Home · All Classes · Modules

QPicture Class Reference
^{^{[QtGui module]}}

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

Inherits QPaintDevice.

Methods

__init__ (self, int formatVersion = -1)
__init__ (self, QPicture)
QRect boundingRect (self)
str data (self)
detach (self)
int devType (self)
bool isDetached (self)
bool isNull (self)
bool load (self, QIODevice dev, str format = None)
bool load (self, QString fileName, str format = None)
int metric (self, QPaintDevice.PaintDeviceMetric m)
QPaintEngine paintEngine (self)
bool play (self, QPainter p)
bool save (self, QIODevice dev, str format = None)
bool save (self, QString fileName, str format = None)
setBoundingRect (self, QRect r)
setData (self, str data)
int size (self)
swap (self, QPicture other)

Static Methods

QStringList inputFormatList ()
list-of-QByteArray inputFormats ()
QStringList outputFormatList ()
list-of-QByteArray outputFormats ()
str pictureFormat (QString fileName)

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. 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().

Method Documentation

QPicture.init (self, 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.

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.