Qt 4.8
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The QTextObjectInterface class allows drawing of custom text objects in QTextDocument. More...
#include <qabstracttextdocumentlayout.h>
Public Functions | |
virtual void | drawObject (QPainter *painter, const QRectF &rect, QTextDocument *doc, int posInDocument, const QTextFormat &format)=0 |
Draws this text object using the specified painter. More... | |
virtual QSizeF | intrinsicSize (QTextDocument *doc, int posInDocument, const QTextFormat &format)=0 |
The intrinsicSize() function returns the size of the text object represented by format in the given document (doc) at the given position (posInDocument). More... | |
virtual | ~QTextObjectInterface () |
Destroys this QTextObjectInterface. More... | |
The QTextObjectInterface class allows drawing of custom text objects in QTextDocument.
A text object describes the structure of one or more elements in a text document; for instance, images imported from HTML are implemented using text objects. A text object knows how to lay out and draw its elements when a document is being rendered.
Qt allows custom text objects to be inserted into a document by registering a custom object type with QTextCharFormat. A QTextObjectInterface must also be implemented for this type and be registered with the QAbstractTextDocumentLayout of the document. When the object type is encountered while rendering a QTextDocument, the intrinsicSize() and drawObject() functions of the interface are called.
The following list explains the required steps of inserting a custom text object into a document:
A class implementing a text object needs to inherit both QObject and QTextObjectInterface. QObject must be the first class inherited. For instance:
The data of a text object is usually stored in the QTextCharFormat using QTextCharFormat::setProperty(), and then retrieved with QTextCharFormat::property().
Definition at line 136 of file qabstracttextdocumentlayout.h.
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inlinevirtual |
Destroys this QTextObjectInterface.
Definition at line 139 of file qabstracttextdocumentlayout.h.
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pure virtual |
Draws this text object using the specified painter.
The size of the rectangle, rect, to draw in is the size previously calculated by intrinsicSize(). The rectangles position is relative to the painter.
You also get the document (doc) and the position (posInDocument) of the format in that document.
Implemented in QTextImageHandler.
Referenced by QTextDocumentLayoutPrivate::drawFlow().
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pure virtual |
The intrinsicSize() function returns the size of the text object represented by format in the given document (doc) at the given position (posInDocument).
The size calculated will be used for subsequent calls to drawObject() for this format.
Implemented in QTextImageHandler.