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# QPicture Class Reference

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

    #include <QPicture>

Inherits QPaintDevice.

- List of all members, including inherited members
- Compatibility members

### Public Functions

- QPicture ( int formatVersion = -1 )
- QPicture ( const QPicture & pic )
- ~QPicture ()
- QRect boundingRect () const
- const char * data () const
- bool isNull () const
- bool load ( const QString & fileName, const char * format = 0 )
- bool load ( QIODevice * dev, const char * format = 0 )
- bool play ( QPainter * painter )
- bool save ( const QString & fileName, const char * format = 0 )
- bool save ( QIODevice * dev, const char * format = 0 )
- void setBoundingRect ( const QRect & r )
- virtual void setData ( const char * data, uint size )
- uint size () const
- QPicture & operator= ( const QPicture & p )

- 2 public functions inherited from QPaintDevice

### Static Public Members

- QStringList inputFormatList ()
- QList<QByteArray> inputFormats ()
- QStringList outputFormatList ()
- QList<QByteArray> outputFormats ()
- const char * pictureFormat ( const QString & fileName )

### Protected Functions

- virtual int metric ( int m ) const

### Related Non-Members

- QDataStream & operator<< ( QDataStream & s, const QPicture & r )
- QDataStream & operator>> ( QDataStream & s, QPicture & r )

## Detailed Description

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

A picture serializes painter commands to an IO device in a platform-independent format. For example, a picture created under Windows can be read on a Sun SPARC.

Pictures are called meta-files on some platforms.

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 can also be stored in a picture, e.g. fonts, pixmaps, regions, transformed graphics, etc.

QPicture can also read and write SVG (Scalable Vector Graphics) files; these files are in an XML format specified by W3C. (See the load() and save() functions.)

QPicture is an implicitly shared class.

Example of how to record a picture:

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

Example of how to replay a picture:

        QPicture  pic;
        pic.load("drawing.pic");     // load picture
        QPainter  p;
        p.begin(&myWidget);          // paint in myWidget
        p.drawPicture(pic);          // draw the picture
        p.end();                     // painting done

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

## Member Function Documentation

### QPicture::QPicture ( int formatVersion = -1 )

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.

- formatVersion == 1 is binary compatible with Qt 1.x and later.
- formatVersion == 2 is binary compatible with Qt 2.0.x and later.
- formatVersion == 3 is binary compatible with Qt 2.1.x and later.
- formatVersion == 4 is binary compatible with Qt 3.0.x and later.
- formatVersion == 5 is binary compatible with Qt 3.1.

Note that the default formatVersion is -1 which signifies the current release, i.e. for Qt 3.1 a formatVersion of 5 is the same as the default formatVersion of -1.

Reading pictures generated by earlier versions of Qt is supported and needs no special coding; the format is automatically detected.

### QPicture::QPicture ( const QPicture & pic )

Constructs a shallow copy of pic.

### QPicture::~QPicture ()

Destroys the picture.

### QRect QPicture::boundingRect () const

Returns the picture's bounding rectangle or an invalid rectangle if the picture contains no 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() and isNull().

### QStringList QPicture::inputFormatList () `[static]`

Returns a list of picture formats that are supported for picture input.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

        QStringList list = myPicture.inputFormatList();
        QStringList::Iterator it = list.begin();
        while(it != list.end()) {
            myProcessing(*it);
            ++it;
        }

See also outputFormatList(), inputFormats(), and QPictureIO.

### QList<QByteArray> QPicture::inputFormats () `[static]`

Returns a list of picture formats that are supported for picture input.

See also outputFormats(), inputFormatList(), and QPictureIO.

### bool QPicture::isNull () const

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

### bool QPicture::load ( const QString & fileName, const char * format = 0 )

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

By default, the file will be interpreted as being in the native QPicture format. Specifying the format string is optional and is only needed for importing picture data stored in a different format.

Currently, the only external format supported is the W3C SVG format. The corresponding format string is "svg".

See also save().

### bool QPicture::load ( QIODevice * dev, const char * format = 0 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

dev is the device to use for loading.

### int QPicture::metric ( int m ) const `[virtual protected]`

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

Use the QPaintDeviceMetrics class instead.

A picture has the following hard-coded values: dpi=72, numcolors=16777216 and depth=24.

m is the metric to get.

Reimplemented from QPaintDevice.

### QStringList QPicture::outputFormatList () `[static]`

Returns a list of picture formats that are supported for picture output.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

        QStringList list = myPicture.outputFormatList();
        QStringList::Iterator it = list.begin();
        while(it != list.end()) {
            myProcessing(*it);
            ++it;
        }

See also inputFormatList(), outputFormats(), and QPictureIO.

### QList<QByteArray> QPicture::outputFormats () `[static]`

Returns a list of picture formats that are supported for picture output.

See also inputFormats(), outputFormatList(), and QPictureIO.

### const char * QPicture::pictureFormat ( const QString & fileName ) `[static]`

Returns a string that specifies the picture format of the file fileName, or 0 if the file cannot be read or if the format is not recognized.

The QPictureIO documentation lists the guaranteed supported picture formats, or use QPicture::inputFormats() and QPicture::outputFormats() to get lists that include the installed formats.

See also load() and save().

### 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).

### bool QPicture::save ( const QString & fileName, const char * format = 0 )

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

Specifying the file format string is optional. By default the data will be saved in the native QPicture file format. Currently the only other format that you can save in is W3C's SVG format; use a format name of "svg" to save in SVG format.

See also load().

### bool QPicture::save ( QIODevice * dev, const char * format = 0 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

dev is the device to use for saving.

### void QPicture::setBoundingRect ( const QRect & r )

Sets the picture's bounding rectangle to r. The automatically calculated value is overridden.

### 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() and size().

### uint QPicture::size () const

Returns the size of the picture data.

See also data().

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

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

## Related Non-Members

### QDataStream & operator<< ( QDataStream & s, const QPicture & r )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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

### QDataStream & operator>> ( QDataStream & s, QPicture & r )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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