#include <qquickcanvasitem_p.h>

Inheritance diagram for QQuickCanvasItem:

Collaboration diagram for QQuickCanvasItem:

Public Types
enum	RenderTarget { Image , FramebufferObject }

enum	RenderStrategy { Immediate , Threaded , Cooperative }

Public Types inherited from QQuickItem
enum	Flag { ItemClipsChildrenToShape = 0x01 , ItemIsFocusScope = 0x04 , ItemHasContents = 0x08 , ItemAcceptsDrops = 0x10 , ItemIsViewport = 0x20 , ItemObservesViewport = 0x40 }

enum	ItemChange { ItemChildAddedChange , ItemChildRemovedChange , ItemSceneChange , ItemVisibleHasChanged , ItemParentHasChanged , ItemOpacityHasChanged , ItemActiveFocusHasChanged , ItemRotationHasChanged , ItemAntialiasingHasChanged , ItemDevicePixelRatioHasChanged , ItemEnabledHasChanged }
	Used in conjunction with QQuickItem::itemChange() to notify the item about certain types of changes. More...

enum	TransformOrigin { TopLeft , Top , TopRight , Left , Center , Right , BottomLeft , Bottom , BottomRight }
	\variable QQuickItem::ItemChangeData::realValue The numeric value that has changed: \l {QQuickItem::opacity()}{opacity}, \l {QQuickItem::rotation()}{rotation}, or \l {QScreen::devicePixelRatio}{device pixel ratio}. More...

Public Slots
void	loadImage (const QUrl &url, QSizeF sourceSize=QSizeF())
	\qmlsignal QtQuick::Canvas::imageLoaded()

void	unloadImage (const QUrl &url)
	\qmlmethod QtQuick::Canvas::unloadImage(url image)

bool	isImageLoaded (const QUrl &url) const
	\qmlmethod QtQuick::Canvas::isImageLoaded(url image) Returns true if the image is successfully loaded and ready to use.

bool	isImageLoading (const QUrl &url) const
	\qmlmethod QtQuick::Canvas::isImageLoading(url image) Returns true if the image is currently loading.

bool	isImageError (const QUrl &url) const
	\qmlmethod QtQuick::Canvas::isImageError(url image)

Public Slots inherited from QQuickItem
void	update ()
	Schedules a call to updatePaintNode() for this item.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	paint (const QRect &region)

void	painted ()

void	availableChanged ()

void	contextTypeChanged ()

void	contextChanged ()

void	canvasSizeChanged ()

void	tileSizeChanged ()

void	canvasWindowChanged ()

void	renderTargetChanged ()

void	renderStrategyChanged ()

void	imageLoaded ()

Signals inherited from QQuickItem
void	childrenRectChanged (const QRectF &)

void	baselineOffsetChanged (qreal)

void	stateChanged (const QString &)

void	focusChanged (bool)

void	activeFocusChanged (bool)

	Q_REVISION (2, 1) void activeFocusOnTabChanged(bool)

void	parentChanged (QQuickItem *)

void	transformOriginChanged (TransformOrigin)

void	smoothChanged (bool)

void	antialiasingChanged (bool)

void	clipChanged (bool)

	Q_REVISION (2, 1) void windowChanged(QQuickWindow *window)

void	childrenChanged ()

void	opacityChanged ()

void	enabledChanged ()

void	visibleChanged ()

void	visibleChildrenChanged ()

void	rotationChanged ()

void	scaleChanged ()

void	xChanged ()

void	yChanged ()

void	widthChanged ()

void	heightChanged ()

void	zChanged ()

void	implicitWidthChanged ()

void	implicitHeightChanged ()

	Q_REVISION (2, 11) void containmentMaskChanged()

	Q_REVISION (6, 0) void paletteChanged()

	Q_REVISION (6, 0) void paletteCreated()

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
	QQuickCanvasItem (QQuickItem *parent=nullptr)
	\qmltype Canvas \instantiates QQuickCanvasItem \inqmlmodule QtQuick

	~QQuickCanvasItem ()

bool	isAvailable () const
	\qmlproperty bool QtQuick::Canvas::available

QString	contextType () const
	\qmlproperty string QtQuick::Canvas::contextType The type of drawing context to use.

void	setContextType (const QString &contextType)

QJSValue	context () const
	\qmlproperty object QtQuick::Canvas::context Holds the active drawing context.

QSizeF	canvasSize () const
	\qmlproperty size QtQuick::Canvas::canvasSize Holds the logical canvas size that the context paints on.

void	setCanvasSize (const QSizeF &)

QSize	tileSize () const
	\qmlproperty size QtQuick::Canvas::tileSize Holds the canvas rendering tile size.

void	setTileSize (const QSize &)

QRectF	canvasWindow () const
	\qmlproperty rect QtQuick::Canvas::canvasWindow Holds the current canvas visible window.

void	setCanvasWindow (const QRectF &rect)

RenderTarget	renderTarget () const
	\qmlproperty enumeration QtQuick::Canvas::renderTarget Holds the current canvas render target.

void	setRenderTarget (RenderTarget target)

RenderStrategy	renderStrategy () const
	\qmlproperty enumeration QtQuick::Canvas::renderStrategy Holds the current canvas rendering strategy.

void	setRenderStrategy (RenderStrategy strategy)

QQuickCanvasContext *	rawContext () const

QImage	toImage (const QRectF &rect=QRectF()) const

Q_INVOKABLE void	getContext (QQmlV4Function *args)
	\qmlmethod object QtQuick::Canvas::getContext(string contextId, ... args)

Q_INVOKABLE void	requestAnimationFrame (QQmlV4Function *args)
	\qmlmethod int QtQuick::Canvas::requestAnimationFrame(callback)

Q_INVOKABLE void	cancelRequestAnimationFrame (QQmlV4Function *args)
	\qmlmethod QtQuick::Canvas::cancelRequestAnimationFrame(int handle)

Q_INVOKABLE void	requestPaint ()
	\qmlmethod QtQuick::Canvas::requestPaint()

Q_INVOKABLE void	markDirty (const QRectF &dirtyRect=QRectF())
	\qmlmethod QtQuick::Canvas::markDirty(rect area)

Q_INVOKABLE bool	save (const QString &filename, const QSizeF &imageSize=QSizeF()) const
	\qmlmethod bool QtQuick::Canvas::save(string filename, size imageSize = undefined)

Q_INVOKABLE QString	toDataURL (const QString &type=QLatin1String("image/png")) const
	\qmlmethod string QtQuick::Canvas::toDataURL(string mimeType)

QQmlRefPointer< QQuickCanvasPixmap >	loadedPixmap (const QUrl &url, QSizeF sourceSize=QSizeF())

bool	isTextureProvider () const override
	Returns true if this item is a texture provider.

