/* Chuong trinh ve duong cong Bezier */
#include <conio.h>
#include <graphics.h>
#define NPOINTS 7
struct xycoord {
double xcoord, ycoord;
};
/* Tra ve gia tri Factorial cua q (q!) */
double fact(int q)
{
int f=1, c;
for (c=q; c>1; c--)
f *= c;
return (f);
}
double C(int n, int i)
{
return (fact(n) / (fact(i) * fact(n-i)));
}
double blend(int i, int n, double u, double binomial)
{
double partial;
int j;
partial = binomial;
for (j=1; j<= i; j++)
partial *= u;
for (j=1; j<= (n-i); j++)
partial *= (1.0 - u);
return partial;
}
void BezierFcn (double *x, double *y, double u, double coeff[],
int n, struct xycoord p[])
{
int i;
double b;
*x = *y = 0;
for (i=0; i<=n; i++)
{
b = blend (i, n, u, coeff[i]);
*x += (b * p[i].xcoord);
*y += (b * p[i].ycoord);
}
}
void drawBezier(struct xycoord p[], int npts, int segments)
{
int i, oldx, oldy;
double u, x, y;
double coeff[20];
for (i=0; i<npts; i++)
coeff[i] = C(npts-1, i);
for (i=0; i<=segments; i++)
{
u = (double) i / segments;
BezierFcn(&x, &y, u, coeff, npts - 1, p);
if (i==0)
{
moveto(x, y);
oldx = x;
oldy = y;
}
else
{
lineto(x, y);
oldx = x;
oldy = y;
}
}
}
void main()
{
int gr_drive = DETECT, gr_mode, n;
struct xycoord pt[] = { {400,270}, {400,120}, {100,120}, {100,540},
{510,480}, {475,270}, {600,270}};
int order[] = {0, 1, 2, 3, 4, 5, 6};
initgraph(&gr_drive, &gr_mode, "");
setcolor(YELLOW);
rectangle(0, 0, getmaxx(), getmaxy());
drawBezier(pt, NPOINTS, 40);
getch();
closegraph();
}
Tiêu đề: Chuong trinh ve duong cong Bezier 
10/07/10, 09:56 pm