Program to implement Polygon Clipping Algorithm

Program to implement Polygon Clipping Algorithm #include<iostream.h> #include<conio.h> #include<math.h> #include<graphics.h> #include<dos.h> #include<process.h> int pixels[2][4]; float xn1,xn2,yn1,yn2,x3,y3,m; void show_quadrant() { cleardevice(); rectangle(120,40,320,240); rectangle(320,40,520,240); rectangle(120,240,320,440); rectangle(320,240,520,440); for(int i=130;i<=510;i+=10) { if(i==320) continue; outtextxy(i,237,"+"); } for(i=50;i<=430;i+=10) { if(i==240) continue; outtextxy(317,i,"-"); } outtextxy(310,230,"O"); outtextxy(530,240,"X"); outtextxy(320,450,"-Y"); outtextxy(100,240,"-X"); outtextxy(320,30,"Y"); } void midpt(int x1,int y1,int x2,int y2,int xmin,int ymin,int xmax,int ymax) { int fl=1; int pixels[2][4],i,j; for(i=0;i<2;i++) for(j=0;j<4;j++) pixels[i][j]=0; if(y1>ymax) pixels[0][0]=1; if(y1<ymin) pixels[0][1]=1; if(x1>xmax) pixels[0][2]=1; if(x1<xmin) pixels[0][3]=1; if(y2>ymax) pixels[1][0]=1; if(y2<ymin) pixels[1][1]=1; if(x2>xmax) pixels[1][2]=1; if(x2<xmin) pixels[1][3]=1; for(j=0;j<4;j++) { if(pixels[0][j]==0&&pixels[1][j]==0) continue; if(pixels[0][j]==1&&pixels[1][j]==1) { fl=3; break; } fl=2; } switch(fl) { case 1: line(320+x1,240-y1,320+x2,240-y2); break; case 3: cout<<" a" Line Is Not Visible...:-("; break; case 2: int ox1=x1,ox2=x2,oy1=y1,oy2=y2; xn1=x1; yn1=y1; xn2=x2; yn2=y2; fl=0; x3=x1; y3=y1; while(1) { if(!(y1>ymax || y1<ymin || x1>xmax || x1<xmin) && (x3 || y3)!=0.1) break; x3=(x1+x2)/2.0; y3=(y1+y2)/2.0; if(!(y3>ymax || y3<ymin || x3>xmax || x3<xmin)) fl=1; else fl=0; if(fl) { x2=x3; y2=y3; } else { x1=x3; y1=y3; } } xn1=x3; yn1=y3; fl=0; x1=ox1; x2=ox2; y1=oy1; y2=oy2; x3=x2; y3=y2; while(1) { if(!(y2>ymax || y2<ymin || x2>xmax || x2<xmin) && (x3 || y3)!=0.1) break; x3=(x1+x2)/2.0; y3=(y1+y2)/2.0; if(!(y3>ymax || y3<ymin || x3>xmax || x3<xmin)) fl=1; else fl=0; if(fl) { x1=x3; y1=y3; } else { x2=x3; y2=y3; } } xn2=x3; yn2=y3; line(320+xn1,240-yn1,320+xn2,240-yn2); break; } } void show_message() { char *mess[]={"-","=","["," ","P","o","l","y","g","o","n"," ", "C","l","i","p","p","i","n","g"," ","]","=","-"}; int xx=28,xxx=52,i,j; _setcursortype(_NOCURSOR); for(i=0,j=24;i<16,j>=12;i++,j--) { gotoxy(xx,1); cout<<mess[i]; xx++; gotoxy(xxx,1); cout<<mess[j]; xxx--; delay(50); } _setcursortype(_NORMALCURSOR); } void main() { clrscr(); int gd=DETECT,gm,i,j; int xmin,ymin,xmax,ymax,x[10],y[10],ver; int choice,ed[20],num; show_message(); cout<<" " Enter The Co-Ordinates Of The Clipping Window.""; cout<<" " Enter X(min) & Y(min) ":="; cin>>xmin>>ymin; cout<<" " Enter X(max) & Y(max) ":="; cin>>xmax>>ymax; cout<<" " Enter The No Of Vertices Of Polygon ":="; cin>>ver; for(i=0;i<ver;i++) { cout<<" " Vertex X["<<i+1<<"] Y["<<i+1<<"] ":="; cin>>x[i]>>y[i]; } x[ver]=x[0]; y[ver]=y[0]; clrscr(); initgraph(&gd,&gm,"..\bgi"); clearviewport(); show_quadrant(); line(320+xmin,240-ymin,320+xmin,240-ymax); line(320+xmin,240-ymax,320+xmax,240-ymax); line(320+xmax,240-ymax,320+xmax,240-ymin); line(320+xmax,240-ymin,320+xmin,240-ymin); for(i=0;i<ver;i++) line(320+x[i],240-y[i],320+x[i+1],240-y[i+1]); getch(); cleardevice(); show_quadrant(); line(320+xmin,240-ymin,320+xmin,240-ymax); line(320+xmin,240-ymax,320+xmax,240-ymax); line(320+xmax,240-ymax,320+xmax,240-ymin); line(320+xmax,240-ymin,320+xmin,240-ymin); for(i=0;i<ver;i++) { midpt(x[i],y[i],x[i+1],y[i+1],xmin,ymin,xmax,ymax); } getch(); closegraph(); }