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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\page qt-embedded-charinput.html
\title Qt for Embedded Linux Character Input
\ingroup qt-embedded-linux
When running a \l {Qt for Embedded Linux} application, it either runs as a
server or connects to an existing server. The keyboard driver is
loaded by the server application when it starts running, using
Qt's \l {How to Create Qt Plugins}{plugin system}.
Internally in the client/server protocol, all system generated
events, including key events, are passed to the server application
which then propagates the event to the appropriate client. Note
that key events do not always come from a keyboard device, they
can can also be generated by the server process using input
widgets.
\table
\header \o Input Widgets
\row
\o
The server process may call the static QWSServer::sendKeyEvent()
function at any time. Typically, this is done by popping up a
widget that enables the user specify characters with the pointer
device.
Note that the key input widget should not take focus since the
server would then just send the key events back to the input
widget. One way to make sure that the input widget never takes
focus is to set the Qt::Tool widget flag in the QWidget
constructor.
The \l{Qt Extended} environment contains various input widgets such as
Handwriting Recognition and Virtual Keyboard.
\endtable
\tableofcontents
\section1 Available Keyboard Drivers
\l {Qt for Embedded Linux} provides ready-made drivers for the console
(TTY) and the standard Linux Input Subsystem (USB, PS/2, ...). Run the
\c configure script to list the available drivers:
\snippet doc/src/snippets/code/doc_src_emb-charinput.qdoc 0
Note that only the console (TTY) keyboard driver handles console
switching (\bold{Ctrl+Alt+F1}, ..., \bold{Ctrl+Alt+F10}) and
termination (\bold{Ctrl+Alt+Backspace}).
In the default Qt configuration, only the "TTY" driver is
enabled. The various drivers can be enabled and disabled using the
\c configure script. For example:
\snippet doc/src/snippets/code/doc_src_emb-charinput.qdoc 1
Custom keyboard drivers can be implemented by subclassing the
QWSKeyboardHandler class and creating a keyboard driver plugin
(derived from the QKbdDriverPlugin class). The default
implementation of the QKbdDriverFactory class will automatically
detect the plugin, loading the driver into the server application
at run-time.
\section1 Keymaps
Starting with 4.6, \l {Qt for Embedded Linux} has gained support for
user defined keymaps. Keymap handling is supported by the built-in
keyboard drivers \c TTY and \c LinuxInput. Custom keyboard drivers can
use the existing keymap handling code via
QWSKeyboardHandler::processKeycode().
By default Qt will use an internal, compiled-in US keymap.
See the options below for how to load a different keymap.
\section1 Specifying a Keyboard Driver
To specify which driver to use, set the QWS_KEYBOARD environment
variable. For example (if the current shell is bash, ksh, zsh or
sh):
\snippet doc/src/snippets/code/doc_src_emb-charinput.qdoc 2
The \c <driver> arguments are \c TTY, \c LinuxInput and \l
{QKbdDriverPlugin::keys()}{keys} identifying custom drivers, and the
driver specific options are typically a device, e.g., \c /dev/tty0.
Multiple keyboard drivers can be specified in one go:
\snippet doc/src/snippets/code/doc_src_emb-charinput.qdoc 3
Input will be read from all specified drivers.
Currently the following options are supported by both the \c TTY and \c
LinuxInput driver:
\table
\header \o Option \o Description
\row \o \c /dev/xxx \o
Open the specified device, instead of the driver's default device.
\row \o \c repeat-delay=<d> \o
Time (in milliseconds) until auto-repeat kicks in.
\row \o \c repeat-rate=<r> \o
Time (in milliseconds) specifying the interval between auto-repeats.
\row \o \c keymap=xx.qmap \o
File name of a keymap file in Qt's \c qmap format. See \l {kmap2qmap}
for instructions on how to create thoes files.\br Note that the file
name can of course also be the name of a QResource.
\row \o \c disable-zap \o
Disable the QWS server "Zap" shortcut \bold{Ctrl+Alt+Backspace}
\row \o \c enable-compose \o
Activate Latin-1 composing features in the built-in US keymap. You can
use the right \c AltGr or right \c Alt is used as a dead key modifier,
while \c AltGr+. is the compose key. For example:
\list
\o \c AltGr + \c " + \c u = \uuml (u with diaeresis / umlaut u)
\o \c AltGr + \c . + \c / + \c o = \oslash (slashed o)
\endlist
\endtable
*/
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