source: libcaca/trunk/cucul/cucul.c @ 811

Last change on this file since 811 was 811, checked in by Sam Hocevar, 14 years ago
  • Renamed caca_t into caca_display_t.
  • Renamed canvas handle variables from "c" to "cv". Eh ouais mon gros.
  • Property svn:keywords set to Id
File size: 10.5 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: cucul.c 811 2006-04-18 15:11:25Z 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 the main functions used by \e libcucul applications
16 *  to initialise a drawing context.
17 */
18
19#include "config.h"
20
21#if !defined(__KERNEL__)
22#   include <stdio.h>
23#   include <stdlib.h>
24#   include <string.h>
25#endif
26
27#include "cucul.h"
28#include "cucul_internals.h"
29
30/** \brief Initialise a \e libcucul canvas.
31 *
32 *  This function initialises internal \e libcucul structures and the backend
33 *  that will be used for subsequent graphical operations. It must be the
34 *  first \e libcucul function to be called in a function. cucul_free() should
35 *  be called at the end of the program to free all allocated resources.
36 *
37 *  If one of the desired canvas coordinates is zero, a default canvas size
38 *  of 80x32 is used instead.
39 *
40 *  \param width The desired canvas width
41 *  \param height The desired canvas height
42 *  \return A libcucul canvas handle upon success, NULL if an error occurred.
43 */
44cucul_canvas_t * cucul_create(unsigned int width, unsigned int height)
45{
46    cucul_canvas_t *cv = malloc(sizeof(cucul_canvas_t));
47
48    cv->refcount = 0;
49
50    cv->fgcolor = CUCUL_COLOR_LIGHTGRAY;
51    cv->bgcolor = CUCUL_COLOR_BLACK;
52
53    cv->width = cv->height = 0;
54    cv->chars = NULL;
55    cv->attr = NULL;
56    cv->empty_line = cv->scratch_line = NULL;
57
58    /* Initialise to a default size. 80x32 is arbitrary but matches AAlib's
59     * default X11 window. When a graphic driver attaches to us, it can set
60     * a different size. */
61    if(width && height)
62        _cucul_set_size(cv, width, height);
63    else
64        _cucul_set_size(cv, 80, 32);
65
66    if(_cucul_init_dither())
67    {
68        free(cv);
69        return NULL;
70    }
71
72    return cv;
73}
74
75/** \brief Load a memory area into a canvas.
76 *
77 *  This function loads a memory area containing an exported canvas into
78 *  a new \e libcucul canvas.
79 *
80 *  \param data The memory area to be loaded into a canvas.
81 *  \param size The length of the memory area.
82 *  \return A libcucul canvas, or NULL in case of error.
83 */
84cucul_canvas_t *cucul_load(void *data, unsigned int size)
85{
86    cucul_canvas_t *cv;
87    uint8_t *buf = (uint8_t *)data;
88    unsigned int width, height, n;
89
90    if(size < 12)
91        return NULL;
92
93    if(buf[0] != 'C' || buf[1] != 'A' || buf[2] != 'C' || buf[3] != 'A')
94        return NULL;
95
96    width = ((uint32_t)buf[4] << 24) | ((uint32_t)buf[5] << 16)
97          | ((uint32_t)buf[6] << 8) | (uint32_t)buf[7];
98    height = ((uint32_t)buf[8] << 24) | ((uint32_t)buf[9] << 16)
99           | ((uint32_t)buf[10] << 8) | (uint32_t)buf[11];
100
101    if(!width || !height)
102        return NULL;
103
104    if(size != 12 + width * height * 8 + 4)
105        return NULL;
106
107    if(buf[size - 4] != 'A' || buf[size - 3] != 'C'
108        || buf[size - 2] != 'A' || buf[size - 1] != 'C')
109        return NULL;
110
111    cv = cucul_create(width, height);
112
113    if(!cv)
114        return NULL;
115
116    for(n = height * width; n--; )
117    {
118        cv->chars[n] = ((uint32_t)buf[12 + 8 * n] << 24)
119                     | ((uint32_t)buf[13 + 8 * n] << 16)
120                     | ((uint32_t)buf[14 + 8 * n] << 8)
121                     | (uint32_t)buf[15 + 8 * n];
122        cv->attr[n] = ((uint32_t)buf[16 + 8 * n] << 24)
123                    | ((uint32_t)buf[17 + 8 * n] << 16)
124                    | ((uint32_t)buf[18 + 8 * n] << 8)
125                    | (uint32_t)buf[19 + 8 * n];
126    }
127
128    return cv;
129}
130
131/** \brief Resize a canvas.
