private bool ProcessDoubleTap(TouchLocation touch)
{
if (!GestureIsEnabled(GestureType.DoubleTap) || _tapDisabled || _lastTap.State == TouchLocationState.Invalid)
{
return(false);
}
// If the new tap is too far away from the last then
// this cannot be a double tap event.
var dist = Vector2.Distance(touch.Position, _lastTap.Position);
if (dist > TapJitterTolerance)
{
return(false);
}
// Check that this tap happened within the standard
// double tap time threshold of 300 milliseconds.
var elapsed = touch.Timestamp - _lastTap.Timestamp;
if (elapsed.TotalMilliseconds > 300)
{
return(false);
}
GestureList.Enqueue(new GestureSample(
GestureType.DoubleTap, touch.Timestamp,
touch.Position, Vector2.Zero,
Vector2.Zero, Vector2.Zero));
// Disable taps until after the next release.
_tapDisabled = true;
return(true);
}
/// <summary>
/// Apply the given new touch to the state. If it is a Pressed it will be added as a new touch, otherwise we update the existing touch it matches
/// </summary>
private void ApplyTouch(List <TouchLocation> state, TouchLocation touch)
{
if (touch.State == TouchLocationState.Pressed)
{
state.Add(touch);
return;
}
//Find the matching touch
for (var i = 0; i < state.Count; i++)
{
var existingTouch = state[i];
if (existingTouch.Id == touch.Id)
{
//If we are moving straight from Pressed to Released and we've existed for multiple frames, that means we've never been seen, so just get rid of us
if (existingTouch.State == TouchLocationState.Pressed && touch.State == TouchLocationState.Released && existingTouch.PressTimestamp != touch.Timestamp)
{
state.RemoveAt(i);
}
else
{
//Otherwise update the touch based on the new one
existingTouch.UpdateState(touch);
state[i] = existingTouch;
}
break;
}
}
}
private void ProcessTap(TouchLocation touch)
{
if (_tapDisabled)
{
return;
}
// If the release is too far away from the press
// position then this cannot be a tap event.
var dist = Vector2.Distance(touch.PressPosition, touch.Position);
if (dist > TapJitterTolerance)
{
return;
}
// If we pressed and held too long then don't
// generate a tap event for it.
var elapsed = CurrentTimestamp - touch.PressTimestamp;
if (elapsed > TimeRequiredForHold)
{
return;
}
// Store the last tap for
// double tap processing.
_lastTap = touch;
// Fire off the tap event immediately.
if (GestureIsEnabled(GestureType.Tap))
{
var tap = new GestureSample(
GestureType.Tap, touch.Timestamp,
touch.Position, Vector2.Zero,
Vector2.Zero, Vector2.Zero);
GestureList.Enqueue(tap);
}
}
private void ProcessHold(TouchLocation touch)
{
if (!GestureIsEnabled(GestureType.Hold) || _holdDisabled)
{
return;
}
var elapsed = CurrentTimestamp - touch.PressTimestamp;
if (elapsed < TimeRequiredForHold)
{
return;
}
_holdDisabled = true;
GestureList.Enqueue(
new GestureSample(GestureType.Hold,
touch.Timestamp,
touch.Position, Vector2.Zero,
Vector2.Zero, Vector2.Zero));
}
private void ProcessDrag(TouchLocation touch)
{
var dragH = GestureIsEnabled(GestureType.HorizontalDrag);
var dragV = GestureIsEnabled(GestureType.VerticalDrag);
var dragF = GestureIsEnabled(GestureType.FreeDrag);
if (!dragH && !dragV && !dragF)
{
return;
}
// Make sure this is a move event and that we have
// a previous touch location.
TouchLocation prevTouch;
if (touch.State != TouchLocationState.Moved || !touch.TryGetPreviousLocation(out prevTouch))
{
return;
}
var delta = touch.Position - prevTouch.Position;
// If we're free dragging then stick to it.
if (_dragGestureStarted != GestureType.FreeDrag)
{
var isHorizontalDelta = Math.Abs(delta.X) > Math.Abs(delta.Y * 2.0f);
var isVerticalDelta = Math.Abs(delta.Y) > Math.Abs(delta.X * 2.0f);
var classify = _dragGestureStarted == GestureType.None;
// Once we enter either vertical or horizontal drags
// we stick to it... regardless of the delta.
if (dragH && ((classify && isHorizontalDelta) || _dragGestureStarted == GestureType.HorizontalDrag))
{
delta.Y = 0;
_dragGestureStarted = GestureType.HorizontalDrag;
}
else if (dragV && ((classify && isVerticalDelta) || _dragGestureStarted == GestureType.VerticalDrag))
{
delta.X = 0;
_dragGestureStarted = GestureType.VerticalDrag;
}
// If the delta isn't either horizontal or vertical
//then it could be a free drag if not classified.
else if (dragF && classify)
{
_dragGestureStarted = GestureType.FreeDrag;
}
else
{
// If we couldn't classify the drag then
// it is nothing... set it to complete.
_dragGestureStarted = GestureType.DragComplete;
}
}
// If the drag could not be classified then no gesture.
if (_dragGestureStarted == GestureType.None || _dragGestureStarted == GestureType.DragComplete)
{
return;
}
_tapDisabled = true;
_holdDisabled = true;
GestureList.Enqueue(new GestureSample(
_dragGestureStarted, touch.Timestamp,
touch.Position, Vector2.Zero,
delta, Vector2.Zero));
}
internal void AddEvent(int id, TouchLocationState state, Vector2 position, bool isMouse)
{
// Different platforms return different touch identifiers
// based on the specifics of their implementation and the
// system drivers.
//
// Sometimes these ids are suitable for our use, but other
// times it can recycle ids or do cute things like return
// the same id for double tap events.
//
// We instead provide consistent ids by generating them
// ourselves on the press and looking them up on move
// and release events.
//
if (state == TouchLocationState.Pressed)
{
if (isMouse)
{
// Mouse pointing devices always use a reserved Id
_touchIds[id] = MouseTouchId;
}
else
{
_touchIds[id] = _nextTouchId++;
}
}
// Try to find the touch id.
int touchId;
if (!_touchIds.TryGetValue(id, out touchId))
{
// If we got here that means either the device is sending
// us bad, out of order, or old touch events. In any case
// just ignore them.
return;
}
if (!isMouse || EnableMouseTouchPoint || EnableMouseGestures)
{
// Add the new touch event keeping the list from getting
// too large if no one happens to be requesting the state.
var evt = new TouchLocation(touchId, state, position * _touchScale, CurrentTimestamp);
if (!isMouse || EnableMouseTouchPoint)
{
ApplyTouch(_touchState, evt);
}
//If we have gestures enabled then collect events for those too.
//We also have to keep tracking any touches while we know about touches so we don't miss releases even if gesture recognition is disabled
if ((EnabledGestures != GestureType.None || _gestureState.Count > 0) && (!isMouse || EnableMouseGestures))
{
ApplyTouch(_gestureState, evt);
if (EnabledGestures != GestureType.None)
{
UpdateGestures(true);
}
AgeTouches(_gestureState);
}
}
// If this is a release unmap the hardware id.
if (state == TouchLocationState.Released)
{
_touchIds.Remove(id);
}
}
