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 "codec_internal.h"
34 #include "internal.h"
35
36 #define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */
37 #define ATTR_FAINT 0x02 /**< Faint (mode 2) */
38 #define ATTR_ITALICS 0x04 /**< Italics (mode 3) */
39 #define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */
40 #define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */
41 #define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */
42 #define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */
43
44 #define DEFAULT_FG_COLOR 7 /**< CGA color index */
45 #define DEFAULT_BG_COLOR 0
46 #define DEFAULT_SCREEN_MODE 3 /**< 80x25 */
47
48 #define FONT_WIDTH 8 /**< Font width */
49
50 /** map ansi color index to cga palette index */
51 static const uint8_t ansi_to_cga[16] = {
52 0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
53 };
54
55 typedef struct AnsiContext {
56 AVFrame *frame;
57 int x; /**< x cursor position (pixels) */
58 int y; /**< y cursor position (pixels) */
59 int sx; /**< saved x cursor position (pixels) */
60 int sy; /**< saved y cursor position (pixels) */
61 const uint8_t* font; /**< font */
62 int font_height; /**< font height */
63 int attributes; /**< attribute flags */
64 int fg; /**< foreground color */
65 int bg; /**< background color */
66 int first_frame;
67
68 /* ansi parser state machine */
69 enum {
70 STATE_NORMAL = 0,
71 STATE_ESCAPE,
72 STATE_CODE,
73 STATE_MUSIC_PREAMBLE
74 } state;
75 #define MAX_NB_ARGS 4
76 int args[MAX_NB_ARGS];
77 int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */
78 } AnsiContext;
79
decode_init(AVCodecContext * avctx)80 static av_cold int decode_init(AVCodecContext *avctx)
81 {
82 AnsiContext *s = avctx->priv_data;
83 avctx->pix_fmt = AV_PIX_FMT_PAL8;
84
85 /* defaults */
86 s->font = avpriv_vga16_font;
87 s->font_height = 16;
88 s->fg = DEFAULT_FG_COLOR;
89 s->bg = DEFAULT_BG_COLOR;
90
91 if (!avctx->width || !avctx->height) {
92 int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);
93 if (ret < 0)
94 return ret;
95 } else if (avctx->width % FONT_WIDTH || avctx->height % s->font_height) {
96 av_log(avctx, AV_LOG_ERROR, "Invalid dimensions %d %d\n", avctx->width, avctx->height);
97 return AVERROR(EINVAL);
98 }
99
100 s->frame = av_frame_alloc();
101 if (!s->frame)
102 return AVERROR(ENOMEM);
103
104 return 0;
105 }
106
set_palette(uint32_t * pal)107 static void set_palette(uint32_t *pal)
108 {
109 int r, g, b;
110 memcpy(pal, ff_cga_palette, 16 * 4);
111 pal += 16;
112 #define COLOR(x) ((x) * 40 + 55)
113 for (r = 0; r < 6; r++)
114 for (g = 0; g < 6; g++)
115 for (b = 0; b < 6; b++)
116 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
117 #define GRAY(x) ((x) * 10 + 8)
118 for (g = 0; g < 24; g++)
119 *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
120 }
121
hscroll(AVCodecContext * avctx)122 static void hscroll(AVCodecContext *avctx)
123 {
124 AnsiContext *s = avctx->priv_data;
125 int i;
126
127 if (s->y <= avctx->height - 2*s->font_height) {
128 s->y += s->font_height;
129 return;
130 }
131
132 i = 0;
133 for (; i < avctx->height - s->font_height; i++)
134 memcpy(s->frame->data[0] + i * s->frame->linesize[0],
135 s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
136 avctx->width);
137 for (; i < avctx->height; i++)
138 memset(s->frame->data[0] + i * s->frame->linesize[0],
139 DEFAULT_BG_COLOR, avctx->width);
140 }
141
erase_line(AVCodecContext * avctx,int xoffset,int xlength)142 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
143 {
144 AnsiContext *s = avctx->priv_data;
145 int i;
146 for (i = 0; i < s->font_height; i++)
147 memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
148 DEFAULT_BG_COLOR, xlength);
149 }
150
erase_screen(AVCodecContext * avctx)151 static void erase_screen(AVCodecContext *avctx)
152 {
153 AnsiContext *s = avctx->priv_data;
154 int i;
155 for (i = 0; i < avctx->height; i++)
156 memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
157 s->x = s->y = 0;
158 }
159
160 /**
161 * Draw character to screen
162 */
draw_char(AVCodecContext * avctx,int c)163 static void draw_char(AVCodecContext *avctx, int c)
164 {
165 AnsiContext *s = avctx->priv_data;
166 int fg = s->fg;
167 int bg = s->bg;
168
169 if ((s->attributes & ATTR_BOLD))
170 fg += 8;
171 if ((s->attributes & ATTR_BLINK))
172 bg += 8;
173 if ((s->attributes & ATTR_REVERSE))
174 FFSWAP(int, fg, bg);
175 if ((s->attributes & ATTR_CONCEALED))
