summaryrefslogtreecommitdiff
path: root/libavcodec/ansi.c (plain)
blob: 3c82dcd338c38bca77dd34b8f5e61b1b41120d26
1/*
2 * ASCII/ANSI art decoder
3 * Copyright (c) 2010 Peter Ross <pross@xvid.org>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * ASCII/ANSI art decoder
25 */
26
27#include "libavutil/common.h"
28#include "libavutil/frame.h"
29#include "libavutil/lfg.h"
30#include "libavutil/xga_font_data.h"
31#include "avcodec.h"
32#include "cga_data.h"
33#include "internal.h"
34
35#define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */
36#define ATTR_FAINT 0x02 /**< Faint (mode 2) */
37#define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */
38#define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */
39#define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */
40#define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */
41
42#define DEFAULT_FG_COLOR 7 /**< CGA color index */
43#define DEFAULT_BG_COLOR 0
44#define DEFAULT_SCREEN_MODE 3 /**< 80x25 */
45
46#define FONT_WIDTH 8 /**< Font width */
47
48/** map ansi color index to cga palette index */
49static const uint8_t ansi_to_cga[16] = {
50 0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
51};
52
53typedef struct AnsiContext {
54 AVFrame *frame;
55 int x; /**< x cursor position (pixels) */
56 int y; /**< y cursor position (pixels) */
57 int sx; /**< saved x cursor position (pixels) */
58 int sy; /**< saved y cursor position (pixels) */
59 const uint8_t* font; /**< font */
60 int font_height; /**< font height */
61 int attributes; /**< attribute flags */
62 int fg; /**< foreground color */
63 int bg; /**< background color */
64 int first_frame;
65
66 /* ansi parser state machine */
67 enum {
68 STATE_NORMAL = 0,
69 STATE_ESCAPE,
70 STATE_CODE,
71 STATE_MUSIC_PREAMBLE
72 } state;
73#define MAX_NB_ARGS 4
74 int args[MAX_NB_ARGS];
75 int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */
76} AnsiContext;
77
78static av_cold int decode_init(AVCodecContext *avctx)
79{
80 AnsiContext *s = avctx->priv_data;
81 avctx->pix_fmt = AV_PIX_FMT_PAL8;
82
83 s->frame = av_frame_alloc();
84 if (!s->frame)
85 return AVERROR(ENOMEM);
86
87 /* defaults */
88 s->font = avpriv_vga16_font;
89 s->font_height = 16;
90 s->fg = DEFAULT_FG_COLOR;
91 s->bg = DEFAULT_BG_COLOR;
92
93 if (!avctx->width || !avctx->height) {
94 int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);
95 if (ret < 0)
96 return ret;
97 } else if (avctx->width % FONT_WIDTH || avctx->height % s->font_height) {
98 av_log(avctx, AV_LOG_ERROR, "Invalid dimensions %d %d\n", avctx->width, avctx->height);
99 return AVERROR(EINVAL);
100 }
101 return 0;
102}
103
104static void set_palette(uint32_t *pal)
105{
106 int r, g, b;
107 memcpy(pal, ff_cga_palette, 16 * 4);
108 pal += 16;
109#define COLOR(x) ((x) * 40 + 55)
110 for (r = 0; r < 6; r++)
111 for (g = 0; g < 6; g++)
112 for (b = 0; b < 6; b++)
113 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
114#define GRAY(x) ((x) * 10 + 8)
115 for (g = 0; g < 24; g++)
116 *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
117}
118
119static void hscroll(AVCodecContext *avctx)
120{
121 AnsiContext *s = avctx->priv_data;
122 int i;
123
124 if (s->y <= avctx->height - 2*s->font_height) {
125 s->y += s->font_height;
126 return;
127 }
128
129 i = 0;
130 for (; i < avctx->height - s->font_height; i++)
131 memcpy(s->frame->data[0] + i * s->frame->linesize[0],
132 s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
133 avctx->width);
134 for (; i < avctx->height; i++)
135 memset(s->frame->data[0] + i * s->frame->linesize[0],
136 DEFAULT_BG_COLOR, avctx->width);
137}
138
139static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
140{
141 AnsiContext *s = avctx->priv_data;
142 int i;
143 for (i = 0; i < s->font_height; i++)
144 memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
145 DEFAULT_BG_COLOR, xlength);
146}
147
148static void erase_screen(AVCodecContext *avctx)
149{
150 AnsiContext *s = avctx->priv_data;
151 int i;
152 for (i = 0; i < avctx->height; i++)
153 memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
154 s->x = s->y = 0;
155}
156
157/**
158 * Draw character to screen
159 */
160static void draw_char(AVCodecContext *avctx, int c)
161{
162 AnsiContext *s = avctx->priv_data;
163 int fg = s->fg;
164 int bg = s->bg;
165
166 if ((s->attributes & ATTR_BOLD))
167 fg += 8;