QSGTextureProvider *	textureProvider () const override
	Returns the texture provider for an item.

Public Member Functions inherited from QQuickItem
	QQuickItem (QQuickItem *parent=nullptr)
	Constructs a QQuickItem with the given parent.

	~QQuickItem () override
	Destroys the QQuickItem.

QQuickWindow *	window () const
	Returns the window in which this item is rendered.

QQuickItem *	parentItem () const

void	setParentItem (QQuickItem *parent)

void	stackBefore (const QQuickItem *)
	Moves the specified sibling item to the index before this item within the list of children.

void	stackAfter (const QQuickItem *)
	Moves the specified sibling item to the index after this item within the list of children.

QRectF	childrenRect ()
	\qmlpropertygroup QtQuick::Item::childrenRect \qmlproperty real QtQuick::Item::childrenRect.x \qmlproperty real QtQuick::Item::childrenRect.y \qmlproperty real QtQuick::Item::childrenRect.width \qmlproperty real QtQuick::Item::childrenRect.height \readonly

QList< QQuickItem * >	childItems () const
	Returns the children of this item.

bool	clip () const
	\qmlproperty bool QtQuick::Item::clip This property holds whether clipping is enabled.

void	setClip (bool)

QString	state () const
	\qmlproperty string QtQuick::Item::state

void	setState (const QString &)

qreal	baselineOffset () const
	\qmlproperty int QtQuick::Item::baselineOffset

void	setBaselineOffset (qreal)

QQmlListProperty< QQuickTransform >	transform ()

qreal	x () const

qreal	y () const

QPointF	position () const

void	setX (qreal)

void	setY (qreal)

void	setPosition (const QPointF &)

QBindable< qreal >	bindableX ()

QBindable< qreal >	bindableY ()

qreal	width () const

void	setWidth (qreal)

void	resetWidth ()

void	setImplicitWidth (qreal)

qreal	implicitWidth () const
	Returns the width of the item that is implied by other properties that determine the content.

QBindable< qreal >	bindableWidth ()

qreal	height () const

void	setHeight (qreal)

void	resetHeight ()

void	setImplicitHeight (qreal)

qreal	implicitHeight () const

QBindable< qreal >	bindableHeight ()

QSizeF	size () const

void	setSize (const QSizeF &size)

TransformOrigin	transformOrigin () const

void	setTransformOrigin (TransformOrigin)

QPointF	transformOriginPoint () const

void	setTransformOriginPoint (const QPointF &)

qreal	z () const

void	setZ (qreal)

qreal	rotation () const

void	setRotation (qreal)

qreal	scale () const

void	setScale (qreal)

qreal	opacity () const

void	setOpacity (qreal)

bool	isVisible () const

void	setVisible (bool)

bool	isEnabled () const

void	setEnabled (bool)

bool	smooth () const

void	setSmooth (bool)

bool	activeFocusOnTab () const
	\qmlproperty bool QtQuick::Item::activeFocusOnTab

void	setActiveFocusOnTab (bool)

bool	antialiasing () const

void	setAntialiasing (bool)

void	resetAntialiasing ()

Flags	flags () const
	Returns the item flags for this item.

void	setFlag (Flag flag, bool enabled=true)
	Enables the specified flag for this item if enabled is true; if enabled is false, the flag is disabled.

void	setFlags (Flags flags)
	Enables the specified flags for this item.

virtual QRectF	boundingRect () const
	Returns the extents of the item in its own coordinate system: a rectangle from {0, 0} to \l width() and \l height().

virtual QRectF	clipRect () const
	Returns the rectangular area within this item that is currently visible in \l viewportItem(), if there is a viewport and the \l ItemObservesViewport flag is set; otherwise, the extents of this item in its own coordinate system: a rectangle from {0, 0} to \l width() and \l height().

QQuickItem *	viewportItem () const
	If the \l ItemObservesViewport flag is set, returns the nearest parent with the \l ItemIsViewport flag.

bool	hasActiveFocus () const

bool	hasFocus () const

void	setFocus (bool)

void	setFocus (bool focus, Qt::FocusReason reason)

bool	isFocusScope () const
	Returns true if this item is a focus scope, and false otherwise.

QQuickItem *	scopedFocusItem () const
	If this item is a focus scope, this returns the item in its focus chain that currently has focus.

bool	isAncestorOf (const QQuickItem *child) const
	Returns `true` if this item is an ancestor of child (i.e., if this item is child's parent, or one of child's parent's ancestors).

Qt::MouseButtons	acceptedMouseButtons () const
	Returns the mouse buttons accepted by this item.

void	setAcceptedMouseButtons (Qt::MouseButtons buttons)
	Sets the mouse buttons accepted by this item to buttons.

bool	acceptHoverEvents () const
	Returns whether hover events are accepted by this item.

void	setAcceptHoverEvents (bool enabled)
	If enabled is true, this sets the item to accept hover events; otherwise, hover events are not accepted by this item.

bool	acceptTouchEvents () const
	Returns whether touch events are accepted by this item.

void	setAcceptTouchEvents (bool accept)
	If enabled is true, this sets the item to accept touch events; otherwise, touch events are not accepted by this item.

bool	isUnderMouse () const

void	grabMouse ()

void	ungrabMouse ()

bool	keepMouseGrab () const
	Returns whether mouse input should exclusively remain with this item.

void	setKeepMouseGrab (bool)
	Sets whether the mouse input should remain exclusively with this item.

bool	filtersChildMouseEvents () const
	Returns whether pointer events intended for this item's children should be filtered through this item.

void	setFiltersChildMouseEvents (bool filter)
	Sets whether pointer events intended for this item's children should be filtered through this item.

void	grabTouchPoints (const QList< int > &ids)

void	ungrabTouchPoints ()

bool	keepTouchGrab () const
	Returns whether the touch points grabbed by this item should exclusively remain with this item.

void	setKeepTouchGrab (bool)
	Sets whether the touch points grabbed by this item should remain exclusively with this item.

	Q_REVISION (2, 4) Q_INVOKABLE bool grabToImage(const QJSValue &callback

QSharedPointer< QQuickItemGrabResult >	grabToImage (const QSize &targetSize=QSize())
	Grabs the item into an in-memory image.

virtual Q_INVOKABLE bool	contains (const QPointF &point) const
	\qmlmethod bool QtQuick::Item::contains(point point)

QObject *	containmentMask () const

void	setContainmentMask (QObject *mask)

QTransform	itemTransform (QQuickItem , bool ) const
	\qmlmethod point QtQuick::Item::mapFromItem(Item item, real x, real y) \qmlmethod point QtQuick::Item::mapFromItem(Item item, point p) \qmlmethod rect QtQuick::Item::mapFromItem(Item item, real x, real y, real width, real height) \qmlmethod rect QtQuick::Item::mapFromItem(Item item, rect r)

QPointF	mapToScene (const QPointF &point) const
	Maps the given point in this item's coordinate system to the equivalent point within the scene's coordinate system, and returns the mapped coordinate.

