cohen.bak

line clipping algorithm

//Implementation of Cohen-Sutherland Line Clipping Algorithm

#include <stdio.h>
#include <conio.h>
#include <graphics.h>

int Left=0,Right=1,Top=2,Bottom=3;
int wx1,wy1,wx2,wy2;

int getCode(int x,int y){
	int code=0;
	if(x<wx1) code+=(1<<Left);
	else if(x>wx2) code+=(1<<Right);
	if(y<wy1) code+=(1<<Top);
	else if(y>wy2) code+=(1<<Bottom);
	return code;
}

int Clip(int &x1,int &y1,int x2,int y2){
	float m,tx,ty;
	int code1,code2;

	m=(y2-y1)/(float)(x2-x1);

	code1=getCode(x1,y1);

	while(code1!=0){
		//Check Left Boundary
		if(code1&(1<<Left)){
			tx=wx1-x1;
			ty=y1+(tx*m);
			x1=wx1; y1=ty;
			printf("\nClipping on Left: %d, %d",x1,y1);
			code1=getCode(x1,y1);
		}

		//Check Right Boundary
		if(code1&(1<<Right)){
			tx=wx2-x1;
			ty=y1+(tx*m);
			x1=wx2; y1=ty;
			printf("\nClipping on Right: %d, %d",x1,y1);
			code1=getCode(x1,y1);
		}

		//Check Top Boundary
		if(code1&(1<<Top)){
			ty=wy1-y1;
			tx=x1+(ty/m);
			x1=tx; y1=wy1;
			printf("\nClipping on Top: %d, %d",x1,y1);
			code1=getCode(x1,y1);
		}

		//Check Bottom Boundary
		if(code1&(1<<Bottom)){
			ty=wy2-y1;
			tx=x1+(ty/m);
			x1=tx; y1=wy2;
			printf("\nClipping on Bottom: %d, %d",x1,y1);
			code1=getCode(x1,y1);
		}

		code2=getCode(x2,y2);
		if((code2&code1)!=0) return 0;
	}
	return 1;
}

int main(){
	int x1,y1,x2,y2;
	int code1,code2,flag;
	int gdriver=VGA,gmode=VGAHI;
	initgraph(&gdriver,&gmode,"");

	printf("\n C o h e n   S u t h e r l a n d   L i n e   C l i p p i n g   A l g o r i t h m");
	printf(" 哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪哪