form1.cs

苏金明编写的《用VB.NET和VC#.NET开发交互式CAD系统》一书的源代码

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Drawing2D;

namespace 曲线的拾取
{
	/// <summary>
	/// Form1 的摘要说明。
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		/// <summary>
		/// 必需的设计器变量。
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Windows 窗体设计器支持所必需的
			//
			InitializeComponent();

			//
			// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
			//
		}

		/// <summary>
		/// 清理所有正在使用的资源。
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{
			this.components = new System.ComponentModel.Container();
			this.Size = new System.Drawing.Size(300,300);
			this.Text = "Form1";
		}
		#endregion

		/// <summary>
		/// 应用程序的主入口点。
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		protected override void OnPaint(PaintEventArgs e)
		{
			Graphics g = e.Graphics;
			g.FillRectangle(Brushes.White, this.ClientRectangle);
			GraphicsPath gp;
			gp = Definegp();
			g.DrawPath(new Pen(Color.Black, 2), gp);
		}

		protected override void OnMouseMove(MouseEventArgs e)
		{
			Graphics g = CreateGraphics();
			GraphicsPath gp=new GraphicsPath();
			gp = Definegp();
			RectangleF rect = gp.GetBounds();
			bool picked= false;

			//如果拾取点位于曲线的包围矩形中
			if (rect.Contains(e.X, e.Y))
			{
				//如果拾取点在曲线的轮廓线上可见
				if (gp.IsOutlineVisible(e.X, e.Y, Pens.Black))
				{
					//则曲线被拾取
					picked = true;
				}
			}
			//曲线被拾取时用红色虚线表示，否则
			//用黑色实线表示
			if (picked)
			{
				g.DrawPath(new Pen(Color.White, 2), gp);
				Pen aPen=new Pen(Color.Red, 2);
				aPen.DashStyle = DashStyle.Dash;
				g.DrawPath(aPen, gp);
			}
			else
			{
				g.DrawPath(new Pen(Color.Black, 2), gp);
			}
		}

		private GraphicsPath Definegp()
	    {
			GraphicsPath gp=new GraphicsPath();
			//定义顶点，添加基数样条曲线到路径
			Point point1=new Point(10, 100);
			Point point2=new Point(80, 20);
			Point point3=new Point(150, 300);
			Point point4=new Point(200, 100);
			Point point5=new Point(300, 200);
			Point point6=new Point(500, 150);
			Point[] points= {point1, point2, point3, point4, point5, point6};
			gp.AddCurve(points);
			return gp;
		}
	}
}