MetroGauges-Old/MetroGauges/Controls/LineWithRect.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using System.Windows.Shapes;

namespace MetroGauges.Controls
{

    public class Circle
    {
        double _r, _x, _y;

        public double R { get { return _r; } }
        public double X { get { return _x; } }
        public double Y { get { return _y; } }

        Circle(double r, double x, double y) {
            _r = r;
            _x = x;
            _y = y;
        }


    }

        public class LineWithRect
    {
        public Rect rect = new Rect();
        public Transform LineStart;
        public Transform lineEnd;

        Point leftDown
        {
            get
            {
                return new Point(rect.X, rect.Y+rect.Height);
            }
        }
        Point leftUp
        {
            get
            {
                return new Point(rect.X, rect.Y);
            }
        }
        Point RigtDown
        {
            get
            {
                return new Point(rect.X+rect.Width, rect.Y+rect.Height);
            }
        }
        Point RightUp
        {
            get
            {
                return new Point(rect.X+rect.Width, rect.Y);
            }
        }


    

        // 线是否在矩形内
       public bool LineInRect(Point lineStart, Point lineEnd, Rect rect)
        {
            return rect.Contains(lineStart) || rect.Contains(lineEnd);
        }

        // 线与矩形是否相交
        public bool LineIntersectRect(Point lineStart, Point lineEnd, Rect rect)
        {
            if (LineIntersectLine(lineStart, lineEnd, leftDown, leftUp))
                return true;
            if (LineIntersectLine(lineStart, lineEnd, leftUp, RightUp))
                return true;
            if (LineIntersectLine(lineStart, lineEnd, RightUp, RigtDown))
                return true;
            if (LineIntersectLine(lineStart, lineEnd, RigtDown, leftDown))
                return true;

            return false;
        }

        // 线与线是否相交
        public bool LineIntersectLine(Point l1Start, Point l1End, Point l2Start, Point l2End)
        {
            return QuickReject(l1Start, l1End, l2Start, l2End) && Straddle(l1Start, l1End, l2Start, l2End);
        }

        // 快速排序。  true=通过， false=不通过
        public bool QuickReject(Point l1Start, Point l1End, Point l2Start, Point l2End)
        {
            double l1xMax = Math.Max(l1Start.X, l1End.X);
            double l1yMax = Math.Max(l1Start.Y, l1End.Y);
            double l1xMin = Math.Min(l1Start.X, l1End.X);
            double l1yMin = Math.Min(l1Start.Y, l1End.Y);

            double l2xMax = Math.Max(l2Start.X, l2End.X);
            double l2yMax = Math.Max(l2Start.Y, l2End.Y);
            double l2xMin = Math.Min(l2Start.X, l2End.X);
            double l2yMin = Math.Min(l2Start.Y, l2End.Y);

            if (l1xMax < l2xMin || l1yMax < l2yMin || l2xMax < l1xMin || l2yMax < l1yMin)
                return false;

            return true;
        }

        // 跨立实验
        public bool Straddle(Point l1Start, Point l1End, Point l2Start, Point l2End)
        {
           double l1x1 = l1Start.X;
            double l1x2 = l1End.X;
            double l1y1 = l1Start.Y;
            double l1y2 = l1End.Y;
            double l2x1 = l2Start.X;
            double l2x2 = l2End.X;
            double l2y1 = l2Start.Y;
            double l2y2 = l2End.Y;

            if ((((l1x1 - l2x1) * (l2y2 - l2y1) - (l1y1 - l2y1) * (l2x2 - l2x1)) *
                 ((l1x2 - l2x1) * (l2y2 - l2y1) - (l1y2 - l2y1) * (l2x2 - l2x1))) > 0 ||
                (((l2x1 - l1x1) * (l1y2 - l1y1) - (l2y1 - l1y1) * (l1x2 - l1x1)) *
                 ((l2x2 - l1x1) * (l1y2 - l1y1) - (l2y2 - l1y1) * (l1x2 - l1x1))) > 0)
            {
                return false;
            }

            return true;
        }

        //相/判断直线p1p2与圆c是否相交，交返回true，否则返回false
        public bool CheckLineCrircleReject(Point p1, Point p2, Circle c)
        {
            bool flag1 = (p1.X - c.X) * (p1.X - c.X) + (p1.Y - c.Y) * (p1.Y - c.Y) <= c.R * c.R;
            bool flag2 = (p2.X - c.X) * (p2.X - c.X) + (p2.Y - c.Y) * (p2.Y - c.Y) <= c.R * c.R;
            if (flag1 && flag2) //情况一、两点都在圆内 :一定不相交 
                return false;
            else if (flag1 || flag2) //情况二、一个点在圆内，一个点在圆外：一定相交 
                return true;
            else //情况三、两个点都在圆外 
            {
                double A, B, C, dist1, dist2, angle1, angle2;
                //将直线p1p2化为一般式：Ax+By+C=0的形式。先化为两点式，然后由两点式得出一般式 
                A = p1.Y - p2.Y;
                B = p2.X - p1.X;
                C = p1.X * p2.Y - p2.X * p1.Y;
                //使用距离公式判断圆心到直线ax+by+c=0的距离是否大于半径 
                dist1 = A * c.X + B * c.Y + C;
                dist1 *= dist1;
                dist2 = (A * A + B * B) * c.R * c.R;
                if (dist1 > dist2)//圆心到直线p1p2的距离大于半径，不相交 
                    return false;
                angle1 = (c.X - p1.X) * (p2.X - p1.X) + (c.Y - p1.Y) * (p2.Y - p1.Y);
                angle2 = (c.X - p2.X) * (p1.X - p2.X) + (c.Y - p2.Y) * (p1.Y - p2.Y);
                if (angle1 > 0 && angle2 > 0)//余弦为正，则是锐角，一定相交 
                    return true;
                else
                    return false;
            }
        }


    }
}