QRectF	mapRectToItem (const QQuickItem *item, const QRectF &rect) const
	Maps the given rect in this item's coordinate system to the equivalent rectangular area within item's coordinate system, and returns the mapped rectangle value.

QRectF	mapRectToScene (const QRectF &rect) const
	Maps the given rect in this item's coordinate system to the equivalent rectangular area within the scene's coordinate system, and returns the mapped rectangle value.

QPointF	mapFromScene (const QPointF &point) const
	Maps the given point in the scene's coordinate system to the equivalent point within this item's coordinate system, and returns the mapped coordinate.

QRectF	mapRectFromItem (const QQuickItem *item, const QRectF &rect) const
	Maps the given rect in item's coordinate system to the equivalent rectangular area within this item's coordinate system, and returns the mapped rectangle value.

QRectF	mapRectFromScene (const QRectF &rect) const
	Maps the given rect in the scene's coordinate system to the equivalent rectangular area within this item's coordinate system, and returns the mapped rectangle value.

void	polish ()
	Schedules a polish event for this item.

Q_INVOKABLE QPointF	mapFromItem (const QQuickItem *item, const QPointF &point) const
	Maps the given point in item's coordinate system to the equivalent point within this item's coordinate system, and returns the mapped coordinate.

Q_INVOKABLE QPointF	mapFromItem (const QQuickItem *item, qreal x, qreal y)

Q_INVOKABLE QRectF	mapFromItem (const QQuickItem *item, const QRectF &rect) const

Q_INVOKABLE QRectF	mapFromItem (const QQuickItem *item, qreal x, qreal y, qreal width, qreal height) const

Q_INVOKABLE QPointF	mapToItem (const QQuickItem *item, const QPointF &point) const
	Maps the given point in this item's coordinate system to the equivalent point within item's coordinate system, and returns the mapped coordinate.

Q_INVOKABLE QPointF	mapToItem (const QQuickItem *item, qreal x, qreal y)

Q_INVOKABLE QRectF	mapToItem (const QQuickItem *item, const QRectF &rect) const

Q_INVOKABLE QRectF	mapToItem (const QQuickItem *item, qreal x, qreal y, qreal width, qreal height) const

	Q_REVISION (2, 7) Q_INVOKABLE QPointF mapFromGlobal(qreal x

	Q_REVISION (2, 7) Q_INVOKABLE QPointF mapFromGlobal(const QPointF &point) const

	Q_REVISION (2, 7) Q_INVOKABLE QPointF mapToGlobal(qreal x

	Q_REVISION (2, 7) Q_INVOKABLE QPointF mapToGlobal(const QPointF &point) const

Q_INVOKABLE void	forceActiveFocus ()
	\qmlmethod point QtQuick::Item::mapToItem(Item item, real x, real y) \qmlmethod point QtQuick::Item::mapToItem(Item item, point p) \qmlmethod rect QtQuick::Item::mapToItem(Item item, real x, real y, real width, real height) \qmlmethod rect QtQuick::Item::mapToItem(Item item, rect r)

Q_INVOKABLE void	forceActiveFocus (Qt::FocusReason reason)
	\qmlmethod QtQuick::Item::forceActiveFocus(Qt::FocusReason reason) This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Forces active focus on the item with the given reason.

	Q_REVISION (2, 1) Q_INVOKABLE QQuickItem *nextItemInFocusChain(bool forward

Q_INVOKABLE QQuickItem *	childAt (qreal x, qreal y) const
	\qmlmethod QtQuick::Item::childAt(real x, real y)

	Q_REVISION (6, 3) Q_INVOKABLE void ensurePolished()

	Q_REVISION (6, 3) Q_INVOKABLE void dumpItemTree() const

virtual bool	isTextureProvider () const
	Returns true if this item is a texture provider.

virtual QSGTextureProvider *	textureProvider () const
	Returns the texture provider for an item.

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	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.

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< QString >	bindableObjectName ()

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).

QThread *	thread () const
	Returns the thread in which the object lives.

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.

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::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

template<typename T >
T	findChild (const QString &aName=QString(), 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 (const QString &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 >
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 QObjectList &	children () 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< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () 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`.

Public Member Functions inherited from QQmlParserStatus
	QQmlParserStatus ()

virtual	~QQmlParserStatus ()

virtual void	classBegin ()=0
	Invoked after class creation, but before any properties have been set.

virtual void	componentComplete ()=0
	Invoked after the root component that caused this instantiation has completed construction.

Protected Member Functions
void	componentComplete () override
	Invoked after the root component that caused this instantiation has completed construction.

void	itemChange (QQuickItem::ItemChange, const QQuickItem::ItemChangeData &) override
	Called when change occurs for this item.

void	updatePolish () override
	This function should perform any layout as required for this item.

QSGNode *	updatePaintNode (QSGNode , UpdatePaintNodeData ) override
	Called on the render thread when it is time to sync the state of the item with the scene graph.

void	geometryChange (const QRectF &newGeometry, const QRectF &oldGeometry) override

void	releaseResources () override
	This function is called when an item should release graphics resources which are not already managed by the nodes returned from QQuickItem::updatePaintNode().

bool	event (QEvent *event) override
	This virtual function receives events to an object and should return true if the event e was recognized and processed.

Protected Member Functions inherited from QQuickItem
bool	event (QEvent *) override
	\reimp

bool	isComponentComplete () const
	Returns true if construction of the QML component is complete; otherwise returns false.

virtual void	itemChange (ItemChange, const ItemChangeData &)
	Called when change occurs for this item.

virtual void	geometryChange (const QRectF &newGeometry, const QRectF &oldGeometry)

bool	widthValid () const
	Returns whether the width property has been set explicitly.

bool	heightValid () const
	Returns whether the height property has been set explicitly.

void	setImplicitSize (qreal, qreal)

void	classBegin () override
	\reimp Derived classes should call the base class method before adding their own action to perform at classBegin.

void	componentComplete () override
	\reimp Derived classes should call the base class method before adding their own actions to perform at componentComplete.

virtual void	keyPressEvent (QKeyEvent *event)
	This event handler can be reimplemented in a subclass to receive key press events for an item.

virtual void	keyReleaseEvent (QKeyEvent *event)
	This event handler can be reimplemented in a subclass to receive key release events for an item.

