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diff --git a/doc/src/porting/qt4-accessibility.qdoc b/doc/src/porting/qt4-accessibility.qdoc new file mode 100644 index 0000000..b5a7b28 --- /dev/null +++ b/doc/src/porting/qt4-accessibility.qdoc @@ -0,0 +1,162 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \page qt4-accessibility.html + \title Cross-Platform Accessibility Support in Qt 4 + + \contentspage {What's New in Qt 4}{Home} + \previouspage The New Qt Designer + \nextpage The Qt 4 Database GUI Layer + + Qt 4 allows developers to write cross-platform applications that + are usable by visually impaired users as well as by users with + other disabilities. Qt accessibility will make applications + accessible to more users and opens the governmental market, where + accessibility is often a requirement. + + \section1 General Overview + + The accessibility classes have been extended in + various ways since Qt 3. We added new functions and new enum + values, and revised the API to make it more consistent with the + rest of Qt. We also added two properties to QWidget, + \l{QWidget::accessibleName}{accessibleName} and + \l{QWidget::accessibleDescription}{accessibleDescription}, that + can be set in \e{Qt Designer} to provide basic help texts without + having to write any code. + + Qt's accessibility architecture is as follows. Qt offers one + generic interface, QAccessibleInterface, that can be used to + wrap all widgets and objects (e.g., QPushButton). This single + interface provides all the metadata necessary for the assistive + technologies. Qt provides implementations of this interface for + its built-in widgets as plugins. + + A more detailed overview of the accessibility support in Qt can + be found on the \l Accessibility page. + + \section1 Enabling Accessibility Support + + By default, Qt applications are run with accessibility support + enabled on Windows and Mac OS X. On Unix/X11 platforms, applications + must be launched in an environment with the \c QT_ACCESSIBILITY + variable set to 1. For example, this is set in the following way with + the bash shell: + + \snippet doc/src/snippets/code/doc_src_qt4-accessibility.qdoc environment + + Accessibility features are built into Qt by default when the libraries + are configured and built. + + \section1 Creating New Accessible Interfaces + + When you develop custom widgets, you can create custom subclasses + of QAccessibleInterface and distribute them as plugins (using + QAccessiblePlugin) or compile them into the application. + Likewise, Qt's predefined accessibility support can be built as + plugin (the default) or directly into the Qt library. The main + advantage of using plugins is that the accessibility classes are + only loaded into memory if they are actually used; they don't + slow down the common case where no assistive technology is being + used. + + In addition to QAccessibleInterface, Qt includes two convenience + classes, QAccessibleObject and QAccessibleWidget, that + provide the lowest common denominator of metadata (e.g., widget + geometry, window title, basic help text). You can use them as + base classes when wrapping your custom QObject or QWidget + subclasses. + + Another new feature in Qt 4 is that Qt can now support other + backends in addition to the predefined ones. This is done by + subclassing QAccessibleBridge. + + \omit + \section1 Software Layering + + Qt Application + | links to + Qt Accessibility Module + | Plugin (in-process) + Qt ATK Bridge + | links to + ATK + | Plugin (in-process) + at-spi + | CORBA + assistive technologies + + Windows: + + Qt Application + | links to + Qt Accessibility Module + | COM (?) + MSAA + | ? + assistive technologies + + Mac: + + ? + \endomit + + \section1 Example Code + + The first example illustrates how to provide accessibility + information for a custom widget. We can use QAccessibleWidget as + a base class and reimplement various functions: + + \snippet doc/src/snippets/code/doc_src_qt4-accessibility.qdoc 0 + + Here's how we would implement the + \l{QAccessibleInterface::doAction()}{doAction()} function to call + a function named click() on the wrapped MyWidget object when the + user invokes the object's default action or "presses" it. + + \snippet doc/src/snippets/code/doc_src_qt4-accessibility.qdoc 1 + + To export the widget interface as a plugin, we must subclass + QAccessibleFactory: + + \snippet doc/src/snippets/code/doc_src_qt4-accessibility.qdoc 2 +*/ |