source: libcaca/trunk/cucul/conic.c @ 678

Last change on this file since 678 was 678, checked in by Sam Hocevar, 14 years ago
  • Made cucul_putchar32() an internal-only function.
  • Changed the line, box, ellipsis etc. prototypes so that they use an UTF-8 string instead of a single character as their last argument.
  • Property svn:keywords set to Id
File size: 5.7 KB
Line 
1/*
2 *  libcucul      Canvas for ultrafast compositing of Unicode letters
3 *  Copyright (c) 2002-2006 Sam Hocevar <sam@zoy.org>
4 *                All Rights Reserved
5 *
6 *  This library is free software; you can redistribute it and/or
7 *  modify it under the terms of the Do What The Fuck You Want To
8 *  Public License, Version 2, as published by Sam Hocevar. See
9 *  http://sam.zoy.org/wtfpl/COPYING for more details.
10 */
11
12/** \file conic.c
13 *  \version \$Id: conic.c 678 2006-03-23 14:07:32Z sam $
14 *  \author Sam Hocevar <sam@zoy.org>
15 *  \brief Ellipse and circle drawing
16 *
17 *  This file contains ellipse and circle drawing functions, both filled
18 *  and outline.
19 */
20
21#include "config.h"
22
23#if !defined(__KERNEL__)
24#   include <stdlib.h>
25#endif
26
27#include "cucul.h"
28#include "cucul_internals.h"
29
30static void ellipsepoints(cucul_t *, int, int, int, int, uint32_t);
31
32/**
33 * \brief Draw a circle on the screen using the given character.
34 *
35 * \param x Center X coordinate.
36 * \param y Center Y coordinate.
37 * \param r Circle radius.
38 * \param c Character to draw the circle outline with.
39 * \return void
40 */
41void cucul_draw_circle(cucul_t *qq, int x, int y, int r, char const *str)
42{
43    int test, dx, dy;
44    uint32_t c = _cucul_utf8_to_utf32(str);
45
46    /* Optimized Bresenham. Kick ass. */
47    for(test = 0, dx = 0, dy = r ; dx <= dy ; dx++)
48    {
49        ellipsepoints(qq, x, y, dx, dy, c);
50        ellipsepoints(qq, x, y, dy, dx, c);
51
52        test += test > 0 ? dx - dy-- : dx;
53    }
54}
55
56/**
57 * \brief Fill an ellipse on the screen using the given character.
58 *
59 * \param xo Center X coordinate.
60 * \param yo Center Y coordinate.
61 * \param a Ellipse X radius.
62 * \param b Ellipse Y radius.
63 * \param c Character to fill the ellipse with.
64 * \return void
65 */
66void cucul_fill_ellipse(cucul_t *qq, int xo, int yo, int a, int b,
67                        char const *str)
68{
69    int d2;
70    int x = 0;
71    int y = b;
72    int d1 = b*b - (a*a*b) + (a*a/4);
73
74    while(a*a*y - a*a/2 > b*b*(x+1))
75    {
76        if(d1 < 0)
77        {
78            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
79        }
80        else
81        {
82            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
83            cucul_draw_line(qq, xo - x, yo - y, xo + x, yo - y, str);
84            cucul_draw_line(qq, xo - x, yo + y, xo + x, yo + y, str);
85            y--;
86        }
87        x++;
88    }
89
90    cucul_draw_line(qq, xo - x, yo - y, xo + x, yo - y, str);
91    cucul_draw_line(qq, xo - x, yo + y, xo + x, yo + y, str);
92
93    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
94    while(y > 0)
95    {
96        if(d2 < 0)
97        {
98            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
99            x++;
100        }
101        else
102        {
103            d2 += a*a*(-2*y+3);
104        }
105
106        y--;
107        cucul_draw_line(qq, xo - x, yo - y, xo + x, yo - y, str);
108        cucul_draw_line(qq, xo - x, yo + y, xo + x, yo + y, str);
109    }
110}
111
112/**
113 * \brief Draw an ellipse on the screen using the given character.