virtual void	focusInEvent (QFocusEvent *)
	This event handler can be reimplemented in a subclass to receive focus-in events for an item.

virtual void	focusOutEvent (QFocusEvent *)
	This event handler can be reimplemented in a subclass to receive focus-out events for an item.

virtual void	mousePressEvent (QMouseEvent *event)
	This event handler can be reimplemented in a subclass to receive mouse press events for an item.

virtual void	mouseMoveEvent (QMouseEvent *event)
	This event handler can be reimplemented in a subclass to receive mouse move events for an item.

virtual void	mouseReleaseEvent (QMouseEvent *event)
	This event handler can be reimplemented in a subclass to receive mouse release events for an item.

virtual void	mouseDoubleClickEvent (QMouseEvent *event)
	This event handler can be reimplemented in a subclass to receive mouse double-click events for an item.

virtual void	mouseUngrabEvent ()
	This event handler can be reimplemented in a subclass to be notified when a mouse ungrab event has occurred on this item.

virtual void	touchUngrabEvent ()
	This event handler can be reimplemented in a subclass to be notified when a touch ungrab event has occurred on this item.

virtual void	touchEvent (QTouchEvent *event)
	This event handler can be reimplemented in a subclass to receive touch events for an item.

virtual void	hoverEnterEvent (QHoverEvent *event)
	This event handler can be reimplemented in a subclass to receive hover-enter events for an item.

virtual void	hoverMoveEvent (QHoverEvent *event)
	This event handler can be reimplemented in a subclass to receive hover-move events for an item.

virtual void	hoverLeaveEvent (QHoverEvent *event)
	This event handler can be reimplemented in a subclass to receive hover-leave events for an item.

virtual bool	childMouseEventFilter (QQuickItem , QEvent )
	Reimplement this method to filter the pointer events that are received by this item's children.

virtual QSGNode *	updatePaintNode (QSGNode , UpdatePaintNodeData )
	Called on the render thread when it is time to sync the state of the item with the scene graph.

virtual void	releaseResources ()
	This function is called when an item should release graphics resources which are not already managed by the nodes returned from QQuickItem::updatePaintNode().

virtual void	updatePolish ()
	This function should perform any layout as required for this item.

	QQuickItem (QQuickItemPrivate &dd, QQuickItem *parent=nullptr)

Protected Member Functions inherited from QObject
QObject *	sender () 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
bool	available

QString	contextType

QJSValue	context

QSizeF	canvasSize

QSize	tileSize

QRectF	canvasWindow

RenderTarget	renderTarget

RenderStrategy	renderStrategy

Properties inherited from QQuickItem
QQuickItem *	parent
	\qmlproperty Item QtQuick::Item::parent This property holds the visual parent of the item.

qreal	x
	\qmlproperty real QtQuick::Item::x \qmlproperty real QtQuick::Item::y \qmlproperty real QtQuick::Item::width \qmlproperty real QtQuick::Item::height

qreal	y
	Defines the item's y position relative to its parent.

qreal	z
	\qmlproperty real QtQuick::Item::z

qreal	width
	This property holds the width of this item.

qreal	height
	This property holds the height of this item.

qreal	opacity
	\qmlproperty real QtQuick::Item::opacity

bool	enabled
	\qmlproperty bool QtQuick::Item::enabled

bool	visible
	\qmlproperty bool QtQuick::Item::visible

qreal	rotation
	\qmlproperty real QtQuick::Item::rotation This property holds the rotation of the item in degrees clockwise around its transformOrigin.

qreal	scale
	\qmlproperty real QtQuick::Item::scale This property holds the scale factor for this item.

TransformOrigin	transformOrigin
	\qmlproperty enumeration QtQuick::Item::transformOrigin This property holds the origin point around which scale and rotation transform.

QPointF	transformOriginPoint

QQmlListProperty< QQuickTransform >	transform
	\qmlproperty list<Transform> QtQuick::Item::transform This property holds the list of transformations to apply.

bool	smooth
	\qmlproperty bool QtQuick::Item::smooth

bool	antialiasing
	\qmlproperty bool QtQuick::Item::antialiasing

qreal	implicitWidth

qreal	implicitHeight

QObject *	containmentMask
	\qmlproperty QObject* QtQuick::Item::containmentMask

Properties inherited from QObject
QString	objectName
	the name of this object

Additional Inherited Members
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)

Public Attributes inherited from QQuickItem
const QSize &	targetSize = QSize())

qreal y	const

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

Definition at line 55 of file qquickcanvasitem_p.h.

Member Enumeration Documentation

◆ RenderStrategy

enum QQuickCanvasItem::RenderStrategy

Enumerator
Immediate
Threaded
Cooperative

Definition at line 77 of file qquickcanvasitem_p.h.

◆ RenderTarget

enum QQuickCanvasItem::RenderTarget

Enumerator
Image
FramebufferObject

Definition at line 71 of file qquickcanvasitem_p.h.

Constructor & Destructor Documentation

◆ QQuickCanvasItem()

QQuickCanvasItem::QQuickCanvasItem ( QQuickItem * parent = nullptr )

\qmltype Canvas \instantiates QQuickCanvasItem \inqmlmodule QtQuick

Since: 5.0 \inherits Item

Provides a 2D canvas item enabling drawing via JavaScript.

The Canvas item allows drawing of straight and curved lines, simple and complex shapes, graphs, and referenced graphic images. It can also add text, colors, shadows, gradients, and patterns, and do low level pixel operations. The Canvas output may be saved as an image file or serialized to a URL.

Rendering to the Canvas is done using a Context2D object, usually as a result of the \l paint signal.

To define a drawing area in the Canvas item set the width and height properties. For example, the following code creates a Canvas item which has a drawing area with a height of 100 pixels and width of 200 pixels: \qml import QtQuick 2.0 Canvas { id: mycanvas width: 100 height: 200 onPaint: { var ctx = getContext("2d"); ctx.fillStyle = Qt.rgba(1, 0, 0, 1); ctx.fillRect(0, 0, width, height); } } \endqml

Currently the Canvas item only supports the two-dimensional rendering context.

Definition at line 258 of file qquickcanvasitem.cpp.

References QQuickItem::ItemHasContents, and QQuickItem::setFlag().

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◆ ~QQuickCanvasItem()

QQuickCanvasItem::~QQuickCanvasItem ( )

Definition at line 264 of file qquickcanvasitem.cpp.

References d, QQuickWindowQObjectCleanupJob::schedule(), and QQuickItem::window().

