animations that are not time driven, or where you cannot easily predict its duration (e.g., event driven audio playback in a game).

If the animation is a parallel QAnimationGroup, the duration will be the longest duration of all its animations. If the animation is a sequential QAnimationGroup, the duration will be the sum of the duration of all its animations.

See also
loopCount

Implements QAbstractAnimation.

Definition at line 477 of file qvariantanimation.cpp.

◆ easingCurve()

QEasingCurve QVariantAnimation::easingCurve ( ) const

Definition at line 351 of file qvariantanimation.cpp.

◆ endValue()

QVariant QVariantAnimation::endValue ( ) const

Definition at line 533 of file qvariantanimation.cpp.

◆ event()

bool QVariantAnimation::event ( QEvent * event)
overrideprotectedvirtual

\reimp

Reimplemented from QAbstractAnimation.

Definition at line 631 of file qvariantanimation.cpp.

◆ interpolated()

QVariant QVariantAnimation::interpolated ( const QVariant & from,
const QVariant & to,
qreal progress ) const
protectedvirtual

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 QEasingCurve::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
QEasingCurve

Definition at line 666 of file qvariantanimation.cpp.

◆ keyValueAt()

QVariant QVariantAnimation::keyValueAt ( qreal step) const

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()

Definition at line 551 of file qvariantanimation.cpp.

◆ keyValues()

QVariantAnimation::KeyValues QVariantAnimation::keyValues ( ) const

Returns the key frames of this animation.

See also
keyValueAt(), setKeyValues()

Definition at line 583 of file qvariantanimation.cpp.

◆ setDuration()

void QVariantAnimation::setDuration ( int msecs)

Definition at line 483 of file qvariantanimation.cpp.

◆ setEasingCurve()

void QVariantAnimation::setEasingCurve ( const QEasingCurve & easing)

Definition at line 357 of file qvariantanimation.cpp.

◆ setEndValue()

void QVariantAnimation::setEndValue ( const QVariant & value)

Definition at line 538 of file qvariantanimation.cpp.

◆ setKeyValueAt()

void QVariantAnimation::setKeyValueAt ( qreal step,
const QVariant & value )

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()

Definition at line 573 of file qvariantanimation.cpp.

◆ setKeyValues()

void QVariantAnimation::setKeyValues ( const KeyValues & keyValues)

Replaces the current set of key frames with the given keyValues.

the step of the key frames must be in the range 0 to 1.

See also
keyValues(), keyValueAt()

Definition at line 594 of file qvariantanimation.cpp.

◆ setStartValue()

void QVariantAnimation::setStartValue ( const QVariant & value)

Definition at line 520 of file qvariantanimation.cpp.

◆ startValue()

QVariant QVariantAnimation::startValue ( ) const

Definition at line 515 of file qvariantanimation.cpp.

◆ updateCurrentTime()

void QVariantAnimation::updateCurrentTime ( int )
overrideprotectedvirtual

\reimp

Implements QAbstractAnimation.

Definition at line 674 of file qvariantanimation.cpp.

◆ updateCurrentValue()

void QVariantAnimation::updateCurrentValue ( const QVariant & value)
protectedvirtual

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
currentValue

Reimplemented in QPropertyAnimation.

Definition at line 110 of file qvariantanimation.cpp.

◆ updateState()

void QVariantAnimation::updateState ( QAbstractAnimation::State newState,
QAbstractAnimation::State oldState )
overrideprotectedvirtual

\reimp

Reimplemented from QAbstractAnimation.

Definition at line 639 of file qvariantanimation.cpp.

◆ valueChanged

void QVariantAnimation::valueChanged ( const QVariant & value)
signal

QVariantAnimation emits this signal whenever the current value changes.

See also
currentValue, startValue, endValue

Friends And Related Symbol Documentation

◆ qRegisterAnimationInterpolator

template<typename T >
void qRegisterAnimationInterpolator ( QVariant(* func )(const T &, const T &, qreal))
friend

\threadsafe

Registers a custom interpolator func for the template type {T}. The interpolator has to be registered before the animation is constructed. To unregister (and use the default interpolator) set func to \nullptr.

Definition at line 81 of file qvariantanimation.h.

Property Documentation

◆ currentValue

QVariant QVariantAnimation::currentValue
read

the current value of the animation.

This property describes the current value; an interpolated value between the \l{startValue}{start value} and the \l{endValue}{end value}, using the current time for progress. The value itself is obtained from interpolated(), which is called repeatedly as the animation is running.

QVariantAnimation calls the virtual updateCurrentValue() function when the current value changes. This is particularly useful for subclasses that need to track updates. For example, QPropertyAnimation uses this function to animate Qt \l{Qt's Property System}{properties}.

See also
startValue, endValue

Definition at line 23 of file qvariantanimation.h.

◆ duration

int QVariantAnimation::duration
readwrite

the duration of the animation

This property describes the duration in milliseconds of the animation. The default duration is 250 milliseconds.

See also
QAbstractAnimation::duration()

Definition at line 24 of file qvariantanimation.h.

◆ easingCurve

QEasingCurve QVariantAnimation::easingCurve
readwrite

the easing curve of the animation

This property defines the easing curve of the animation. By default, a linear easing curve is used, resulting in linear interpolation. Other curves are provided, for instance, QEasingCurve::InCirc, which provides a circular entry curve. Another example is QEasingCurve::InOutElastic, which provides an elastic effect on the values of the interpolated variant.

QVariantAnimation will use the QEasingCurve::valueForProgress() to transform the "normalized progress" (currentTime / totalDuration) of the animation into the effective progress actually used by the animation. It is this effective progress that will be the progress when interpolated() is called. Also, the steps in the keyValues are referring to this effective progress.

The easing curve is used with the interpolator, the interpolated() virtual function, and the animation's duration to control how the current value changes as the animation progresses.

Definition at line 25 of file qvariantanimation.h.

◆ endValue

QVariant QVariantAnimation::endValue
readwrite

the end value of the animation

This property describes the end value of the animation.

See also
startValue

Definition at line 22 of file qvariantanimation.h.

◆ startValue

QVariant QVariantAnimation::startValue
readwrite

the optional start value of the animation

This property describes the optional start value of the animation. If omitted, or if a null QVariant is assigned as the start value, the animation will use the current position of the end when the animation is started.

See also
endValue

Definition at line 21 of file qvariantanimation.h.


The documentation for this class was generated from the following files: