Cg my own programs
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The document contains C code for implementing various computer graphics algorithms including line drawing algorithms like Bresenham's line drawing algorithm, DDA line drawing algorithm, and symmetrical DDA line drawing algorithm. It also contains circle drawing algorithms using trigonometric, polynomial, Bresenham's and mid-point circle algorithms. Further, it includes ellipse drawing algorithms using trigonometric and polynomial methods. Finally, it shows an implementation of the Liang-Barsky line clipping algorithm.
Cg my own programs
- 1. 1 /* Bresenham's Line drawing program */ #include<stdio.h> #include<math.h> #include<dos.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,xs,ys,xe,ye,dx,dy,x,y,d,inc1,inc2,xend,yend; float m; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter line starting & ending end points"); scanf("%d%d%d%d",&xs,&ys,&xe,&ye); dx=(xe-xs); dy=(ye-ys); if(dx==0) { x=xs; if(dy<0) { y=ye; yend=ys; } else
- 2. 2 { y=ys; yend=ye; } while(y<=yend) { delay(10); putpixel(x,y,GREEN); if(d>=0) { d=d+inc2; } else d=d+inc1; y=y+1; } } if(dx!=0) { m=(float) dy/dx; if(m<=1) { inc1=2*abs(dy); inc2=2*abs(dy-dx); d=inc1-abs(dx);
- 5. 5 else d=d+inc1; y=y+1; } }} getch(); } /* Simple DDA Line drawing program */ #include<stdio.h> #include<process.h> #include<math.h> #include<dos.h> #include<conio.h> #include<graphics.h> float round(float r) { return(r+0.5); } void main() { int gdriver=DETECT,gmode,xs,ys,xe,ye,dx,dy,length,xend,yend; float x,y,xinc,yinc; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter line starting & ending end points");
- 7. 7 printf("x=%f y=%f",x,y); if(dy>dx) length=dy; else length=dx; if(dx==0 && dy==0) { putpixel(x,y,YELLOW); getch(); exit(0); } xinc=(float)dx/length; yinc=(float)dy/length; if(dx==0) { while(y<=yend) { putpixel(floor(round(x)),floor(round(y)),RED); x=x+xinc; y=y+yinc; } } else if(dx!=0) { while(x<=xend)
- 8. 8 { putpixel(floor(round(x)),floor(round(y)),BLUE); x=x+xinc; y=y+yinc; }} getch(); } /* Symmetrical DDA Line drawing program */ #include<stdio.h> #include<process.h> #include<math.h> #include<dos.h> #include<conio.h> #include<graphics.h> float round(float r) { return(r+0.5); } void main() { int gdriver=DETECT,gmode,xs,ys,xe,ye,dx,dy,length,xend,yend; float x,y,xinc,yinc,n; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter line starting & ending end points");
- 10. 10 printf("x=%f y=%f",x,y); if(dy>dx) length=dy; else length=dx; if(dx==0 && dy==0) { putpixel(x,y,YELLOW); getch(); exit(0); } n=log(length)/log(2); xinc=(float)dx/pow(2,ceil(n)); yinc=(float)dy/pow(2,ceil(n)); if(dx==0) { while(y<=yend) { putpixel(floor(round(x)),floor(round(y)),RED); x=x+xinc; y=y+yinc; } } else if(dx!=0) {
- 11. 11 while(x<=xend) { putpixel(floor(round(x)),floor(round(y)),BLUE); x=x+xinc; y=y+yinc; }} getch(); } /* Circle drawing program using Trigonometric method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k; float xend,x,y,temp,thetainc,theta,thetaend,angle; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates and radius of circle"); scanf("%d%d%d",&h,&k,&r); temp=3.141/180; thetainc=1.0/r; theta=0; thetaend=45;
- 12. 12 while(theta<=thetaend) { angle=temp*theta; x=r*cos(angle); y=r*sin(angle); putpixel(x+h,y+k,RED); putpixel(y+h,x+k,RED); putpixel(-y+h,x+k,RED); putpixel(-x+h,y+k,RED); putpixel(-x+h,-y+k,RED); putpixel(-y+h,-x+k,RED); putpixel(y+h,-x+k,RED); putpixel(x+h,-y+k,RED); theta=theta+thetainc; } getch(); } /* Circle drawing program using Polynomial method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k;
- 13. 13 float xend,x,y; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates and radius of circle"); scanf("%d%d%d",&h,&k,&r); xend=r/1.414; x=0; y=r; while(x<=xend) { y=sqrt(r*r-x*x); putpixel(x+h,y+k,RED); putpixel(y+h,x+k,RED); putpixel(-y+h,x+k,RED); putpixel(-x+h,y+k,RED); putpixel(-x+h,-y+k,RED); putpixel(-y+h,-x+k,RED); putpixel(y+h,-x+k,RED); putpixel(x+h,-y+k,RED); x++; } getch(); }
- 14. 14 /* Circle drawing program using Bresenham's method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k,x,y,d; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates and radius of circle"); scanf("%d%d%d",&h,&k,&r); x=0; y=r; d=3-2*r; while(x<=y) { putpixel(x+h,y+k,RED); putpixel(y+h,x+k,RED); putpixel(-y+h,x+k,RED); putpixel(-x+h,y+k,RED); putpixel(-x+h,-y+k,RED); putpixel(-y+h,-x+k,RED); putpixel(y+h,-x+k,RED); putpixel(x+h,-y+k,RED);
- 15. 15 if(d<0) d=d+4*x+6; else { d=d+4*(x-y)+10; y--; } x++; } getch(); } /* Circle drawing program using Mid-Point method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k,x,y,d; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates and radius of circle"); scanf("%d%d%d",&h,&k,&r); x=0; y=r;
- 17. 17 /* Ellipse drawing program using Trigonometric method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k,a,b; float xend,x,y,temp,thetainc,theta,thetaend,angle; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates of ellipse"); scanf("%d%d",&h,&k); printf("enter major and minor axis of ellipse"); scanf("%d%d",&a,&b); temp=3.141/180; thetainc=3.141/(2*a); theta=0; thetaend=90; while(theta<=thetaend) { angle=temp*theta; x=a*cos(angle); y=b*sin(angle); putpixel(x+h,y+k,RED);
- 18. 18 putpixel(-x+h,y+k,RED); putpixel(-x+h,-y+k,RED); putpixel(x+h,-y+k,RED); theta=theta+thetainc; } getch(); } /* Ellipse drawing program using Polynomial method*/ #include<stdio.h> #include<math.h> #include<conio.h> #include<graphics.h> void main() { int gdriver=DETECT,gmode,r,h,k,a,b; float xend,x,y; clrscr(); initgraph(&gdriver,&gmode,""); printf("enter centre coordinates of ellipse"); scanf("%d%d",&h,&k); printf("enter major and minor axis of ellipse"); scanf("%d%d",&a,&b); x=0; xend=a; while(x<=xend)
