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<li class="level1"><a href="#available-keyboard-drivers">Available Keyboard Drivers</a></li>
<li class="level1"><a href="#keymaps">Keymaps</a></li>
<li class="level1"><a href="#specifying-a-keyboard-driver">Specifying a Keyboard Driver</a></li>
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<h1 class="title">Qt for Embedded Linux Character Input</h1>
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<p>When running a <a href="qt-embedded-linux.html">Qt for Embedded Linux</a> 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 <a href="plugins-howto.html">plugin system</a>.</p>
<p>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.</p>
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<thead><tr class="qt-style"><th >Input Widgets</th></tr></thead>
<tr valign="top" class="odd"><td >The server process may call the static <a href="qwsserver.html#sendKeyEvent">QWSServer::sendKeyEvent</a>() function at any time. Typically, this is done by popping up a widget that enables the user specify characters with the pointer device.<p>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 <a href="qt.html#WindowType-enum">Qt::Tool</a> widget flag in the <a href="qwidget.html">QWidget</a> constructor.</p>
<p>The Qt Extended environment contains various input widgets such as Handwriting Recognition and Virtual Keyboard.</p>
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<a name="available-keyboard-drivers"></a>
<h2>Available Keyboard Drivers</h2>
<p><a href="qt-embedded-linux.html">Qt for Embedded Linux</a> provides ready-made drivers for the console (TTY) and the standard Linux Input Subsystem (USB, PS/2, ...). Run the <tt>configure</tt> script to list the available drivers:</p>
<pre class="cpp"> ./configure -help</pre>
<p>Note that only the console (TTY) keyboard driver handles console switching (<b>Ctrl+Alt+F1</b>, ..., <b>Ctrl+Alt+F10</b>) and termination (<b>Ctrl+Alt+Backspace</b>).</p>
<p>In the default Qt configuration, only the "TTY" driver is enabled. The various drivers can be enabled and disabled using the <tt>configure</tt> script. For example:</p>
<pre class="cpp"> configure -qt-kbd-linuxinput</pre>
<p>Custom keyboard drivers can be implemented by subclassing the <a href="qwskeyboardhandler.html">QWSKeyboardHandler</a> class and creating a keyboard driver plugin (derived from the <a href="qkbddriverplugin.html">QKbdDriverPlugin</a> class). The default implementation of the <a href="qkbddriverfactory.html">QKbdDriverFactory</a> class will automatically detect the plugin, loading the driver into the server application at run-time.</p>
<a name="keymaps"></a>
<h2>Keymaps</h2>
<p>Starting with 4.6, <a href="qt-embedded-linux.html">Qt for Embedded Linux</a> has gained support for user defined keymaps. Keymap handling is supported by the built-in keyboard drivers <tt>TTY</tt> and <tt>LinuxInput</tt>. Custom keyboard drivers can use the existing keymap handling code via <a href="qwskeyboardhandler.html#processKeycode">QWSKeyboardHandler::processKeycode</a>().</p>
<p>By default Qt will use an internal, compiled-in US keymap. See the options below for how to load a different keymap.</p>
<a name="specifying-a-keyboard-driver"></a>
<h2>Specifying a Keyboard Driver</h2>
<p>To specify which driver to use, set the <a href="qt-embedded-envvars.html#qws-keyboard">QWS_KEYBOARD</a> environment variable. For example (if the current shell is bash, ksh, zsh or sh):</p>
<pre class="cpp"> export QWS_KEYBOARD=<driver>[:<driver specific options>]</pre>
<p>The <tt><driver></tt> arguments are <tt>TTY</tt>, <tt>LinuxInput</tt> and <a href="qkbddriverplugin.html#keys">keys</a> identifying custom drivers, and the driver specific options are typically a device, e.g., <tt>/dev/tty0</tt>.</p>
<p>Multiple keyboard drivers can be specified in one go:</p>
<pre class="cpp"> export QWS_KEYBOARD="<driver>[:<driver specific options>]
<driver>[:<driver specific options>]
<driver>[:<driver specific options>]"</pre>
<p>Input will be read from all specified drivers.</p>
<p>Currently the following options are supported by both the <tt>TTY</tt> and <tt>LinuxInput</tt> driver:</p>
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<thead><tr class="qt-style"><th >Option</th><th >Description</th></tr></thead>
<tr valign="top" class="odd"><td ><tt>/dev/xxx</tt></td><td >Open the specified device, instead of the driver's default device.</td></tr>
<tr valign="top" class="even"><td ><tt>repeat-delay=<d></tt></td><td >Time (in milliseconds) until auto-repeat kicks in.</td></tr>
<tr valign="top" class="odd"><td ><tt>repeat-rate=<r></tt></td><td >Time (in milliseconds) specifying the interval between auto-repeats.</td></tr>
<tr valign="top" class="even"><td ><tt>keymap=xx.qmap</tt></td><td >File name of a keymap file in Qt's <tt>qmap</tt> format. See <a href="qt-embedded-kmap2qmap.html">kmap2qmap</a> for instructions on how to create thoes files.<br /> Note that the file name can of course also be the name of a <a href="qresource.html">QResource</a>.</td></tr>
<tr valign="top" class="odd"><td ><tt>disable-zap</tt></td><td >Disable the QWS server "Zap" shortcut <b>Ctrl+Alt+Backspace</b></td></tr>
<tr valign="top" class="even"><td ><tt>enable-compose</tt></td><td >Activate Latin-1 composing features in the built-in US keymap. You can use the right <tt>AltGr</tt> or right <tt>Alt</tt> is used as a dead key modifier, while <tt>AltGr+</tt>. is the compose key. For example:<ul>
<li><tt>AltGr</tt> + <tt>"</tt> + <tt>u</tt> = ü (u with diaeresis / umlaut u)</li>
<li><tt>AltGr</tt> + <tt>.</tt> + <tt>/</tt> + <tt>o</tt> = ø (slashed o)</li>
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