Revit.Plugln/FWindSoft/FWindSoft.Revit/Extension/Graphic/LineExtension.cs

using Autodesk.Revit.DB;
using FWindSoft.SystemExtensions;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FWindSoft.Revit
{
    public static class LineExtension
    {
        /// <summary>
        /// 两直线平行
        /// </summary>
        /// <param name="line1"></param>
        /// <param name="line2"></param>
        /// <returns></returns>
        public static bool IsParallel(this Line line1, Line line2)
        {
            return line1.Direction.IsParallel(line2.Direction);
        }
        /// <summary>
        /// 获取线的端点与指定点 最远的点    
        /// </summary>
        /// <param name="line"></param>
        /// <param name="point"></param>
        /// <returns></returns>
        public static XYZ GetFarnessPoint(this Line line, XYZ point)
        {
            XYZ start = line.StartPoint();
            XYZ end = line.EndPoint();
            return start.DistanceTo(point).Less(end.DistanceTo(point)) ? end : start;
        }

        /// <summary>
        /// 获取线的端点与指定点 最近的点        
        /// </summary>
        /// <param name="line"></param>
        /// <param name="point"></param>
        /// <returns></returns>
        public static XYZ GetNearnessPoint(this Line line, XYZ point)
        {
            XYZ start = line.StartPoint();
            XYZ end = line.EndPoint();
            return start.DistanceTo(point).Less(end.DistanceTo(point)) ? start : end;
        }

        /// <summary>
        /// 获取空间直线的垂足点
        /// </summary>
        /// <param name="baseLine"></param>
        /// <param name="line2"></param>
        /// <returns></returns>
        public static XYZ GetSpatialIntersection(this Line baseLine, Line line2)
        {
            //两条法向量构建，和baseLine上一点构建平面，line2中的点在平面内的投影线。求投影线和baseLine1两条直线的夹角
            XYZ basePoint = null;
            do
            {
                if (baseLine.IsParallel(line2))
                {
                    break;
                }
                var normal = baseLine.Direction.CrossProduct(line2.Direction);
                var origin = baseLine.Origin;
                var start = line2.Origin;
                var end = start + 10 * line2.Direction;
                if (line2.IsBound)
                {
                    start = line2.StartPoint();
                    end = line2.EndPoint();
                }
                //取投影点
                XYZ point1 = start.GetPlaneProject(normal, origin);
                XYZ point2 = end.GetPlaneProject(normal, origin);
                if (point1.IsEqual(point2))
                {
                    basePoint = point1;
                }
                else
                {
                    var unBoundLine1 = baseLine.CloneUnbound();
                    var unboundLine2 = point1.NewLine(point2).CloneUnbound();
                    basePoint = unBoundLine1.GetIntersection(unboundLine2);
                }

            } while (false);
            return basePoint;
        }

        /// <summary>
        /// 是否共线
        /// </summary>
        /// <param name="baseLine"></param>
        /// <param name="line2"></param>
        /// <returns></returns>
        public static bool IsCollinear(this Line baseLine,Line line2)
        {
            return baseLine.IsParallel(line2) && baseLine.Direction.IsParallel(line2.Origin - baseLine.Origin);
        }
        /// <summary>
        /// 获取输入点在直线上的投影点
        /// </summary>
        /// <param name="line"></param>
        /// <param name="input"></param>
        /// <returns></returns>
        public static XYZ GetProject(this  Line line, XYZ input)
        {
            var origin = line.Origin;
            var direction = line.Direction;
            var useVector = input - origin;
            var project = useVector.DotProduct(direction) * direction + origin;
            return project;
        }
    }
}