- 19. 19 { y=b*sqrt(1-(x*x)/(a*a)); putpixel(x+h,y+k,RED); putpixel(-x+h,y+k,RED); putpixel(-x+h,-y+k,RED); putpixel(x+h,-y+k,RED); x++; } getch(); } Laing Barsky line clipping algorithm #include<graphics.h> #include<dos.h> #include<conio.h> #include<stdlib.h> void main() { int gd, gm ; int x1 , y1 , x2 , y2 ; int wxmin,wymin,wxmax, wymax ; float u1 = 0.0,u2 = 1.0 ; int p1 , q1 , p2 , q2 , p3 , q3 , p4 ,q4 ; float r1 , r2 , r3 , r4 ;
- 20. 20 int x11 , y11 , x22 , y22 ; clrscr(); printf("Enter the windows left xmin , top boundry yminn"); scanf("%d%d",&wxmin,&wymin); printf("Enter the windows right xmax ,bottom boundry ymaxn"); scanf("%d%d",&wxmax,&wymax); printf("Enter line x1 , y1 co-ordinaten"); scanf("%d%d",&x1,&y1); printf("Enter line x2 , y2 co-ordinaten"); scanf("%d%d",&x2,&y2); printf("liang barsky express these 4 inequalities using lpk<=qpkn"); p1 = -(x2 - x1 ); q1 = x1 - wxmin ; p2 = ( x2 - x1 ) ; q2 = wxmax - x1 ; p3 = - ( y2 - y1 ) ; q3 = y1 - wymin ; p4 = ( y2 - y1 ) ; q4 = wymax - y1 ; printf("p1=0 line is parallel to left clippingn"); printf("p2=0 line is parallel to right clippingn"); printf("p3=0 line is parallel to bottom clippingn"); printf("p4=0 line is parallel to top clippingn"); if( ( ( p1 == 0.0 ) && ( q1 < 0.0 ) ) || ( ( p2 == 0.0 ) && ( q2 < 0.0 ) ) || ( ( p3 == 0.0 ) && ( q3 < 0.0 ) ) || ( ( p4 == 0.0 ) && ( q4 < 0.0 ) ) ) {
- 21. 21 printf("Line is rejectedn"); getch(); detectgraph(&gd,&gm); initgraph(&gd,&gm,"c:tcbgi"); setcolor(RED); rectangle(wxmin,wymax,wxmax,wymin); setcolor(BLUE); line(x1,y1,x2,y2); getch(); setcolor(WHITE); line(x1,y1,x2,y2); getch(); } else { if( p1 != 0.0 ) { r1 =(float) q1 /p1 ; if( p1 < 0 ) u1 = max(r1 , u1 ); else u2 = min(r1 , u2 ); } if( p2 != 0.0 ) {
- 22. 22 r2 = (float ) q2 /p2 ; if( p2 < 0 ) u1 = max(r2 , u1 ); else u2 = min(r2 , u2 ); } if( p3 != 0.0 ) { r3 = (float )q3 /p3 ; if( p3 < 0 ) u1 = max(r3 , u1 ); else u2 = min(r3 , u2 ); } if( p4 != 0.0 ) { r4 = (float )q4 /p4 ; if( p4 < 0 ) u1 = max(r4 , u1 ); else u2 = min(r4 , u2 ); } if( u1 > u2 )
- 23. 23 printf("line rejectedn"); else { x11 = x1 + u1 * ( x2 - x1 ) ; y11 = y1 + u1 * ( y2 - y1 ) ; x22 = x1 + u2 * ( x2 - x1 ); y22 = y1 + u2 * ( y2 - y1 ); printf("Original line cordinatesn"); printf("x1 = %d , y1 = %d, x2 = %d, y2 = %dn",x1,y1,x2,y2); printf("Windows coordinate are n"); printf("wxmin = %d, wymin = %d,wxmax = %d , wymax = %d ",wxmin,wymin,wxmax,wymax); printf("New coordinates are n"); printf("x1 = %d, y1 = %d,x2 = %d , y2 = %dn",x11,y11,x22,y22); detectgraph(&gd,&gm); initgraph(&gd,&gm,"C:TCBGI"); setcolor(2); rectangle(wxmin,wymax,wxmax,wymin); setcolor(1); line(x1,y1,x2,y2); getch(); setcolor(0); line(x1,y1,x2,y2);
