C graphics program to shear a rectangle

#include<graphics.h>
#include<conio.h>
void main()
{
int gd=DETECT,gm,option,xref,yref;
int i,maxx,maxy,x1,y1,x2,y2,x3,y3,x4,y4,gap=50;
float shx=0.0,shy=0.0;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("enter the  endpoints of the top of the rectangle (x1,y1) & (x2,y2):");
 scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
 printf("enter the endpoints of bottom of the rectangle (x3,y3) & (x4,y4)");
 scanf("%d%d%d%d",&x3,&y3,&x4,&y4);
 printf(" Enter the axis to shear\n");
 printf(" 1 - X axis Shear\n");
 printf(" 2 - Y axis shear\n");
 scanf("%d",&option );
 if(option==1)
 {
 printf("enter the value for x-axis shear( can be fraction too):");
 scanf("%f",&shx);
 }
 else
 {
 printf("enter the value for y-axis shear( can be fraction too):");
 scanf("%f",&shy);
 }

clearviewport();
maxx= getmaxx();
maxy=getmaxy();
line(3,maxy-1,maxx-5,maxy-1);
line(5,5,5,maxy-3);

for( i= 0;i<maxx-5;i=i+gap)              // code to display co-ordinates
{
outtextxy(i+3,maxy-7,"|");
itoa(i,str,10);
outtextxy(i,maxy-10,str);
}
for( i= maxy;i>0;i=i-gap)
{
outtextxy(3,i,"-");
itoa(maxy-i,str,10);
outtextxy(9,i,str);

}
 setcolor(50);                // drawing rectangle using endpoints
 line(x1,maxy-y1,x2,maxy-y2);
 line(x3,maxy-y3,x4,maxy-y4);
 line(x1,maxy-y1,x3,maxy-y3);
 line(x2,maxy-y2,x4,maxy-y4);
 outtextxy(10,10,"hit any key to see the shearing effect" );
 getch();
 setcolor(0);    // to hide the rectangle drawn
  line(x1,maxy-y1,x2,maxy-y2);
  line(x3,maxy-y3,x4,maxy-y4);
  line(x1,maxy-y1,x3,maxy-y3);
  line(x2,maxy-y2,x4,maxy-y4);

   setcolor(58);    // to redraw the rectangle
 if(option==1)
  {
  // shearing about x axis so only  points x1 and x2 need to be recomputed
  line(x1+shx*y1,maxy-y1,x2+shx*y2,maxy-y2);
  line(x3,maxy-y3,x4,maxy-y4);
  line(x1+shx*y1,maxy-y1,x3,maxy-y3);
  line(x2+shx*y2,maxy-y2,x4,maxy-y4);

 }
 else
 {
   // shearing about y axis so only  points y2 and y4 need to be recomputed
  line(x1,maxy-y1,x2,maxy-(y2+shy*x2));
  line(x3,maxy-y3,x4,maxy-(y4+shy*x4));
  line(x1,maxy-y1,x3,maxy-y3);
  line(x2,maxy-(y2+shy*x2),x4,maxy-(y4+shy*x4));

 }
 getch();
 closegraph();
}

 
        Original Image             Shearing w.r.t  Y - axis     Shearing w.r.t  X - axis   

Sample Input
    x1 ,y1, x2, y2 : 200 200 300 200
    x3, y3, x4, y4 : 200 100 300 100  
x- shear value: any value even fractional ( eg 0.4)
y- shear value: any value even fractional ( eg 0.5)

