QWSCalibratedMouseHandler Class Reference

Member Function Documentation

void QWSCalibratedMouseHandler::calibrate ( const QWSPointerCalibrationData * data ) [virtual]

Reimplemented from QWSMouseHandler::calibrate().

Updates the calibration parameters based on coordinate mapping of the given data.

Create an instance of the QWSPointerCalibrationData class, fill in the device and screen coordinates and pass that object to the mouse driver using this function.

See also clearCalibration() and transform().

void QWSCalibratedMouseHandler::clearCalibration () [virtual]

Reimplemented from QWSMouseHandler::clearCalibration().

Clears the current calibration, i.e., makes the mouse driver return mouse events in raw device coordinates instead of screen coordinates.

See also calibrate().

void QWSCalibratedMouseHandler::readCalibration () [protected]

Reads previously written calibration parameters which are stored in /etc/pointercal (separated by whitespace and in alphabetical order).

You can override the default /etc/pointercal by specifying another file using the POINTERCAL_FILE environment variable.

See also writeCalibration().

bool QWSCalibratedMouseHandler::sendFiltered ( const QPoint & position, int state ) [protected]

Notifies the system of a new mouse event after applying a noise reduction filter. Returns true if the filtering process is successful; otherwise returns false. Note that if the filtering process failes, the system is not notified about the event.

The given position is the global position of the mouse. The state parameter is a bitmask of the Qt::MouseButton enum's values indicating which mouse buttons are pressed.

The noice is reduced by calculating an average position from a collection of mouse event positions and then calling the mouseChanged() function with the new position. The number of positions that is used is determined by the filter size.

See also mouseChanged() and setFilterSize().

void QWSCalibratedMouseHandler::setFilterSize ( int size ) [protected]

Sets the size of the filter used in noise reduction to the given size.

The sendFiltered() function reduces noice by calculating an average position from a collection of mouse event positions. The filter size determines the number of positions that forms the basis for these calculations.

See also sendFiltered().

QPoint QWSCalibratedMouseHandler::transform ( const QPoint & position ) [protected]

Transforms the given position from device coordinates to screen coordinates, and returns the transformed position.

This function is typically called explicitly on the points passed to the QWSMouseHandler::mouseChanged() function.

This implementation is a linear transformation using 7 parameters (a, b, c, d, e, f and s) to transform the device coordinates (Xd, Yd) into screen coordinates (Xs, Ys) using the following equations:

 s*Xs = a*Xd + b*Yd + c
 s*Ys = d*Xd + e*Yd + f

See also mouseChanged().

void QWSCalibratedMouseHandler::writeCalibration () [protected]

Saves the current calibration parameters in /etc/pointercal (separated by whitespace and in alphabetical order).

You can override the default /etc/pointercal by specifying another file using the POINTERCAL_FILE environment variable.

See also readCalibration().