- 24. 24 setcolor(3); line(x11,y11,x22,y22); getch(); } } } 2d transformation #include<stdio.h> #include<conio.h> #include<math.h> #include<graphics.h> int x1,y1,x2,y2; void translation() { int tx,ty,xn1,xn2,yn1,yn2; printf("Enter the Translation Vector:"); scanf("%dn%d",&tx,&ty); cleardevice(); outtextxy(400,100,"TRANSLATION"); xn1=x1+tx; yn1=y1+ty; xn2=x2+tx; yn2=y2+ty; line(x1,y1,x2,y2); line(xn1,yn1,xn2,yn2);
- 25. 25 getch(); } void scaling() { int xn1,yn1,xn2,yn2; float sx,sy; printf("Enter the Sacling Factor:"); scanf("%f%f",&sx,&sy); cleardevice(); outtextxy(300,200,"SCALING"); xn1=x1*sx; yn1=y1*sy; xn2=x2*sx; yn2=y2*sy; line(x1,y1,x2,y2); line(xn1,yn1,xn2,yn2); getch(); } void rotation() { int r; float rx,xn1,yn1,xn2,yn2; printf("Enter the Angle for Rotation:"); scanf("%d",&r); cleardevice();
- 26. 26 outtextxy(500,200,"ROTATION"); rx=(r*3.14)/180; xn1=x1*cos(rx)-y1*sin(rx); yn1=y1*cos(rx)+x1*sin(rx); xn2=x2*cos(rx)-y2*sin(rx); yn2=y2*cos(rx)+x2*sin(rx); line(x1,y1,x2,y2); line(xn1,yn1,xn2,yn2); getch(); } void shearing() { int sh; float xn1,yn1,xn2,yn2; printf("Enter the value of Shearing"); scanf("%d",&sh); cleardevice(); outtextxy(500,100,"SHEARING"); xn1=x1+sh*y1; yn1=y1; xn2=x2+sh*y2; yn2=y2; line(x1,y1,x2,y2); line(xn1,yn1,xn2,yn2); getch();
- 28. 28 { printf("Enter the Co-ordinates x1,y1,x2,y2:"); scanf("%d%d%d%d",&x1,&y1,&x2,&y2); cleardevice(); outtextxy(200,100,"ORIGINAL OBJECT"); line(x1,y1,x2,y2); getch(); } void main() { int ch,gd=DETECT,gm; initgraph(&gd,&gm,"C:/tc/bgi"); get(); do { cleardevice(); outtextxy(10,10,"1.Translation"); outtextxy(10,20,"2.Scaling"); outtextxy(10,30,"3.Rotation"); outtextxy(10,40,"4.Shearing"); outtextxy(10,50,"5.Reflection"); outtextxy(10,60,"6.Exit"); outtextxy(10,70,"Enter Your Choice:"); scanf("%d",&ch); switch(ch)
- 29. 29 { case 1: { translation(); break; } case 2: { scaling(); break; } case 3: { rotation(); break; } case 4: { shearing(); break; } case 5: { reflection(); break;
- 30. 30 } case 6: { exit(0); break; } } } while(ch<6); } 2d Viewing Transformation #include<stdio.h> #include<conio.h> #include<graphics.h> void main() { int gm,gr,xwmin,ywmin,xwmax, ywmax,xvmin,yvmin,xvmax,yvmax,xw,yw,xv,yv,sx,sy; clrscr(); detectgraph(&gm,&gr); initgraph(&gm,&gr,"d:tcBGI"); printf("Enter the window min coordinate(xwmin,ywmin):n"); scanf("%d%d",&xwmin,&ywmin); printf("Enter the window max coordinate(xwmax,ywmax):n");
- 31. 31 scanf("%d%d",&xwmax,&ywmax); printf("Enter the viewport min coordinate(xvmin,yvmin):n"); scanf("%d%d",&xvmin,&yvmin); printf("Enter the viewport max coordinate(xvmax,yvmax):n"); scanf("%d%d",&xvmax,&yvmax); sx=(xvmax-xvmin)/(xwmax-xwmin); sy=(yvmax-yvmin)/(ywmax-ywmin); printf("Enter the point coordinate(xw,yw) in the window:n"); scanf("%d%d",&xw,&yw); xv=(sx*(xw-xwmin))+xvmin; yv=(sy*(yw-ywmin))+yvmin; cleardevice(); getch(); rectangle(xwmin,ywmax,xwmax,ywmin); putpixel(xw,yw,15); getch(); cleardevice();getch(); rectangle(xvmin,yvmax,xvmax,yvmin); putpixel(xv,yv,15); getch(); }