C graphics program to display smiling face

/* Computer C Graphics Program to display smiling face */



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

void main()
{
   int gd = DETECT, gm, area, temp1, temp2, left = 25, top = 75;
   void *p;

   initgraph(&gd,&gm,"..\\bgi");

   setcolor(YELLOW);
   circle(50,100,25);
   setfillstyle(SOLID_FILL,YELLOW);
   floodfill(50,100,YELLOW);

   setcolor(RED);
   setfillstyle(SOLID_FILL,RED);
   fillellipse(44,85,2,6);
   fillellipse(56,85,2,6);

   ellipse(50,100,205,335,20,9);
   ellipse(50,100,205,335,20,10);
   ellipse(50,100,205,335,20,11);

   area = imagesize(left, top, left + 50, top + 50);
   p = malloc(area);

   setcolor(WHITE);
   settextstyle(SANS_SERIF_FONT,HORIZ_DIR,2);
   outtextxy(155,451,"Smiling Face Animation");

   setcolor(BLUE);
   rectangle(0,0,639,449);

   while(!kbhit())
   {
      temp1 = 1 + random ( 588 );
      temp2 = 1 + random ( 380 );

      getimage(left, top, left + 50, top + 50, p);
      putimage(left, top, p, XOR_PUT);
      putimage(temp1 , temp2, p, XOR_PUT);
      delay(200);
      left = temp1;
      top = temp2;
      delay(200);
   }

   getch();
   closegraph();
}

Program to display circles within circle

/* Program to display circles within circle */



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

void main()
{
   int gd = DETECT, gm, x, y, color, angle = 0;
   struct arccoordstype a, b;

   initgraph(&gd, &gm, "..\\bgi");
   delay(2000);

   while(angle<=360)

   {
   setcolor(BLACK);
      arc(getmaxx()/2,getmaxy()/2,angle,angle+2,50);
      setcolor(BLUE);
      getarccoords(&a);
      circle(a.xstart,a.ystart,25);
      setcolor(BLACK);
      arc(getmaxx()/2,getmaxy()/2,angle,angle+2,100);
      setcolor(RED);
      getarccoords(&a);
      circle(a.xstart,a.ystart,25);
      setcolor(BLACK);
      arc(getmaxx()/2,getmaxy()/2,angle,angle+2,150);
      getarccoords(&a);
      setcolor(GREEN);
      circle(a.xstart,a.ystart,25);
      angle = angle+5;
      delay(50);
   }

   getch();
   closegraph();
   }

C graphics program to simulate a Traffic light

/* This program will simulate a traffic light */

#include<graphics.h>
#include<conio.h>
#include<dos.h>
#include<stdlib.h>

main()
{
   int gd = DETECT, gm, midx, midy;

   initgraph(&gd, &gm, "..\\bgi");

   midx = getmaxx()/2;
   midy = getmaxy()/2;

   setcolor(RED);
   settextstyle(SCRIPT_FONT, HORIZ_DIR, 3);
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(midx, midy-10, "Traffic Light Simulation");
   outtextxy(midx, midy+10, "Press any key to start");
   getch();
   cleardevice();
   setcolor(WHITE);
   settextstyle(DEFAULT_FONT, HORIZ_DIR, 1);
   rectangle(midx-30,midy-80,midx+30,midy+80);
   circle(midx, midy-50, 22);
   setfillstyle(SOLID_FILL,RED);
   floodfill(midx, midy-50,WHITE);
   setcolor(BLUE);
   outtextxy(midx,midy-50,"STOP");
   delay(1000);
   graphdefaults();
   cleardevice();
   setcolor(WHITE);
   rectangle(midx-30,midy-80,midx+30,midy+80);
   circle(midx, midy, 20);
   setfillstyle(SOLID_FILL,YELLOW);
   floodfill(midx, midy,WHITE);
   setcolor(BLUE);
   outtextxy(midx-18,midy-3,"READY");

   delay(2000);
   cleardevice();
   setcolor(WHITE);
   rectangle(midx-30,midy-80,midx+30,midy+80);
   circle(midx, midy+50, 22);
   setfillstyle(SOLID_FILL,GREEN);
   floodfill(midx, midy+50,WHITE);
   setcolor(BLUE);
   outtextxy(midx-7,midy+48,"GO");
   setcolor(RED);
   settextstyle(SCRIPT_FONT, HORIZ_DIR, 4);
   outtextxy(midx-150, midy+100, "Press any key to exit...");