114 *
115 * \param xo Center X coordinate.
116 * \param yo Center Y coordinate.
117 * \param a Ellipse X radius.
118 * \param b Ellipse Y radius.
119 * \param c Character to draw the ellipse outline with.
120 * \return void
121 */
122void cucul_draw_ellipse(cucul_t *qq, int xo, int yo, int a, int b,
123                        char const *str)
124{
125    int d2;
126    int x = 0;
127    int y = b;
128    int d1 = b*b - (a*a*b) + (a*a/4);
129    uint32_t c = _cucul_utf8_to_utf32(str);
130
131    ellipsepoints(qq, xo, yo, x, y, c);
132
133    while(a*a*y - a*a/2 > b*b*(x+1))
134    {
135        if(d1 < 0)
136        {
137            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
138        }
139        else
140        {
141            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
142            y--;
143        }
144        x++;
145        ellipsepoints(qq, xo, yo, x, y, c);
146    }
147
148    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
149    while(y > 0)
150    {
151        if(d2 < 0)
152        {
153            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
154            x++;
155        }
156        else
157        {
158            d2 += a*a*(-2*y+3);
159        }
160
161        y--;
162        ellipsepoints(qq, xo, yo, x, y, c);
163    }
164}
165
166/**
167 * \brief Draw a thin ellipse on the screen.
168 *
169 * \param xo Center X coordinate.
170 * \param yo Center Y coordinate.
171 * \param a Ellipse X radius.
172 * \param b Ellipse Y radius.
173 * \return void
174 */
175void cucul_draw_thin_ellipse(cucul_t *qq, int xo, int yo, int a, int b)
176{
177    /* FIXME: this is not correct */
178    int d2;
179    int x = 0;
180    int y = b;
181    int d1 = b*b - (a*a*b) + (a*a/4);
182
183    ellipsepoints(qq, xo, yo, x, y, '-');
184
185    while(a*a*y - a*a/2 > b*b*(x+1))
186    {
187        if(d1 < 0)
188        {
189            d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */
190        }
191        else
192        {
193            d1 += b*b*(2*x*1) + a*a*(-2*y+2);
194            y--;
195        }
196        x++;
197        ellipsepoints(qq, xo, yo, x, y, '-');
198    }
199
200    d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b;
201    while(y > 0)
202    {
203        if(d2 < 0)
204        {
205            d2 += b*b*(2*x+2) + a*a*(-2*y+3);
206            x++;
207        }
208        else
209        {
210            d2 += a*a*(-2*y+3);
211        }
212
213        y--;
214        ellipsepoints(qq, xo, yo, x, y, '|');
215    }
216}
217
218static void ellipsepoints(cucul_t *qq, int xo, int yo, int x, int y, uint32_t c)
219{
220    uint8_t b = 0;
221
222    if(xo + x >= 0 && xo + x < (int)qq->width)
223        b |= 0x1;
224    if(xo - x >= 0 && xo - x < (int)qq->width)
225        b |= 0x2;
226    if(yo + y >= 0 && yo + y < (int)qq->height)
227        b |= 0x4;
228    if(yo - y >= 0 && yo - y < (int)qq->height)
229        b |= 0x8;
230
231    if((b & (0x1|0x4)) == (0x1|0x4))
232        _cucul_putchar32(qq, xo + x, yo + y, c);
233
234    if((b & (0x2|0x4)) == (0x2|0x4))
235        _cucul_putchar32(qq, xo - x, yo + y, c);
236
237    if((b & (0x1|0x8)) == (0x1|0x8))
238        _cucul_putchar32(qq, xo + x, yo - y, c);
239
240    if((b & (0x2|0x8)) == (0x2|0x8))
241        _cucul_putchar32(qq, xo - x, yo - y, c);
242}
243
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