1/* 2 * ASCII/ANSI art decoder 3 * Copyright (c) 2010 Peter Ross <pross@xvid.org> 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; 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/lfg.h" 28#include "avcodec.h" 29#include "cga_data.h" 30 31#define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */ 32#define ATTR_FAINT 0x02 /**< Faint (mode 2) */ 33#define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */ 34#define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */ 35#define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */ 36#define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */ 37 38#define DEFAULT_FG_COLOR 7 /**< CGA color index */ 39#define DEFAULT_BG_COLOR 0 40#define DEFAULT_SCREEN_MODE 3 /**< 80x25 */ 41 42#define FONT_WIDTH 8 /**< Font width */ 43 44/** map ansi color index to cga palette index */ 45static const uint8_t ansi_to_cga[16] = { 46 0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15 47}; 48 49typedef struct { 50 AVFrame frame; 51 int x; /**< x cursor position (pixels) */ 52 int y; /**< y cursor position (pixels) */ 53 int sx; /**< saved x cursor position (pixels) */ 54 int sy; /**< saved y cursor position (pixels) */ 55 const uint8_t* font; /**< font */ 56 int font_height; /**< font height */ 57 int attributes; /**< attribute flags */ 58 int fg; /**< foreground color */ 59 int bg; /**< background color */ 60 61 /* ansi parser state machine */ 62 enum { 63 STATE_NORMAL = 0, 64 STATE_ESCAPE, 65 STATE_CODE, 66 STATE_MUSIC_PREAMBLE 67 } state; 68#define MAX_NB_ARGS 4 69 int args[MAX_NB_ARGS]; 70 int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */ 71} AnsiContext; 72 73static av_cold int decode_init(AVCodecContext *avctx) 74{ 75 AnsiContext *s = avctx->priv_data; 76 avctx->pix_fmt = PIX_FMT_PAL8; 77 78 /* defaults */ 79 s->font = ff_vga16_font; 80 s->font_height = 16; 81 s->fg = DEFAULT_FG_COLOR; 82 s->bg = DEFAULT_BG_COLOR; 83 84 if (!avctx->width || !avctx->height) 85 avcodec_set_dimensions(avctx, 80<<3, 25<<4); 86 87 return 0; 88} 89 90static void hscroll(AVCodecContext *avctx) 91{ 92 AnsiContext *s = avctx->priv_data; 93 int i; 94 95 if (s->y < avctx->height - s->font_height) { 96 s->y += s->font_height; 97 return; 98 } 99 100 i = 0; 101 for (; i < avctx->height - s->font_height; i++) 102 memcpy(s->frame.data[0] + i * s->frame.linesize[0], 103 s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0], 104 avctx->width); 105 for (; i < avctx->height; i++) 106 memset(s->frame.data[0] + i * s->frame.linesize[0], 107 DEFAULT_BG_COLOR, avctx->width); 108} 109 110static void erase_line(AVCodecContext * avctx, int xoffset, int xlength) 111{ 112 AnsiContext *s = avctx->priv_data; 113 int i; 114 for (i = 0; i < s->font_height; i++) 115 memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset, 116 DEFAULT_BG_COLOR, xlength); 117} 118 119static void erase_screen(AVCodecContext *avctx) 120{ 121 AnsiContext *s = avctx->priv_data; 122 int i; 123 for (i = 0; i < avctx->height; i++) 124 memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width); 125 s->x = s->y = 0; 126} 127 128/** 129 * Draw character to screen 130 */ 131static void draw_char(AVCodecContext *avctx, int c) 132{ 133 AnsiContext *s = avctx->priv_data; 134 int fg = s->fg; 135 int bg = s->bg; 136 137 if ((s->attributes & ATTR_BOLD)) 138 fg += 8; 139 if ((s->attributes & ATTR_BLINK)) 140 bg += 8; 141 if ((s->attributes & ATTR_REVERSE)) 142 FFSWAP(int, fg, bg); 143 if ((s->attributes & ATTR_CONCEALED)) 144 fg = bg; 145 ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x, 146 s->frame.linesize[0], s->font, s->font_height, c, fg, bg); 147 s->x += FONT_WIDTH; 148 if (s->x >= avctx->width) { 149 s->x = 0; 150 hscroll(avctx); 151 } 152} 153 154/** 