ffmpeg/libavcodec/ansi.c

   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 */
  49 static 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
  53 typedef 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
  78 static 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     }
  98     return 0;
  99 }
 100
 101 static void set_palette(uint32_t *pal)
 102 {
 103     int r, g, b;
 104     memcpy(pal, ff_cga_palette, 16 * 4);
 105     pal += 16;
 106 #define COLOR(x) ((x) * 40 + 55)
 107     for (r = 0; r < 6; r++)
 108         for (g = 0; g < 6; g++)
 109             for (b = 0; b < 6; b++)
 110                 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
 111 #define GRAY(x) ((x) * 10 + 8)
 112     for (g = 0; g < 24; g++)
 113         *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
 114 }
 115
 116 static void hscroll(AVCodecContext *avctx)
 117 {
 118     AnsiContext *s = avctx->priv_data;
 119     int i;
 120
 121     if (s->y <= avctx->height - 2*s->font_height) {
 122         s->y += s->font_height;
 123         return;
 124     }
 125
 126     i = 0;
 127     for (; i < avctx->height - s->font_height; i++)
 128         memcpy(s->frame->data[0] + i * s->frame->linesize[0],
 129                s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
 130                avctx->width);
 131     for (; i < avctx->height; i++)
 132         memset(s->frame->data[0] + i * s->frame->linesize[0],
 133             DEFAULT_BG_COLOR, avctx->width);
 134 }
 135
 136 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
 137 {
 138     AnsiContext *s = avctx->priv_data;
 139     int i;
 140     for (i = 0; i < s->font_height; i++)
 141         memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
 142             DEFAULT_BG_COLOR, xlength);
 143 }
 144
 145 static void erase_screen(AVCodecContext *avctx)
 146 {
 147     AnsiContext *s = avctx->priv_data;
 148     int i;
 149     for (i = 0; i < avctx->height; i++)
 150         memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
 151     s->x = s->y = 0;
 152 }
 153
 154 /**
 155  * Draw character to screen
 156  */
 157 static void draw_char(AVCodecContext *avctx, int c)
 158 {
 159     AnsiContext *s = avctx->priv_data;
 160     int fg = s->fg;
 161     int bg = s->bg;
 162
 163     if ((s->attributes & ATTR_BOLD))
 164         fg += 8;
 165     if ((s->attributes & ATTR_BLINK))
 166         bg += 8;
 167     if ((s->attributes & ATTR_REVERSE))
 168         FFSWAP(int, fg, bg);
 169     if ((s->attributes & ATTR_CONCEALED))
 170         fg = bg;
 171     ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
 172                     s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
 173     s->x += FONT_WIDTH;
 174     if (s->x > avctx->width - FONT_WIDTH) {
 175         s->x = 0;
 176         hscroll(avctx);
 177     }
 178 }
 179
 180 /**
 181  * Execute ANSI escape code
 182  * @return 0 on success, negative on error
 183  */
 184 static int execute_code(AVCodecContext * avctx, int c)
 185 {
 186     AnsiContext *s = avctx->priv_data;
 187     int ret, i;
 188     int width  = avctx->width;
 189     int height = avctx->height;
 190
 191     switch(c) {
 192     case 'A': //Cursor Up
 193         s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
 194         break;
 195     case 'B': //Cursor Down
 196         s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
 197         break;
 198     case 'C': //Cursor Right
 199         s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
 200         break;
 201     case 'D': //Cursor Left
 202         s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
 203         break;
 204     case 'H': //Cursor Position
 205     case 'f': //Horizontal and Vertical Position
 206         s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
 207         s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
 208         break;
 209     case 'h': //set creen mode
 210     case 'l': //reset screen mode
 211         if (s->nb_args < 2)
 212             s->args[0] = DEFAULT_SCREEN_MODE;
 213         switch(s->args[0]) {
 214         case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
 215             s->font = avpriv_cga_font;
 216             s->font_height = 8;
 217             width  = 40<<3;
 218             height = 25<<3;
 219             break;
 220         case 2: case 3: //640x400 (25 rows)
 221             s->font = avpriv_vga16_font;
 222             s->font_height = 16;
 223             width  = 80<<3;
 224             height = 25<<4;
 225             break;
 226         case 6: case 14: //640x200 (25 rows)
 227             s->font = avpriv_cga_font;
 228             s->font_height = 8;
 229             width  = 80<<3;
 230             height = 25<<3;
 231             break;
 232         case 7: //set line wrapping
