计算机图形学 直线裁剪代码.doc

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;namespace LineCut_Cohen public partial class Form1 : Form public Form1() InitializeComponent(); /定义钻石参数 int x0 = 100; int y0 = 100; int n = 13; int r = 50; int x; int y; / /计算钻石顶点 by tiantian / public void ZuanShi() float t = (float)3.14159 * 2 / n; x = new intn; y = new intn; for (int i = 0; i n; i+) xi = (int)(r * Math.Cos(i * t) + x0); yi = (int)(r * Math.Sin(i * t) + y0); / /计算点(x,y)的编码 / void CompOutCode(int x, int y, Rectangle rect, OutCode outCode) outCode.all = 0; outCode.top = outCode.bottom = 0; if (y rect.Bottom)/rect类的bottom相当于我们惯常用的坐标系的top by:tiantian outCode.top = 1; outCode.all += 1; outCode.right = outCode.left = 0; if (x rect.Right) outCode.right = 1; outCode.all += 1; else if (x rect.Left) outCode.left = 1; outCode.all += 1; / /线段裁剪，p0(x0,y0),p1(x1,y1)为待裁剪线断，rect为裁剪窗口 / bool ChoenSutherlandLineClip(ref int x0, ref int y0, ref int x1, ref int y1, Rectangle rect) /这里必须是引用传递！by:tiantian Boolean accept, done; OutCode outCode0 = new OutCode(); OutCode outCode1 = new OutCode(); OutCode outCodeOut = new OutCode(); int x = 0; int y = 0; accept = false; done = false; CompOutCode(x0, y0, rect, outCode0); CompOutCode(x1, y1, rect, outCode1); do int code0 = outCode0.Code(); int code1 = outCode1.Code(); if (outCode0.all = 0) & (outCode1.all = 0) /完全可见 accept = true; done = true; else if (code0 & code1) != 0) /显然不可见 by tt done = true; else /进行求交测试 if (outCode0.all != 0) /判断哪一点位于窗口之外 outCodeOut = outCode0; else outCodeOut = outCode1; if (outCodeOut.left = 1)/线段与窗口的左边相交 x = rect.Left; y = y0 + (y1 - y0) * (x - x0) / (x1 - x0); else if (outCodeOut.right = 1)/线段与窗口的右边相交 x = rect.Right; y = y0 + (y1 - y0) * (x - x0) / (x1 - x0); else if (outCodeOut.top = 1)/线段与窗口的上边相交 y = rect.Bottom; x = x0 + (x1 - x0) * (y - y0) / (y1 - y0); else if (outCodeOut.bottom = 1)/线段与窗口的下边相交 y = rect.Top; x = x0 + (x1 - x0) * (y - y0) / (y1 - y0); /以交点为界，将线段位于窗口边所在的直线的外侧的部分丢弃。 /对剩余的继续裁剪 if (outCodeOut.all = outCode0.all) x0 = x; y0 = y; CompOutCode(x0, y0, rect, outCode0); else x1 = x; y1 = y; CompOutCode(x1, y1, rect, outCode1); while (!done); return accept; / /画图函数 / private void Form1_Paint_1(object sender, PaintEventArgs e) Graphics g = e.Graphics; Pen myPen = new Pen(Color.Blue, 1f); g.Clear(Color.Black); ZuanShi(); for (int i = 0; i = n - 2; i+) for (int j = i + 1; j = n - 1; j+) g.DrawLine(myPen, xi, yi, xj, yj); / /裁剪按钮 / private void button1_Click(object sender, EventArgs e) /定义矩形 Point p = new Point(50, 50); Size size = new Size(50, 50); Rectangle rect = new Rectangle(p, size); Graphics g = this.CreateGraphics(); Pen myPen = new Pen(Color.Yellow, 1f); g.Clear(Color.Black); ZuanShi(); int xi, xj, yi, yj;/用来存储顶点值的变量 by tiantian for (int i = 0; i = n - 2; i+) for (int j = i + 1; j = n - 1; j+) xi = xi; xj = xj;/裁剪函数为引用传递，会改变顶点的值，先把这些值存储起来 by:tiantian yi = yi; yj = yj; if (ChoenSutherlandLineClip(ref xi, ref yi, ref xj, ref yj, rect) g.DrawLine(myPen, xi, yi, xj, yj); xi = xi; xj = xj;/恢复顶点值 yi = yi; yj = yj; private void button2_Click(object sender, EventArgs e) Graphics g = this.CreateGraphics(); Pen myPen = new Pen(Color.Blue, 1f); g.Clear(Color.Black); ZuanShi(); for (int i = 0; i = n - 2; i+) for (int j = i + 1; j = n - 1; j+) g.DrawLine(myPen, xi, yi, xj, yj); using System;using System.Collections.Generic;using System.Text;namespace LineCut_Cohen class OutCode /顶点编码值类 b