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 { 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 ff_set_dimensions(avctx, 80 << 3, 25 << 4); 95 96 return 0; 97} 98 99static void set_palette(uint32_t *pal) 100{ 101 int r, g, b; 102 memcpy(pal, ff_cga_palette, 16 * 4); 103 pal += 16; 104#define COLOR(x) ((x) * 40 + 55) 105 for (r = 0; r < 6; r++) 106 for (g = 0; g < 6; g++) 107 for (b = 0; b < 6; b++) 108 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b); 109#define GRAY(x) ((x) * 10 + 8) 110 for (g = 0; g < 24; g++) 111 *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g); 112} 113 114static void hscroll(AVCodecContext *avctx) 115{ 116 AnsiContext *s = avctx->priv_data; 117 int i; 118 119 if (s->y <= avctx->height - 2*s->font_height) { 120 s->y += s->font_height; 121 return; 122 } 123 124 i = 0; 125 for (; i < avctx->height - s->font_height; i++) 126 memcpy(s->frame->data[0] + i * s->frame->linesize[0], 127 s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0], 128 avctx->width); 129 for (; i < avctx->height; i++) 130 memset(s->frame->data[0] + i * s->frame->linesize[0], 131 DEFAULT_BG_COLOR, avctx->width); 132} 133 134static void erase_line(AVCodecContext * avctx, int xoffset, int xlength) 135{ 136 AnsiContext *s = avctx->priv_data; 137 int i; 138 for (i = 0; i < s->font_height; i++) 139 memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset, 140 DEFAULT_BG_COLOR, xlength); 141} 142 143static void erase_screen(AVCodecContext *avctx) 144{ 145 AnsiContext *s = avctx->priv_data; 146 int i; 147 for (i = 0; i < avctx->height; i++) 148 memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width); 149 s->x = s->y = 0; 150} 151 152/** 153 * Draw character to screen 154 */ 155static void draw_char(AVCodecContext *avctx, int c) 156{ 157 AnsiContext *s = avctx->priv_data; 158 int fg = s->fg; 159 int bg = s->bg; 160 161 if ((s->attributes & ATTR_BOLD)) 162 fg += 8; 163 if ((s->attributes & ATTR_BLINK)) 164 bg += 8; 165 if ((s->attributes & ATTR_REVERSE)) 166 FFSWAP(int, fg, bg); 167 if ((s->attributes & ATTR_CONCEALED)) 168 fg = bg; 169 ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x, 170 s->frame->linesize[0], s->font, s->font_height, c, fg, bg); 171 s->x += FONT_WIDTH; 172 if (s->x > avctx->width - FONT_WIDTH) { 173 s->x = 0; 174 hscroll(avctx); 175 } 176} 177 178/** 179 * Execute ANSI escape code 180 * @return 0 on success, negative on error 181 */ 182static int execute_code(AVCodecContext * avctx, int c) 183{ 184 AnsiContext *s = avctx->priv_data; 185 int ret, i; 186 int width = avctx->width; 187 int height = avctx->height; 188 189 switch(c) { 190 case 'A': //Cursor Up 191 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0); 192 break; 193 case 'B': //Cursor Down 194 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height); 195 break; 196 case 'C': //Cursor Right 197 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH); 198 break; 199 case 'D': //Cursor Left 200 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0); 201 break; 202 case 'H': //Cursor Position 203 case 'f': //Horizontal and Vertical Position 204 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0; 205 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0; 206 break; 207 case 'h': //set creen mode 208 case 'l': //reset screen mode 209 if (s->nb_args < 2) 210 s->args[0] = DEFAULT_SCREEN_MODE; 211 switch(s->args[0]) { 212 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows) 213 s->font = avpriv_cga_font; 214 s->font_height = 8; 