private void NotifyUpdate(bool pointerAdded = false)
{
// Note: Make sure to update the _sumOfPublishedDelta before raising the event, so if an exception is raised
// or if the manipulation is Completed, the Complete event args can use the updated _sumOfPublishedDelta.
var cumulative = GetCumulative();
switch (_state)
{
case ManipulationState.Starting when pointerAdded:
_state = ManipulationState.Started;
_sumOfPublishedDelta = cumulative;
_recognizer.ManipulationStarted?.Invoke(
_recognizer,
new ManipulationStartedEventArgs(_deviceType, _currents.Center, cumulative));
// No needs to publish an update when we start the manipulation due to an additional pointer as cumulative will be empty.
break;
case ManipulationState.Starting when cumulative.IsSignificant(_startThresholds):
_state = ManipulationState.Started;
_sumOfPublishedDelta = cumulative;
// Note: We first start with an empty delta, then invoke Update.
// This is required to patch a common issue in applications that are using only the
// ManipulationUpdated.Delta property to track the pointer (like the WCT GridSplitter).
// UWP seems to do that only for Touch and Pen (i.e. the Delta is not empty on start with a mouse),
// but there is no side effect to use the same behavior for all pointer types.
_recognizer.ManipulationStarted?.Invoke(
_recognizer,
new ManipulationStartedEventArgs(_deviceType, _origins.Center, ManipulationDelta.Empty));
_recognizer.ManipulationUpdated?.Invoke(
_recognizer,
new ManipulationUpdatedEventArgs(_deviceType, _currents.Center, cumulative, cumulative, isInertial: false));
break;
case ManipulationState.Started:
// Even if Scale and Angle are expected to be default when we add a pointer (i.e. forceUpdate == true),
// the 'delta' and 'cumulative' might still contains some TranslateX|Y compared to the previous Pointer1 location.
var delta = GetDelta(cumulative);
if (pointerAdded || delta.IsSignificant(_deltaThresholds))
{
_sumOfPublishedDelta = _sumOfPublishedDelta.Add(delta);
_recognizer.ManipulationUpdated?.Invoke(
_recognizer,
new ManipulationUpdatedEventArgs(_deviceType, _currents.Center, delta, cumulative, isInertial: false));
}
break;
}
}
/// <summary> /// Gets the cumulative delta, including the manipulation cumulative when this processor was started /// </summary> public ManipulationDelta GetCumulative() => _cumulative0.Add(_inertiaCumulative);
private void NotifyUpdate(bool pointerAdded = false)
{
// Note: Make sure to update the _sumOfPublishedDelta before raising the event, so if an exception is raised
// or if the manipulation is Completed, the Complete event args can use the updated _sumOfPublishedDelta.
var cumulative = GetCumulative();
switch (_state)
{
case ManipulationState.Starting when IsBeginningOfDragManipulation():
// On UWP if the element was configured to allow both Drag and Manipulations,
// both events are going to be raised (... until the drag "content" is being render an captures all pointers).
// This results as a manipulation started which is never completed.
// If user uses double touch the manipulation will however start and complete when user adds / remove the 2nd finger.
// On Uno, as allowing both Manipulations and drop on the same element is really a stretch case (and is bugish on UWP),
// we accept as a known limitation that once dragging started no manipulation event would be fired.
_state = ManipulationState.Started;
IsDragManipulation = true;
_recognizer.Dragging?.Invoke(
_recognizer,
new DraggingEventArgs(_currents.Pointer1, DraggingState.Started));
break;
case ManipulationState.Starting when pointerAdded:
_state = ManipulationState.Started;
_sumOfPublishedDelta = cumulative;
_recognizer.ManipulationStarted?.Invoke(
_recognizer,
new ManipulationStartedEventArgs(_deviceType, _currents.Center, cumulative));
// No needs to publish an update when we start the manipulation due to an additional pointer as cumulative will be empty.
break;
case ManipulationState.Starting when cumulative.IsSignificant(_startThresholds):
_state = ManipulationState.Started;
_sumOfPublishedDelta = cumulative;
// Note: We first start with an empty delta, then invoke Update.
// This is required to patch a common issue in applications that are using only the
// ManipulationUpdated.Delta property to track the pointer (like the WCT GridSplitter).
// UWP seems to do that only for Touch and Pen (i.e. the Delta is not empty on start with a mouse),
// but there is no side effect to use the same behavior for all pointer types.
_recognizer.ManipulationStarted?.Invoke(
_recognizer,
new ManipulationStartedEventArgs(_deviceType, _origins.Center, ManipulationDelta.Empty));
_recognizer.ManipulationUpdated?.Invoke(
_recognizer,
new ManipulationUpdatedEventArgs(_deviceType, _currents.Center, cumulative, cumulative, isInertial: false));
break;
case ManipulationState.Started when IsDragManipulation:
_recognizer.Dragging?.Invoke(
_recognizer,
new DraggingEventArgs(_currents.Pointer1, DraggingState.Continuing));
break;
case ManipulationState.Started:
// Even if Scale and Angle are expected to be default when we add a pointer (i.e. forceUpdate == true),
// the 'delta' and 'cumulative' might still contains some TranslateX|Y compared to the previous Pointer1 location.
var delta = GetDelta(cumulative);
if (pointerAdded || delta.IsSignificant(_deltaThresholds))
{
_sumOfPublishedDelta = _sumOfPublishedDelta.Add(delta);
_recognizer.ManipulationUpdated?.Invoke(
_recognizer,
new ManipulationUpdatedEventArgs(_deviceType, _currents.Center, delta, cumulative, isInertial: false));
}
break;
}
}