155 * Execute ANSI escape code 156 * @return 0 on success, negative on error 157 */ 158static int execute_code(AVCodecContext * avctx, int c) 159{ 160 AnsiContext *s = avctx->priv_data; 161 int ret, i, width, height; 162 switch(c) { 163 case 'A': //Cursor Up 164 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0); 165 break; 166 case 'B': //Cursor Down 167 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height); 168 break; 169 case 'C': //Cursor Right 170 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH); 171 break; 172 case 'D': //Cursor Left 173 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0); 174 break; 175 case 'H': //Cursor Position 176 case 'f': //Horizontal and Vertical Position 177 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0; 178 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0; 179 break; 180 case 'h': //set creen mode 181 case 'l': //reset screen mode 182 if (s->nb_args < 2) 183 s->args[0] = DEFAULT_SCREEN_MODE; 184 switch(s->args[0]) { 185 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows) 186 s->font = ff_cga_font; 187 s->font_height = 8; 188 width = 40<<3; 189 height = 25<<3; 190 break; 191 case 2: case 3: //640x400 (25 rows) 192 s->font = ff_vga16_font; 193 s->font_height = 16; 194 width = 80<<3; 195 height = 25<<4; 196 break; 197 case 6: case 14: //640x200 (25 rows) 198 s->font = ff_cga_font; 199 s->font_height = 8; 200 width = 80<<3; 201 height = 25<<3; 202 break; 203 case 7: //set line wrapping 204 break; 205 case 15: case 16: //640x350 (43 rows) 206 s->font = ff_cga_font; 207 s->font_height = 8; 208 width = 80<<3; 209 height = 43<<3; 210 break; 211 case 17: case 18: //640x480 (60 rows) 212 s->font = ff_cga_font; 213 s->font_height = 8; 214 width = 80<<3; 215 height = 60<<4; 216 break; 217 default: 218 av_log_ask_for_sample(avctx, "unsupported screen mode\n"); 219 } 220 if (width != avctx->width || height != avctx->height) { 221 if (s->frame.data[0]) 222 avctx->release_buffer(avctx, &s->frame); 223 avcodec_set_dimensions(avctx, width, height); 224 ret = avctx->get_buffer(avctx, &s->frame); 225 if (ret < 0) { 226 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 227 return ret; 228 } 229 s->frame.pict_type = AV_PICTURE_TYPE_I; 230 s->frame.palette_has_changed = 1; 231 memcpy(s->frame.data[1], ff_cga_palette, 16 * 4); 232 erase_screen(avctx); 233 } else if (c == 'l') { 234 erase_screen(avctx); 235 } 236 break; 237 case 'J': //Erase in Page 238 switch (s->args[0]) { 239 case 0: 240 erase_line(avctx, s->x, avctx->width - s->x); 241 if (s->y < avctx->height - s->font_height) 242 memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0], 243 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]); 244 break; 245 case 1: 246 erase_line(avctx, 0, s->x); 247 if (s->y > 0) 248 memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]); 249 break; 250 case 2: 251 erase_screen(avctx); 252 } 253 break; 254 case 'K': //Erase in Line 255 switch(s->args[0]) { 256 case 0: 257 erase_line(avctx, s->x, avctx->width - s->x); 258 break; 259 case 1: 260 erase_line(avctx, 0, s->x); 261 break; 262 case 2: 263 erase_line(avctx, 0, avctx->width); 264 } 265 break; 266 case 'm': //Select Graphics Rendition 267 if (s->nb_args == 0) { 268 s->nb_args = 1; 269 s->args[0] = 0; 270 } 271 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) { 272 int m = s->args[i]; 273 if (m == 0) { 274 s->attributes = 0; 275 s->fg = DEFAULT_FG_COLOR; 276 s->bg = DEFAULT_BG_COLOR; 277 } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) { 278 s->attributes |= 1 << (m - 1); 279 } else if (m >= 30 && m <= 38) { 280 s->fg = ansi_to_cga[m - 30]; 281 } else if (m == 39) { 282 s->fg = ansi_to_cga[DEFAULT_FG_COLOR]; 283 } else if (m >= 40 && m <= 