The QPicture class is a paint device that records and replays QPainter commands. More...

#include <qpicture.h>

Inheritance diagram for QPicture:

Collaboration diagram for QPicture:

Public Types
typedef QExplicitlySharedDataPointer< QPicturePrivate >	DataPtr
Public Types inherited from QPaintDevice
enum	PaintDeviceMetric { PdmWidth = 1 , PdmHeight , PdmWidthMM , PdmHeightMM , PdmNumColors , PdmDepth , PdmDpiX , PdmDpiY , PdmPhysicalDpiX , PdmPhysicalDpiY , PdmDevicePixelRatio , PdmDevicePixelRatioScaled , PdmDevicePixelRatioF_EncodedA , PdmDevicePixelRatioF_EncodedB }

Public Member Functions
	QPicture (int formatVersion=-1)
	Constructs an empty picture.
	QPicture (const QPicture &)
	Constructs a copy of pic.
	~QPicture ()
	Destroys the picture.
bool	isNull () const
	Returns `true` if the picture contains no data; otherwise returns false.
int	devType () const override
uint	size () const
	Returns the size of the picture data.
const char *	data () const
	Returns a pointer to the picture data.
virtual void	setData (const char *data, uint size)
	Sets the picture data directly from data and size.
bool	play (QPainter *p)
	Replays the picture using painter, and returns `true` if successful; otherwise returns `false`.
bool	load (QIODevice *dev)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.dev is the device to use for loading.
bool	load (const QString &fileName)
	Loads a picture from the file specified by fileName and returns true if successful; otherwise invalidates the picture and returns `false`.
bool	save (QIODevice *dev)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.dev is the device to use for saving.
bool	save (const QString &fileName)
	Saves a picture to the file specified by fileName and returns true if successful; otherwise returns `false`.
QRect	boundingRect () const
	Returns the picture's bounding rectangle or an invalid rectangle if the picture contains no data.
void	setBoundingRect (const QRect &r)
	Sets the picture's bounding rectangle to r.
QPicture &	operator= (const QPicture &p)
	Move-assigns other to this QPicture instance.
void	swap (QPicture &other) noexcept
	\memberswap{picture}
void	detach ()
bool	isDetached () const
QPaintEngine *	paintEngine () const override
DataPtr &	data_ptr ()
Public Member Functions inherited from QPaintDevice
virtual	~QPaintDevice ()
bool	paintingActive () const
int	width () const
int	height () const
int	widthMM () const
int	heightMM () const
int	logicalDpiX () const
int	logicalDpiY () const
int	physicalDpiX () const
int	physicalDpiY () const
qreal	devicePixelRatio () const
qreal	devicePixelRatioF () const
int	colorCount () const
int	depth () const

Protected Member Functions
	QPicture (QPicturePrivate &data)
int	metric (PaintDeviceMetric m) const override
Protected Member Functions inherited from QPaintDevice
	QPaintDevice () noexcept
virtual void	initPainter (QPainter *painter) const
virtual QPaintDevice *	redirected (QPoint *offset) const
virtual QPainter *	sharedPainter () const
double	getDecodedMetricF (PaintDeviceMetric metricA, PaintDeviceMetric metricB) const

Friends
class	QPicturePaintEngine
class	QAlphaPaintEngine
class	QPreviewPaintEngine
Q_GUI_EXPORT QDataStream &	operator<< (QDataStream &in, const QPicture &p)
	Writes picture r to the stream s and returns a reference to the stream.
Q_GUI_EXPORT QDataStream &	operator>> (QDataStream &in, QPicture &p)
	Reads a picture from the stream s into picture r and returns a reference to the stream.

Additional Inherited Members
Static Public Member Functions inherited from QPaintDevice
static qreal	devicePixelRatioFScale ()
static int	encodeMetricF (PaintDeviceMetric metric, double value)
Protected Attributes inherited from QPaintDevice
ushort	painters

Detailed Description

The QPicture class is a paint device that records and replays QPainter commands.

\inmodule QtGui

A picture serializes painter commands to an IO device in a platform-independent format. They are sometimes referred to as meta-files.

Qt pictures use a proprietary binary format. Unlike native picture (meta-file) formats on many window systems, Qt pictures have no limitations regarding their contents. Everything that can be painted on a widget or pixmap (e.g., fonts, pixmaps, regions, transformed graphics, etc.) can also be stored in a picture.