132 *
133 *  This function sets the canvas width and height, in character cells.
134 *
135 *  The contents of the canvas are preserved to the extent of the new
136 *  canvas size. Newly allocated character cells at the right and/or at
137 *  the bottom of the canvas are filled with spaces.
138 *
139 *  It is an error to try to resize the canvas if an output driver has
140 *  been attached to the canvas using caca_attach(). You need to remove
141 *  the output driver using caca_detach() before you can change the
142 *  canvas size again. However, the caca output driver can cause a canvas
143 *  resize through user interaction. See the caca_event() documentation
144 *  for more about this.
145 *
146 *  \param cv A libcucul canvas
147 *  \param width The desired canvas width
148 *  \param height The desired canvas height
149 */
150void cucul_set_size(cucul_canvas_t *cv, unsigned int width, unsigned int height)
151{
152    if(cv->refcount)
153        return;
154
155    _cucul_set_size(cv, width, height);
156}
157
158/** \brief Get the canvas width.
159 *
160 *  This function returns the current canvas width, in character cells.
161 *
162 *  \param cv A libcucul canvas
163 *  \return The canvas width.
164 */
165unsigned int cucul_get_width(cucul_canvas_t *cv)
166{
167    return cv->width;
168}
169
170/** \brief Get the canvas height.
171 *
172 *  This function returns the current canvas height, in character cells.
173 *
174 *  \param cv A libcucul canvas
175 *  \return The canvas height.
176 */
177unsigned int cucul_get_height(cucul_canvas_t *cv)
178{
179    return cv->height;
180}
181
182/** \brief Translate a colour index into the colour's name.
183 *
184 *  This function translates a cucul_color enum into a human-readable
185 *  description string of the associated colour.
186 *
187 *  \param color The colour value.
188 *  \return A static string containing the colour's name.
189 */
190char const *cucul_get_color_name(unsigned int color)
191{
192    static char const *color_names[] =
193    {
194        "black",
195        "blue",
196        "green",
197        "cyan",
198        "red",
199        "magenta",
200        "brown",
201        "light gray",
202        "dark gray",
203        "light blue",
204        "light green",
205        "light cyan",
206        "light red",
207        "light magenta",
208        "yellow",
209        "white",
210    };
211
212    if(color < 0 || color > 15)
213        return "unknown";
214
215    return color_names[color];
216}
217
218/** \brief Uninitialise \e libcucul.
219 *
220 *  This function frees all resources allocated by cucul_create(). After
221 *  cucul_free() has been called, no other \e libcucul functions may be used
222 *  unless a new call to cucul_create() is done.
223 *
224 *  \param cv A libcucul canvas
225 */
226void cucul_free(cucul_canvas_t *cv)
227{
228    _cucul_end_dither();
229
230    free(cv->empty_line);
231    free(cv->scratch_line);
232
233    free(cv->chars);
234    free(cv->attr);
235
236    free(cv);
237}
238
239/** \brief Generate a random integer within a range.
240 *
241 *  \param min The lower bound of the integer range.
242 *  \param max The upper bound of the integer range.
243 *  \return A random integer comprised between \p min and \p max, inclusive.
244 */
245int cucul_rand(int min, int max)
246{
247    return min + (int)((1.0*(max-min+1)) * rand() / (RAND_MAX+1.0));
248}
249
250/** \brief Get the buffer size.
251 *
252 *  This function returns the length (in bytes) of the memory area stored
253 *  in the given \e libcucul buffer.
