QWSMouseHandler Class Reference
[QtGui module]

Detailed Description

The QWSMouseHandler class is a base class for mouse drivers in Qt for Embedded Linux.

Note that this class is only available in Qt for Embedded Linux.

Qt for Embedded Linux provides ready-made drivers for several mouse protocols, see the pointer handling documentation for details. Custom mouse drivers can be implemented by subclassing the QWSMouseHandler class and creating a mouse driver plugin (derived from QMouseDriverPlugin). The default implementation of the QMouseDriverFactory class will automatically detect the plugin, and load the driver into the server application at run-time using Qt's plugin system.

The mouse driver receives mouse events from the system device and encapsulates each event with an instance of the QWSEvent class which it then passes to the server application (the server is responsible for propagating the event to the appropriate client). To receive mouse events, a QWSMouseHandler object will usually create a QSocketNotifier object for the given device. The QSocketNotifier class provides support for monitoring activity on a file descriptor. When the socket notifier receives data, it will call the mouse driver's mouseChanged() function to send the event to the Qt for Embedded Linux server application for relaying to clients.

If you are creating a driver for a device that needs calibration or noise reduction, such as a touchscreen, use the QWSCalibratedMouseHandler subclass instead to take advantage of the calibrate() and clearCalibration() functions. The Mouse Calibration demonstrates how to write a simple program using the mechanisms provided by the QWSMouseHandler class to calibrate a mouse driver.

Note that when deriving from the QWSMouseHandler class, the resume() and suspend() functions must be reimplemented to control the flow of mouse input, i.e., the default implementation does nothing. Reimplementations of these functions typically call the QSocketNotifier::setEnabled() function to enable or disable the socket notifier, respectively.

In addition, QWSMouseHandler provides the setScreen() function that allows you to specify a screen for your mouse driver and the limitToScreen() function that ensures that a given position is within this screen's boundaries (changing the position if necessary). Finally, QWSMouseHandler provides the pos() function returning the current mouse position.

See also QMouseDriverPlugin, QMouseDriverFactory, and Qt for Embedded Linux Pointer Handling.

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