168 if ((s->attributes & ATTR_BLINK))
169 bg += 8;
170 if ((s->attributes & ATTR_REVERSE))
171 FFSWAP(int, fg, bg);
172 if ((s->attributes & ATTR_CONCEALED))
173 fg = bg;
174 ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
175 s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
176 s->x += FONT_WIDTH;
177 if (s->x > avctx->width - FONT_WIDTH) {
178 s->x = 0;
179 hscroll(avctx);
180 }
181}
182
183/**
184 * Execute ANSI escape code
185 * @return 0 on success, negative on error
186 */
187static int execute_code(AVCodecContext * avctx, int c)
188{
189 AnsiContext *s = avctx->priv_data;
190 int ret, i;
191 int width = avctx->width;
192 int height = avctx->height;
193
194 switch(c) {
195 case 'A': //Cursor Up
196 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
197 break;
198 case 'B': //Cursor Down
199 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
200 break;
201 case 'C': //Cursor Right
202 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
203 break;
204 case 'D': //Cursor Left
205 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
206 break;
207 case 'H': //Cursor Position
208 case 'f': //Horizontal and Vertical Position
209 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
210 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
211 break;
212 case 'h': //set screen mode
213 case 'l': //reset screen mode
214 if (s->nb_args < 2)
215 s->args[0] = DEFAULT_SCREEN_MODE;
216 switch(s->args[0]) {
217 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
218 s->font = avpriv_cga_font;
219 s->font_height = 8;
220 width = 40<<3;
221 height = 25<<3;
222 break;
223 case 2: case 3: //640x400 (25 rows)
224 s->font = avpriv_vga16_font;
225 s->font_height = 16;
226 width = 80<<3;
227 height = 25<<4;
228 break;
229 case 6: case 14: //640x200 (25 rows)
230 s->font = avpriv_cga_font;
231 s->font_height = 8;
232 width = 80<<3;
233 height = 25<<3;
234 break;
235 case 7: //set line wrapping
236 break;
237 case 15: case 16: //640x350 (43 rows)
238 s->font = avpriv_cga_font;
239 s->font_height = 8;
240 width = 80<<3;
241 height = 43<<3;
242 break;
243 case 17: case 18: //640x480 (60 rows)
244 s->font = avpriv_cga_font;
245 s->font_height = 8;
246 width = 80<<3;
247 height = 60<<4;
248 break;
249 default:
250 avpriv_request_sample(avctx, "Unsupported screen mode");
251 }
252 s->x = av_clip(s->x, 0, width - FONT_WIDTH);
253 s->y = av_clip(s->y, 0, height - s->font_height);
254 if (width != avctx->width || height != avctx->height) {
255 av_frame_unref(s->frame);
256 ret = ff_set_dimensions(avctx, width, height);
257 if (ret < 0)
258 return ret;
259 if ((ret = ff_get_buffer(avctx, s->frame,
260 AV_GET_BUFFER_FLAG_REF)) < 0)
261 return ret;
262 s->frame->pict_type = AV_PICTURE_TYPE_I;
263 s->frame->palette_has_changed = 1;
264 set_palette((uint32_t *)s->frame->data[1]);
265 erase_screen(avctx);
266 } else if (c == 'l') {
267 erase_screen(avctx);
268 }
269 break;
270 case 'J': //Erase in Page
271 switch (s->args[0]) {
272 case 0:
273 erase_line(avctx, s->x, avctx->width - s->x);
274 if (s->y < avctx->height - s->font_height)
275 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
276 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
277 break;
278 case 1:
279 erase_line(avctx, 0, s->x);
280 if (s->y > 0)
281 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
282 break;
283 case 2:
284 erase_screen(avctx);
285 }
286 break;
287 case 'K': //Erase in Line
288 switch(s->args[0]) {
289 case 0:
290 erase_line(avctx, s->x, avctx->width - s->x);
291 break;
292 case 1:
293 erase_line(avctx, 0, s->x);
294 break;
295 case 2:
296 erase_line(avctx, 0, avctx->width);
297 }
298 break;
299 case 'm': //Select Graphics Rendition
300 if (s->nb_args == 0) {
301 s->nb_args = 1;
302 s->args[0] = 0;
303 }
304 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
305 int m = s->args[i];
306 if (m == 0) {
307 s->attributes = 0;
308 s->fg = DEFAULT_FG_COLOR;
309 s->bg = DEFAULT_BG_COLOR;
310 } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
311 s->attributes |= 1 << (m - 1);
312 } else if (m >= 30 && m <= 37) {
313 s->fg = ansi_to_cga[m - 30];
314 } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
315 int index = s->args[i + 2];
316 s->fg = index < 16 ? ansi_to_cga[index] : index;
317 i += 2;
318 } else if (m == 39) {
319 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
