com.trolltech.qt.gui
Class QTextObjectInterface

java.lang.Object
  com.trolltech.qt.internal.QSignalEmitterInternal
      com.trolltech.qt.QSignalEmitter
          com.trolltech.qt.QtJambiObject
              com.trolltech.qt.core.QObject
                  com.trolltech.qt.gui.QTextObjectInterface

All Implemented Interfaces:

QtJambiInterface

public abstract class QTextObjectInterface
extends QObject

The QTextObjectInterface class allows drawing of custom text objects in QTextDocuments. 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:

• Choose an objectType. The objectType is an integer with a value greater or equal to QTextFormat::UserObject .
• Create a QTextCharFormat object and set the object type to the chosen type using the setObjectType() function.
• Implement the QTextObjectInterface class.
• Call QAbstractTextDocumentLayout::registerHandler() with an instance of your QTextObjectInterface subclass to register your object type.
• Insert QChar::ObjectReplacementCharacter with the aforementioned QTextCharFormat of the chosen object type into the document. As mentioned, the functions of QTextObjectInterfaceintrinsicSize() and drawObject() will then be called with the QTextFormat as parameter whenever the replacement character is encountered.

A class implementing a text object needs to inherit both QObject and QTextObjectInterface. QObject must be the first class inherited. For instance:

class SvgTextObject : public QObject, public QTextObjectInterface
{
    Q_OBJECT
    Q_INTERFACES(QTextObjectInterface)

The data of a text object is usually stored in the QTextCharFormat using QTextCharFormat::setProperty(), and then retrieved with QTextCharFormat::property().

Warning: Copy and Paste operations ignore custom text objects.

See also:

Text Object Example, QTextCharFormat, and QTextLayout.

Nested Class Summary

Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter

QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9

Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal

com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal

Field Summary

Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal

currentSender

Constructor Summary

QTextObjectInterface()
This is an overloaded method provided for convenience.

Method Summary

abstract void	drawObject(QPainter painter, QRectF rect, QTextDocument doc, int posInDocument, QTextFormat format) Draws this text object using the specified painter.
abstract QSizeF	intrinsicSize(QTextDocument doc, int posInDocument, QTextFormat format) The intrinsicSize() function returns the size of the text object represented by format in the given document (doc) at the given position (posInDocument).

Methods inherited from class com.trolltech.qt.core.QObject

childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty

Methods inherited from class com.trolltech.qt.QtJambiObject

dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr

Methods inherited from class com.trolltech.qt.QSignalEmitter

blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread

Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal

__qt_signalInitialization

Methods inherited from class java.lang.Object

clone, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.trolltech.qt.QtJambiInterface

disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership

Constructor Detail

QTextObjectInterface

public QTextObjectInterface()

This is an overloaded method provided for convenience.

Method Detail

drawObject

public abstract void drawObject(QPainter painter,
                                QRectF rect,
                                QTextDocument doc,
                                int posInDocument,
                                QTextFormat format)

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.

See also:

intrinsicSize().

intrinsicSize

public abstract QSizeF intrinsicSize(QTextDocument doc,
                                     int posInDocument,
                                     QTextFormat format)

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.

See also:

drawObject().