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 */ 51static 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 55typedef 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 80static 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 107static 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 122static 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 142static 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 151static 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 */ 163static 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 */ 190static 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 357static 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 470static 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 478static const FFCodecDefault ansi_defaults[] = { 479 { "max_pixels", "640*480" }, 480 { NULL }, 481}; 482 483const 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