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Member Function Documentation

◆ availableChanged

void QQuickCanvasItem::availableChanged ( )

signal

◆ cancelRequestAnimationFrame()

void QQuickCanvasItem::cancelRequestAnimationFrame ( QQmlV4Function * args )

\qmlmethod QtQuick::Canvas::cancelRequestAnimationFrame(int handle)

This function will cancel the animation callback referenced by handle.

Definition at line 886 of file qquickcanvasitem.cpp.

References args, QV4::Encode::null(), qmlWarning(), and QList< T >::remove().

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◆ canvasSize()

QSizeF QQuickCanvasItem::canvasSize ( ) const

\qmlproperty size QtQuick::Canvas::canvasSize Holds the logical canvas size that the context paints on.

By default, the canvas size is the same size as the current canvas item size.

By setting the canvasSize, tileSize and canvasWindow, the Canvas item can act as a large virtual canvas with many separately rendered tile rectangles. Only those tiles within the current canvas window are painted by the Canvas render engine.

See also: tileSize, canvasWindow

Definition at line 352 of file qquickcanvasitem.cpp.

References d.

◆ canvasSizeChanged

void QQuickCanvasItem::canvasSizeChanged ( )

signal

Referenced by geometryChange(), and setCanvasSize().

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◆ canvasWindow()

QRectF QQuickCanvasItem::canvasWindow ( ) const

\qmlproperty rect QtQuick::Canvas::canvasWindow Holds the current canvas visible window.

By default the canvasWindow size is the same as the Canvas item size with the top-left point as (0, 0).

If the canvasSize is different to the Canvas item size, the Canvas item can display different visible areas by changing the canvas windowSize and/or position.

Deprecated:: This feature is incomplete. For details, see QTBUG-33129.

See also: canvasSize, tileSize

Definition at line 423 of file qquickcanvasitem.cpp.

References d.

◆ canvasWindowChanged

void QQuickCanvasItem::canvasWindowChanged ( )

signal

Referenced by geometryChange(), and setCanvasWindow().

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◆ componentComplete()

void QQuickCanvasItem::componentComplete ( )

overrideprotectedvirtual

Invoked after the root component that caused this instantiation has completed construction.

At this point all static values and binding values have been assigned to the class.

Implements QQmlParserStatus.

Definition at line 628 of file qquickcanvasitem.cpp.

References QQmlContext::baseUrl(), QQuickItem::componentComplete(), QQmlEngine::contextForObject(), d, and qmlEngine().

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◆ context()

QJSValue QQuickCanvasItem::context ( ) const

\qmlproperty object QtQuick::Canvas::context Holds the active drawing context.

If the canvas is ready and there has been a successful call to getContext() or the contextType property has been set with a supported context type, this property will contain the current drawing context, otherwise null.

Definition at line 332 of file qquickcanvasitem.cpp.

References d, and QJSValuePrivate::fromReturnedValue().

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◆ contextChanged

void QQuickCanvasItem::contextChanged ( )

signal

◆ contextType()

QString QQuickCanvasItem::contextType ( ) const

\qmlproperty string QtQuick::Canvas::contextType The type of drawing context to use.

This property is set to the name of the active context type.

If set explicitly the canvas will attempt to create a context of the named type after becoming available.

The type name is the same as used in the getContext() call, for the 2d canvas the value will be "2d".

See also: getContext(), available

Definition at line 298 of file qquickcanvasitem.cpp.

◆ contextTypeChanged

void QQuickCanvasItem::contextTypeChanged ( )

signal

Referenced by setContextType().

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◆ event()

bool QQuickCanvasItem::event ( QEvent * e )

overrideprotectedvirtual

This virtual function receives events to an object and should return true if the event e was recognized and processed.

The event() function can be reimplemented to customize the behavior of an object.

Make sure you call the parent event class implementation for all the events you did not handle.

Example:

class MyClass : public QWidget
{
    Q_OBJECT
 
public:
    MyClass(QWidget *parent = nullptr);
    ~MyClass();
 
    bool event(QEvent* ev) override
    {
        if (ev->type() == QEvent::PolishRequest) {
            // overwrite handling of PolishRequest if any
            doThings();
            return true;
        } else  if (ev->type() == QEvent::Show) {
            // complement handling of Show if any
            doThings2();
            QWidget::event(ev);
            return true;
        }
        // Make sure the rest of events are handled
        return QWidget::event(ev);
    }
};

See also: installEventFilter(), timerEvent(), QCoreApplication::sendEvent(), QCoreApplication::postEvent()

Reimplemented from QObject.

Definition at line 594 of file qquickcanvasitem.cpp.

References QQuickItem::event(), QQuickItem::polish(), and QEvent::PolishRequest.

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◆ geometryChange()

void QQuickCanvasItem::geometryChange	(	const QRectF &	newGeometry,
		const QRectF &	oldGeometry
	)

overrideprotectedvirtual

Since: 6.0

This function is called to handle this item's changes in geometry from oldGeometry to newGeometry. If the two geometries are the same, it doesn't do anything.

Derived classes must call the base class method within their implementation.

Reimplemented from QQuickItem.

Definition at line 543 of file qquickcanvasitem.cpp.

References canvasSizeChanged(), canvasWindowChanged(), d, emit, QQuickItem::geometryChange(), QQuickItem::height, QQuickItem::isVisible(), rect, requestPaint(), QRectF::size(), tileSizeChanged(), QSizeF::toSize(), and QQuickItem::width.

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◆ getContext()

void QQuickCanvasItem::getContext ( QQmlV4Function * args )

\qmlmethod object QtQuick::Canvas::getContext(string contextId, ... args)

Returns a drawing context, or null if no context is available.

The contextId parameter names the required context. The Canvas item will return a context that implements the required drawing mode. After the first call to getContext, any subsequent call to getContext with the same contextId will return the same context object. Any additional arguments (args) are currently ignored.

If the context type is not supported or the canvas has previously been requested to provide a different and incompatible context type, null will be returned.

Canvas only supports a 2d context.

Definition at line 813 of file qquickcanvasitem.cpp.

References args, Qt::CaseInsensitive, d, QV4::Encode::null(), qmlWarning(), and str.

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◆ imageLoaded

void QQuickCanvasItem::imageLoaded ( )

signal

Referenced by loadImage().

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◆ isAvailable()

bool QQuickCanvasItem::isAvailable ( ) const

\qmlproperty bool QtQuick::Canvas::available

Indicates when Canvas is able to provide a drawing context to operate on.

Definition at line 278 of file qquickcanvasitem.cpp.

◆ isImageError

bool QQuickCanvasItem::isImageError ( const QUrl & url ) const

slot

\qmlmethod QtQuick::Canvas::isImageError(url image)

Returns true if the image failed to load, false otherwise.

See also: loadImage()

Definition at line 1039 of file qquickcanvasitem.cpp.

