The QQuickImageProvider class provides an interface for supporting pixmaps and threaded image requests in QML. More...

#include <qquickimageprovider.h>

Inheritance diagram for QQuickImageProvider:

Collaboration diagram for QQuickImageProvider:

Public Member Functions
	QQuickImageProvider (ImageType type, Flags flags=Flags())
	Creates an image provider that will provide images of the given type and behave according to the given flags.

	~QQuickImageProvider () override
	Destroys the QQuickImageProvider.

ImageType	imageType () const override
	Returns the image type supported by this provider.

Flags	flags () const override
	Returns the flags set for this provider.

virtual QImage	requestImage (const QString &id, QSize *size, const QSize &requestedSize)
	Implement this method to return the image with id.

virtual QPixmap	requestPixmap (const QString &id, QSize *size, const QSize &requestedSize)
	Implement this method to return the pixmap with id.

virtual QQuickTextureFactory *	requestTexture (const QString &id, QSize *size, const QSize &requestedSize)
	Implement this method to return the texture with id.

Public Member Functions inherited from QQmlImageProviderBase
virtual	~QQmlImageProviderBase ()

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.

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 >
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 >
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 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`.

Friends
class	QQuickImageProviderWithOptions

Additional Inherited Members
Public Types inherited from QQmlImageProviderBase
enum	ImageType : int { Invalid = 0 , Image , Pixmap , Texture , ImageResponse }
	Defines the type of image supported by this image provider. More...

enum	Flag { ForceAsynchronousImageLoading = 0x01 }
	Defines specific requirements or features of this image provider. More...

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

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.

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 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)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object

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

The QQuickImageProvider class provides an interface for supporting pixmaps and threaded image requests in QML.

Since: 5.0 \inmodule QtQuick

QQuickImageProvider is used to provide advanced image loading features in QML applications. It allows images in QML to be:

\list

Loaded using QPixmaps rather than actual image files
Loaded asynchronously in a separate thread \endlist

To specify that an image should be loaded by an image provider, use the {"image:"} scheme for the URL source of the image, followed by the identifiers of the image provider and the requested image. For example:

\qml Image { source: "image://myimageprovider/image.png" } \endqml

This specifies that the image should be loaded by the image provider named "myimageprovider", and the image to be loaded is named "image.png". The QML engine invokes the appropriate image provider according to the providers that have been registered through QQmlEngine::addImageProvider().

Note that the identifiers are case-insensitive, but the rest of the URL will be passed on with preserved case. For example, the below snippet would still specify that the image is loaded by the image provider named "myimageprovider", but it would request a different image than the above snippet ("Image.png" instead of "image.png"). \qml Image { source: "image://MyImageProvider/Image.png" } \endqml

If you want the rest of the URL to be case insensitive, you will have to take care of that yourself inside your image provider.

Definition at line 61 of file qquickimageprovider.h.

Constructor & Destructor Documentation

◆ QQuickImageProvider()

QQuickImageProvider::QQuickImageProvider	(	ImageType	type,
		Flags	flags = Flags() )

Creates an image provider that will provide images of the given type and behave according to the given flags.

Definition at line 309 of file qquickimageprovider.cpp.

References flags(), QQuickImageProviderPrivate::flags, QQuickImageProviderPrivate::isProviderWithOptions, and QQuickImageProviderPrivate::type.

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◆ ~QQuickImageProvider()

QQuickImageProvider::~QQuickImageProvider ( )

override

Destroys the QQuickImageProvider.

Note: The destructor of your derived class need to be thread safe.

Definition at line 322 of file qquickimageprovider.cpp.

Member Function Documentation

◆ flags()

QQuickImageProvider::Flags QQuickImageProvider::flags ( ) const

overridevirtual

Returns the flags set for this provider.

Implements QQmlImageProviderBase.

Definition at line 338 of file qquickimageprovider.cpp.

References QQuickImageProviderPrivate::flags.

Referenced by QQuickImageProvider(), and QQuickImageProviderWithOptions::QQuickImageProviderWithOptions().

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◆ imageType()

QQuickImageProvider::ImageType QQuickImageProvider::imageType ( ) const

overridevirtual

Returns the image type supported by this provider.

Implements QQmlImageProviderBase.

Definition at line 330 of file qquickimageprovider.cpp.

References QQuickImageProviderPrivate::type.

Referenced by QQuickImageProviderWithOptions::requestImageResponse().

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◆ requestImage()

QImage QQuickImageProvider::requestImage	(	const QString &	id,
		QSize *	size,
		const QSize &	requestedSize )

virtual

Implement this method to return the image with id.

The default implementation returns an empty image.

The id is the requested image source, with the "image:" scheme and provider identifier removed. For example, if the image \l{Image::}{source} was "image://myprovider/icons/home", the given id would be "icons/home".

The requestedSize corresponds to the \l {Image::sourceSize} requested by an Image item. If requestedSize is a valid size, the image returned should be of that size.

In all cases, size must be set to the original size of the image. This is used to set the \l {Item::}{width} and \l {Item::}{height} of the relevant \l Image if these values have not been set explicitly.

Note: this method may be called by multiple threads, so ensure the implementation of this method is reentrant.

Reimplemented in QQuickImageProviderWithOptions, and QQuickImagePreviewProvider.

Definition at line 362 of file qquickimageprovider.cpp.

References Q_UNUSED, qWarning, and QQuickImageProviderPrivate::type.

Referenced by QQuickImageProviderWithOptions::requestImage().

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◆ requestPixmap()

QPixmap QQuickImageProvider::requestPixmap	(	const QString &	id,
		QSize *	size,
		const QSize &	requestedSize )

virtual

Implement this method to return the pixmap with id.

The default implementation returns an empty pixmap.

The id is the requested image source, with the "image:" scheme and provider identifier removed. For example, if the image \l{Image::}{source} was "image://myprovider/icons/home", the given id would be "icons/home".

The requestedSize corresponds to the \l {Image::sourceSize} requested by an Image item. If requestedSize is a valid size, the image returned should be of that size.

In all cases, size must be set to the original size of the image. This is used to set the \l {Item::}{width} and \l {Item::}{height} of the relevant \l Image if these values have not been set explicitly.

Note: this method may be called by multiple threads, so ensure the implementation of this method is reentrant.

Reimplemented in ColorImageProvider, and QQuickImageProviderWithOptions.

Definition at line 391 of file qquickimageprovider.cpp.

References Q_UNUSED, qWarning, and QQuickImageProviderPrivate::type.

Referenced by QQuickImageProviderWithOptions::requestPixmap().

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◆ requestTexture()

QQuickTextureFactory * QQuickImageProvider::requestTexture	(	const QString &	id,
		QSize *	size,
		const QSize &	requestedSize )

virtual

Implement this method to return the texture with id.

The default implementation returns \nullptr.

The id is the requested image source, with the "image:" scheme and provider identifier removed. For example, if the image \l{Image::}{source} was "image://myprovider/icons/home", the given id would be "icons/home".

The requestedSize corresponds to the \l {Image::sourceSize} requested by an Image item. If requestedSize is a valid size, the image returned should be of that size.

In all cases, size must be set to the original size of the image. This is used to set the \l {Item::}{width} and \l {Item::}{height} of the relevant \l Image if these values have not been set explicitly.