逐点比较法.docx

#include "conio.h"
#include "graphics.h"
#include"stdlib.h"

void cb_line(int x1,int y1,int x2,int y2)
{
int dx,dy,n,k,i,f;
int x,y;

dx=abs(x2-x1);
dy=abs(y2-y1);
n=dx+dy;
x=x1;
y=y1;
if(x2>=x1)
k=y2>=y1?1:4;
else
k=y2>=y1?2:3;

putpixel(x,y,GREEN);
f=0;
for(i=0;i<n;i++)
{
if(f>=0)
switch(k){
case 1:putpixel(x++,y,GREEN); f-=dy;break;
case 2:putpixel(x,y++,GREEN); f-=dx;break;
case 3:putpixel(x--,y,GREEN); f-=dy;break;
case 4:putpixel(x,y--,GREEN); f-=dx;break;
}
else
switch(k){
case 1:putpixel(x,y++,GREEN);f+=dx;break;
case 2:putpixel(x--,y,GREEN);f+=dy;break;
case 3:putpixel(x,y--,GREEN);f+=dx;break;
case 4:putpixel(x++,y,GREEN);f+=dy;break;
}

delay(2000);
}
}
void main()
{
int x1,y1,x2,y2;
int gdriver, gmode;

detectgraph(&gdriver, &gmode);
initgraph(&gdriver,&gmode,"");

cleardevice();
setbkcolor(WHITE);

x1=30;
y1=350;
x2=500;
y2=20;
setcolor(RED);
line(x1,y1,x2,y2);
cb_line(x1,y1,x2,y2);

getch();
closegraph();
}