176 fg = bg;
177 ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
178 s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
179 s->x += FONT_WIDTH;
180 if (s->x > avctx->width - FONT_WIDTH) {
181 s->x = 0;
182 hscroll(avctx);
183 }
184 }
185
186 /**
187 * Execute ANSI escape code
188 * @return 0 on success, negative on error
189 */
execute_code(AVCodecContext * avctx,int c)190 static int execute_code(AVCodecContext * avctx, int c)
191 {
192 AnsiContext *s = avctx->priv_data;
193 int ret, i;
194 int width = avctx->width;
195 int height = avctx->height;
196
197 switch(c) {
198 case 'A': //Cursor Up
199 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
200 break;
201 case 'B': //Cursor Down
202 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
203 break;
204 case 'C': //Cursor Right
205 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
206 break;
207 case 'D': //Cursor Left
208 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
209 break;
210 case 'H': //Cursor Position
211 case 'f': //Horizontal and Vertical Position
212 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
213 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
214 break;
215 case 'h': //set screen mode
216 case 'l': //reset screen mode
217 if (s->nb_args < 2)
218 s->args[0] = DEFAULT_SCREEN_MODE;
219 switch(s->args[0]) {
220 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
221 s->font = avpriv_cga_font;
222 s->font_height = 8;
223 width = 40<<3;
224 height = 25<<3;
225 break;
226 case 2: case 3: //640x400 (25 rows)
227 s->font = avpriv_vga16_font;
228 s->font_height = 16;
229 width = 80<<3;
230 height = 25<<4;
231 break;
232 case 6: case 14: //640x200 (25 rows)
233 s->font = avpriv_cga_font;
234 s->font_height = 8;
235 width = 80<<3;
236 height = 25<<3;
237 break;
238 case 7: //set line wrapping
239 break;
240 case 15: case 16: //640x350 (43 rows)
241 s->font = avpriv_cga_font;
242 s->font_height = 8;
243 width = 80<<3;
244 height = 43<<3;
245 break;
246 case 17: case 18: //640x480 (60 rows)
247 s->font = avpriv_cga_font;
248 s->font_height = 8;
249 width = 80<<3;
250 height = 60<<4;
251 break;
252 default:
253 avpriv_request_sample(avctx, "Unsupported screen mode");
254 }
255 s->x = av_clip(s->x, 0, width - FONT_WIDTH);
256 s->y = av_clip(s->y, 0, height - s->font_height);
257 if (width != avctx->width || height != avctx->height) {
258 av_frame_unref(s->frame);
259 ret = ff_set_dimensions(avctx, width, height);
260 if (ret < 0)
261 return ret;
262 if ((ret = ff_get_buffer(avctx, s->frame,
263 AV_GET_BUFFER_FLAG_REF)) < 0)
264 return ret;
265 s->frame->pict_type = AV_PICTURE_TYPE_I;
266 s->frame->palette_has_changed = 1;
267 set_palette((uint32_t *)s->frame->data[1]);
268 erase_screen(avctx);
269 } else if (c == 'l') {
270 erase_screen(avctx);
271 }
272 break;
273 case 'J': //Erase in Page
274 switch (s->args[0]) {
275 case 0:
276 erase_line(avctx, s->x, avctx->width - s->x);
277 if (s->y < avctx->height - s->font_height)
278 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
279 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
280 break;
281 case 1:
282 erase_line(avctx, 0, s->x);
283 if (s->y > 0)
284 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
285 break;
286 case 2:
287 erase_screen(avctx);
288 }
289 break;
290 case 'K': //Erase in Line
291 switch(s->args[0]) {
292 case 0:
293 erase_line(avctx, s->x, avctx->width - s->x);
294 break;
295 case 1:
296 erase_line(avctx, 0, s->x);
297 break;
298 case 2:
299 erase_line(avctx, 0, avctx->width);
300 }
301 break;
302 case 'm': //Select Graphics Rendition
303 if (s->nb_args == 0) {
304 s->nb_args = 1;
305 s->args[0] = 0;
306 }
307 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
308 int m = s->args[i];
309 if (m == 0) {
310 s->attributes = 0;
311 s->fg = DEFAULT_FG_COLOR;
312 s->bg = DEFAULT_BG_COLOR;
313 } else if (m == 1 || m == 2 || m == 3 || m == 4 || m == 5 || m == 7 || m == 8) {
314 s->attributes |= 1 << (m - 1);
315 } else if (m >= 30 && m <= 37) {
316 s->fg = ansi_to_cga[m - 30];
317 } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
318 int index = s->args[i + 2];
319 s->fg = index < 16 ? ansi_to_cga[index] : index;
320 i += 2;
321 } else if (m == 39) {
322 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
323 } else if (m >= 40 && m <= 47) {
324 s->bg = ansi_to_cga[m - 40];
325 } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
326 int index = s->args[i + 2];
327 s->bg = index < 16 ? ansi_to_cga[index] : index;
328 i += 2;
329 } else if (m == 49) {
330 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
331 } else {
332 avpriv_request_sample(avctx, "Unsupported rendition parameter");
333 }
334 }
335 break;
336 case 'n': //Device Status Report
337 case 'R': //report current line and column
338 /* ignore */
339 break;
340 case 's': //Save Cursor Position
341 s->sx = s->x;
342 s->sy = s->y;
343 break;
344 case 'u': //Restore Cursor Position
345 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
346 s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
347 break;
348 default:
349 avpriv_request_sample(avctx, "Unknown escape code");
350 break;
351 }
352 s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH);
353 s->y = av_clip(s->y, 0, avctx->height - s->font_height);
354 return 0;
355 }
356
decode_frame(AVCodecContext * avctx,AVFrame * rframe,int * got_frame,AVPacket * avpkt)357 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
358 int *got_frame, AVPacket *avpkt)
359 {
360 AnsiContext *s = avctx->priv_data;
361 const uint8_t *buf = avpkt->data;
362 int buf_size = avpkt->size;
363 const uint8_t *buf_end = buf+buf_size;
364 int ret, i, count;
365
366 if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
367 return ret;
368 if (!avctx->frame_number) {
369 for (i=0; i<avctx->height; i++)
370 memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);
371 memset(s->frame->data[1], 0, AVPALETTE_SIZE);
372 }
373
374 s->frame->pict_type = AV_PICTURE_TYPE_I;
375 s->frame->palette_has_changed = 1;
376 set_palette((uint32_t *)s->frame->data[1]);
377 if (!s->first_frame) {
378 erase_screen(avctx);
379 s->first_frame = 1;
380 }
381
382 while(buf < buf_end) {
383 switch(s->state) {
384 case STATE_NORMAL:
385 switch (buf[0]) {
386 case 0x00: //NUL
387 case 0x07: //BEL
388 case 0x1A: //SUB
389 /* ignore */
390 break;
391 case 0x08: //BS
392 s->x = FFMAX(s->x - 1, 0);
393 break;
394 case 0x09: //HT
395 i = s->x / FONT_WIDTH;
396 count = ((i + 8) & ~7) - i;
397 for (i = 0; i < count; i++)
398 draw_char(avctx, ' ');
399 break;
400 case 0x0A: //LF
401 hscroll(avctx);
402 case 0x0D: //CR
403 s->x = 0;
404 break;
405 case 0x0C: //FF
406 erase_screen(avctx);
407 break;
408 case 0x1B: //ESC
409 s->state = STATE_ESCAPE;
410 break;
411 default:
412 draw_char(avctx, buf[0]);
413 }
414 break;
415 case STATE_ESCAPE:
416 if (buf[0] == '[') {
417 s->state = STATE_CODE;
418 s->nb_args = 0;
419 s->args[0] = -1;
420 } else {
421 s->state = STATE_NORMAL;
422 draw_char(avctx, 0x1B);
423 continue;
424 }
425 break;
426 case STATE_CODE:
427 switch(buf[0]) {
428 case '0': case '1': case '2': case '3': case '4':
429 case '5': case '6': case '7': case '8': case '9':
430 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)
431 s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
432 break;
433 case ';':
434 if (s->nb_args < MAX_NB_ARGS)
435 s->nb_args++;
436 if (s->nb_args < MAX_NB_ARGS)
437 s->args[s->nb_args] = 0;
438 break;
439 case 'M':
440 s->state = STATE_MUSIC_PREAMBLE;
441 break;
442 case '=': case '?':
443 /* ignore */
444 break;
445 default:
446 if (s->nb_args > MAX_NB_ARGS)
447 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
448 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
449 s->nb_args++;
450 if ((ret = execute_code(avctx, buf[0])) < 0)
451 return ret;
452 s->state = STATE_NORMAL;
453 }
454 break;
455 case STATE_MUSIC_PREAMBLE:
456 if (buf[0] == 0x0E || buf[0] == 0x1B)
457 s->state = STATE_NORMAL;
458 /* ignore music data */
459 break;
460 }
461 buf++;
462 }
463
464 *got_frame = 1;
465 if ((ret = av_frame_ref(rframe, s->frame)) < 0)
466 return ret;
467 return buf_size;
468 }
469
decode_close(AVCodecContext * avctx)470 static av_cold int decode_close(AVCodecContext *avctx)
471 {
472 AnsiContext *s = avctx->priv_data;
473
474 av_frame_free(&s->frame);
475 return 0;
476 }
477
478 static const FFCodecDefault ansi_defaults[] = {
479 { "max_pixels", "640*480" },
480 { NULL },
481 };
482
483 const FFCodec ff_ansi_decoder = {
484 .p.name = "ansi",
485 .p.long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
486 .p.type = AVMEDIA_TYPE_VIDEO,
487 .p.id = AV_CODEC_ID_ANSI,
488 .priv_data_size = sizeof(AnsiContext),
489 .init = decode_init,
490 .close = decode_close,
491 FF_CODEC_DECODE_CB(decode_frame),
492 .p.capabilities = AV_CODEC_CAP_DR1,
493 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
494 .defaults = ansi_defaults,
495 };
496