   getch();
   closegraph();
   return 0;
}

C graphics program to simulate Solar system

 /* This program will simulate a Solar system */

#include<stdio.h>
#include<graphics.h>
#include<conio.h>
#include<math.h>
#include<dos.h>
void main()
{
int i=0,j=260,k=30,l=150,m=90;
int n=230,o=10,p=280,q=220;
float pi=3.1424,a,b,c,d,e,f,g,h,z;
int gd=DETECT,gm;
initgraph(&gd,&gm,"..\\bgi");
outtextxy(0,10,"SOLAR SYSTEM");
outtextxy(500,10,"press any key...");
circle(320,240,20);               /* sun */
setfillstyle(1,4);
floodfill(320,240,15);
outtextxy(310,237,"sun");
circle(260,240,8);
setfillstyle(1,2);
floodfill(258,240,15);
floodfill(262,240,15);
outtextxy(240,220,"mercury");
circle(320,300,12);
setfillstyle(1,1);
floodfill(320,298,15);
floodfill(320,302,15);
outtextxy(335,300,"venus");
circle(320,160,10);
setfillstyle(1,5);
floodfill(320,161,15);
floodfill(320,159,15);
outtextxy(332,150, "earth");
circle(453,300,11);
setfillstyle(1,6);
floodfill(445,300,15);
floodfill(448,309,15);
outtextxy(458,280,"mars");
circle(520,240,14);
setfillstyle(1,7);
floodfill(519,240,15);
floodfill(521,240,15);
outtextxy(500,257,"jupiter");
circle(169,122,12);
setfillstyle(1,12);
floodfill(159,125,15);
floodfill(175,125,15);
outtextxy(130,137,"saturn");
circle(320,420,9);
setfillstyle(1,13);
floodfill(320,417,15);
floodfill(320,423,15);
outtextxy(310,400,"urenus");
circle(40,240,9);
setfillstyle(1,10);
floodfill(38,240,15);
floodfill(42,240,15);
outtextxy(25,220,"neptune");
circle(150,420,7);
setfillstyle(1,14);
floodfill(150,419,15);
floodfill(149,422,15);
outtextxy(120,430,"pluto");
getch();
while(!kbhit())             /*animation*/
{
a=(pi/180)*i;
b=(pi/180)*j;
c=(pi/180)*k;
d=(pi/180)*l;
e=(pi/180)*m;
f=(pi/180)*n;
g=(pi/180)*o;
h=(pi/180)*p;
z=(pi/180)*q;
cleardevice();
circle(320,240,20);
setfillstyle(1,4);
floodfill(320,240,15);
outtextxy(310,237,"sun");

circle(320+60*sin(a),240-35*cos(a),8);
setfillstyle(1,2);
pieslice(320+60*sin(a),240-35*cos(a),0,360,8);
circle(320+100*sin(b),240-60*cos(b),12);
setfillstyle(1,1);
pieslice(320+100*sin(b),240-60*cos(b),0,360,12);
circle(320+130*sin(c),240-80*cos(c),10);
setfillstyle(1,5);
pieslice(320+130*sin(c),240-80*cos(c),0,360,10);
circle(320+170*sin(d),240-100*cos(d),11);
setfillstyle(1,6);
pieslice(320+170*sin(d),240-100*cos(d),0,360,11);
circle(320+200*sin(e),240-130*cos(e),14);
setfillstyle(1,7);
pieslice(320+200*sin(e),240-130*cos(e),0,360,14);
circle(320+230*sin(f),240-155*cos(f),12);
setfillstyle(1,12);
pieslice(320+230*sin(f),240-155*cos(f),0,360,12);
circle(320+260*sin(g),240-180*cos(g),9);
setfillstyle(1,13);
pieslice(320+260*sin(g),240-180*cos(g),0,360,9);
circle(320+280*sin(h),240-200*cos(h),9);
setfillstyle(1,10);
pieslice(320+280*sin(h),240-200*cos(h),0,360,9);
circle(320+300*sin(z),240-220*cos(z),7);
setfillstyle(1,14);
pieslice(320+300*sin(z),240-220*cos(z),0,360,7);
delay(20);
i++;
j++;
k++;
l++;
m++;
n++;
o++;
p++;
q+=2;
}
getch();
}

program using cohen sutherland line clipping algorithm

/* This program will clip a line using cohen sutherland line clipping algorithm */