QPicture is resolution independent, i.e. a QPicture can be displayed on different devices (for example svg, pdf, ps, printer and screen) looking the same. This is, for instance, needed for WYSIWYG print preview. QPicture runs in the default system dpi, and scales the painter to match differences in resolution depending on the window system.

Example of how to record a picture:

QPicture picture;
QPainter painter;
painter.begin(&picture);           // paint in picture
painter.drawEllipse(10,20, 80,70); // draw an ellipse
painter.end();                     // painting done
picture.save("drawing.pic");       // save picture

Note that the list of painter commands is reset on each call to the QPainter::begin() function.

Example of how to replay a picture:

QPicture picture;
picture.load("drawing.pic");           // load picture
QPainter painter;
painter.begin(&myImage);               // paint in myImage
painter.drawPicture(0, 0, picture);    // draw the picture at (0,0)
painter.end();                         // painting done

Pictures can also be drawn using play(). Some basic data about a picture is available, for example, size(), isNull() and boundingRect().

Note: QPicture uses QDataStream for serialization. The \l {QDataStream#Corruption and Security}{same reservations} against reading untrusted data apply.

See also: QMovie

Definition at line 18 of file qpicture.h.

Member Typedef Documentation

◆ DataPtr

typedef QExplicitlySharedDataPointer<QPicturePrivate> QPicture::DataPtr

Definition at line 69 of file qpicture.h.

Constructor & Destructor Documentation

◆ QPicture() [1/3]

QPicture::QPicture ( int formatVersion = -1 )

explicit

Constructs an empty picture.

The formatVersion parameter may be used to create a QPicture that can be read by applications that are compiled with earlier versions of Qt.

Note that the default formatVersion is -1 which signifies the current release, i.e. for Qt 4.0 a formatVersion of 7 is the same as the default formatVersion of -1.

Reading pictures generated by earlier versions of Qt is not supported in Qt 4.0.

Definition at line 113 of file qpicture.cpp.

◆ QPicture() [2/3]

QPicture::QPicture ( const QPicture & pic )

Constructs a copy of pic.

This constructor is fast thanks to \l{implicit sharing}.

Definition at line 138 of file qpicture.cpp.

◆ ~QPicture()

QPicture::~QPicture ( )

Destroys the picture.

Definition at line 153 of file qpicture.cpp.

◆ QPicture() [3/3]

QPicture::QPicture ( QPicturePrivate & dptr )

protected

Definition at line 144 of file qpicture.cpp.

Member Function Documentation

◆ boundingRect()

QRect QPicture::boundingRect ( ) const

Returns the picture's bounding rectangle or an invalid rectangle if the picture contains no data.

Definition at line 307 of file qpicture.cpp.

◆ data()

const char * QPicture::data ( ) const

Returns a pointer to the picture data.

The pointer is only valid until the next non-const function is called on this picture. The returned pointer is 0 if the picture contains no data.

See also: size(), isNull()

Definition at line 201 of file qpicture.cpp.

◆ data_ptr()

DataPtr & QPicture::data_ptr ( )

inline

Definition at line 70 of file qpicture.h.

◆ detach()

void QPicture::detach ( )

Detaches from shared picture data and makes sure that this picture is the only one referring to the data.

If multiple pictures share common data, this picture makes a copy of the data and detaches itself from the sharing mechanism. Nothing is done if there is just a single reference.

Definition at line 206 of file qpicture.cpp.

◆ devType()

int QPicture::devType ( ) const

overridevirtual

Reimplemented from QPaintDevice.

Definition at line 160 of file qpicture.cpp.

◆ isDetached()

bool QPicture::isDetached ( ) const

Definition at line 211 of file qpicture.cpp.

◆ isNull()

bool QPicture::isNull ( ) const

Returns true if the picture contains no data; otherwise returns false.

Definition at line 191 of file qpicture.cpp.

◆ load() [1/2]

bool QPicture::load ( const QString & fileName )

Loads a picture from the file specified by fileName and returns true if successful; otherwise invalidates the picture and returns false.

See also: save()

Definition at line 238 of file qpicture.cpp.