254 *
255 *  \param buf A \e libcucul buffer
256 *  \return The buffer data length.
257 */
258unsigned long int cucul_get_buffer_size(cucul_buffer_t *buf)
259{
260    return buf->size;
261}
262
263/** \brief Get the buffer data.
264 *
265 *  This function returns a pointer to the memory area stored in the given
266 *  \e libcucul buffer.
267 *
268 *  \param buf A \e libcucul buffer
269 *  \return A pointer to the buffer memory area.
270 */
271void * cucul_get_buffer_data(cucul_buffer_t *buf)
272{
273    return buf->data;
274}
275
276/** \brief Free a buffer.
277 *
278 *  This function frees the structures associated with the given
279 *  \e libcucul buffer.
280 *
281 *  \param buf A \e libcucul buffer
282 */
283void cucul_free_buffer(cucul_buffer_t *buf)
284{
285    free(buf->data);
286    free(buf);
287}
288
289/*
290 * XXX: The following functions are local.
291 */
292
293void _cucul_set_size(cucul_canvas_t *cv, unsigned int width,
294                                         unsigned int height)
295{
296    unsigned int x, y, old_width, old_height, new_size, old_size;
297
298    old_width = cv->width;
299    old_height = cv->height;
300    old_size = old_width * old_height;
301
302    cv->width = width;
303    cv->height = height;
304    new_size = width * height;
305
306    /* Step 1: if new area is bigger, resize the memory area now. */
307    if(new_size > old_size)
308    {
309        cv->chars = realloc(cv->chars, new_size * sizeof(uint32_t));
310        cv->attr = realloc(cv->attr, new_size * sizeof(uint32_t));
311    }
312
313    /* Step 2: move line data if necessary. */
314    if(width == old_width)
315    {
316        /* Width did not change, which means we do not need to move data. */
317        ;
318    }
319    else if(width > old_width)
320    {
321        /* New width is bigger than old width, which means we need to
322         * copy lines starting from the bottom of the screen otherwise
323         * we will overwrite information. */
324        for(y = height < old_height ? height : old_height; y--; )
325        {
326            for(x = old_width; x--; )
327            {
328                cv->chars[y * width + x] = cv->chars[y * old_width + x];
329                cv->attr[y * width + x] = cv->attr[y * old_width + x];
330            }
331
332            /* Zero the end of the line */
333            for(x = width - old_width; x--; )
334                cv->chars[y * width + old_width + x] = (uint32_t)' ';
335            memset(cv->attr + y * width + old_width, 0,
336                   (width - old_width) * 4);
337        }
338    }
339    else
340    {
341        /* New width is smaller. Copy as many lines as possible. Ignore
342         * the first line, it is already in place. */
343        unsigned int lines = height < old_height ? height : old_height;
344
345        for(y = 1; y < lines; y++)
346        {
347            for(x = 0; x < width; x++)
348            {
349                cv->chars[y * width + x] = cv->chars[y * old_width + x];
350                cv->attr[y * width + x] = cv->attr[y * old_width + x];
351            }
352        }
353    }
354
355    /* Step 3: fill the bottom of the new screen if necessary. */
356    if(height > old_height)
357    {
358        /* Zero the bottom of the screen */
359        for(x = (height - old_height) * width; x--; )
360            cv->chars[old_height * width + x] = (uint32_t)' ';
361        memset(cv->attr + old_height * width, 0,
362               (height - old_height) * width * 4);
363    }
364
365    /* Step 4: if new area is smaller, resize memory area now. */
366    if(new_size <= old_size)
367    {
368        cv->chars = realloc(cv->chars, new_size * sizeof(uint32_t));
369        cv->attr = realloc(cv->attr, new_size * sizeof(uint32_t));
370    }
371
372    /* Recompute the scratch line and the empty line */
373    if(width != old_width)
374    {
375        cv->empty_line = realloc(cv->empty_line, width + 1);
376        memset(cv->empty_line, ' ', width);
377        cv->empty_line[width] = '\0';
378
379        cv->scratch_line = realloc(cv->scratch_line, width + 1);
380    }
381}
382
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