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

enum { TOP=0x1, BOTTOM=0x2, RIGHT=0x4, LEFT=0x8 };

void lineclip(x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax )
float x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax;
{

int gd,gm;
unsigned int code0,code1,codeout;
int accept = 0, done=0;

code0 = calcode(x0,y0,xwmin,ywmin,xwmax,ywmax);
code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax);

do{
if(!(code0 | code1))
{ accept =1 ; done =1; }
else
if(code0 & code1) done = 1;
else
{
float x,y;
codeout = code0 ? code0 : code1;
if(codeout & TOP)
{
x = x0 + (x1-x0)*(ywmax-y0)/(y1-y0);
y = ywmax;
}
else
if( codeout & BOTTOM)
{
x = x0 + (x1-x0)*(ywmin-y0)/(y1-y0);
y = ywmin;
}
else
if ( codeout & RIGHT)
{
y = y0+(y1-y0)*(xwmax-x0)/(x1-x0);
x = xwmax;
}
else
{
y = y0 + (y1-y0)*(xwmin-x0)/(x1-x0);
x = xwmin;
}
if( codeout == code0)
{
x0 = x; y0 = y;
code0=calcode(x0,y0,xwmin,ywmin,xwmax,ywmax);
}
else
{
x1 = x; y1 = y;
code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax);
}
}
} while( done == 0);

if(accept) line(x0,y0,x1,y1);

rectangle(xwmin,ywmin,xwmax,ywmax);


}


int calcode (x,y,xwmin,ywmin,xwmax,ywmax)
float x,y,xwmin,ywmin,xwmax,ywmax;
{
int code =0;

if(y> ywmax)
code |=TOP;
else if( y<ywmin)
code |= BOTTOM;
else if(x > xwmax)
code |= RIGHT;
else if ( x< xwmin)
code |= LEFT;

return(code);
}


void main()
{

float x2,y2,x1,y1,xwmin,ywmin,xwmax,ywmax;
int gd=DETECT,gm;

clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("\n\n\tEnter the co-ordinates of Line :");

printf("\n\n\tX1 Y1 : ");
scanf("%f %f",&x1,&y1);

printf("\n\n\tX2 Y2 : ");
scanf("%f %f",&x2,&y2);


printf("\n\tEnter the co_ordinates of window :\n ");
printf("\n\txwmin , ywmin : ");
scanf("%f %f",&xwmin,&ywmin);
printf("\n\txwmax , ywmax : ");
scanf("%f %f",&xwmax,&ywmax);
clearviewport();
line(x1,y1,x2,y2);
rectangle(xwmin,ywmin,xwmax,ywmax);
getch();
clearviewport();

lineclip(x1,y1,x2,y2,xwmin,ywmin,xwmax,ywmax );
getch();
closegraph();

}

Sample Input :

                   x1 ,y1        : 50 50
                   x2 ,y2        : 100 100
                  xwin , ymin : 75 75
                  xmax , ymax : 150 150

C graphics program for reflection about X- axis, Y axis,Y=X axis

/* This program will  reflect an object ( triangle ) about X- axis, Y- axis and Y=X axis */

#include<graphics.h>
#include<math.h>
#include<conio.h>
#include<stdio.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x3,y3,x,y,dy,dx,p,gap=50,temp,option;
int x1dash,x2dash,x3dash,y1dash,y2dash,y3dash;
double theta;
float m;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("Enter first co-ords of the triangle\n");
scanf("%d %d",&x1,&y1);
printf("Enter second co-ords of the triangle\n");
scanf("%d  %d",&x2,&y2);
printf("Enter third co-ords of the triangle\n");
scanf("%d  %d",&x3,&y3);

xmid= getmaxx()/2;
ymid= getmaxy()/2;
line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{
outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);

