public static LineSegment2D MergeSegments(LineSegment2D[] segments)
{
var points = segments.Select(s => s.P1).Union(segments.Select(s => s.P2)).ToArray();
var a = (double) points.Length*points.Sum(p => p.X*p.Y) - points.Sum(p => p.X)*points.Sum(p => p.Y);
a /= points.Length*points.Sum(p => p.X*p.X) - Math.Pow(points.Sum(p => p.X), 2);
var b = (points.Sum(p => p.Y) - a*points.Sum(p => p.X))/points.Length;
var y1 = points.Min(p => p.Y);
var y2 = points.Max(p => p.Y);
var x1 = (int) ((y1 - b)/a);
var x2 = (int) ((y2 - b)/a);
return new LineSegment2D(new Point(x1, y1), new Point(x2, y2));
}
public static List<Rectangle> Compute(Size imageSize, LineSegment2D[] lines)
{
const double scaleStep = 0.5;
const double minScale = 0.1;
const double ratio = 1.5;
var allLines = lines.Select(RotateLineSegment2D).ToArray();
var left = default(LineSegment2D);
var right = default(LineSegment2D);
var leftPoint = new Point(int.MinValue, 0);
var rightPoint = new Point(int.MaxValue, 0);
var viewPoint = imageSize.Width/2;
foreach (var line in allLines)
{
var start = FindStartingPoint(line, imageSize.Width, imageSize.Height, false);
if (start.X >= leftPoint.X && start.X <= viewPoint)
{
left = line;
leftPoint = start;
}
else if (start.X <= rightPoint.X && start.X > viewPoint)
{
right = line;
rightPoint = start;
}
}
var maxY = Math.Min(FindStartingPoint(left, imageSize.Width, imageSize.Height, true).Y,
FindStartingPoint(right, imageSize.Width, imageSize.Height, true).Y);
leftPoint = FindStartingPoint(left, imageSize.Width, maxY, false);
rightPoint = FindStartingPoint(right, imageSize.Width, maxY, false);
var intersection = Intersection(left, right);
var windowSize = rightPoint.X - leftPoint.X;
var windowMiddlePoint = new Point(leftPoint.X + windowSize/2, leftPoint.Y);
var windowDirection =
new PointF(-(left.Direction.X + right.Direction.X*left.Direction.Y/right.Direction.Y)/2,
-left.Direction.Y);
var middleDistance =
(float) Math.Sqrt(windowDirection.X*windowDirection.X + windowDirection.Y*windowDirection.Y);
windowDirection = new PointF(windowDirection.X/middleDistance, windowDirection.Y/middleDistance);
//calculate step count
var stepCount = 0;
var temp = minScale;
do
{
temp = temp/scaleStep;
++stepCount;
} while (temp < 1);
var coefficient = DistanceHelper.Distance(windowMiddlePoint, intersection);
var scale = 1.0;
var windows = new List<Rectangle>();
for (var i = 0; i < stepCount; ++i)
{
var windowWidth = windowSize*scale;
var windowHeight = windowWidth/ratio;
var length = (1.0 - scale)*coefficient;
var position = new Point((int) (windowMiddlePoint.X + windowDirection.X*length),
(int) (windowMiddlePoint.Y + windowDirection.Y*length));
var windowLeft = position.X - windowWidth/2;
var windowDown = position.Y - windowHeight;
windows.Add(new Rectangle((int) windowLeft, (int) windowDown, (int) windowWidth, (int) windowHeight));
scale *= scaleStep;
}
return windows;
}
