public void OnDrag(NoteAreaDragEvent dragEvent)
{
if (dragEvent.GeneralDragEvent.InputButton != PointerEventData.InputButton.Middle &&
Touch.activeTouches.Count < 2)
{
return;
}
if (Touch.activeTouches.Count == 2)
{
if (twoFingerGestureStartDistance < 0)
{
twoFingerGestureStartDistance = Vector2.Distance(Touch.activeTouches[0].screenPosition, Touch.activeTouches[1].screenPosition);
}
else
{
// The touches must all move in the same direction. Thus, their distance to each other must be (near) constant.
float distance = Vector2.Distance(Touch.activeTouches[0].screenPosition, Touch.activeTouches[1].screenPosition);
if (Math.Abs(distance - twoFingerGestureStartDistance) > TouchGestureMoveInSameDirectionThreshold)
{
CancelDrag();
return;
}
}
}
int newViewportX = viewportXBeginDrag - dragEvent.MillisDistance;
int newViewportY = viewportYBeginDrag - dragEvent.MidiNoteDistance;
noteArea.SetViewport(newViewportX, newViewportY, noteArea.ViewportWidth, noteArea.ViewportHeight);
}