include stdafx include Окружность эллипс void circle HDC hdc int x0 in

#include "stdafx.h"
#include "Окружность и эллипс.h"

void circle(HDC hdc, int x0, int y0, int R, COLORREF color)
{
	int x=0;
	int y=R;
	int d=1-R;
	int d1=3;
	int d2=-2*R+5;

	SetPixel(hdc, x0, y0+R, color);
	SetPixel(hdc, x0, y0-R, color);
	SetPixel(hdc, x0+R, y0, color);
	SetPixel(hdc, x0-R, y0, color);

	while (x<y)
	{
		if (d<0)
		{
			d=d+d1;
			d1=d1+2;
			d2=d2+2;
			x++;
		}
		else
		{
			d=d+d2;
			d2=d2+4;
			d1=d1+2;
			x++;
			y--;
		}
		SetPixel(hdc,x0+x,y0+y,color);
		SetPixel(hdc,x0+y,y0+x,color);
		SetPixel(hdc,x0-x,y0+y,color);
		SetPixel(hdc,x0-y,y0+x,color);
		SetPixel(hdc,x0+x,y0-y,color);
		SetPixel(hdc,x0+y,y0-x,color);
		SetPixel(hdc,x0-x,y0-y,color);
		SetPixel(hdc,x0-y,y0-x,color);
	}
}

void ellipse(HDC hdc, int x0, int y0, int a, int b, COLORREF color)
{
	if (a == b) circle(hdc, x0, y0, a, color);

	int x=0;
	int y=b;
	int d=4*b*b+a*a*(1-4*b);
	int d1=12*b*b;
	int d2=12*b*b+8*a*a-8*a*a*b;
	
	SetPixel(hdc, x0, y0+b, color);
	SetPixel(hdc, x0, y0-b, color);

	while (a*a*y > b*b*x)
	{
		if (d<0)
		{
			d=d+d1;
			d1=d1+8*b*b;
			d2=d2+8*b*b;
			x++;
		}
		else
		{
			d=d+d2;
			d1=d1+8*b*b;
			d2=d2+8*(b*b+a*a);
			x++;
			y--;
		}
		SetPixel(hdc, x0+x, y0+y, color);
		SetPixel(hdc, x0+x, y0-y, color);
		SetPixel(hdc, x0-x, y0-y, color);
		SetPixel(hdc, x0-x, y0+y, color);
	}

	d1=8*b*b*(1+x)+4*a*a*(3-2*y);
	d2=4*a*a*(3-2*y);
	while (y>=0)
	{
		if(d<0)
		{
			d=d+d1;
			d1=d1+8*a*a;
			d2=d2+8*a*a;
			y--;
			x++;
		}
		else
		{
			d=d+d2;
			d1=d1+8*(a*a+b*b);
			d2=d2+8*a*a;
			y--;
		}
		SetPixel(hdc, x0+x, y0+y, color);
		SetPixel(hdc, x0+x, y0-y, color);
		SetPixel(hdc, x0-x, y0-y, color);
		SetPixel(hdc, x0-x, y0+y, color);
	}

}