References d, and url.

◆ isImageLoaded

bool QQuickCanvasItem::isImageLoaded ( const QUrl & url ) const

slot

\qmlmethod QtQuick::Canvas::isImageLoaded(url image) Returns true if the image is successfully loaded and ready to use.

See also: loadImage()

Definition at line 1066 of file qquickcanvasitem.cpp.

References d, and url.

◆ isImageLoading

bool QQuickCanvasItem::isImageLoading ( const QUrl & url ) const

slot

\qmlmethod QtQuick::Canvas::isImageLoading(url image) Returns true if the image is currently loading.

See also: loadImage()

Definition at line 1053 of file qquickcanvasitem.cpp.

References d, and url.

◆ isTextureProvider()

bool QQuickCanvasItem::isTextureProvider ( ) const

overridevirtual

Returns true if this item is a texture provider.

The default implementation returns false.

This function can be called from any thread.

Reimplemented from QQuickItem.

Definition at line 766 of file qquickcanvasitem.cpp.

◆ itemChange()

void QQuickCanvasItem::itemChange	(	QQuickItem::ItemChange	change,
		const QQuickItem::ItemChangeData &	value
	)

overrideprotectedvirtual

Called when change occurs for this item.

value contains extra information relating to the change, when applicable.

If you re-implement this method in a subclass, be sure to call

QQuickItem::itemChange(change, value);

QQuickItem::itemChange

virtual void itemChange(ItemChange, const ItemChangeData &)

Called when change occurs for this item.

Definition qquickitem.cpp:5684

value

EGLOutputLayerEXT EGLint EGLAttrib value

[5]

Definition qeglstreamconvenience_p.h:46

typically at the end of your implementation, to ensure the \l windowChanged() signal will be emitted.

Reimplemented from QQuickItem.

Definition at line 636 of file qquickcanvasitem.cpp.

References QObject::connect(), QQuickItemPrivate::ContentUpdateMask, context, QQuickWindowPrivate::context, d, FramebufferObject, QQuickWindowPrivate::get(), QMetaObject::invokeMethod(), QQuickItem::itemChange(), QQuickItem::ItemSceneChange, Qt::QueuedConnection, requestPaint(), SIGNAL, and SLOT.

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◆ loadedPixmap()

QQmlRefPointer< QQuickCanvasPixmap > QQuickCanvasItem::loadedPixmap	(	const QUrl &	url,
		QSizeF	sourceSize = `QSizeF()`
	)

Definition at line 961 of file qquickcanvasitem.cpp.

References d, loadImage(), and url.

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◆ loadImage

void QQuickCanvasItem::loadImage	(	const QUrl &	url,
		QSizeF	sourceSize = `QSizeF()`
	)

slot

\qmlsignal QtQuick::Canvas::imageLoaded()

This signal is emitted when an image has been loaded.

See also: loadImage()

\qmlmethod QtQuick::Canvas::loadImage(url image, size sourceSize = undefined)

Loads the given image asynchronously.

Once the image is ready, imageLoaded() signal will be emitted. The loaded image can be unloaded with the unloadImage() method.

Note: Only loaded images can be painted on the Canvas item.

If sourceSize is specified, the image will be scaled to that size during loading. This is useful for loading scalable (vector) images (eg. SVGs) at their intended display size. This parameter was introduced in Qt 6.7.

See also: unloadImage(), imageLoaded(), isImageLoaded(), Context2D::createImageData(), Context2D::drawImage()

Definition at line 996 of file qquickcanvasitem.cpp.

References QQmlRefPointer< T >::adopt(), QQuickPixmap::Asynchronous, QQuickPixmap::Cache, d, imageLoaded(), QPixmap::load(), pix, qmlEngine(), SIGNAL, QSizeF::toSize(), and url.

Referenced by loadedPixmap().

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◆ markDirty()

void QQuickCanvasItem::markDirty ( const QRectF & rect = QRectF() )

\qmlmethod QtQuick::Canvas::markDirty(rect area)

Marks the given area as dirty, so that when this area is visible the canvas renderer will redraw it. This will trigger the paint signal.

See also: paint, requestPaint()

Definition at line 922 of file qquickcanvasitem.cpp.

References d, QQuickItem::polish(), and rect.

Referenced by requestPaint().

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◆ paint

void QQuickCanvasItem::paint ( const QRect & region )

signal

Referenced by updatePolish().

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◆ painted

void QQuickCanvasItem::painted ( )

signal

◆ rawContext()

QQuickCanvasContext * QQuickCanvasItem::rawContext ( ) const

Definition at line 519 of file qquickcanvasitem.cpp.

◆ releaseResources()

void QQuickCanvasItem::releaseResources ( )

overrideprotectedvirtual

This function is called when an item should release graphics resources which are not already managed by the nodes returned from QQuickItem::updatePaintNode().

This happens when the item is about to be removed from the window it was previously rendering to. The item is guaranteed to have a \l {QQuickItem::window()}{window} when the function is called.

The function is called on the GUI thread and the state of the rendering thread, when it is used, is unknown. Objects should not be deleted directly, but instead scheduled for cleanup using QQuickWindow::scheduleRenderJob().

See also: {Graphics Resource Handling}

Reimplemented from QQuickItem.

Definition at line 575 of file qquickcanvasitem.cpp.

References d, QQuickWindowQObjectCleanupJob::schedule(), and QQuickItem::window().

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◆ renderStrategy()

QQuickCanvasItem::RenderStrategy QQuickCanvasItem::renderStrategy ( ) const

\qmlproperty enumeration QtQuick::Canvas::renderStrategy Holds the current canvas rendering strategy.

\value Canvas.Immediate context will perform graphics commands immediately in the main UI thread. \value Canvas.Threaded context will defer graphics commands to a private rendering thread. \value Canvas.Cooperative context will defer graphics commands to the applications global render thread.

This hint is supplied along with renderTarget to the graphics context to determine the method of rendering. A renderStrategy, renderTarget or a combination may not be supported by a graphics context, in which case the context will choose appropriate options and Canvas will signal the change to the properties.

Configuration or runtime tests may cause the QML Scene Graph to render in the GUI thread. Selecting Canvas.Cooperative, does not guarantee rendering will occur on a thread separate from the GUI thread.

The default value is Canvas.Immediate.

See also: renderTarget

Definition at line 501 of file qquickcanvasitem.cpp.

◆ renderStrategyChanged

void QQuickCanvasItem::renderStrategyChanged ( )

signal

Referenced by setRenderStrategy().

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◆ renderTarget()

QQuickCanvasItem::RenderTarget QQuickCanvasItem::renderTarget ( ) const

\qmlproperty enumeration QtQuick::Canvas::renderTarget Holds the current canvas render target.

