public static CgmRectangle GetRectangle(Polyline polyline)
{
if (IsRectangle(polyline))
{
var points = polyline.Points;
// rectangle is descriped counter clock-wise starting right
if (CgmPoint.IsSame(points[0].Y, points[1].Y) && CgmPoint.IsSame(points[1].X, points[2].X) && CgmPoint.IsSame(points[2].Y, points[3].Y))
{
if (points[1].Y < points[2].Y)
{
return(CgmRectangle.FromPoints(points[1], points[0], points[2], points[3]));
}
else if (points[0].X < points[1].X) // starting left
{
return(CgmRectangle.FromPoints(points[3], points[2], points[0], points[1]));
}
else
{
return(CgmRectangle.FromPoints(points[2], points[3], points[1], points[0]));
}
}
// rectangle is described clock wise
if (CgmPoint.IsSame(points[0].X, points[1].X) && CgmPoint.IsSame(points[1].Y, points[2].Y) && CgmPoint.IsSame(points[2].X, points[3].X))
{
return(CgmRectangle.FromPoints(points[4], points[0], points[3], points[1]));
}
}
return(CgmRectangle.Empty);
}
private static IEnumerable <CgmRectangle> FindRectangleInSimpleLines(IEnumerable <Polyline> simpleLines)
{
// get all horizontal lines
var horizontalLines = simpleLines.Where(l => IsHorizontalLine(l.Points[0], l.Points[1])).Select(l => new CgmLine(l.Points[0], l.Points[1]));
var verticalLines = simpleLines.Where(l => IsVerticalLine(l.Points[0], l.Points[1])).Select(l => new CgmLine(l.Points[0], l.Points[1]));
var rects = new List <RectanglePoints>();
// loop through horizontal lines and find the two parelles each
foreach (var horzLine in horizontalLines)
{
var others = horizontalLines.Where(l => CgmPoint.IsSame(l.A.X, horzLine.A.X) && l.A.Y > horzLine.A.Y);
if (others.Any())
{
var nearest = others.OrderBy(l => l.A.Y).Last();
rects.Add(new RectanglePoints(horzLine, nearest));
}
}
// loop the vertical lines and find the ones linking to the horizontal ones
foreach (var verticalLine in verticalLines)
{
var l = rects.FirstOrDefault(h => h.IsUpperLeft(verticalLine.A));
if (l != null && l.IsLowerLeft(verticalLine.B))
{
l.SetLowerLeft(verticalLine.B);
continue;
}
l = rects.FirstOrDefault(h => h.IsUpperRight(verticalLine.A));
if (l != null && l.IsLowerRight(verticalLine.B))
{
l.SetLowerRight(verticalLine.B);
}
}
return(rects.Where(r => r.IsValid).Select(r => r.ToRectangle()));
}
internal static void ValidationCorners(CgmPoint leftUpperCorner, CgmPoint rightUpperCorner, CgmPoint leftLowerCorner, CgmPoint rightLowerCorner)
{
if (!CgmPoint.IsSame(leftUpperCorner.Y, rightUpperCorner.Y))
{
throw new ArgumentException("The left upper corner is not at the same height as the right upper corner");
}
if (!CgmPoint.IsSame(leftLowerCorner.Y, rightLowerCorner.Y))
{
throw new ArgumentException("The left lower corner is not at the same height as the right lower corner");
}
if (!CgmPoint.IsSame(leftUpperCorner.X, leftLowerCorner.X))
{
throw new ArgumentException("The left upper corner is not at the same X as the left lower corner");
}
if (!CgmPoint.IsSame(rightUpperCorner.X, rightLowerCorner.X))
{
throw new ArgumentException("The right upper corner is not at the same X as the right lower corner");
}
}
private static bool IsVerticalLine(CgmPoint a, CgmPoint b)
{
return(CgmPoint.IsSame(a.X, b.X) && !CgmPoint.IsSame(a.Y, b.Y));
}
private static bool IsHorizontalLine(CgmPoint a, CgmPoint b)
{
return(CgmPoint.IsSame(a.Y, b.Y) && !CgmPoint.IsSame(a.X, b.X));
}
