source: ttyvaders/trunk/libcaca/conic.c @ 186

Last change on this file since 186 was 186, checked in by Sam Hocevar, 17 years ago
  • Renamed libee to libcaca. Far less collisions.
  • Property svn:keywords set to Id
File size: 4.7 KB
Line 
1/*
2 *   libcaca       ASCII-Art library
3 *   Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org>
4 *                 All Rights Reserved
5 *
6 *   $Id: conic.c 186 2003-11-16 00:33:35Z sam $
7 *
8 *   This program is free software; you can redistribute it and/or modify
9 *   it under the terms of the GNU General Public License as published by
10 *   the Free Software Foundation; either version 2 of the License, or
11 *   (at your option) any later version.
12 *
13 *   This program is distributed in the hope that it will be useful,
14 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
15 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 *   GNU General Public License for more details.
17 *
18 *   You should have received a copy of the GNU General Public License
19 *   along with this program; if not, write to the Free Software
20 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#include "config.h"
24
25#ifdef HAVE_INTTYPES_H
26#   include <inttypes.h>
27#else
28typedef unsigned char uint8_t;
29#endif
30
31#include <stdlib.h>
32
33#include "caca.h"
34#include "caca_internals.h"
35
36static void ellipsepoints(int, int, int, int, char);
37
38void caca_draw_circle(int x, int y, int r, char c)
39{
40    int test, dx, dy;
41
42    /* Optimized Bresenham. Kick ass. */
43    for(test = 0, dx = 0, dy = r ; dx <= dy ; dx++)
44    {
45        ellipsepoints(x, y, dx, dy, c);
46        ellipsepoints(x, y, dy, dx, c);
47
48        test += test > 0 ? dx - dy-- : dx;
49    }
50}
51
52void caca_fill_ellipse(int xo, int yo, int a, int b, char c)
53{
54    int d2;
55    int x = 0;
56    int y = b;
57    int d1 = b*b - (a*a*b) + (a*a/4);
58
59    while(a*a*y - a*a/2 > b*b*(x+1))
60    {
61        if(d1 < 0)
62        {
63            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
64        }
65        else
66        {
67            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
68            caca_draw_line(xo - x, yo - y, xo + x, yo - y, c);
69            caca_draw_line(xo - x, yo + y, xo + x, yo + y, c);
70            y--;
71        }
72        x++;
73    }
74
75    caca_draw_line(xo - x, yo - y, xo + x, yo - y, c);
76    caca_draw_line(xo - x, yo + y, xo + x, yo + y, c);
77
78    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
79    while(y > 0)
80    {
81        if(d2 < 0)
82        {
83            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
84            x++;
85        }
86        else
87        {
88            d2 += a*a*(-2*y+3);
89        }
90
91        y--;
92        caca_draw_line(xo - x, yo - y, xo + x, yo - y, c);
93        caca_draw_line(xo - x, yo + y, xo + x, yo + y, c);
94    }
95}
96
97void caca_draw_ellipse(int xo, int yo, int a, int b, char c)
98{
99    int d2;
100    int x = 0;
101    int y = b;
102    int d1 = b*b - (a*a*b) + (a*a/4);
103
104    ellipsepoints(xo, yo, x, y, c);
105
106    while(a*a*y - a*a/2 > b*b*(x+1))
107    {
108        if(d1 < 0)
109        {
110            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
111        }
112        else
113        {
114            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
115            y--;
116        }
117        x++;
118        ellipsepoints(xo, yo, x, y, c);
119    }
120
121    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
122    while(y > 0)
123    {
124        if(d2 < 0)
125        {
126            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
127            x++;
128        }
129        else
130        {
131            d2 += a*a*(-2*y+3);
132        }
133
134        y--;
135        ellipsepoints(xo, yo, x, y, c);
136    }
137}
138
139void caca_draw_thin_ellipse(int xo, int yo, int a, int b)
140{
141    /* FIXME: this is not correct */
142    int d2;
143    int x = 0;
144    int y = b;
145    int d1 = b*b - (a*a*b) + (a*a/4);
146
147    ellipsepoints(xo, yo, x, y, '-');
148
149    while(a*a*y - a*a/2 > b*b*(x+1))
150    {
151        if(d1 < 0)
152        {
153            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
154        }
155        else
156        {
157            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
158            y--;
159        }
160        x++;
161        ellipsepoints(xo, yo, x, y, '-');
162    }
163
164    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
165    while(y > 0)
166    {
167        if(d2 < 0)
168        {
169            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
170            x++;
171        }
172        else
173        {
174            d2 += a*a*(-2*y+3);
175        }
176
177        y--;
178        ellipsepoints(xo, yo, x, y, '|');
179    }
180}
181
182static void ellipsepoints(int xo, int yo, int x, int y, char c)
183{
184    uint8_t b = 0;
185
186    if(xo + x >= 0 && xo + x < caca_get_width())
187        b |= 0x1;
188    if(xo - x >= 0 && xo - x < caca_get_width())
189        b |= 0x2;
190    if(yo + y >= 0 && yo + y < caca_get_height())
191        b |= 0x4;
192    if(yo - y >= 0 && yo - y < caca_get_height())
193        b |= 0x8;
194
195    if((b & (0x1|0x4)) == (0x1|0x4))
196        caca_putchar(xo + x, yo + y, c);
197
198    if((b & (0x2|0x4)) == (0x2|0x4))
199        caca_putchar(xo - x, yo + y, c);
200
201    if((b & (0x1|0x8)) == (0x1|0x8))
202        caca_putchar(xo + x, yo - y, c);
203
204    if((b & (0x2|0x8)) == (0x2|0x8))
205        caca_putchar(xo - x, yo - y, c);
206}
207
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