320 } else if (m >= 40 && m <= 47) {
321 s->bg = ansi_to_cga[m - 40];
322 } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
323 int index = s->args[i + 2];
324 s->bg = index < 16 ? ansi_to_cga[index] : index;
325 i += 2;
326 } else if (m == 49) {
327 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
328 } else {
329 avpriv_request_sample(avctx, "Unsupported rendition parameter");
330 }
331 }
332 break;
333 case 'n': //Device Status Report
334 case 'R': //report current line and column
335 /* ignore */
336 break;
337 case 's': //Save Cursor Position
338 s->sx = s->x;
339 s->sy = s->y;
340 break;
341 case 'u': //Restore Cursor Position
342 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
343 s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
344 break;
345 default:
346 avpriv_request_sample(avctx, "Unknown escape code");
347 break;
348 }
349 s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH);
350 s->y = av_clip(s->y, 0, avctx->height - s->font_height);
351 return 0;
352}
353
354static int decode_frame(AVCodecContext *avctx,
355 void *data, int *got_frame,
356 AVPacket *avpkt)
357{
358 AnsiContext *s = avctx->priv_data;
359 uint8_t *buf = avpkt->data;
360 int buf_size = avpkt->size;
361 const uint8_t *buf_end = buf+buf_size;
362 int ret, i, count;
363
364 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
365 return ret;
366 if (!avctx->frame_number) {
367 for (i=0; i<avctx->height; i++)
368 memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);
369 memset(s->frame->data[1], 0, AVPALETTE_SIZE);
370 }
371
372 s->frame->pict_type = AV_PICTURE_TYPE_I;
373 s->frame->palette_has_changed = 1;
374 set_palette((uint32_t *)s->frame->data[1]);
375 if (!s->first_frame) {
376 erase_screen(avctx);
377 s->first_frame = 1;
378 }
379
380 while(buf < buf_end) {
381 switch(s->state) {
382 case STATE_NORMAL:
383 switch (buf[0]) {
384 case 0x00: //NUL
385 case 0x07: //BEL
386 case 0x1A: //SUB
387 /* ignore */
388 break;
389 case 0x08: //BS
390 s->x = FFMAX(s->x - 1, 0);
391 break;
392 case 0x09: //HT
393 i = s->x / FONT_WIDTH;
394 count = ((i + 8) & ~7) - i;
395 for (i = 0; i < count; i++)
396 draw_char(avctx, ' ');
397 break;
398 case 0x0A: //LF
399 hscroll(avctx);
400 case 0x0D: //CR
401 s->x = 0;
402 break;
403 case 0x0C: //FF
404 erase_screen(avctx);
405 break;
406 case 0x1B: //ESC
407 s->state = STATE_ESCAPE;
408 break;
409 default:
410 draw_char(avctx, buf[0]);
411 }
412 break;
413 case STATE_ESCAPE:
414 if (buf[0] == '[') {
415 s->state = STATE_CODE;
416 s->nb_args = 0;
417 s->args[0] = -1;
418 } else {
419 s->state = STATE_NORMAL;
420 draw_char(avctx, 0x1B);
421 continue;
422 }
423 break;
424 case STATE_CODE:
425 switch(buf[0]) {
426 case '0': case '1': case '2': case '3': case '4':
427 case '5': case '6': case '7': case '8': case '9':
428 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)
429 s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
430 break;
431 case ';':
432 s->nb_args++;
433 if (s->nb_args < MAX_NB_ARGS)
434 s->args[s->nb_args] = 0;
435 break;
436 case 'M':
437 s->state = STATE_MUSIC_PREAMBLE;
438 break;
439 case '=': case '?':
440 /* ignore */
441 break;
442 default:
443 if (s->nb_args > MAX_NB_ARGS)
444 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
445 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
446 s->nb_args++;
447 if ((ret = execute_code(avctx, buf[0])) < 0)
448 return ret;
449 s->state = STATE_NORMAL;
450 }
451 break;
452 case STATE_MUSIC_PREAMBLE:
453 if (buf[0] == 0x0E || buf[0] == 0x1B)
454 s->state = STATE_NORMAL;
455 /* ignore music data */
456 break;
457 }
458 buf++;
459 }
460
461 *got_frame = 1;
462 if ((ret = av_frame_ref(data, s->frame)) < 0)
463 return ret;
464 return buf_size;
465}
466
467static av_cold int decode_close(AVCodecContext *avctx)
468{
469 AnsiContext *s = avctx->priv_data;
470
471 av_frame_free(&s->frame);
472 return 0;
473}
474
475AVCodec ff_ansi_decoder = {
476 .name = "ansi",
477 .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
478 .type = AVMEDIA_TYPE_VIDEO,
479 .id = AV_CODEC_ID_ANSI,
480 .priv_data_size = sizeof(AnsiContext),
481 .init = decode_init,
482 .close = decode_close,
483 .decode = decode_frame,
484 .capabilities = AV_CODEC_CAP_DR1,
485 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
486};
487
generated by cgit at 2024-05-17 03:05:45 (GMT)