CopperSpice API  1.7.2
QGraphicsTransform Class Referenceabstract

The QGraphicsTransform class is an abstract base class for building advanced transformations on QGraphicsItems. More...

Inheritance diagram for QGraphicsTransform:
QObject QGraphicsRotation QGraphicsScale

Public Methods

 QGraphicsTransform (QObject *parent=nullptr)
 
 ~QGraphicsTransform ()
 
virtual void applyTo (QMatrix4x4 *matrix) const = 0
 
- Public Methods inherited from QObject
 QObject (QObject *parent=nullptr)
 
 ~QObject ()
 
bool blockSignals (bool block)
 
const QList< QObject * > & children () const
 
bool connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
bool connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
bool disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const
 
bool disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const
 
bool disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const
 
void dumpObjectInfo ()
 
void dumpObjectTree ()
 
QList< QStringdynamicPropertyNames () const
 
virtual bool event (QEvent *event)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
template<typename T >
findChild (const QString &childName=QString ()) const
 
template<class T >
QList< T > findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 
template<class T >
QList< T > findChildren (const QString &objName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 
bool inherits (const QString &className) const
 
void installEventFilter (QObject *filterObj)
 
bool isWidgetType () const
 
bool isWindowType () const
 
void killTimer (int id)
 
const QMetaObjectmetaObject () const
 
void moveToThread (QThread *targetThread)
 
QString objectName () const
 
QObject * parent () const
 
template<class T = QVariant>
property (const QString &name) const
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setParent (QObject *parent)
 
bool setProperty (const QString &name, const QVariant &value)
 
bool signalsBlocked () const
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 
QThreadthread () const
 

Protected Slots

void update ()
 

Friends

class QGraphicsItem
 

Additional Inherited Members

- Public Signals inherited from QObject
void destroyed (QObject *obj=nullptr)
 
void objectNameChanged (const QString &objectName)
 
- Public Slots inherited from QObject
void deleteLater ()
 
- Static Public Methods inherited from QObject
static bool connect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
static bool connect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())
 
static bool connect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)
 
static bool disconnect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod)
 
static bool disconnect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod)
 
static bool disconnect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...))
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)
 
static QMetaObjectstaticMetaObject ()
 
static QString tr (const char *text, const char *comment=nullptr, std::optional< int > numArg=std::optional< int >())
 
- Protected Methods inherited from QObject
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const QMetaMethod &signalMethod) const
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const QMetaMethod &signalMethod) const
 
bool isSignalConnected (const QMetaMethod &signalMethod) const
 
int receivers (const QString &signal) const
 
QObject * sender () const
 
int senderSignalIndex () const
 
virtual void timerEvent (QTimerEvent *event)
 
- Properties inherited from QObject
 objectName
 

Detailed Description

The QGraphicsTransform class is an abstract base class for building advanced transformations on QGraphicsItems.

As an alternative to QGraphicsItem::transform, QGraphicsTransform lets you create and control advanced transformations that can be configured independently using specialized properties.

QGraphicsItem allows you to assign any number of QGraphicsTransform instances to one QGraphicsItem. Each QGraphicsTransform is applied in order, one at a time, to the QGraphicsItem it's assigned to.

QGraphicsTransform is particularly useful for animations. Whereas QGraphicsItem::setTransform() lets you assign any transform directly to an item, there is no direct way to interpolate between two different transformations (e.g., when transitioning between two states, each for which the item has a different arbitrary transform assigned). Using QGraphicsTransform you can interpolate the property values of each independent transformation. The resulting operation is then combined into a single transform which is applied to QGraphicsItem.

Transformations are computed in true 3D space using QMatrix4x4. When the transformation is applied to a QGraphicsItem, it will be projected back to a 2D QTransform. When multiple QGraphicsTransform objects are applied to a QGraphicsItem, all of the transformations are computed in true 3D space, with the projection back to 2D only occurring after the last QGraphicsTransform is applied. The exception to this is QGraphicsRotation, which projects back to 2D after each rotation to preserve the perspective effect around the X and Y axes.

If you want to create your own configurable transformation, you can create a subclass of QGraphicsTransform (or any or the existing subclasses), and reimplement the pure virtual applyTo() function, which takes a pointer to a QMatrix4x4. Each operation you would like to apply should be exposed as properties (e.g., customTransform->setVerticalShear(2.5)). Inside you reimplementation of applyTo(), you can modify the provided transform respectively.

QGraphicsTransform can be used together with QGraphicsItem::setTransform(), QGraphicsItem::setRotation(), and QGraphicsItem::setScale().

See also
QGraphicsItem::transform(), QGraphicsScale, QGraphicsRotation

Constructor & Destructor Documentation

QGraphicsTransform::QGraphicsTransform ( QObject parent = nullptr)

Constructs a new QGraphicsTransform with the given parent.

QGraphicsTransform::~QGraphicsTransform ( )

Destroys the graphics transform.

Method Documentation

void QGraphicsTransform::applyTo ( QMatrix4x4 matrix) const
pure virtual

This pure virtual method has to be reimplemented in derived classes.

It applies this transformation to matrix.

See also
QGraphicsItem::transform(), QMatrix4x4::toTransform()

Implemented in QGraphicsRotation, and QGraphicsScale.

void QGraphicsTransform::update ( )
protectedslot

Notifies that this transform operation has changed its parameters in such a way that applyTo() will return a different result than before.

When implementing you own custom graphics transform, you must call this function every time you change a parameter, to let QGraphicsItem know that its transformation needs to be updated.

See also
applyTo()