setcolor(255);
printf("Reflection about \n");
printf("X axis :  1\n");
printf("Y axis : 2\n");
printf("X=Y axis : 3\n");
printf(" Enter the option (1-3):");
scanf("%d",&option);
switch( option)
{
case 1:  y1=-y1; y2=-y2;y3=-y3; break;

case 2:  x1=-x1;x2=-x2;x3=-x3;break;

case 3:  y1=-y1; y2=-y2;y3=-y3;
     theta= ((double) 90 *3.14f )/(double)180;
    x1dash=x1*cos(theta)-y1*sin(theta);
    x2dash=x2*cos(theta)-y2*sin(theta);
    x3dash=x3*cos(theta)-y3*sin(theta);
    y1dash=x1*sin(theta)+y1*cos(theta);
    y2dash=x2*sin(theta)+y2*cos(theta);
    y3dash=x3*sin(theta)+y3*cos(theta);
    x1=x1dash;x2=x2dash;x3=x3dash;
    y1=y1dash;y2=y2dash;y3=y3dash;

}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);

getch();
closegraph();
}

Sample Input :

  x1 ,y1   :  50   50
  x2, y2   : 100 100
  x3 ,y3   :150   50   

Program using Bresenham's line drawing algorithm ( all quadrants)

/* This program will draw x- y coordinate system and will draw lines in all quadrants using   Bresenham's line drawing algorithm  */

#include<graphics.h>
#include<conio.h>
#include<stdio.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x,y,dy,dx,p,gap=50,temp;
float m;
char str[3];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("Enter first co-ords of line\n");
scanf("%d",&x1);
scanf("%d",&y1);
printf("Enter second co-ords of line\n");
scanf("%d",&x2);
scanf("%d",&y2);
if (y1>y2)    // needed for -ve slope to work
{temp=x1;
x1=x2;
x2=temp;
temp=y1;
y1=y2;
y2=temp;
}
dy=abs(y2-y1);
dx=abs(x2-x1);
m=(float)(dy)/(dx);
dy=abs(dy);
dx=abs(dx);
xmid= getmaxx()/2;
ymid =getmaxy()/2;
x2=x2+xmid;
y2=ymid-y2;
x=x1;y=y1;
if(m>1.0)
{
x=y1;
y=x1;
}


line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{
outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}

x=x+xmid;
y=ymid -y;
p=2*dy-dx;
while(x<x2)
{
if(p>=0)
{
putpixel(x,y,5);

y=y-1;
p=p+2*dy-2*dx;
}
else
{
putpixel(x,y,5);
p=p+2*dy;
}
x=x+1;
}
getch();
closegraph();
}

C graphics program to rotate an object about the origin

/* This program will  rotate an object ( triangle) about the origin */

#include<graphics.h>
#include<conio.h>
#include<stdio.h>
#include<math.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x3,y3,x,y,dy,dx,p,gap=50,temp;
int x1dash,x2dash,x3dash,y1dash,y2dash,y3dash;
float m;
double theta;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("Enter first co-ords of the triangle\n");
scanf("%d %d",&x1,&y1);
printf("Enter second co-ords of the triangle\n");
scanf("%d  %d",&x2,&y2);
printf("Enter third co-ords of the triangle\n");
scanf("%d  %d",&x3,&y3);

xmid= getmaxx()/2;
ymid= getmaxy()/2;
line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{
outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);

printf("Enter the degree to rotate");
scanf("%lf",&theta);
theta= ((float) theta *3.14f )/(float)180;
x1dash=x1*cos(theta)-y1*sin(theta);
x2dash=x2*cos(theta)-y2*sin(theta);
x3dash=x3*cos(theta)-y3*sin(theta);
y1dash=x1*sin(theta)+y1*cos(theta);
y2dash=x2*sin(theta)+y2*cos(theta);
y3dash=x3*sin(theta)+y3*cos(theta);

line(x1dash+xmid,ymid-y1dash,x2dash+xmid,ymid-y2dash);
line(x2dash+xmid,ymid-y2dash,x3dash+xmid,ymid-y3dash);
line(x3dash+xmid,ymid-y3dash,x1dash+xmid,ymid-y1dash);

