📅  最后修改于: 2022-03-11 14:45:41.113000             🧑  作者: Mango
#include
#include
#include
#include
#include
#include
class bresen
{
float x,y,a, b,r,p,h,k,p1,p2;
public:
void get ();
void cal ();
};
void main ()
{
bresen b;
b.get ();
b.cal ();
getch ();
}
void bresen :: get ()
{
cout<<"\n ENTER CENTER OF ELLIPSE";
cout<<"\n ENTER (h, k) ";
cin>>h>>k;
cout<<"\n ENTER LENGTH OF MAJOR AND MINOR AXIS";
cin>>a>>b;
}
void bresen ::cal ()
{
/* request auto detection */
int gdriver = DETECT,gmode, errorcode;
int midx, midy, i;
/* initialize graphics and local variables */
initgraph (&gdriver, &gmode, " ");
/* read result of initialization */
errorcode = graphresult ();
if (errorcode ! = grOK) /*an error occurred */
{
printf("Graphics error: %s \n", grapherrormsg (errorcode);
printf ("Press any key to halt:");
getch ();
exit (1); /* terminate with an error code */
}
x=0;
y=b;
// REGION 1
p1 =(b * b)-(a * a * b) + (a * a)/4);
{
putpixel (x+h, y+k, RED);
putpixel (-x+h, -y+k, RED);
putpixel (x+h, -y+k, RED);
putpixel (-x+h, y+k, RED);
if (p1 < 0)
p1 += ((2 *b * b) *(x+1))-((2 * a * a)*(y-1)) + (b * b);
else
{
p1+= ((2 *b * b) *(x+1))-((2 * a * a)*(y-1))-(b * b);
y--;
}
x++;
}
//REGION 2
p2 =((b * b)* (x + 0.5))+((a * a)*(y-1) * (y-1))-(a * a *b * b);
while (y>=0)
{
If (p2>0)
p2=p2-((2 * a * a)* (y-1))+(a *a);
else
{
p2=p2-((2 * a * a)* (y-1))+((2 * b * b)*(x+1))+(a * a);
x++;
}
y--;
putpixel (x+h, y+k, RED);
putpixel (-x+h, -y+k, RED);
putpixel (x+h, -y+k, RED);
putpixel (-x+h, y+k, RED);
}
getch();
}