/// <summary>
/// Processes touchdown events.
/// </summary>
/// <param name="e">Touch down event arguments.</param>
/// <returns>State of event handling.</returns>
public bool ProcessTouchDown(TouchEventArgs e)
{
// If more than two touchpoints are active ignore any additional touch points.
if (_firstPoint.Key != null && _secondPoint.Key != null)
{
return(true);
}
// If no other multitouch manager is currently working or we are the working one continue.
if (_operator == null || _operator == this)
{
// If there is no current working multitouch manager assign ourself as the working one.
if (_operator == null)
{
_operator = this;
}
// Register touchpoints and store them.
if (RegisterTouchPoints(e))
{
return(false);
}
}
else
{
return(e.Handled);
}
// This case should never happen if called correctly:
// We are working and the touch point we get from the agruments is neither the first
// nor the second of two maximal touch points. So we ignore this event.
return(true);
}
/// <summary>
/// Unregisters touchpoints from the storage.
/// </summary>
/// <param name="e">Touch event arguments.</param>
/// <returns>Handled state of the event arguments.</returns>
private bool UnregisterTouchPoints(TouchEventArgs e)
{
bool handledState = false;
// Register release of first finger and kill touch point.
if (_firstPoint.Key != null && e.TouchDevice.Id == (int)_firstPoint.Key)
{
_firstPoint = new DictionaryEntry(null, null);
_isDragAndDropAction = false;
_fingerOnePositions.Clear();
}
// Register release of second finger and kill touch point.
if (_secondPoint.Key != null && e.TouchDevice.Id == (int)_secondPoint.Key)
{
_secondPoint = new DictionaryEntry(null, null);
_fingerTwoPositions.Clear();
handledState = true;
IsZooming = false;
if (OwnerIsTasbboardControl)
{
InvokeTaskboardZoomEnded(null);
}
else if (OwnerIsWorkItemControl)
{
InvokeWorkitemZoomended(null);
}
}
// If we do not have any active touch points we are done working and unregister as
// currently working multitouch manager to enable the processing of further touch events.
if (_firstPoint.Key == null && _secondPoint.Key == null)
{
_operator = null;
}
// Clear queue for delta values, it is only relevant for 2fingergestures, so it is obsolete
// if a finger, no matter which one, is released
_deltaQueue.Clear();
return(handledState);
}