getch();
closegraph();
}


Sample Input :

  x1 ,y1   :  50   50
  x2, y2   : 100 100
  x3 ,y3   :150   50   

C graphics program to rotate an object using arbitrary point

/* This program will  rotate an object ( triangle) using an arbitrary point */

#include<graphics.h>
#include<conio.h>
#include<stdio.h>
#include<math.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x3,y3,x,y,dy,dx,p,gap=50,temp,xr,yr;
int x1dash,y1dash,x2dash,y2dash,x3dash,y3dash;
float m;
double theta;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("Enter first co-ords of the triangle\n");
scanf("%d %d",&x1,&y1);
printf("Enter second co-ords of the triangle\n");
scanf("%d  %d",&x2,&y2);
printf("Enter third co-ords of the triangle\n");
scanf("%d  %d",&x3,&y3);

xmid= getmaxx()/2;
ymid= getmaxy()/2;
line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{
outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);

printf("Enter the degree to rotate");
scanf("%lf",&theta);
theta= ((float) theta *3.14f )/(float)180;  // converting theta to radian
printf("Enter the arbitrary point to rotate");
scanf("%d%d",&xr,&yr);
x1dash=xr+(x1-xr)*cos(theta)-(y1-yr)*sin(theta);
x2dash=xr+(x2-xr)*cos(theta)-(y2-yr)*sin(theta);
x3dash=xr+(x3-xr)*cos(theta)-(y3-yr)*sin(theta);

y1dash=yr+(x1-xr)*sin(theta)+(y1-yr)*cos(theta);
y2dash=yr+(x2-xr)*sin(theta)+(y2-yr)*cos(theta);
y3dash=yr+(x3-xr)*sin(theta)+(y3-yr)*cos(theta);

line(x1dash+xmid,ymid-y1dash,x2dash+xmid,ymid-y2dash);
line(x2dash+xmid,ymid-y2dash,x3dash+xmid,ymid-y3dash);
line(x3dash+xmid,ymid-y3dash,x1dash+xmid,ymid-y1dash);

getch();
closegraph();
}

C graphics program to scale a triangle ( in all quadrants)

 /* This program will  scale an object ( triangle )   in all quadrants  */

#include<graphics.h>
#include<conio.h>
#include<stdio.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x3,y3,x,y,dy,dx,p,gap=50,temp;
float m,sxscale,syscale;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");

printf("Enter first co-ords of the triangle ( eg : 50 50 ) \n");
scanf("%d %d",&x1,&y1);
printf("Enter second co-ords of the triangle ( eg : 100 100 )\n");
scanf("%d  %d",&x2,&y2);
printf("Enter third co-ords of the triangle ( eg : 150 150 ) \n");
scanf("%d  %d",&x3,&y3);

xmid= getmaxx()/2;
ymid= getmaxy()/2;
line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{
outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);
printf("\nEnter the scaling factor for x axis");
scanf("%f",&sxscale);
printf("\nEnter the scaling factor for y axis");
scanf("%f",&syscale);

setcolor(0);  // to hide drawn triangle
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);
setcolor(255);

line(x1*sxscale+xmid,ymid-y1*syscale,x2*sxscale+xmid,ymid-y2*syscale);
line(x2*sxscale+xmid,ymid-y2*syscale,x3*sxscale+xmid,ymid-y3*syscale);
line(x3*sxscale+xmid,ymid-y3*syscale,x1*sxscale+xmid,ymid-y1*syscale);

getch();
closegraph();
}


Sample Input :

  x1 ,y1   :  50   50
  x2, y2   : 100 100
  x3 ,y3   :150   50   

C graphics program to translate a triangle from one position to another in both directions (x and y ) in all quadrants

 /* This C program will  translate a triangle from one position to another in both directions (x and y ) in all quadrants and is compiled  using Turbo C++ ver 3.0*/

