/// <summary>
/// Calculate the intersection point between the segment and line.
/// </summary>
/// <param name="sEq">The segment equation.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection point.</returns>
public static Point GetIntersection(SegmentEquation sEq, LinearEquation lEq)
{
var pt = LinearEquation.GetIntersection(sEq, lEq);
if (sEq.IsPointInRange(pt))
{
return(pt);
}
return(null);
}
/// <summary>
/// Calculate the intersection point between the 2 segments.
/// </summary>
/// <param name="eq1">The first segment equation.</param>
/// <param name="eq2">The second segment equation.</param>
/// <returns>Returns the intersection point.</returns>
public static Point GetIntersection(SegmentEquation eq1, SegmentEquation eq2)
{
var pt = LinearEquation.GetIntersection(eq1, eq2);
if (eq1.IsPointInRange(pt) && eq2.IsPointInRange(pt))
{
return(pt);
}
return(null);
}
/// <summary>
/// Calculate the intersection point between the segment and line (Special).
/// </summary>
/// <param name="sEq">The segment equation.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection points.</returns>
public static Point GetIntersectionSp(SegmentEquation sEq, LinearEquation lEq)
{
var pt = SegmentEquation.GetIntersection(sEq, lEq);
if (pt == sEq.endpoint1)
{
if (pt.Y <= sEq.endpoint2.Y)
{
pt = null;
}
}
else if (pt == sEq.endpoint2)
{
if (pt.Y <= sEq.endpoint1.Y)
{
pt = null;
}
}
return(pt);
}
/// <summary>
/// Calculate the intersection point between the 2 lines.
/// </summary>
/// <param name="eq1">The first line equation.</param>
/// <param name="eq2">The second line equation.</param>
/// <returns>Return the intersection point.</returns>
public static Point GetIntersection(LinearEquation eq1, LinearEquation eq2)
{
if (eq1.slope == eq2.slope)
{
return(null);
}
if (double.IsInfinity(eq1.slope))
{
return(new Point(eq1.bias, eq2.GetCoordY(eq1.bias)));
}
if (double.IsInfinity(eq2.slope))
{
return(new Point(eq2.bias, eq1.GetCoordY(eq2.bias)));
}
double x = (eq2.bias - eq1.bias) / (eq1.slope - eq2.slope);
double y = eq1.GetCoordY(x);
return(new Point(x, y));
}
/// <summary>
/// Judge wether the specified point lies within the interior or on the boundary of the specified polygon.
/// </summary>
/// <param name="pt">The specified point.</param>
/// <returns>Return true if the specified point intersects the polygon, otherwise false.</returns>
public bool IsIntersects(Point pt)
{
var line = new LinearEquation(pt, LinearType.ParallelXAxis);
var pts = SegmentEquation.GetIntersectionSp(this.sides, line);
int counter = 0;
foreach (var point in pts)
{
if (point == pt)
{
return true;
}
else
{
if (point.X < pt.X)
{
counter++;
}
}
}
return counter % 2 == 1;
}
/// <summary>
/// Judge wether the specified point lies within the interior or on the boundary of the specified polygon.
/// </summary>
/// <param name="pt">The specified point.</param>
/// <returns>Return true if the specified point intersects the polygon, otherwise false.</returns>
public bool IsIntersects(Point pt)
{
var line = new LinearEquation(pt, LinearType.ParallelXAxis);
var pts = SegmentEquation.GetIntersectionSp(this.sides, line);
int counter = 0;
foreach (var point in pts)
{
if (point == pt)
{
return(true);
}
else
{
if (point.X < pt.X)
{
counter++;
}
}
}
return(counter % 2 == 1);
}
/// <summary>
/// Calculate the intersection points when a line across many segments (Special).
/// </summary>
/// <param name="sEqs">The segment equations.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection points.</returns>
public static List<Point> GetIntersectionSp(IEnumerable<SegmentEquation> sEqs, LinearEquation lEq)
{
var pts = new List<Point>();
foreach (var sEq in sEqs)
{
var pt = SegmentEquation.GetIntersectionSp(sEq, lEq);
if (null != pt && sEq.IsPointInRange(pt))
{
pts.Add(pt);
}
}
return pts;
}
/// <summary>
/// Calculate the intersection point between the segment and line (Special).
/// </summary>
/// <param name="sEq">The segment equation.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection points.</returns>
public static Point GetIntersectionSp(SegmentEquation sEq, LinearEquation lEq)
{
var pt = SegmentEquation.GetIntersection(sEq, lEq);
if (pt == sEq.endpoint1)
{
if (pt.Y <= sEq.endpoint2.Y)
{
pt = null;
}
}
else if (pt == sEq.endpoint2)
{
if (pt.Y <= sEq.endpoint1.Y)
{
pt = null;
}
}
return pt;
}
/// <summary>
/// Calculate the intersection point between the segment and line.
/// </summary>
/// <param name="sEq">The segment equation.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection point.</returns>
public static Point GetIntersection(SegmentEquation sEq, LinearEquation lEq)
{
var pt = LinearEquation.GetIntersection(sEq, lEq);
if (sEq.IsPointInRange(pt))
{
return pt;
}
return null;
}
/// <summary>
/// Calculate the intersection points when a line across many segments (Special).
/// </summary>
/// <param name="sEqs">The segment equations.</param>
/// <param name="lEq">The line equation.</param>
/// <returns>Returns the intersection points.</returns>
public static List <Point> GetIntersectionSp(IEnumerable <SegmentEquation> sEqs, LinearEquation lEq)
{
var pts = new List <Point>();
foreach (var sEq in sEqs)
{
var pt = SegmentEquation.GetIntersectionSp(sEq, lEq);
if (null != pt && sEq.IsPointInRange(pt))
{
pts.Add(pt);
}
}
return(pts);
}
/// <summary>
/// Calculate the intersection point between the 2 lines.
/// </summary>
/// <param name="eq1">The first line equation.</param>
/// <param name="eq2">The second line equation.</param>
/// <returns>Return the intersection point.</returns>
public static Point GetIntersection(LinearEquation eq1, LinearEquation eq2)
{
if (eq1.slope == eq2.slope)
{
return null;
}
if (double.IsInfinity(eq1.slope))
{
return new Point(eq1.bias, eq2.GetCoordY(eq1.bias));
}
if (double.IsInfinity(eq2.slope))
{
return new Point(eq2.bias, eq1.GetCoordY(eq2.bias));
}
double x = (eq2.bias - eq1.bias) / (eq1.slope - eq2.slope);
double y = eq1.GetCoordY(x);
return new Point(x, y);
}