215 width = 40<<3; 216 height = 25<<3; 217 break; 218 case 2: case 3: //640x400 (25 rows) 219 s->font = avpriv_vga16_font; 220 s->font_height = 16; 221 width = 80<<3; 222 height = 25<<4; 223 break; 224 case 6: case 14: //640x200 (25 rows) 225 s->font = avpriv_cga_font; 226 s->font_height = 8; 227 width = 80<<3; 228 height = 25<<3; 229 break; 230 case 7: //set line wrapping 231 break; 232 case 15: case 16: //640x350 (43 rows) 233 s->font = avpriv_cga_font; 234 s->font_height = 8; 235 width = 80<<3; 236 height = 43<<3; 237 break; 238 case 17: case 18: //640x480 (60 rows) 239 s->font = avpriv_cga_font; 240 s->font_height = 8; 241 width = 80<<3; 242 height = 60<<4; 243 break; 244 default: 245 avpriv_request_sample(avctx, "Unsupported screen mode"); 246 } 247 s->x = av_clip(s->x, 0, width - FONT_WIDTH); 248 s->y = av_clip(s->y, 0, height - s->font_height); 249 if (width != avctx->width || height != avctx->height) { 250 av_frame_unref(s->frame); 251 ret = ff_set_dimensions(avctx, width, height); 252 if (ret < 0) 253 return ret; 254 if ((ret = ff_get_buffer(avctx, s->frame, 255 AV_GET_BUFFER_FLAG_REF)) < 0) 256 return ret; 257 s->frame->pict_type = AV_PICTURE_TYPE_I; 258 s->frame->palette_has_changed = 1; 259 set_palette((uint32_t *)s->frame->data[1]); 260 erase_screen(avctx); 261 } else if (c == 'l') { 262 erase_screen(avctx); 263 } 264 break; 265 case 'J': //Erase in Page 266 switch (s->args[0]) { 267 case 0: 268 erase_line(avctx, s->x, avctx->width - s->x); 269 if (s->y < avctx->height - s->font_height) 270 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0], 271 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]); 272 break; 273 case 1: 274 erase_line(avctx, 0, s->x); 275 if (s->y > 0) 276 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]); 277 break; 278 case 2: 279 erase_screen(avctx); 280 } 281 break; 282 case 'K': //Erase in Line 283 switch(s->args[0]) { 284 case 0: 285 erase_line(avctx, s->x, avctx->width - s->x); 286 break; 287 case 1: 288 erase_line(avctx, 0, s->x); 289 break; 290 case 2: 291 erase_line(avctx, 0, avctx->width); 292 } 293 break; 294 case 'm': //Select Graphics Rendition 295 if (s->nb_args == 0) { 296 s->nb_args = 1; 297 s->args[0] = 0; 298 } 299 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) { 300 int m = s->args[i]; 301 if (m == 0) { 302 s->attributes = 0; 303 s->fg = DEFAULT_FG_COLOR; 304 s->bg = DEFAULT_BG_COLOR; 305 } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) { 306 s->attributes |= 1 << (m - 1); 307 } else if (m >= 30 && m <= 37) { 308 s->fg = ansi_to_cga[m - 30]; 309 } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) { 310 int index = s->args[i + 2]; 311 s->fg = index < 16 ? ansi_to_cga[index] : index; 312 i += 2; 313 } else if (m == 39) { 314 s->fg = ansi_to_cga[DEFAULT_FG_COLOR]; 315 } else if (m >= 40 && m <= 47) { 316 s->bg = ansi_to_cga[m - 40]; 317 } else if (m == 48 && 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->bg = index < 16 ? ansi_to_cga[index] : index; 320 i += 2; 321 } else if (m == 49) { 322 s->fg = ansi_to_cga[DEFAULT_BG_COLOR]; 323 } else { 324 avpriv_request_sample(avctx, "Unsupported rendition parameter"); 325 } 326 } 327 break; 328 case 'n': //Device Status Report 329 case 'R': //report current line and column 330 /* ignore */ 331 break; 332 case 's': //Save Cursor Position 333 s->sx = s->x; 334 s->sy = s->y; 335 break; 336 case 'u': //Restore Cursor Position 337 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH); 338 s->y = av_clip(s->sy, 