com.trolltech.qt.gui
Class QImageIOPlugin

java.lang.Object
  com.trolltech.qt.QSignalEmitter
      com.trolltech.qt.QtJambiObject
          com.trolltech.qt.core.QObject
              com.trolltech.qt.gui.QImageIOPlugin

All Implemented Interfaces:

QAbstractFactoryInterface, QAbstractImageIOHandlerFactoryInterface, QtJambiInterface

public abstract class QImageIOPlugin
extends QObject
implements QAbstractImageIOHandlerFactoryInterface, QAbstractFactoryInterface

The QImageIOPlugin class defines an interface for writing an image format plugin. QImageIOPlugin is a factory for creating QImageIOHandler objects, which are used internally by QImageReader and QImageWriter to add support for different image formats to Qt.

Writing an image I/O plugin is achieved by subclassing this base class, reimplementing the pure virtual functions capabilities(), create(), and keys(), and exporting the class with the Q_EXPORT_PLUGIN2() macro. See How to Create Qt Plugins for details.

An image format plugin can support three capabilities: reading (CanRead ), writing (CanWrite ) and incremental reading (CanReadIncremental ). Reimplement capabilities() in you subclass to expose the capabilities of your image format.

create() should create an instance of your QImageIOHandler subclass, with the provided device and format properly set, and return this handler. You must also reimplement keys() so that Qt knows which image formats your plugin supports.

Different plugins can support different capabilities. For example, you may have one plugin that supports reading the GIF format, and another that supports writing. Qt will select the correct plugin for the job, depending on the return value of capabilities(). If several plugins support the same capability, Qt will select one arbitrarily.

See also:

QImageIOHandler, and How to Create Qt Plugins.

Nested Class Summary

static class	QImageIOPlugin.Capabilities This is a flags class for com.trolltech.qt.gui.QImageIOPlugin.Capability
static class	QImageIOPlugin.Capability This enum describes the capabilities of a QImageIOPlugin.

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

QtJambiObject.QPrivateConstructor

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

QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I>

Constructor Summary

	QImageIOPlugin() Constructs an image plugin with the given parent.
	QImageIOPlugin(QObject parent) Constructs an image plugin with the given parent.
protected	QImageIOPlugin(QtJambiObject.QPrivateConstructor p) This method is internal to Qt Jambi.

Method Summary

long	__qt_cast_to_QAbstractFactory(long ptr) This method is internal to Qt Jambi.
long	__qt_cast_to_QAbstractImageIOHandlerFactory(long ptr) This method is internal to Qt Jambi.
abstract QImageIOPlugin.Capabilities	capabilities(QIODevice device, QByteArray format) Returns the capabilities on the plugin, based on the data in device and the format format.
abstract QImageIOHandler	create(QIODevice device, QByteArray format) Creates and returns a QImageIOHandler subclass, with device and format set.
static QImageIOPlugin	fromNativePointer(QNativePointer nativePointer) This method returns the QImageIOPlugin instance pointed to by nativePointer.
abstract java.util.List<java.lang.String>	keys() Returns the list of image keys this plugin supports.

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

blockSignals, 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, signalsBlocked, startTimer, thread, timerEvent, toString, userProperty

Methods inherited from class com.trolltech.qt.QtJambiObject

disableGarbageCollection, dispose, disposed, equals, finalize, nativeId, nativePointer, reassignNativeResources, reenableGarbageCollection, setJavaOwnership, tr, tr, tr

Methods inherited from class com.trolltech.qt.QSignalEmitter

__qt_signalInitialization, disconnect, disconnect, signalSender

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

QImageIOPlugin

public QImageIOPlugin()

Constructs an image plugin with the given parent. This is invoked automatically by the Q_EXPORT_PLUGIN2() macro.

QImageIOPlugin

public QImageIOPlugin(QObject parent)

Constructs an image plugin with the given parent. This is invoked automatically by the Q_EXPORT_PLUGIN2() macro.

QImageIOPlugin

protected QImageIOPlugin(QtJambiObject.QPrivateConstructor p)

This method is internal to Qt Jambi.

Method Detail

capabilities

public abstract QImageIOPlugin.Capabilities capabilities(QIODevice device,
                                                         QByteArray format)

Returns the capabilities on the plugin, based on the data in device and the format format. For example, if the QImageIOHandler supports the BMP format, and the data in the device starts with the characters "BM", this function should return CanRead . If format is "bmp" and the handler supports both reading and writing, this function should return CanRead | CanWrite .

create

public abstract QImageIOHandler create(QIODevice device,
                                       QByteArray format)

Creates and returns a QImageIOHandler subclass, with device and format set. The format must come from the list returned by keys(). Format names are case sensitive.

See also:

keys().

Specified by:

create in interface QAbstractImageIOHandlerFactoryInterface

keys

public abstract java.util.List<java.lang.String> keys()

Returns the list of image keys this plugin supports.

These keys are usually the names of the image formats that are implemented in the plugin (e.g., "jpg" or "gif").

See also:

capabilities().

Specified by:

keys in interface QAbstractFactoryInterface

Specified by:

keys in interface QAbstractImageIOHandlerFactoryInterface

fromNativePointer

public static QImageIOPlugin fromNativePointer(QNativePointer nativePointer)

This method returns the QImageIOPlugin instance pointed to by nativePointer.

__qt_cast_to_QAbstractImageIOHandlerFactory

public long __qt_cast_to_QAbstractImageIOHandlerFactory(long ptr)

This method is internal to Qt Jambi.

Specified by:

__qt_cast_to_QAbstractImageIOHandlerFactory in interface QAbstractImageIOHandlerFactoryInterface

__qt_cast_to_QAbstractFactory

public long __qt_cast_to_QAbstractFactory(long ptr)

This method is internal to Qt Jambi.

Specified by:

__qt_cast_to_QAbstractFactory in interface QAbstractFactoryInterface