private void Callback(IntPtr clientData, ref UnsafeNativeMethods.INTERACTION_CONTEXT_OUTPUT output)
{
SystemGesture gesture = SystemGesture.None;
// Create the appropriate gesture based on interaction output
switch (output.interactionId)
{
case UnsafeNativeMethods.INTERACTION_ID.INTERACTION_ID_TAP:
{
gesture = SystemGesture.Tap;
}
break;
case UnsafeNativeMethods.INTERACTION_ID.INTERACTION_ID_SECONDARY_TAP:
{
gesture = SystemGesture.RightTap;
}
break;
case UnsafeNativeMethods.INTERACTION_ID.INTERACTION_ID_HOLD:
{
_firedHold = true;
if (output.interactionFlags.HasFlag(UnsafeNativeMethods.INTERACTION_FLAGS.INTERACTION_FLAG_BEGIN))
{
gesture = SystemGesture.HoldEnter;
}
else
{
gesture = SystemGesture.HoldLeave;
}
}
break;
case UnsafeNativeMethods.INTERACTION_ID.INTERACTION_ID_MANIPULATION:
{
gesture = DetectDragOrFlick(output);
}
break;
}
if (gesture != SystemGesture.None)
{
InteractionDetected?.Invoke(this,
new RawStylusSystemGestureInputReport(
InputMode.Foreground,
Environment.TickCount,
_stylusDevice.CriticalActiveSource,
(Func <StylusPointDescription>)null,
-1,
-1,
gesture,
Convert.ToInt32(output.x),
Convert.ToInt32(output.y),
0));
}
}
private SystemGesture DetectDragOrFlick(UnsafeNativeMethods.INTERACTION_CONTEXT_OUTPUT output)
{
SystemGesture gesture = SystemGesture.None;
if (output.interactionFlags.HasFlag(UnsafeNativeMethods.INTERACTION_FLAGS.INTERACTION_FLAG_END))
{
// At the end of an interaction, any drag/flick/hold state is no longer needed
_firedDrag = false;
_firedHold = false;
_firedFlick = false;
}
else
{
// If we have not already fired a drag/flick and we cannot be a flick
if (!_firedDrag && !_firedFlick &&
(!_flickEngine?.Result?.CanBeFlick ?? true))
{
// Convert screen pixels to inches using current DPI
DpiScale dpi = VisualTreeHelper.GetDpi(_stylusDevice.CriticalActiveSource.RootVisual);
double xChangeInches = output.arguments.manipulation.cumulative.translationX / dpi.PixelsPerInchX;
double yChangeInches = output.arguments.manipulation.cumulative.translationY / dpi.PixelsPerInchY;
// If the cumulative change is greater than our threshold
// (taken from WISP, converted to inches) then fire a drag.
if (xChangeInches > DragThresholdInches || yChangeInches > DragThresholdInches)
{
// If we have a current hold being tracked, convert to right drag
gesture = (_firedHold) ? SystemGesture.RightDrag : SystemGesture.Drag;
// This pointer has seen a drag
_firedDrag = true;
}
}
}
return(gesture);
}
