cline.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;

namespace VCSharp
{
	/// <summary>
	/// CLine 的摘要说明。
	/// </summary>
	/// 

	//直线段类
	public class CLine:CGElement
	{
		protected PointF m_Begin;
		protected PointF m_End;
		Module m=new Module();

		public PointF LBegin
		{
			get{return m_Begin;}
			set{m_Begin=value;}
		}

		public PointF LEnd
		{
			get{return m_End;}
			set{m_End=value;}
		}

		public CLine()
		{
            Init();
		}

		public CLine(PointF pBegin,PointF pEnd)
		{
			Init();
			m_Begin=pBegin;
			m_End=pEnd;
		}

		public CLine(CLine aline)
		{
			m_Begin=aline.LBegin;
			m_End=aline.LEnd;
		}

		private new void Init()
		{
			base.Init();
			m_Begin=new PointF(0,0);
			m_End=new PointF(0,0);
		}

		//绘直线段
		override  public void Draw(Graphics g,DrawMode aDrawMode)
		{
			long aPen,oldP;

			//将控制点的坐标由世界坐标转换为页面坐标
			PointF eb=m.WorldtoPage(m_Begin);
			PointF ee=m.WorldtoPage(m_End);

			//获得当前绘图环境的句柄
			IntPtr hdc=g.GetHdc();

			//设置画笔参数
			int[] penPara=DrawSettings(hdc,aDrawMode);
			//创建画笔
			aPen=Win32API.CreatePen(penPara[0],penPara[1],penPara[2]);
			//把画笔选入绘图环境，并返回原来的画笔
			oldP=Win32API.SelectObject(hdc,aPen);
			Win32API.LPPOINT prePos=new Win32API.LPPOINT();
		    //把画笔移动到直线段的起点处
	        Win32API.MoveToEx(hdc, (int)(eb.X), (int)(eb.Y), prePos);
	        //绘直线段到终点
	        Win32API.LineTo(hdc, (int)(ee.X), (int)(ee.Y));
			//把原来的画笔选入绘图环境
			Win32API.SelectObject(hdc, oldP);
			//删除新创建的画笔
			Win32API.DeleteObject(aPen);
			//释放绘图环境句柄
			g.ReleaseHdc(hdc);
		}
	}
}