public StrokeSegment (Stroke stroke, int startIndex, int lastIndex)
{
_points = stroke.Points;
if (startIndex >= _points.Length) throw new ArgumentOutOfRangeException ("startIndex");
if (lastIndex >= _points.Length) throw new ArgumentOutOfRangeException ("lastIndex");
StartIndex = startIndex;
EndIndex = lastIndex;
}
public Stroke GetSimplifiedStroke (int startIndex, float error, int maxSegments)
{
var segs = GetSimplifiedSegments (startIndex, error, maxSegments);
var ss = new Stroke (CreatedTime);
ss.AddPoint (segs [0].StartPoint);
foreach (var s in segs) {
ss.AddPoint (s.EndPoint);
}
return ss;
}
public bool IntersectsWith (LineSegmentF lineSegment)
{
var other = new Stroke ();
other.AddPoint (lineSegment.Start);
other.AddPoint (lineSegment.End);
return GetIntersectionWith (other) != null;
}
public IntersectionInfo GetIntersectionWith (Stroke other)
{
for (var i = 0; i < _points.Count - 1; i++) {
var x1 = _points [i].X;
var y1 = _points [i].Y;
var x21 = _points [i + 1].X - x1;
var y21 = _points [i + 1].Y - y1;
for (var j = 0; j < other._points.Count - 1; j++) {
var x3 = other._points [j].X;
var y3 = other._points [j].Y;
var x43 = other._points [j + 1].X - x3;
var y43 = other._points [j + 1].Y - y3;
var x13 = x1 - x3;
var y13 = y1 - y3;
var d = y43*x21 - x43*y21;
if (d == 0.0f) continue;
var na = x43*y13 - y43*x13;
var ua = na / d;
if (ua < 0 || ua > 1) continue;
var nb = x21*y13 - y21*x13;
var ub = nb / d;
if (ub >= 0 && ub <= 1) {
var loc = new PointF (x1 + ua * x21, y1 + ua * y21);
return new IntersectionInfo (loc);
}
}
}
return null;
}
public bool IntersectsWith (Stroke other)
{
return GetIntersectionWith (other) != null;
}