◆ load() [2/2]

bool QPicture::load ( QIODevice * dev )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.dev is the device to use for loading.

Definition at line 254 of file qpicture.cpp.

◆ metric()

int QPicture::metric ( PaintDeviceMetric m ) const

overrideprotectedvirtual

Internal implementation of the virtual QPaintDevice::metric() function.

A picture has the following hard-coded values: numcolors=16777216 and depth=24.

m is the metric to get.

Reimplemented from QPaintDevice.

Definition at line 893 of file qpicture.cpp.

◆ operator=()

QPicture & QPicture::operator= ( const QPicture & p )

Move-assigns other to this QPicture instance.

Assigns picture p to this picture and returns a reference to this picture.

Since: 5.2

Definition at line 956 of file qpicture.cpp.

◆ paintEngine()

QPaintEngine * QPicture::paintEngine ( ) const

overridevirtual

Implements QPaintDevice.

Definition at line 1085 of file qpicture.cpp.

◆ play()

bool QPicture::play ( QPainter * painter )

Replays the picture using painter, and returns true if successful; otherwise returns false.

This function does exactly the same as QPainter::drawPicture() with (x, y) = (0, 0).

Note: The state of the painter isn't preserved by this function.

Definition at line 340 of file qpicture.cpp.

◆ save() [1/2]

bool QPicture::save ( const QString & fileName )

Saves a picture to the file specified by fileName and returns true if successful; otherwise returns false.

See also: load()

Definition at line 270 of file qpicture.cpp.

◆ save() [2/2]

bool QPicture::save ( QIODevice * dev )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.dev is the device to use for saving.

Definition at line 290 of file qpicture.cpp.

◆ setBoundingRect()

void QPicture::setBoundingRect ( const QRect & r )

Sets the picture's bounding rectangle to r.

The automatically calculated value is overridden.

Definition at line 325 of file qpicture.cpp.

◆ setData()

void QPicture::setData	(	const char *	data,
		uint	size )

virtual

Sets the picture data directly from data and size.

This function copies the input data.

See also: data(), size()

Definition at line 223 of file qpicture.cpp.

◆ size()

uint QPicture::size ( ) const

Returns the size of the picture data.

See also: data()

Definition at line 196 of file qpicture.cpp.

◆ swap()

void QPicture::swap ( QPicture & other )

inlinenoexcept

\memberswap{picture}

Definition at line 45 of file qpicture.h.

◆ operator<<

QDataStream & operator<<	(	QDataStream &	in,
		const QPicture &	p )

friend

Writes picture r to the stream s and returns a reference to the stream.

Definition at line 1104 of file qpicture.cpp.

◆ operator>>

QDataStream & operator>>	(	QDataStream &	in,
		QPicture &	p )

friend

Reads a picture from the stream s into picture r and returns a reference to the stream.

Definition at line 1123 of file qpicture.cpp.

◆ QAlphaPaintEngine

friend class QAlphaPaintEngine

friend

Definition at line 65 of file qpicture.h.

◆ QPicturePaintEngine

friend class QPicturePaintEngine

friend

Definition at line 64 of file qpicture.h.

◆ QPreviewPaintEngine

friend class QPreviewPaintEngine

friend

Definition at line 66 of file qpicture.h.

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

qtbase/src/gui/image/qpicture.h (6ff4c3d787ecc2e6d2740f22d0406b34346faede)
qtbase/src/gui/image/qpicture.cpp (fe3129ed4119754a10820407330e7d5f9d04adb0)

Public Types

Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ DataPtr

Constructor & Destructor Documentation

◆ QPicture() [1/3]

◆ QPicture() [2/3]

◆ ~QPicture()

◆ QPicture() [3/3]

Member Function Documentation

◆ boundingRect()

◆ data()

◆ data_ptr()

◆ detach()

◆ devType()

◆ isDetached()

◆ isNull()

◆ load() [1/2]

◆ load() [2/2]

◆ metric()

◆ operator=()

◆ paintEngine()

◆ play()

◆ save() [1/2]

◆ save() [2/2]

◆ setBoundingRect()

◆ setData()

◆ size()

◆ swap()

Friends And Related Symbol Documentation

◆ operator<<

◆ operator>>

◆ QAlphaPaintEngine

◆ QPicturePaintEngine

◆ QPreviewPaintEngine