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/* ****************************************************************************
 * circle.c -- Draw a circle.
 * Copyright (C) 2011 Pierre "PierrotLL" Le Gall <legallpierre89@gmail.com>
 * Copyright (C) 2016-2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of the 'casiowin/monochromelib' module,
 * in libcarrot, an experimental modular libc project.
 *
 * This file is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * This file is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Lesser Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this file.  If not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************* */
#include <monochrome.h>

void ML_circle(int x, int y, int radius, ML_Color color)
{
	int plot_x, plot_y, d;

	if(radius < 0) return;
	plot_x = 0;
	plot_y = radius;
	d = 1 - radius;

	ML_pixel(x, y+plot_y, color);
	if(radius)
	{
		ML_pixel(x, y-plot_y, color);
		ML_pixel(x+plot_y, y, color);
		ML_pixel(x-plot_y, y, color);
	}
	while(plot_y > plot_x)
	{
		if(d < 0)
			d += 2*plot_x+3;
		else
		{
			d += 2*(plot_x-plot_y)+5;
			plot_y--;
		}
		plot_x++;
		if(plot_y >= plot_x)
		{
			ML_pixel(x+plot_x, y+plot_y, color);
			ML_pixel(x-plot_x, y+plot_y, color);
			ML_pixel(x+plot_x, y-plot_y, color);
			ML_pixel(x-plot_x, y-plot_y, color);
		}
		if(plot_y > plot_x)
		{
			ML_pixel(x+plot_y, y+plot_x, color);
			ML_pixel(x-plot_y, y+plot_x, color);
			ML_pixel(x+plot_y, y-plot_x, color);
			ML_pixel(x-plot_y, y-plot_x, color);
		}
	}
}