\value Canvas.Image Render to an in-memory image buffer. \value Canvas.FramebufferObject As of Qt 6.0, this value is ignored.

This hint is supplied along with renderStrategy to the graphics context to determine the method of rendering. A renderStrategy, renderTarget or a combination may not be supported by a graphics context, in which case the context will choose appropriate options and Canvas will signal the change to the properties.

The default render target is Canvas.Image.

Definition at line 458 of file qquickcanvasitem.cpp.

References d.

◆ renderTargetChanged

void QQuickCanvasItem::renderTargetChanged ( )

signal

Referenced by setRenderTarget().

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◆ requestAnimationFrame()

void QQuickCanvasItem::requestAnimationFrame ( QQmlV4Function * args )

\qmlmethod int QtQuick::Canvas::requestAnimationFrame(callback)

This function schedules callback to be invoked before composing the Qt Quick scene.

Definition at line 857 of file qquickcanvasitem.cpp.

References args, d, QV4::Scope::engine, QQuickItem::isVisible(), QV4::Encode::null(), and qmlWarning().

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◆ requestPaint()

void QQuickCanvasItem::requestPaint ( )

\qmlmethod QtQuick::Canvas::requestPaint()

Request the entire visible region be re-drawn.

See also: markDirty()

Definition at line 908 of file qquickcanvasitem.cpp.

References canvasWindow, and markDirty().

Referenced by geometryChange(), and itemChange().

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◆ save()

bool QQuickCanvasItem::save	(	const QString &	filename,
		const QSizeF &	imageSize = `QSizeF()`
	)		const

\qmlmethod bool QtQuick::Canvas::save(string filename, size imageSize = undefined)

Saves the current canvas content into an image file filename. The saved image format is automatically decided by the filename's suffix. Returns true on success. If imageSize is specified, the resulting image will have this size, and will have a devicePixelRatio of 1.0. Otherwise, the \l {QQuickWindow::}{devicePixelRatio()} of the window in which the canvas is displayed is applied to the saved image.

Note: Calling this method will force painting the whole canvas, not just the current canvas visible window.

See also: canvasWindow, canvasSize, toDataURL()

Definition at line 954 of file qquickcanvasitem.cpp.

References d, QUrl::fromLocalFile(), QImage::save(), toImage(), QUrl::toLocalFile(), and url.

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◆ setCanvasSize()

void QQuickCanvasItem::setCanvasSize ( const QSizeF & size )

Definition at line 358 of file qquickcanvasitem.cpp.

References canvasSizeChanged(), d, emit, QQuickItem::polish(), and QQuickItem::size().

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◆ setCanvasWindow()

void QQuickCanvasItem::setCanvasWindow ( const QRectF & rect )

Definition at line 429 of file qquickcanvasitem.cpp.

References canvasWindowChanged(), d, emit, QQuickItem::polish(), and rect.

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◆ setContextType()

void QQuickCanvasItem::setContextType ( const QString & contextType )

Definition at line 303 of file qquickcanvasitem.cpp.

References Qt::CaseInsensitive, QString::compare(), contextType, contextTypeChanged(), d, emit, and qmlWarning().

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◆ setRenderStrategy()

void QQuickCanvasItem::setRenderStrategy ( QQuickCanvasItem::RenderStrategy strategy )

Definition at line 506 of file qquickcanvasitem.cpp.

References d, emit, qmlWarning(), and renderStrategyChanged().

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◆ setRenderTarget()

void QQuickCanvasItem::setRenderTarget ( QQuickCanvasItem::RenderTarget target )

Definition at line 464 of file qquickcanvasitem.cpp.

References d, emit, qmlWarning(), and renderTargetChanged().

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◆ setTileSize()

void QQuickCanvasItem::setTileSize ( const QSize & size )

Definition at line 394 of file qquickcanvasitem.cpp.

References d, emit, QQuickItem::polish(), QQuickItem::size(), and tileSizeChanged().

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◆ textureProvider()

QSGTextureProvider * QQuickCanvasItem::textureProvider ( ) const

overridevirtual

Returns the texture provider for an item.

The default implementation returns \nullptr.

This function may only be called on the rendering thread.

Reimplemented from QQuickItem.

Definition at line 771 of file qquickcanvasitem.cpp.

References QQuickWindowPrivate::context, QThread::currentThread(), d, QQuickWindowPrivate::get(), QQuickItem::isTextureProvider(), qWarning, QQuickItem::textureProvider(), QObject::thread(), and QQuickItem::window().

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◆ tileSize()

QSize QQuickCanvasItem::tileSize ( ) const

\qmlproperty size QtQuick::Canvas::tileSize Holds the canvas rendering tile size.

The Canvas item enters tiled mode by setting canvasSize, tileSize and the canvasWindow. This can improve rendering performance by rendering and caching tiles instead of rendering the whole canvas every time.

Memory will be consumed only by those tiles within the current visible region.

By default the tileSize is the same as the canvasSize.

Deprecated:: This feature is incomplete. For details, see QTBUG-33129.

See also: canvasSize, canvasWindow

Definition at line 388 of file qquickcanvasitem.cpp.

References d.

◆ tileSizeChanged

void QQuickCanvasItem::tileSizeChanged ( )

signal

Referenced by geometryChange(), and setTileSize().

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◆ toDataURL()

QString QQuickCanvasItem::toDataURL ( const QString & mimeType = QLatin1String("image/png") ) const

\qmlmethod string QtQuick::Canvas::toDataURL(string mimeType)

Returns a data URL for the image in the canvas.

The default mimeType is "image/png".

See also: save()

Definition at line 1126 of file qquickcanvasitem.cpp.

References ba, QByteArray::constData(), mime, mimeToType(), mimeType, QStringLiteral, QByteArray::toBase64(), toImage(), and QIODeviceBase::WriteOnly.

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◆ toImage()

QImage QQuickCanvasItem::toImage ( const QRectF & rect = QRectF() ) const

Returns a QImage representing the requested rect which is in device independent pixels of the item. If rect is empty, then it will use the whole item's rect by default.

Definition at line 1080 of file qquickcanvasitem.cpp.

References canvasWindow, d, dpr(), rect, QRectF::size(), QRectF::topLeft(), and QQuickItem::window().

Referenced by save(), and toDataURL().

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◆ unloadImage

void QQuickCanvasItem::unloadImage ( const QUrl & url )

slot

\qmlmethod QtQuick::Canvas::unloadImage(url image)

Unloads the image.

Once an image is unloaded, it cannot be painted by the canvas context unless it is loaded again.

