The QIconEngine class provides an abstract base class for QIcon renderers. More...

#include <qiconengine.h>

Inheritance diagram for QIconEngine:

Collaboration diagram for QIconEngine:

Classes
class	ScaledPixmapArgument

Public Types
enum	IconEngineHook { IsNullHook = 3 , ScaledPixmapHook }
	These enum values are used for virtual_hook() to allow additional queries to icon engine without breaking binary compatibility. More...

Public Member Functions
	QIconEngine ()
virtual	~QIconEngine ()
	Destroys the icon engine.
virtual void	paint (QPainter *painter, const QRect &rect, QIcon::Mode mode, QIcon::State state)=0
	Uses the given painter to paint the icon with the required mode and state into the rectangle rect.
virtual QSize	actualSize (const QSize &size, QIcon::Mode mode, QIcon::State state)
	Returns the actual size of the icon the engine provides for the requested size, mode and state.
virtual QPixmap	pixmap (const QSize &size, QIcon::Mode mode, QIcon::State state)
	Returns the icon as a pixmap with the required size, mode, and state.
virtual void	addPixmap (const QPixmap &pixmap, QIcon::Mode mode, QIcon::State state)
	Called by QIcon::addPixmap().
virtual void	addFile (const QString &fileName, const QSize &size, QIcon::Mode mode, QIcon::State state)
	Called by QIcon::addFile().
virtual QString	key () const
	\variable QIconEngine::ScaledPixmapArgument::size
virtual QIconEngine *	clone () const =0
	Reimplement this method to return a clone of this icon engine.
virtual bool	read (QDataStream &in)
	Reads icon engine contents from the QDataStream in.
virtual bool	write (QDataStream &out) const
	Writes the contents of this engine to the QDataStream out.
virtual QList< QSize >	availableSizes (QIcon::Mode mode=QIcon::Normal, QIcon::State state=QIcon::Off)
	Returns sizes of all images that are contained in the engine for the specific mode and state.
virtual QString	iconName ()
	Returns the name used to create the engine, if available.
virtual bool	isNull ()
virtual QPixmap	scaledPixmap (const QSize &size, QIcon::Mode mode, QIcon::State state, qreal scale)
virtual void	virtual_hook (int id, void *data)
	Additional method to allow extending QIconEngine without adding new virtual methods (and without breaking binary compatibility).

Protected Member Functions
	QIconEngine (const QIconEngine &other)

Detailed Description

The QIconEngine class provides an abstract base class for QIcon renderers.

\inmodule QtGui

An icon engine provides the rendering functions for a QIcon. Each icon has a corresponding icon engine that is responsible for drawing the icon with a requested size, mode and state.

The icon is rendered by the paint() function, and the icon can additionally be obtained as a pixmap with the pixmap() function (the default implementation simply uses paint() to achieve this). The addPixmap() function can be used to add new pixmaps to the icon engine, and is used by QIcon to add specialized custom pixmaps.

The paint(), pixmap(), and addPixmap() functions are all virtual, and can therefore be reimplemented in subclasses of QIconEngine.

See also: QIconEnginePlugin

Definition at line 14 of file qiconengine.h.

Member Enumeration Documentation

◆ IconEngineHook

enum QIconEngine::IconEngineHook

These enum values are used for virtual_hook() to allow additional queries to icon engine without breaking binary compatibility.

\value IsNullHook Allow to query if this engine represents a null icon. The data argument of the virtual_hook() is a pointer to a bool that can be set to true if the icon is null. This enum value was added in Qt 5.7.

\value ScaledPixmapHook Provides a way to get a pixmap that is scaled according to the given scale (typically equal to the \l {High DPI}{device pixel ratio}). The data argument of the virtual_hook() function is a \l ScaledPixmapArgument pointer that contains both the input and output arguments. This enum value was added in Qt 5.9.

See also: virtual_hook()

Enumerator
IsNullHook
ScaledPixmapHook

Definition at line 39 of file qiconengine.h.

Constructor & Destructor Documentation

◆ QIconEngine() [1/2]

QIconEngine::QIconEngine ( )

Since: 5.6 Constructs the icon engine.

Definition at line 58 of file qiconengine.cpp.

◆ ~QIconEngine()

QIconEngine::~QIconEngine ( )

virtual

Destroys the icon engine.

Definition at line 73 of file qiconengine.cpp.

◆ QIconEngine() [2/2]

QIconEngine::QIconEngine ( const QIconEngine & other )

protected

Since: 5.8

Definition at line 66 of file qiconengine.cpp.

Member Function Documentation

◆ actualSize()

QSize QIconEngine::actualSize	(	const QSize &	size,
		QIcon::Mode	mode,
		QIcon::State	state )

virtual

Returns the actual size of the icon the engine provides for the requested size, mode and state.

The default implementation returns the given size.

The returned size is in device-independent pixels (This is relevant for high-dpi pixmaps).

Reimplemented in QAbstractFileIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 49 of file qiconengine.cpp.

◆ addFile()

void QIconEngine::addFile	(	const QString &	fileName,
		const QSize &	size,
		QIcon::Mode	mode,
		QIcon::State	state )

virtual

Called by QIcon::addFile().

Adds a specialized pixmap from the file with the given fileName, size, mode and state. The default pixmap-based engine stores any supplied file names, and it loads the pixmaps on demand instead of using scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra files.

Reimplemented in QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 113 of file qiconengine.cpp.

◆ addPixmap()

void QIconEngine::addPixmap	(	const QPixmap &	pixmap,
		QIcon::Mode	mode,
		QIcon::State	state )

virtual

Called by QIcon::addPixmap().

Adds a specialized pixmap for the given mode and state. The default pixmap-based engine stores any supplied pixmaps, and it uses them instead of scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra pixmaps.

