我们计算机图形学老师发飙了~求帮助~帮我注释一下就成~主要是DDA，Bresenham等基本算法
这课我一点也不会~老是留了作业，让我们编好程序之后，再给老师讲解。我啥也不会，从我们同学那儿要了份代码过来，但是我看不懂。这样下去，到时候老师让我讲我也讲不出来，所以希望坛子里的兄弟们帮我看看这段代码，告诉我到时候怎么给老师说啊~~谢谢了
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WindowsApplication1
{
public partial class Form1 : Form
{
private bool draw;
private int type;
[DllImport("gdi32.dll")]
private static extern int SetPixel(IntPtr hdc, int x1, int y1, int color);
public Form1()
{
InitializeComponent();
}
private uint RGB(Color color)
{
uint R = color.R;
uint G = color.G;
uint B = color.B;
G <<= 8;
B <<= 16;
return ((uint)(R | G | B));
}
//各种图形算法==============================================================================================
//DDA
private void DDA(int x1, int y1, int x2, int y2, Color color, Graphics g)
{
float x, y, xincre, yincre;
int k, i;
k = Math.Abs(x2 - x1);
if (Math.Abs(y2 - y1) > k)
k = Math.Abs(y2 - y1);
xincre = (float)(x2 - x1) / (float)k;
yincre = (float)(y2 - y1) / (float)k;
x = x1;
y = y1;
for (i = 1; i <= k; i++)
{
SetPixel(g.GetHdc(), (int)x, (int)y, (int)RGB(color));
g.ReleaseHdc();
x += xincre;
y += yincre;
}
}
//Bresenham
private void Bresenham(Graphics g, int x1, int y1, int x2, int y2, Color c)
{
int dx, dy, x, y, p, const1, const2, inc, tmp;
dx = x2 - x1;
dy = y2 - y1;
if (dx * dy >= 0)
inc = 1;
else
inc = -1;
if (Math.Abs(dx) > Math.Abs(dy))
{
if (dx < 0)
{
tmp = x1;
x1 = x2;
x2 = tmp;
tmp = y1;
y1 = y2;
y2 = tmp;
dx = -dx;
if (dy < 0)
{
dy = -dy;
}
}
p = 2 * dy - dx;
const1 = 2 * dy;
const2 = 2 * (dy - dx);
x = x1;
y = y1;
SetPixel(g.GetHdc(), x, y, (int)RGB(c));
g.ReleaseHdc();
while (x < x2)
{
x++;
if (p < 0)
p += const1;
else
{
y += inc;
p += const2;
}
SetPixel(g.GetHdc(), x, y, (int)RGB(c));
g.ReleaseHdc();
}
}
else
{
if (dy < 0)
{
tmp = x1;
x1 = x2;
x2 = tmp;
tmp = y1;
y1 = y2;
y2 = tmp;
if (dx < 0)
{
dx = -dx;
}
dy = -dy;
}
p = 2 * dx - dy;
const1 = 2 * dx;
const2 = 2 * (dx - dy);
x = x1;
y = y1;
SetPixel(g.GetHdc(), x, y, (int)RGB(c));
g.ReleaseHdc();
while (y < y2)
{
y++;
if (p < 0)
p += const1;
else
{
x += inc;
p += const2;
}
SetPixel(g.GetHdc(), x, y, (int)RGB(c));
g.ReleaseHdc();
}
}
}
//midcircle
private void midcircle(Graphics g, int xc, int yc, int r,Color c)
{
int x;
int y;
int p;
x=0;
y=r;
p=1-4*r;
while(x<y)
{
circlepoint(g,xc, yc, x, y, c);
if(p<0)
{
p+=8*x+12;
}
else
{
p+=8*(x-y)+20;
y--;
}
x++;
}
}
private void circlepoint(Graphics g,int xc, int yc, int x,int y, Color c)
{
SetPixel(g.GetHdc(), xc+x, yc+y, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc-x, yc+y, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc+x, yc-y, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc-x, yc-y, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc+y, yc+x, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc-y, yc+x, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc+y, yc-x, (int)RGB(c));
g.ReleaseHdc();
SetPixel(g.GetHdc(), xc-y, yc-x, (int)RGB(c));
g.ReleaseHdc();
}
//pictureBox==============================================================================================
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Graphics g=e.Graphics;
if (draw)
{
switch (type)
{
case 1:
DDA(20, 50, 680, 580, Color.Blue, g);
break;
case 2:
Bresenham(e.Graphics, 200, 0, 200, 300, Color.OrangeRed);
Bresenham(e.Graphics, 0, 150, 400, 150, Color.OrangeRed);
Bresenham(e.Graphics, 0, 0, 400, 300, Color.Black);
Bresenham(e.Graphics, 400, 0, 0, 300, Color.Black);
Bresenham(e.Graphics, 200, 150, 380, 200, Color.Blue);
Bresenham(e.Graphics, 200, 150, 270, 310, Color.Blue);
Bresenham(e.Graphics, 200, 150, 50, 200, Color.SeaGreen);
Bresenham(e.Graphics, 100, 280, 200, 150, Color.SeaGreen);
Bresenham(e.Graphics, 150, 0, 200, 150, Color.Purple);
Bresenham(e.Graphics, 50, 100, 200, 150, Color.Purple);
Bresenham(e.Graphics, 200, 150, 250, 30, Color.Red);
Bresenham(e.Graphics, 350, 100, 200, 150, Color.Red);
break;
case 3:
midcircle(g,200, 200, 60, Color.Red);
break;
default:
break;
}
}
}
//控件响应==============================================================================================
private void button1_Click(object sender, EventArgs e)
{
draw = true;
type = 1;
pictureBox1.Invalidate();
}
private void button3_Click(object sender, EventArgs e)
{
draw = true;
type = 2;
pictureBox1.Invalidate();
}
private void button4_Click(object sender, EventArgs e)
{
draw = true;
type = 3;
pictureBox1.Invalidate();
}
//退出==============================================================================================
private void button2_Click(object sender, EventArgs e)
{
this.Close();
Application.Exit();
}
}
}