See also: loadImage(), imageLoaded(), isImageLoaded(), Context2D::createImageData(), Context2D::drawImage

Definition at line 1026 of file qquickcanvasitem.cpp.

References d, and url.

◆ updatePaintNode()

QSGNode * QQuickCanvasItem::updatePaintNode	(	QSGNode *	oldNode,
		UpdatePaintNodeData *	updatePaintNodeData
	)

overrideprotectedvirtual

Called on the render thread when it is time to sync the state of the item with the scene graph.

The function is called as a result of QQuickItem::update(), if the user has set the QQuickItem::ItemHasContents flag on the item.

The function should return the root of the scene graph subtree for this item. Most implementations will return a single QSGGeometryNode containing the visual representation of this item. oldNode is the node that was returned the last time the function was called. updatePaintNodeData provides a pointer to the QSGTransformNode associated with this QQuickItem.

QSGNode *MyItem::updatePaintNode(QSGNode *node, UpdatePaintNodeData *)
{
    QSGSimpleRectNode *n = static_cast<QSGSimpleRectNode *>(node);
    if (!n) {
        n = new QSGSimpleRectNode();
        n->setColor(Qt::red);
    }
    n->setRect(boundingRect());
    return n;
}

The main thread is blocked while this function is executed so it is safe to read values from the QQuickItem instance and other objects in the main thread.

If no call to QQuickItem::updatePaintNode() result in actual scene graph changes, like QSGNode::markDirty() or adding and removing nodes, then the underlying implementation may decide to not render the scene again as the visual outcome is identical.

Warning: It is crucial that graphics operations and interaction with the scene graph happens exclusively on the render thread, primarily during the QQuickItem::updatePaintNode() call. The best rule of thumb is to only use classes with the "QSG" prefix inside the QQuickItem::updatePaintNode() function.; This function is called on the render thread. This means any QObjects or thread local storage that is created will have affinity to the render thread, so apply caution when doing anything other than rendering in this function. Similarly for signals, these will be emitted on the render thread and will thus often be delivered via queued connections.

Note: All classes with QSG prefix should be used solely on the scene graph's rendering thread. See \l {Scene Graph and Rendering} for more information.

See also: QSGMaterial, QSGGeometryNode, QSGGeometry, QSGFlatColorMaterial, QSGTextureMaterial, QSGNode::markDirty(), {Graphics Resource Handling}

Reimplemented from QQuickItem.

Definition at line 708 of file qquickcanvasitem.cpp.

References QQuickItem::antialiasing, QQuickWindowPrivate::context, Cooperative, QSGContext::createInternalImageNode(), d, factory, QQuickWindowPrivate::get(), QSGTexture::Linear, QSGTexture::Nearest, QSGRenderContext::sceneGraphContext(), QSGInternalImageNode::setFiltering(), QSGInternalImageNode::setInnerTargetRect(), QSGInternalImageNode::setTargetRect(), QSGInternalImageNode::setTexture(), QSGInternalImageNode::update(), and QQuickItem::window().

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◆ updatePolish()

void QQuickCanvasItem::updatePolish ( )

overrideprotectedvirtual

This function should perform any layout as required for this item.

When polish() is called, the scene graph schedules a polish event for this item. When the scene graph is ready to render this item, it calls updatePolish() to do any item layout as required before it renders the next frame.

See also: ensurePolished()

Reimplemented from QQuickItem.

Definition at line 666 of file qquickcanvasitem.cpp.

References QQuickItem::antialiasing, QV4::JSCallArguments::args, QMap< Key, T >::cbegin(), QMap< Key, T >::cend(), Cooperative, QDateTime::currentMSecsSinceEpoch(), d, emit, QV4::Value::fromUInt32(), function, QJSEngine::handle(), QQuickItem::isVisible(), it, paint(), qmlEngine(), QV4::JSCallArguments::thisObject, QQuickItem::update(), QQuickItem::updatePolish(), and QV4::QObjectWrapper::wrap().

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Property Documentation

◆ available

bool QQuickCanvasItem::available

read

Definition at line 52 of file qquickcanvasitem_p.h.

◆ canvasSize

QSizeF QQuickCanvasItem::canvasSize

readwrite

Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by QQuickContext2D::init().

◆ canvasWindow

QRectF QQuickCanvasItem::canvasWindow

readwrite

Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by QQuickContext2D::init(), requestPaint(), and toImage().

◆ context

QJSValue QQuickCanvasItem::context

read

Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by itemChange().

◆ contextType

QString QQuickCanvasItem::contextType

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Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by setContextType().

◆ renderStrategy

RenderStrategy QQuickCanvasItem::renderStrategy

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Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by QQuickContext2D::init().

◆ renderTarget

RenderTarget QQuickCanvasItem::renderTarget

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Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by QQuickContext2D::init().

◆ tileSize

QSize QQuickCanvasItem::tileSize

readwrite

Definition at line 52 of file qquickcanvasitem_p.h.

Referenced by QQuickContext2D::init().

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

qtdeclarative/src/quick/items/context2d/qquickcanvasitem_p.h
qtdeclarative/src/quick/items/context2d/qquickcanvasitem.cpp

Public Types

Public Slots

Signals

Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ RenderStrategy

◆ RenderTarget

Constructor & Destructor Documentation

◆ QQuickCanvasItem()

◆ ~QQuickCanvasItem()

Member Function Documentation

◆ availableChanged

◆ cancelRequestAnimationFrame()

◆ canvasSize()

◆ canvasSizeChanged

◆ canvasWindow()

◆ canvasWindowChanged

◆ componentComplete()

◆ context()

◆ contextChanged

◆ contextType()

◆ contextTypeChanged

◆ event()

◆ geometryChange()

◆ getContext()

◆ imageLoaded

◆ isAvailable()

◆ isImageError

◆ isImageLoaded

◆ isImageLoading

◆ isTextureProvider()

◆ itemChange()

◆ loadedPixmap()

◆ loadImage

◆ markDirty()

◆ paint

◆ painted

◆ rawContext()

◆ releaseResources()

◆ renderStrategy()

◆ renderStrategyChanged

◆ renderTarget()

◆ renderTargetChanged

◆ requestAnimationFrame()

◆ requestPaint()

◆ save()

◆ setCanvasSize()

◆ setCanvasWindow()

◆ setContextType()

◆ setRenderStrategy()

◆ setRenderTarget()

◆ setTileSize()

◆ textureProvider()

◆ tileSize()

◆ tileSizeChanged

◆ toDataURL()

◆ toImage()

◆ unloadImage

◆ updatePaintNode()

◆ updatePolish()

Property Documentation

◆ available

◆ canvasSize

◆ canvasWindow

◆ context

◆ contextType

◆ renderStrategy

◆ renderTarget

◆ tileSize