Reimplemented in QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 100 of file qiconengine.cpp.

◆ availableSizes()

QList< QSize > QIconEngine::availableSizes	(	QIcon::Mode	mode = QIcon::Normal,
		QIcon::State	state = QIcon::Off )

virtual

Returns sizes of all images that are contained in the engine for the specific mode and state.

Reimplemented in QAndroidPlatformFileIconEngine, QAppleFileIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, QWindowsFileIconEngine, and QWindowsFileIconEngine.

Definition at line 255 of file qiconengine.cpp.

◆ clone()

virtual QIconEngine * QIconEngine::clone ( ) const

pure virtual

Reimplement this method to return a clone of this icon engine.

Implemented in QAndroidPlatformIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, QSvgIconEngine, QThemeIconEngine, QWindowsIconEngine, and WinFontIconEngine.

◆ iconName()

QString QIconEngine::iconName ( )

virtual

Returns the name used to create the engine, if available.

Reimplemented in QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, and QProxyIconEngine.

Definition at line 263 of file qiconengine.cpp.

◆ isNull()

bool QIconEngine::isNull ( )

virtual

Since: 5.7

Returns true if this icon engine represent a null QIcon.

Reimplemented in QAbstractFileIconEngine, QAndroidPlatformFileIconEngine, QAppleFileIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 275 of file qiconengine.cpp.

◆ key()

QString QIconEngine::key ( ) const

virtual

\variable QIconEngine::ScaledPixmapArgument::size

The requested size of the pixmap.

\variable QIconEngine::ScaledPixmapArgument::mode

The requested mode of the pixmap.

See also: QIcon::Mode

\variable QIconEngine::ScaledPixmapArgument::state

The requested state of the pixmap.

See also: QIcon::State

\variable QIconEngine::ScaledPixmapArgument::scale

The requested scale of the pixmap.

\variable QIconEngine::ScaledPixmapArgument::pixmap

The pixmap that is the best match for the given \l size, \l mode, \l state, and \l scale. This is an output parameter that is set after calling \l virtual_hook().

Returns a key that identifies this icon engine.

Reimplemented in QAndroidPlatformIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, QSvgIconEngine, QThemeIconEngine, QWindowsIconEngine, and WinFontIconEngine.

Definition at line 196 of file qiconengine.cpp.

◆ paint()

virtual void QIconEngine::paint	(	QPainter *	painter,
		const QRect &	rect,
		QIcon::Mode	mode,
		QIcon::State	state )

pure virtual

Uses the given painter to paint the icon with the required mode and state into the rectangle rect.

Implemented in QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, QSvgIconEngine, and WinFontIconEngine.

◆ pixmap()

QPixmap QIconEngine::pixmap	(	const QSize &	size,
		QIcon::Mode	mode,
		QIcon::State	state )

virtual

Returns the icon as a pixmap with the required size, mode, and state.

The default implementation creates a new pixmap and calls paint() to fill it.

Reimplemented in QAbstractFileIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 83 of file qiconengine.cpp.

◆ read()

bool QIconEngine::read ( QDataStream & in )

virtual

Reads icon engine contents from the QDataStream in.

Returns true if the contents were read; otherwise returns false.

QIconEngine's default implementation always return false.

Reimplemented in QPixmapIconEngine, QProxyIconEngine, QSvgIconEngine, and QThemeIconEngine.

Definition at line 212 of file qiconengine.cpp.

◆ scaledPixmap()

QPixmap QIconEngine::scaledPixmap	(	const QSize &	size,
		QIcon::Mode	mode,
		QIcon::State	state,
		qreal	scale )

virtual

Since: 5.9

Returns a pixmap for the given size, mode, state and scale.

The scale argument is typically equal to the \l {High DPI} {device pixel ratio} of the display. The size is given in device-independent pixels.

Note: Some engines may cast scale to an integer.

See also: ScaledPixmapArgument

Reimplemented in QAbstractFileIconEngine, QAppleIconEngine, QFontIconEngine, QIconLoaderEngine, QPixmapIconEngine, QProxyIconEngine, and QSvgIconEngine.

Definition at line 296 of file qiconengine.cpp.

◆ virtual_hook()

void QIconEngine::virtual_hook	(	int	id,
		void *	data )

virtual

Additional method to allow extending QIconEngine without adding new virtual methods (and without breaking binary compatibility).

The actual action and format of data depends on id argument which is in fact a constant from IconEngineHook enum.

See also: IconEngineHook

Reimplemented in QProxyIconEngine.

Definition at line 236 of file qiconengine.cpp.

◆ write()

bool QIconEngine::write ( QDataStream & out ) const

virtual

Writes the contents of this engine to the QDataStream out.

Returns true if the contents were written; otherwise returns false.

QIconEngine's default implementation always return false.

Reimplemented in QPixmapIconEngine, QProxyIconEngine, QSvgIconEngine, and QThemeIconEngine.

Definition at line 223 of file qiconengine.cpp.

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

qtbase/src/gui/image/qiconengine.h (95bb6bc916358d85c72c935dfe57e12ec771c9f9)
qtbase/src/gui/image/qiconengine.cpp (245bdc8ec31755d6ab38b796014bdcab6a1d17ae)

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ IconEngineHook

Constructor & Destructor Documentation

◆ QIconEngine() [1/2]

◆ ~QIconEngine()

◆ QIconEngine() [2/2]

Member Function Documentation

◆ actualSize()

◆ addFile()

◆ addPixmap()

◆ availableSizes()

◆ clone()

◆ iconName()

◆ isNull()

◆ key()

◆ paint()

◆ pixmap()

◆ read()

◆ scaledPixmap()

◆ virtual_hook()

◆ write()