окружность и эллепс

void circle(HDC hdc, int xC, int yC)
{
	int x=0;
	int y=r;
	int d=1-r;
	int delta1=3;
	int delta2=-2*r+5;

	while(x<y)
	{
		SetPixel(hdc, xC+x, y+yC, 0);
		SetPixel(hdc, xC-x, y+yC, 0);
		SetPixel(hdc, xC-x, -y+yC, 0);
		SetPixel(hdc, xC+x, -y+yC, 0);

		SetPixel(hdc, xC+y, x+yC, 0);
		SetPixel(hdc, xC-y, x+yC, 0);
		SetPixel(hdc, xC-y, -x+yC, 0);
		SetPixel(hdc, xC+y, -x+yC, 0);
		if(d<0)
		{
			d+=delta1;
			delta1+=2;
			delta2+=2;
			x++;
		}
		else
		{
			d+=delta2;
			delta2+=4;
			delta1+=2;
			x++;
			y--;
		}
		}
	}

void ellipse(HDC hdc, int x0, int y0)
{
	int a2 = width * width;
    int b2 = height * height;
    int fa2 = 4 * a2, fb2 = 4 * b2;
    int  x, y, sigma;

	// ()
    for (x = 0, y = height, sigma = 2*b2+a2*(1-2*height); b2*x <= a2*y; x++)
    {
       /* if (sigma >= 0)
        {
            sigma += fa2 * (1 - y);
             y--;
        }*/
		 y--;
        sigma += b2 * ((4 * x) + 6);
	    SetPixel (hdc,x0 + x, y0 + y,0);
        SetPixel (hdc,x0 - x, y0 + y,0);
        SetPixel (hdc,x0 + x, y0 - y,0);
        SetPixel (hdc,x0 - x, y0 - y,0);
    }

    //
    for (x = width, y = 0, sigma = 2*a2+b2*(1-2*width); a2*y <= b2*x; y++)
    {
        if (sigma >= 0)
        {
            sigma += fb2 * (1 - x);
            x--;
        }
        sigma += a2 * ((4 * y) + 6);
		SetPixel (hdc,x0 + x, y0 + y,0);
        SetPixel (hdc,x0 - x, y0 + y,0);
        SetPixel (hdc,x0 + x, y0 - y,0);
        SetPixel (hdc,x0 - x, y0 - y,0);
}
}