/// <summary>
/// 对多边形边进行整体偏移
/// </summary>
/// <param name="offsetDist">正值为向外偏，负值为向内偏</param>
/// <returns></returns>
public Polygon2D CreateOffset(double offsetDist)
{
List <Line2D> extendLines = new List <Line2D>();
Edges.ForEach(x => extendLines.Add(x.Offset((new Vector2D(x.Direction.Y, -x.Direction.X)) * offsetDist)));
List <Line2D> offsetLines = new List <Line2D>();
Vector2D firstPoint = extendLines.First().IntersectStraightLine(extendLines.Last());
List <Vector2D> offsetPoints = new List <Vector2D> {
firstPoint
};
for (int i = 0; i < extendLines.Count - 1; i++)
{
Vector2D intersect = extendLines[i].IntersectStraightLine(extendLines[i + 1]);
if (intersect != null)
{
offsetPoints.Add(intersect);
}
}
offsetPoints.Add(firstPoint);
for (int i = 0; i < offsetPoints.Count - 1; i++)
{
offsetLines.Add(Line2D.Create(offsetPoints[i], offsetPoints[i + 1]));
}
return(new Polygon2D(offsetLines));
}
private void GetRectangle(Vector2D p0, Vector2D p1, Vector2D p2, Vector2D p3)
{
List <Vector2D> points = new List <Vector2D> {
p0, p1, p2, p3
};
points.ForEach(x => x.X = Math.Floor(x.X * 1e9) / 1e9);
points.ForEach(x => x.Y = Math.Floor(x.Y * 1e9) / 1e9);
Vector2D first = points.OrderBy(x => x.X).ThenBy(y => y.Y).First();
List <Line2D> tryCurve = new List <Line2D>();
for (int i = 0; i < points.Count - 1; i++)
{
for (int j = i + 1; j < points.Count; j++)
{
tryCurve.Add(Line2D.Create(points[i], points[j]));
}
}
tryCurve = tryCurve.OrderByDescending(x => x.Length).ToList();
tryCurve.RemoveAt(1);
tryCurve.RemoveAt(0);
tryCurve = tryCurve.MakeCounterclockwise();
Bottom = tryCurve[0];
Right = tryCurve[1];
Top = tryCurve[2];
Left = tryCurve[3];
}
/// <summary>
/// 点到直线的距离
/// </summary>
/// <param name="source"></param>
/// <returns></returns>
public double Distance(Vector2D source)
{
double space = 0;
var a = Length;
var b = source.Distance(Start);
var c = source.Distance(End);
if (c < Extension.SMALL_NUMBER || b < Extension.SMALL_NUMBER)
{
return(space);
}
if (a < Extension.SMALL_NUMBER)
{
space = b;
return(space);
}
if (c * c >= a * a + b * b)
{
space = b;
return(space);
}
if (b * b >= a * a + c * c)
{
space = c;
return(space);
}
Vector2D v1 = new Vector2D(source.X, source.Y);
Line2D l1 = Line2D.Create(new Vector2D(this.Start.X, this.Start.Y), new Vector2D(this.End.X, this.End.Y));
space = Line2D.Create(v1, v1.ProjectOn(l1)).Length;
return(space);
}
private List <Line2D> ReArragne(List <Line2D> lines)
{
var newLines = new List <Line2D>();
for (int i = 0; i < lines.Count; i++)
{
var copyLines = new List <Line2D>(lines);
copyLines.RemoveAt(i);
var points = copyLines.Select(t => lines[i].IntersectStraightLine(t)).Where(point => point != null).ToList();
newLines.Add(Line2D.Create(points[0], points[1]));
}
return(newLines);
}