1 /*****************************************************************************
2 * This file is part of gfxprim library. *
4 * Gfxprim is free software; you can redistribute it and/or *
5 * modify it under the terms of the GNU Lesser General Public *
6 * License as published by the Free Software Foundation; either *
7 * version 2.1 of the License, or (at your option) any later version. *
9 * Gfxprim is distributed in the hope that it will be useful, *
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
12 * Lesser General Public License for more details. *
14 * You should have received a copy of the GNU Lesser General Public *
15 * License along with gfxprim; if not, write to the Free Software *
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, *
17 * Boston, MA 02110-1301 USA *
19 * Copyright (C) 2009-2010 Jiri "BlueBear" Dluhos *
20 * <jiri.bluebear.dluhos@gmail.com> *
22 * Copyright (C) 2009-2010 Cyril Hrubis <metan@ucw.cz> *
24 *****************************************************************************/
27 * A filled circle drawing algorithm.
29 * A filled circle is drawn in the same way as an unfilled one,
30 * in a top-down, line per line manner, except that we don't need to draw
31 * four points in each X step. Instead, we just iterate X
32 * until we accumulate enough Y changes to reach the next line,
33 * and then draw the full line.
37 * This macro defines a filled circle drawing function.
39 * CONTEXT_T - user-defined type of drawing context (passed to HLINE)
40 * PIXVAL_T - user-defined pixel value type (passed to HLINE)
41 * HLINE - horizontal line drawing function f(context, x0, x1, y, pixval)
42 * FN_NAME - name of the function to be defined
44 #define DEF_FILLCIRCLE_FN(FN_NAME, CONTEXT_T, PIXVAL_T, HLINE) \
45 void FN_NAME(CONTEXT_T context, int xcenter, int ycenter, \
46 unsigned int r, PIXVAL_T pixval) \
49 for (x = 0, error = -r, y = r; y >= 0; y--) { \
55 HLINE(context, xcenter-x+1, xcenter+x-1, ycenter-y, pixval); \
56 HLINE(context, xcenter-x+1, xcenter+x-1, ycenter+y, pixval); \