/// <summary>
/// Return winding order
/// </summary>
/// <param name="Polygon"></param>
/// <returns></returns>
public static WindingOrder GetWindingOrder(FigPolyline Polygon)
{
double Area = 0;
for (int j = 0; j < Polygon.Points.Count - 1; j++)
{
PointF Start = Polygon.Points[j];
PointF End = Polygon.Points[j + 1];
Area = Area + (Start.X * End.Y) - (End.X * Start.Y);
}
if (!IsClosed(Polygon))
{
PointF Start = Polygon.Points[Polygon.Points.Count - 1];
PointF End = Polygon.Points[0];
Area = Area + (Start.X * End.Y) - (End.X * Start.Y);
}
if (Area < 0)
{
return(WindingOrder.Clockwise);
}
else
{
return(WindingOrder.AntiClockwise);
}
}
public static bool ClipPolyToLine(GraphicsSurface surface, Line ClipLine)
{
bool result = false;
FigPolyline new_fig = new FigPolyline();
if (surface.selected.Count == 0 || surface.selected.Count > 1)
{
return(result); // nothing selected
}
if (surface.selected[0] is FigPolyline)
{
PointF s, p, i;
int j;
FigPolyline inPoly = surface.selected[0] as FigPolyline;
s = inPoly.Points[inPoly.Points.Count - 1];
for (j = 0; j < inPoly.Points.Count; j++)
{
p = inPoly.Points[j];
if (Inside(p, ClipLine)) // {Cases 1 and 4}
{
if (Inside(s, ClipLine))
{
new_fig.Points.Add(p); // {Case 1}
}
else
{
Intersect(s, p, ClipLine, out i);
new_fig.Points.Add(i);
new_fig.Points.Add(p);
}
}
else // {Cases 2 and 3}
{
if (Inside(s, ClipLine)) // {Cases 2}
{
Intersect(s, p, ClipLine, out i);
new_fig.Points.Add(i);
} // {No action for case 3}
}
s = p; // {Advance to next pair of vertices}
}
// replace selected
surface.Drawing.RemoveFigures(surface.selected);
surface.Drawing.AddFigure(new_fig);
// set new selection
surface.selected.Clear();
//surface.AddToSelected(new_fig);
surface.selected.Add(new_fig);
return(result);
}
else
{
return(result);
}
}
public static bool LineIntersectsPolyLines(FigPolyline Line1, List <FigPolyline> Lines)
{
foreach (FigPolyline line in Lines)
{
if (LineIntersectsPolyLine(Line1, line))
{
return(true);
}
}
return(false);
}
/// <summary>
/// Test if a polygon is closed (last point = first point)
/// </summary>
/// <param name="Polygon"></param>
/// <returns></returns>
public static bool IsClosed(FigPolyline Polygon)
{
if (Polygon.Points[0] == Polygon.Points[Polygon.Points.Count - 1])
{
return(true);
}
else
{
return(false);
}
}
public static bool LineIntersectsPolyLine(FigPolyline Line1, FigPolyline Line2)
{
PointF iPt;
for (int j = 0; j < Line1.Points.Count - 1; j++)
{
for (int k = 0; k < Line1.Points.Count - 1; k++)
{
if (Intersect(Line1.Points[j], Line1.Points[j + 1], Line2.Points[k], Line2.Points[k + 1], out iPt))
{
return(true);
}
}
}
return(false);
}
/// <summary>
/// Calculate the area of a polygon
/// </summary>
/// <param name="Polygon"></param>
/// <returns></returns>
public static double CalcPolygonArea(FigPolyline Polygon)
{
double Area = 0;
for (int j = 0; j < Polygon.Points.Count - 1; j++)
{
PointF Start = Polygon.Points[j];
PointF End = Polygon.Points[j + 1];
Area = Area + (Start.X * End.Y) - (End.X * Start.Y);
}
if (!IsClosed(Polygon))
{
PointF Start = Polygon.Points[Polygon.Points.Count - 1];
PointF End = Polygon.Points[0];
Area = Area + (Start.X * End.Y) - (End.X * Start.Y);
}
return(Math.Abs(Area) / 2.0);
}
/// <summary>
/// Replace the selected lines or polylines with a single polyline.
/// </summary>
/// <param name="surface"></param>
/// <returns></returns>
public static bool MakePath(GraphicsSurface surface)
{
bool result = false;
FigPolyline new_fig = new FigPolyline();
if (surface.selected.Count == 0)
{
return(result); // nothing selected
}
foreach (Figure fig in surface.selected)
{
if (!((fig is Line) || (fig is FigPolyline)))
{
return(false);
}
}
foreach (Figure fig in surface.selected)
{
if (new_fig.Points.Count == 0)
{
if (fig is Line)
{
Line line = fig as Line;
new_fig.Points.Add(new PointF(line.p1.X, line.p1.Y));
new_fig.Points.Add(new PointF(line.p2.X, line.p2.Y));
new_fig.LineProperties = line.LineProperties;
}
else
{
FigPolyline poly = fig as FigPolyline;
foreach (PointF p in poly.Points)
{
new_fig.Points.Add(new PointF(p.X, p.Y));
}
new_fig.LineProperties = poly.LineProperties;
}
}
else
{
// check contiguous
if (fig is Line)
{
Line line = fig as Line;
if (new_fig.Points[new_fig.Points.Count - 1] == line.p1)
{
new_fig.Points.Add(new PointF(line.p2.X, line.p2.Y));
}
else if (new_fig.Points[new_fig.Points.Count - 1] == line.p2)
{
new_fig.Points.Add(new PointF(line.p1.X, line.p1.Y));
}
else if (new_fig.Points[0] == line.p1)
{
new_fig.Points.Insert(0, new PointF(line.p2.X, line.p2.Y));
}
else if (new_fig.Points[0] == line.p2)
{
new_fig.Points.Insert(0, new PointF(line.p1.X, line.p1.Y));
}
else
{
return(false);
}
}
else
{
//polyline
FigPolyline poly = fig as FigPolyline;
if (new_fig.Points[new_fig.Points.Count - 1] == poly.Points[0])
{
AddPoints(ref new_fig.Points, poly.Points, 1);
}
else if (new_fig.Points[new_fig.Points.Count - 1] == poly.Points[poly.Points.Count - 1])
{
AddPointsReverse(ref new_fig.Points, poly.Points, 1);
}
}
}
}
surface.Drawing.RemoveFigures(surface.selected);
surface.Drawing.AddFigure(new_fig);
// set new selection
//surface.ClearSelected();
surface.selected.Clear();
//surface.AddToSelected(new_fig);
surface.selected.Add(new_fig);
return(result);
}
