public static void DrawApproximateLine(Graphics g, Pen pen, ApproximateLine line)
{
IntPoint first = line.Points.First();
IntPoint last = line.Points.Last();
IntPoint diff = first - last;
g.DrawLine(pen, new System.Drawing.Point(first.X + diff.X, first.Y + diff.Y),
new System.Drawing.Point(last.X - diff.X, last.Y - diff.Y));
}
public ProcessedBlob(Blob blob, List<IntPoint> edges,
List<IntPoint> hull, Vector4 bounds, ApproximateLine[] lines,
bool isQuad, List<IntPoint> quadPoints = null)
{
Blob = blob;
Edges = edges;
Hull = hull;
Bounds = bounds;
Lines = lines;
IsQuad = isQuad;
if (isQuad)
{
QuadPoints = quadPoints;
}
else
{
QuadPoints = new List<IntPoint>();
}
}
private static ApproximateLine[] findLines(List<IntPoint> points)
{
if (points.Count < 3)
{
return new ApproximateLine[0];
}
List<ApproximateLine> results = new List<ApproximateLine>();
ApproximateLine line = null;
double lineAngle = 0, newAngle, diff, distance;
IntPoint previous = new IntPoint(); //Essentially, initialization is null
bool quitting = false;
for(int i = 0; i < points.Count; i++)
{
IntPoint point = points[i];
if (results.Count > 0 && point == results[0].Points.Last())
{
quitting = true;
}
if (line == null)
{
line = new ApproximateLine();
line.Add(point);
previous = point;
continue;
}
if (line.Points.Count == 1)
{
lineAngle = Math.Atan2((double)point.Y - (double)previous.Y,
(double)point.X - (double)previous.X);
line.Add(point);
}
else
{
newAngle = Math.Atan2((double)point.Y - (double)previous.Y,
(double)point.X - (double)previous.X);
diff = Math.Min((2d * Math.PI) - Math.Abs(newAngle - lineAngle),
Math.Abs(newAngle - lineAngle));
if (diff > AngleErrorMargin)
{
results.Add(line);
if (quitting)
{
break;
}
line = new ApproximateLine();
line.Add(previous);
line.Add(point);
}
else
{
distance = point.DistanceTo(previous);
lineAngle = (lineAngle * line.Length + newAngle * distance) /
(line.Length + distance);
line.Add(point);
}
}
previous = point;
if (i + 1 == points.Count)
{
i = 0;
}
}
results.RemoveAt(0);
return results.ToArray();
}
