/// <summary>
/// The implementation behind the public methods AddPoint/AddPoints
/// </summary>
/// <param name="points">new points to add to the lasso</param>
protected override void AddPointsCore(IEnumerable<Point> points)
{
System.Diagnostics.Debug.Assert((points != null) && (IEnumerablePointHelper.GetCount(points)!= 0));
// Add the new points to the lasso
int lastPointIndex = (0 != _lasso.PointCount) ? (_lasso.PointCount - 1) : 0;
_lasso.AddPoints(points);
// Do nothing if there's not enough points, or there's nobody listening
// The points may be filtered out, so if all the points are filtered out, (lastPointIndex == (_lasso.PointCount - 1).
// For this case, check if the incremental lasso is disabled (i.e., points modified).
if ((_lasso.IsEmpty) || (lastPointIndex == (_lasso.PointCount - 1) && false == _lasso.IsIncrementalLassoDirty)
|| (SelectionChanged == null))
{
return;
}
// Variables for possible HitChanged events to fire
StrokeCollection strokesHit = null;
StrokeCollection strokesUnhit = null;
// Create a lasso that represents the current increment
Lasso lassoUpdate = new Lasso();
if (false == _lasso.IsIncrementalLassoDirty)
{
if (0 < lastPointIndex)
{
lassoUpdate.AddPoint(_lasso[0]);
}
// Only the points the have been successfully added to _lasso will be added to
// lassoUpdate.
for (; lastPointIndex < _lasso.PointCount; lastPointIndex++)
{
lassoUpdate.AddPoint(_lasso[lastPointIndex]);
}
}
// Enumerate through the strokes and update their hit-test results
foreach (StrokeInfo strokeInfo in this.StrokeInfos)
{
Lasso lasso;
if (true == strokeInfo.IsDirty || true == _lasso.IsIncrementalLassoDirty)
{
// If this is the first time this stroke gets hit-tested with this lasso,
// or if the stroke (or its DAs) has changed since the last hit-testing,
// or if the lasso points have been modified,
// then (re)hit-test this stroke against the entire lasso.
lasso = _lasso;
strokeInfo.IsDirty = false;
}
else
{
// Otherwise, hit-test it against the lasso increment first and then only
// those ink points that are in that small lasso need to be hit-tested
// against the big (entire) lasso.
// This is supposed to be a significant piece of optimization, since
// lasso increments are usually very small, they are defined by just
// a few points and they don't capture and/or release too many ink nodes.
lasso = lassoUpdate;
}
// Skip those stroke which bounding box doesn't even intersects with the lasso bounds
double hitWeightChange = 0f;
if (lasso.Bounds.IntersectsWith(strokeInfo.StrokeBounds))
{
// Get the stroke node points for the hit-testing.
StylusPointCollection stylusPoints = strokeInfo.StylusPoints;
// Find out if the lasso update has changed the hit count of the stroke.
for (int i = 0; i < stylusPoints.Count; i++)
{
// Consider only the points that become captured/released with this particular update
if (true == lasso.Contains((Point)stylusPoints[i]))
{
double weight = strokeInfo.GetPointWeight(i);
if (lasso == _lasso || _lasso.Contains((Point)stylusPoints[i]))
{
hitWeightChange += weight;
}
else
{
hitWeightChange -= weight;
}
}
}
}
// Update the stroke hit weight and check whether it has crossed the margin
// in either direction since the last update.
if ((hitWeightChange != 0) || (lasso == _lasso))
{
strokeInfo.HitWeight = (lasso == _lasso) ? hitWeightChange : (strokeInfo.HitWeight + hitWeightChange);
bool isHit = DoubleUtil.GreaterThanOrClose(strokeInfo.HitWeight, strokeInfo.TotalWeight * _percentIntersect / 100f - Stroke.PercentageTolerance);
if (strokeInfo.IsHit != isHit)
{
strokeInfo.IsHit = isHit;
if (isHit)
{
// The hit count became greater than the margin percentage, the stroke
// needs to be reported for selection
if (null == strokesHit)
{
strokesHit = new StrokeCollection();
}
strokesHit.Add(strokeInfo.Stroke);
}
else
{
// The hit count just became less than the margin percentage,
// the stroke needs to be reported for de-selection
if (null == strokesUnhit)
{
strokesUnhit = new StrokeCollection();
}
strokesUnhit.Add(strokeInfo.Stroke);
}
}
}
}
_lasso.IsIncrementalLassoDirty = false;
// Raise StrokesHitChanged event if any strokes has changed thier
// hit status and there're the event subscribers.
if ((null != strokesHit) || (null != strokesUnhit))
{
OnSelectionChanged(new LassoSelectionChangedEventArgs (strokesHit, strokesUnhit));
}
}
/// <summary>
/// Hit tests all segments within the lasso loops
/// </summary>
/// <returns> a StrokeIntersection array for these segments</returns>
internal StrokeIntersection[] HitTest(Lasso lasso)
{
// Check the input parameters
System.Diagnostics.Debug.Assert(lasso != null);
if (lasso.IsEmpty)
{
return new StrokeIntersection[0];
}
// The following will check whether all the points are within the lasso.
// If yes, return the whole stroke as being hit.
if (!lasso.Bounds.IntersectsWith(this.GetBounds()))
{
return new StrokeIntersection[0];
}
return lasso.HitTest(StrokeNodeIterator.GetIterator(this, this.DrawingAttributes));
}