/// <summary>
/// Get the <see cref="PdfPoint"/>s that are the intersections of the line and the curve.
/// </summary>
/// <returns></returns>
public static PdfPoint[] Intersect(this PdfPath.BezierCurve bezierCurve, PdfPath.Line line)
{
var ts = FindIntersectionT(bezierCurve, line);
if (ts.Count() == 0)
{
return(null);
}
List <PdfPoint> points = new List <PdfPoint>();
foreach (var t in ts)
{
PdfPoint point = new PdfPoint(
PdfPath.BezierCurve.ValueWithT(bezierCurve.StartPoint.X,
bezierCurve.FirstControlPoint.X,
bezierCurve.SecondControlPoint.X,
bezierCurve.EndPoint.X,
t),
PdfPath.BezierCurve.ValueWithT(bezierCurve.StartPoint.Y,
bezierCurve.FirstControlPoint.Y,
bezierCurve.SecondControlPoint.Y,
bezierCurve.EndPoint.Y,
t)
);
points.Add(point);
}
return(points.ToArray());
}
/// <summary>
/// Checks if both lines are parallel.
/// </summary>
public static bool ParallelTo(this PdfPath.Line line, PdfPath.Line other)
{
var val1 = (line.To.Y - line.From.Y) * (other.To.X - other.From.X);
var val2 = (other.To.Y - other.From.Y) * (line.To.X - line.From.X);
return(Math.Round(val1 - val2, 5) == 0);
}
/// <summary>
/// Whether the line segment contains the point.
/// </summary>
public static bool Contains(this PdfPath.Line line, PdfPoint point)
{
if (line.To.X == line.From.X)
{
if (point.X == line.To.X)
{
return(Math.Sign(point.Y - line.To.Y) != Math.Sign(point.Y - line.From.Y));
}
return(false);
}
if (line.To.Y == line.From.Y)
{
if (point.Y == line.To.Y)
{
return(Math.Sign(point.X - line.To.X) != Math.Sign(point.X - line.From.X));
}
return(false);
}
var tx = (point.X - line.From.X) / (line.To.X - line.From.X);
var ty = (point.Y - line.From.Y) / (line.To.Y - line.From.Y);
if (Math.Round(tx - ty, 5) != 0)
{
return(false);
}
return(tx >= 0 && tx <= 1);
}
/// <summary>
/// Get the t values that are the intersections of the line and the curve.
/// </summary>
/// <returns>List of t values where the <see cref="PdfPath.BezierCurve"/> and the <see cref="PdfPath.Line"/> intersect.</returns>
public static double[] IntersectT(this PdfPath.BezierCurve bezierCurve, PdfPath.Line line)
{
return(IntersectT(bezierCurve, line.From, line.To));
}
/// <summary>
/// Get the <see cref="PdfPoint"/>s that are the intersections of the line and the curve.
/// </summary>
public static PdfPoint[] Intersect(this PdfPath.BezierCurve bezierCurve, PdfPath.Line line)
{
return(Intersect(bezierCurve, line.From, line.To));
}
/// <summary>
/// Checks if the curve and the line are intersecting.
/// <para>Avoid using this method as it is not optimised. Use <see cref="Intersect(PdfPath.BezierCurve, PdfPath.Line)"/> instead.</para>
/// </summary>
public static bool IntersectsWith(this PdfPath.BezierCurve bezierCurve, PdfPath.Line line)
{
return(IntersectsWith(bezierCurve, line.From, line.To));
}
/// <summary>
/// Checks if both lines are parallel.
/// </summary>
public static bool ParallelTo(this PdfPath.Line line, PdfLine other)
{
return(ParallelTo(line.From, line.To, other.Point1, other.Point2));
}
/// <summary>
/// Get the <see cref="PdfPoint"/> that is the intersection of two lines.
/// </summary>
public static PdfPoint?Intersect(this PdfPath.Line line, PdfLine other)
{
return(Intersect(line.From, line.To, other.Point1, other.Point2));
}
/// <summary>
/// Whether two lines intersect.
/// </summary>
public static bool IntersectsWith(this PdfPath.Line line, PdfLine other)
{
return(IntersectsWith(line.From, line.To, other.Point1, other.Point2));
}
/// <summary>
/// Whether the line segment contains the point.
/// </summary>
public static bool Contains(this PdfPath.Line line, PdfPoint point)
{
return(Contains(line.From, line.To, point));
}
/// <summary>
/// Get the t values that are the intersections of the line and the curve.
/// </summary>
/// <returns>List of t values where the <see cref="PdfPath.BezierCurve"/> and the <see cref="PdfPath.Line"/> intersect.</returns>
public static double[] FindIntersectionT(this PdfPath.BezierCurve bezierCurve, PdfPath.Line line)
{
// if the bounding boxes do not intersect, they cannot intersect
var bezierBbox = bezierCurve.GetBoundingRectangle();
if (!bezierBbox.HasValue)
{
return(null);
}
var lineBbox = line.GetBoundingRectangle();
if (!lineBbox.HasValue)
{
return(null);
}
if (!bezierBbox.Value.IntersectsWith(lineBbox.Value))
{
return(null);
}
double x1 = line.From.X;
double y1 = line.From.Y;
double x2 = line.To.X;
double y2 = line.To.Y;
return(FindIntersectionT(bezierCurve, x1, y1, x2, y2));
}
/// <summary>
/// Get the <see cref="PdfPoint"/> that is the intersection of two lines.
/// </summary>
public static PdfPoint?Intersect(this PdfPath.Line line, PdfPath.Line other)
{
// if the bounding boxes do not intersect, the lines cannot intersect
var thisLineBbox = line.GetBoundingRectangle();
if (!thisLineBbox.HasValue)
{
return(null);
}
var lineBbox = other.GetBoundingRectangle();
if (!lineBbox.HasValue)
{
return(null);
}
if (!thisLineBbox.Value.IntersectsWith(lineBbox.Value))
{
return(null);
}
var eq1 = GetSlopeIntercept(line.From, line.To);
var eq2 = GetSlopeIntercept(other.From, other.To);
if (double.IsNaN(eq1.Slope) && double.IsNaN(eq2.Slope))
{
return(null); // both lines are vertical (hence parallel)
}
if (eq1.Slope == eq2.Slope)
{
return(null); // both lines are parallel
}
var intersection = new PdfPoint();
if (double.IsNaN(eq1.Slope))
{
var x = eq1.Intercept;
var y = eq2.Slope * x + eq2.Intercept;
intersection = new PdfPoint(x, y);
}
else if (double.IsNaN(eq2.Slope))
{
var x = eq2.Intercept;
var y = eq1.Slope * x + eq1.Intercept;
intersection = new PdfPoint(x, y);
}
else
{
var x = (eq2.Intercept - eq1.Intercept) / (eq1.Slope - eq2.Slope);
var y = eq1.Slope * x + eq1.Intercept;
intersection = new PdfPoint(x, y);
}
// check if the intersection point belongs to both segments
// (for the moment we only know it belongs to both lines)
if (!line.Contains(intersection))
{
return(null);
}
if (!other.Contains(intersection))
{
return(null);
}
return(intersection);
}
/// <summary>
/// Whether two lines intersect.
/// </summary>
public static bool IntersectsWith(this PdfPath.Line line, PdfPath.Line other)
{
return(Intersect(line, other) != null);
}