source: libcaca/trunk/cucul/triangle.c @ 769

Last change on this file since 769 was 769, checked in by Sam Hocevar, 14 years ago
  • Removed \file directives from all files except caca.h and cucul.h, to remove redundencies in the Doxygen documentation.
  • Property svn:keywords set to Id
File size: 3.8 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 *  $Id: triangle.c 769 2006-04-14 07:30:53Z sam $
7 *
8 *  This library is free software; you can redistribute it and/or
9 *  modify it under the terms of the Do What The Fuck You Want To
10 *  Public License, Version 2, as published by Sam Hocevar. See
11 *  http://sam.zoy.org/wtfpl/COPYING for more details.
12 */
13
14/*
15 *  This file contains triangle drawing functions, both filled and outline.
16 */
17
18#include "config.h"
19
20#if !defined(__KERNEL__)
21#   include <stdlib.h>
22#endif
23
24#include "cucul.h"
25#include "cucul_internals.h"
26
27/**
28 * \brief Draw a triangle on the screen using the given character.
29 *
30 * \param x1 X coordinate of the first point.
31 * \param y1 Y coordinate of the first point.
32 * \param x2 X coordinate of the second point.
33 * \param y2 Y coordinate of the second point.
34 * \param x3 X coordinate of the third point.
35 * \param y3 Y coordinate of the third point.
36 * \param c Character to draw the triangle outline with.
37 * \return void
38 */
39void cucul_draw_triangle(cucul_t *qq, int x1, int y1, int x2, int y2,
40                         int x3, int y3, char const *str)
41{
42    cucul_draw_line(qq, x1, y1, x2, y2, str);
43    cucul_draw_line(qq, x2, y2, x3, y3, str);
44    cucul_draw_line(qq, x3, y3, x1, y1, str);
45}
46
47/**
48 * \brief Draw a thin triangle on the screen.
49 *
50 * \param x1 X coordinate of the first point.
51 * \param y1 Y coordinate of the first point.
52 * \param x2 X coordinate of the second point.
53 * \param y2 Y coordinate of the second point.
54 * \param x3 X coordinate of the third point.
55 * \param y3 Y coordinate of the third point.
56 * \return void
57 */
58void cucul_draw_thin_triangle(cucul_t *qq, int x1, int y1, int x2, int y2,
59                              int x3, int y3)
60{
61    cucul_draw_thin_line(qq, x1, y1, x2, y2);
62    cucul_draw_thin_line(qq, x2, y2, x3, y3);
63    cucul_draw_thin_line(qq, x3, y3, x1, y1);
64}
65
66/**
67 * \brief Fill a triangle on the screen using the given character.
68 *
69 * \param x1 X coordinate of the first point.
70 * \param y1 Y coordinate of the first point.
71 * \param x2 X coordinate of the second point.
72 * \param y2 Y coordinate of the second point.
73 * \param x3 X coordinate of the third point.
74 * \param y3 Y coordinate of the third point.
75 * \param c Character to fill the triangle with.
76 * \return void
77 */
78void cucul_fill_triangle(cucul_t *qq, int x1, int y1, int x2, int y2,
79                         int x3, int y3, char const *str)
80{
81    int x, y, xa, xb, xmax, ymax;
82    uint32_t c;
83
84    /* Bubble-sort y1 <= y2 <= y3 */
85    if(y1 > y2)
86    {
87        cucul_fill_triangle(qq, x2, y2, x1, y1, x3, y3, str);
88        return;
89    }
90
91    if(y2 > y3)
92    {
93        cucul_fill_triangle(qq, x1, y1, x3, y3, x2, y2, str);
94        return;
95    }
96
97    /* Promote precision */
98    x1 *= 4;
99    x2 *= 4;
100    x3 *= 4;
101
102    xmax = qq->width - 1;
103    ymax = qq->height - 1;
104
105    c = _cucul_utf8_to_utf32(str);
106
107    /* Rasterize our triangle */
108    for(y = y1 < 0 ? 0 : y1; y <= y3 && y <= ymax; y++)
109    {
110        if(y <= y2)
111        {
112            xa = (y1 == y2) ? x2 : x1 + (x2 - x1) * (y - y1) / (y2 - y1);
113            xb = (y1 == y3) ? x3 : x1 + (x3 - x1) * (y - y1) / (y3 - y1);
114        }
115        else
116        {
117            xa = (y3 == y2) ? x2 : x3 + (x2 - x3) * (y - y3) / (y2 - y3);
118            xb = (y3 == y1) ? x1 : x3 + (x1 - x3) * (y - y3) / (y1 - y3);
119        }
120
121        if(xb < xa)
122        {
123            int tmp = xb;
124            xb = xa; xa = tmp;
125        }
126
127        /* Rescale xa and xb, slightly cropping */
128        xa = (xa + 2) / 4;
129        xb = (xb - 2) / 4;
130
131        if(xb < 0) continue;
132        if(xa > xmax) continue;
133        if(xa < 0) xa = 0;
134        if(xb > xmax) xb = xmax;
135
136        for(x = xa; x <= xb; x++)
137            _cucul_putchar32(qq, x, y, c);
138    }
139}
140
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