//Inertia is completed, we can reuse the object
public void Completed(PictureTracker pictureTracker)
{
pictureTracker.Picture = null;
_pictureTrackers.Push(pictureTracker);
}
private PictureTracker GetPictureTracker(int touchId, Point location)
{
PictureTracker pictureTracker;
//See if we already track the picture with the touchId
if (_pictureTrackerMap.TryGetValue(touchId, out pictureTracker))
return pictureTracker;
//Get the picture under the touch location
Picture picture = FindPicture(location);
if (picture == null)
return null;
//See if we track the picture with other ID
pictureTracker = (from KeyValuePair<int, PictureTracker> entry in _pictureTrackerMap
where entry.Value.Picture == picture
select entry.Value).FirstOrDefault();
//First time
if (pictureTracker == null)
{
//take from stack
if (_pictureTrackers.Count > 0)
pictureTracker = _pictureTrackers.Pop();
else //create new
pictureTracker = new PictureTracker(this);
pictureTracker.Picture = picture;
BringPictureToFront(picture);
}
//remember the corelation between the touch id and the picture
_pictureTrackerMap[touchId] = pictureTracker;
return pictureTracker;
}
//We remove the touchID from the tracking map since the fingers are no longer touch
//the picture
public void InInertia(PictureTracker pictureTracker)
{
//remove all touch id from the map
foreach (int id in
(from KeyValuePair<int, PictureTracker> entry in _pictureTrackerMap
where entry.Value == pictureTracker
select entry.Key).ToList())
{
_pictureTrackerMap.Remove(id);
}
}
