中点画直线算法 (11)

中点画直线算法 (11) /* Cohen-Sutherland Ö?Ïß?Ã?ôËã?? */ #include "graphics.h" #include "stdio.h" #include "conio.h" int left=100, right=200, bottom=180, top=50; // ???Ú?ß?ò int a[4], b[4], c[4]; main() { void line_clip(); void getcode(int x, int y, int d[4]); // ??Òå?ñµÃ?˵ãµÄ?úÂëº?Êý int gd=DETECT, gm; int stratx, straty, endx, endy, left, top, right, bottom; int a1, b1, a2, b2, x, y; char ch; initgraph(&gd, &gm, "D:\\TC"); a1=60; b1=40; a2=170; b2=300; stratx=100; straty=50; // Ö?ÏßµÄÆðµã endx=200; endy=180; // Ö?ÏßµÄÖÕµã getcode(a1, b1, a); getcode(a2, b2, b); printf("\n\n\n\n\n\n\n\n\n\n\t\t\t the code of point P1 is:\n"); printf("\t\t\t a[0]=%d, a[1]=%d, a[2]=%d, a[3]=%d\n\n", a[0], a[1], a[2], a[3]); printf("\t\t\t the code of point P2 is:\n"); printf("\t\t\t b[0]=%d, b[1]=%d, b[2]=%d, b[3]=%d", b[0], b[1], b[2], b[3]); setcolor(15); rectangle(stratx, straty, endx, endy); // Éè??Ò??ØÐÎ???Ú line(a1, b1, a2, b2); getch(); line_clip(a1, b1, a2, b2, stratx, straty, endx, endy); // ?????ÚÖ?ÍâµÄÏß?Î?Ã?ôµô setcolor(15); setlinestyle(0, 0, 1); rectangle(stratx, straty, endx, endy); getch(); closegraph(); } /*********?Ã?ôº?Êý************/ void line_clip(int x1, int y1, int x2, int y2, int left,int top,int right, int bottom) { void getcode(int x, int y, int d[4]); int i, x11, y11; // ??Òå??µã×ø?ê int aa=1; getcode(x1, y1, a); getcode(x2, y2, b); // 1?º?Ã?ôÑ,???ªÊ? while(aa!=0){ if((a[0]+a[1]+a[2]+a[3]==0)&&(b[0]+b[1]+b[2]+b[3]==0)){ // Ïß?ÎÍêÈ??É?û aa=0; return; } else if((a[0]&&b[0])+(a[1]&&b[1])+(a[2]&&b[2])+(a[3]&&b[3])!=0){ // Ïß?ÎÍêÈ????É?û setcolor(0); setwritemode(0); // ÉèÖÃ?,ÏßµÄÊä?öÄ?Ê?Ϊ???Ç??Ê? line(x1, y1, x2, y2); aa=0; return; } // 2?ºÏß?Î?È??ÍêÈ??É?û??Ò???ÍêÈ????É?û????Óë?ßÓÐ??µãµÄÏß?εÄ?Ã?ô??Àí else{ if(a[0]+a[1]+a[2]+a[3]==0){ // Ñ?ÕÒ???É?ûµã for(i=0; i<4; i++) c[i]=b[i]; // x2,y2Ϊ???É?ûµã } else{ for(i=0; i<4; i++) c[i]=a[i]; // x1,y1Ϊ???É?ûµã } // 3?ºÖ?ÏßÓë???Ú?ß×?Çó??ÔËËã??Çó?ö??µã??Öµ?øx11??y11 if(c[0]==1){ x11=left; y11=(int)((y2-y1)*(left-x1)/(x2-x1)+y1); } else if(c[1]==1){ x11=right; y11=(int)((y2-y1)*(right-x1)/(x2-x1)+y1); } else if(c[2]==1){ x11=(int)((x2-x1)*(bottom-y1)/(y2-y1)+x1); y11=bottom; } else if(c[3]==1){ x11=(int)((x2-x1)*(top-y1)/(y2-y1)+x1); y11=top; } // 3?ºÇó??ÔËËã?áÊø if((c[0]==a[0])&&(c[1]==a[1])&&(c[2]==a[2])&&(c[3]==a[3])){ setcolor(0); setlinestyle(0, 0, 3); setwritemode(0); line(x1, y1, x11, y11); x1=x11; y1=y11; getcode(x11, y11, a); getch(); } else if((c[0]==b[0])&&(c[1]==b[1])&&(c[2]==b[2])&&(c[3]==b[3])){ setcolor(0); setlinestyle(0, 0, 3); setwritemode(0); line(x2, y2, x11, y11); x2=x11; y2=y11; getcode(x11, y11, b); getch(); } } // 2?ºÓë?ßÓÐ??µãµÄÏß?Î?Ã?ô??Àí?áÊø } // 1?º?Ã?ôÑ,???áÊø } void getcode(int x, int y, int d[4]) { d[0]=0; d[1]=0; d[2]=0; d[3]=0; if(xright) d[1]=1; if(y>bottom) d[2]=1; if(y