47) { 284 s->bg = ansi_to_cga[m - 40]; 285 } else if (m == 49) { 286 s->fg = ansi_to_cga[DEFAULT_BG_COLOR]; 287 } else { 288 av_log_ask_for_sample(avctx, "unsupported rendition parameter\n"); 289 } 290 } 291 break; 292 case 'n': //Device Status Report 293 case 'R': //report current line and column 294 /* ignore */ 295 break; 296 case 's': //Save Cursor Position 297 s->sx = s->x; 298 s->sy = s->y; 299 break; 300 case 'u': //Restore Cursor Position 301 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH); 302 s->y = av_clip(s->sy, 0, avctx->height - s->font_height); 303 break; 304 default: 305 av_log_ask_for_sample(avctx, "unsupported escape code\n"); 306 break; 307 } 308 return 0; 309} 310 311static int decode_frame(AVCodecContext *avctx, 312 void *data, int *data_size, 313 AVPacket *avpkt) 314{ 315 AnsiContext *s = avctx->priv_data; 316 uint8_t *buf = avpkt->data; 317 int buf_size = avpkt->size; 318 const uint8_t *buf_end = buf+buf_size; 319 int ret, i, count; 320 321 ret = avctx->reget_buffer(avctx, &s->frame); 322 if (ret < 0){ 323 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 324 return ret; 325 } 326 s->frame.pict_type = AV_PICTURE_TYPE_I; 327 s->frame.palette_has_changed = 1; 328 memcpy(s->frame.data[1], ff_cga_palette, 16 * 4); 329 330 while(buf < buf_end) { 331 switch(s->state) { 332 case STATE_NORMAL: 333 switch (buf[0]) { 334 case 0x00: //NUL 335 case 0x07: //BEL 336 case 0x1A: //SUB 337 /* ignore */ 338 break; 339 case 0x08: //BS 340 s->x = FFMAX(s->x - 1, 0); 341 break; 342 case 0x09: //HT 343 i = s->x / FONT_WIDTH; 344 count = ((i + 8) & ~7) - i; 345 for (i = 0; i < count; i++) 346 draw_char(avctx, ' '); 347 break; 348 case 0x0A: //LF 349 hscroll(avctx); 350 case 0x0D: //CR 351 s->x = 0; 352 break; 353 case 0x0C: //FF 354 erase_screen(avctx); 355 break; 356 case 0x1B: //ESC 357 s->state = STATE_ESCAPE; 358 break; 359 default: 360 draw_char(avctx, buf[0]); 361 } 362 break; 363 case STATE_ESCAPE: 364 if (buf[0] == '[') { 365 s->state = STATE_CODE; 366 s->nb_args = 0; 367 s->args[0] = 0; 368 } else { 369 s->state = STATE_NORMAL; 370 draw_char(avctx, 0x1B); 371 return -1; 372 continue; 373 } 374 break; 375 case STATE_CODE: 376 switch(buf[0]) { 377 case '0': case '1': case '2': case '3': case '4': 378 case '5': case '6': case '7': case '8': case '9': 379 if (s->nb_args < MAX_NB_ARGS) 380 s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0'; 381 break; 382 case ';': 383 s->nb_args++; 384 if (s->nb_args < MAX_NB_ARGS) 385 s->args[s->nb_args] = 0; 386 break; 387 case 'M': 388 s->state = STATE_MUSIC_PREAMBLE; 389 break; 390 case '=': case '?': 391 /* ignore */ 392 break; 393 default: 394 if (s->nb_args > MAX_NB_ARGS) 395 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args); 396 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args]) 397 s->nb_args++; 398 if (execute_code(avctx, buf[0]) < 0) 399 return -1; 400 s->state = STATE_NORMAL; 401 } 402 break; 403 case STATE_MUSIC_PREAMBLE: 404 if (buf[0] == 0x0E || buf[0] == 0x1B) 405 s->state = STATE_NORMAL; 406 /* ignore music data */ 407 break; 408 } 409 buf++; 410 } 411 412 *data_size = sizeof(AVFrame); 413 *(AVFrame*)data = s->frame; 414 return buf_size; 415} 416 417static av_cold int decode_close(AVCodecContext *avctx) 418{ 419 AnsiContext *s = avctx->priv_data; 420 if (s->frame.data[0]) 421 avctx->release_buffer(avctx, &s->frame); 422 return 0; 423} 424 425AVCodec ff_ansi_decoder = { 426 .name = "ansi", 427 .type = AVMEDIA_TYPE_VIDEO, 428 .id = CODEC_ID_ANSI, 429 .priv_data_size = sizeof(AnsiContext), 430 .init = decode_init, 431 .close = decode_close, 432 .decode = decode_frame, 433 .capabilities = CODEC_CAP_DR1, 434 .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"), 435}; 436