#include<graphics.h>
#include<conio.h>
#include<stdio.h>
void main()
{
int gd=DETECT,gm;
int i,xmid,ymid,x1,y1,x2,y2,x3,y3,xtrans,ytrans,x,y,dy,dx,p,gap=50,temp;
float m;
char str[5];
clrscr();
initgraph(&gd,&gm,"..\\bgi");
setbkcolor(BLUE);
printf("Enter first co-ords of the triangle ( eg : 50 50 ) \n");
scanf("%d %d",&x1,&y1);
printf("Enter second co-ords of the triangle ( eg : 100 100 ) \n");
scanf("%d  %d",&x2,&y2);
printf("Enter third co-ords of the triangle ( eg : 150 50 ) \n");
scanf("%d  %d",&x3,&y3);

xmid= getmaxx()/2;
ymid= getmaxy()/2;
line(5,ymid,getmaxx()-5,ymid);
line(xmid+3,5,xmid+3,getmaxy()-5);

for( i= xmid+gap;i<getmaxx()-5;i=i+gap)
{
outtextxy(i,ymid-3,"|");
itoa(i-xmid,str,10);
outtextxy(i,ymid+3,str);
}
for( i= ymid-gap;i>5;i=i-gap)
{
outtextxy(xmid,i,"-");
itoa(ymid-i,str,10);
outtextxy(xmid+5,i,str);

}
for( i= xmid-gap;i>5;i=i-gap)
{

outtextxy(i,ymid-3,"|");
itoa(-(xmid-i),str,10);
outtextxy(i-6,ymid+3,str);

}
for( i= ymid+gap;i<getmaxy()-5;i=i+gap)
{
outtextxy(xmid,i,"-");
itoa(-(i-ymid),str,10);
outtextxy(xmid+8,i,str);
}
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);
printf("\nEnter the no of points to be moved in X and in Y direction");
scanf("%d  %d",&xtrans,&ytrans);
setcolor(0);  // setting color to black to hide drawn triangle
line(x1+xmid,ymid-y1,x2+xmid,ymid-y2);
line(x2+xmid,ymid-y2,x3+xmid,ymid-y3);
line(x3+xmid,ymid-y3,x1+xmid,ymid-y1);
setcolor(255); // to set color back to white
line(x1+xmid+xtrans,ymid-y1-ytrans,x2+xmid+xtrans,ymid-y2-ytrans);
line(x2+xmid+xtrans,ymid-y2-ytrans,x3+xmid+xtrans,ymid-y3-ytrans);
line(x3+xmid+xtrans,ymid-y3-ytrans,x1+xmid+xtrans,ymid-y1-ytrans);

getch();
closegraph();
}



Sample Input :

  x1 ,y1   :  50   50
  x2, y2   : 100 100
  x3 ,y3   :150   50   

Midpoint Circle drawing algorithm

/* The program will generate a circle using Midpoint Circle drawing algorithm and is also known as Bresenhams Circle drawing algorithm */

 In computer graphics, the midpoint circle algorithm is an algorithm used to determine the points needed for drawing a circle. The Bresenham's line algorithm is derived from mid-point circle algorithm, and is known as Bresenham's circle algorithm

#include<conio.h>
#include<stdio.h>
#include<graphics.h>
void main()
{
int gd=DETECT,gm;
int r,x,y,xc,yc;
float d;
clrscr();
initgraph(&gd,&gm,"..\\bgi");
printf("Enter Radius\n");
scanf("%d",&r);
printf("Enter Center of circle\n");

scanf("%d",&xc);
scanf("%d",&yc);
d=1.25-r;
x=0;
y=r;
do
{
if(d<0)
{

x=x+1;
d=d+2*x+1;
}
else
{

x=x+1;
y=y-1;
d=d+2*x-2*y+1;
}
putpixel(xc+x,yc+y,5);
putpixel(xc-y,yc-x,5);
putpixel(xc+y,yc-x,5);
putpixel(xc-y,yc+x,5);
putpixel(xc+y,yc+x,5);
putpixel(xc-x,yc-y,5);
putpixel(xc+x,yc-y,5);
putpixel(xc-x,yc+y,5);
}
while(x<y);
getch();
closegraph();
}