0, avctx->height - s->font_height); 339 break; 340 default: 341 avpriv_request_sample(avctx, "Unknown escape code"); 342 break; 343 } 344 s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH); 345 s->y = av_clip(s->y, 0, avctx->height - s->font_height); 346 return 0; 347} 348 349static int decode_frame(AVCodecContext *avctx, 350 void *data, int *got_frame, 351 AVPacket *avpkt) 352{ 353 AnsiContext *s = avctx->priv_data; 354 uint8_t *buf = avpkt->data; 355 int buf_size = avpkt->size; 356 const uint8_t *buf_end = buf+buf_size; 357 int ret, i, count; 358 359 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) 360 return ret; 361 if (!avctx->frame_number) { 362 for (i=0; i<avctx->height; i++) 363 memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width); 364 memset(s->frame->data[1], 0, AVPALETTE_SIZE); 365 } 366 367 s->frame->pict_type = AV_PICTURE_TYPE_I; 368 s->frame->palette_has_changed = 1; 369 set_palette((uint32_t *)s->frame->data[1]); 370 if (!s->first_frame) { 371 erase_screen(avctx); 372 s->first_frame = 1; 373 } 374 375 while(buf < buf_end) { 376 switch(s->state) { 377 case STATE_NORMAL: 378 switch (buf[0]) { 379 case 0x00: //NUL 380 case 0x07: //BEL 381 case 0x1A: //SUB 382 /* ignore */ 383 break; 384 case 0x08: //BS 385 s->x = FFMAX(s->x - 1, 0); 386 break; 387 case 0x09: //HT 388 i = s->x / FONT_WIDTH; 389 count = ((i + 8) & ~7) - i; 390 for (i = 0; i < count; i++) 391 draw_char(avctx, ' '); 392 break; 393 case 0x0A: //LF 394 hscroll(avctx); 395 case 0x0D: //CR 396 s->x = 0; 397 break; 398 case 0x0C: //FF 399 erase_screen(avctx); 400 break; 401 case 0x1B: //ESC 402 s->state = STATE_ESCAPE; 403 break; 404 default: 405 draw_char(avctx, buf[0]); 406 } 407 break; 408 case STATE_ESCAPE: 409 if (buf[0] == '[') { 410 s->state = STATE_CODE; 411 s->nb_args = 0; 412 s->args[0] = -1; 413 } else { 414 s->state = STATE_NORMAL; 415 draw_char(avctx, 0x1B); 416 continue; 417 } 418 break; 419 case STATE_CODE: 420 switch(buf[0]) { 421 case '0': case '1': case '2': case '3': case '4': 422 case '5': case '6': case '7': case '8': case '9': 423 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553) 424 s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0'; 425 break; 426 case ';': 427 s->nb_args++; 428 if (s->nb_args < MAX_NB_ARGS) 429 s->args[s->nb_args] = 0; 430 break; 431 case 'M': 432 s->state = STATE_MUSIC_PREAMBLE; 433 break; 434 case '=': case '?': 435 /* ignore */ 436 break; 437 default: 438 if (s->nb_args > MAX_NB_ARGS) 439 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args); 440 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0) 441 s->nb_args++; 442 if ((ret = execute_code(avctx, buf[0])) < 0) 443 return ret; 444 s->state = STATE_NORMAL; 445 } 446 break; 447 case STATE_MUSIC_PREAMBLE: 448 if (buf[0] == 0x0E || buf[0] == 0x1B) 449 s->state = STATE_NORMAL; 450 /* ignore music data */ 451 break; 452 } 453 buf++; 454 } 455 456 *got_frame = 1; 457 if ((ret = av_frame_ref(data, s->frame)) < 0) 458 return ret; 459 return buf_size; 460} 461 462static av_cold int decode_close(AVCodecContext *avctx) 463{ 464 AnsiContext *s = avctx->priv_data; 465 466 av_frame_free(&s->frame); 467 return 0; 468} 469 470AVCodec ff_ansi_decoder = { 471 .name = "ansi", 472 .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"), 473 .type = AVMEDIA_TYPE_VIDEO, 474 .id = AV_CODEC_ID_ANSI, 475 .priv_data_size = sizeof(AnsiContext), 476 .init = decode_init, 477 .close = decode_close, 478 .decode = decode_frame, 479 .capabilities = CODEC_CAP_DR1, 480}; 481