BGD_DECLARE(void) gdImageEllipse(gdImagePtr im, int mx, int my, int w, int h, int c)
{
	int x=0,mx1=0,mx2=0,my1=0,my2=0;
	long aq,bq,dx,dy,r,rx,ry,a,b;

	a=w>>1;
	b=h>>1;
	gdImageSetPixel(im,mx+a, my, c);
	gdImageSetPixel(im,mx-a, my, c);
	mx1 = mx-a;
	my1 = my;
	mx2 = mx+a;
	my2 = my;

	aq = a * a;
	bq = b * b;
	dx = aq << 1;
	dy = bq << 1;
	r  = a * bq;
	rx = r << 1;
	ry = 0;
	x = a;
	while (x > 0) {
		if (r > 0) {
			my1++;
			my2--;
			ry +=dx;
			r  -=ry;
		}
		if (r <= 0) {
			x--;
			mx1++;
			mx2--;
			rx -=dy;
			r  +=rx;
		}
		gdImageSetPixel(im,mx1, my1, c);
		gdImageSetPixel(im,mx1, my2, c);
		gdImageSetPixel(im,mx2, my1, c);
		gdImageSetPixel(im,mx2, my2, c);
	}
}
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