 233             break;
 234         case 15: case 16: //640x350 (43 rows)
 235             s->font = avpriv_cga_font;
 236             s->font_height = 8;
 237             width  = 80<<3;
 238             height = 43<<3;
 239             break;
 240         case 17: case 18: //640x480 (60 rows)
 241             s->font = avpriv_cga_font;
 242             s->font_height = 8;
 243             width  = 80<<3;
 244             height = 60<<4;
 245             break;
 246         default:
 247             avpriv_request_sample(avctx, "Unsupported screen mode");
 248         }
 249         s->x = av_clip(s->x, 0, width  - FONT_WIDTH);
 250         s->y = av_clip(s->y, 0, height - s->font_height);
 251         if (width != avctx->width || height != avctx->height) {
 252             av_frame_unref(s->frame);
 253             ret = ff_set_dimensions(avctx, width, height);
 254             if (ret < 0)
 255                 return ret;
 256             if ((ret = ff_get_buffer(avctx, s->frame,
 257                                      AV_GET_BUFFER_FLAG_REF)) < 0)
 258                 return ret;
 259             s->frame->pict_type           = AV_PICTURE_TYPE_I;
 260             s->frame->palette_has_changed = 1;
 261             set_palette((uint32_t *)s->frame->data[1]);
 262             erase_screen(avctx);
 263         } else if (c == 'l') {
 264             erase_screen(avctx);
 265         }
 266         break;
 267     case 'J': //Erase in Page
 268         switch (s->args[0]) {
 269         case 0:
 270             erase_line(avctx, s->x, avctx->width - s->x);
 271             if (s->y < avctx->height - s->font_height)
 272                 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
 273                     DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
 274             break;
 275         case 1:
 276             erase_line(avctx, 0, s->x);
 277             if (s->y > 0)
 278                 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
 279             break;
 280         case 2:
 281             erase_screen(avctx);
 282         }
 283         break;
 284     case 'K': //Erase in Line
 285         switch(s->args[0]) {
 286         case 0:
 287             erase_line(avctx, s->x, avctx->width - s->x);
 288             break;
 289         case 1:
 290             erase_line(avctx, 0, s->x);
 291             break;
 292         case 2:
 293             erase_line(avctx, 0, avctx->width);
 294         }
 295         break;
 296     case 'm': //Select Graphics Rendition
 297         if (s->nb_args == 0) {
 298             s->nb_args = 1;
 299             s->args[0] = 0;
 300         }
 301         for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
 302             int m = s->args[i];
 303             if (m == 0) {
 304                 s->attributes = 0;
 305                 s->fg = DEFAULT_FG_COLOR;
 306                 s->bg = DEFAULT_BG_COLOR;
 307             } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
 308                 s->attributes |= 1 << (m - 1);
 309             } else if (m >= 30 && m <= 37) {
 310                 s->fg = ansi_to_cga[m - 30];
 311             } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
 312                 int index = s->args[i + 2];
 313                 s->fg = index < 16 ? ansi_to_cga[index] : index;
 314                 i += 2;
 315             } else if (m == 39) {
 316                 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
 317             } else if (m >= 40 && m <= 47) {
 318                 s->bg = ansi_to_cga[m - 40];
 319             } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
 320                 int index = s->args[i + 2];
 321                 s->bg = index < 16 ? ansi_to_cga[index] : index;
 322                 i += 2;
 323             } else if (m == 49) {
 324                 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
 325             } else {
 326                 avpriv_request_sample(avctx, "Unsupported rendition parameter");
 327             }
 328         }
 329         break;
 330     case 'n': //Device Status Report
 331     case 'R': //report current line and column
 332         /* ignore */
 333         break;
 334     case 's': //Save Cursor Position
 335         s->sx = s->x;
 336         s->sy = s->y;
 337         break;
 338     case 'u': //Restore Cursor Position
 339         s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
 340         s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
 341         break;
 342     default:
 343         avpriv_request_sample(avctx, "Unknown escape code");
 344         break;
 345     }
 346     s->x = av_clip(s->x, 0, avctx->width  - FONT_WIDTH);
 347     s->y = av_clip(s->y, 0, avctx->height - s->font_height);
 348     return 0;
 349 }
 350
 351 static int decode_frame(AVCodecContext *avctx,
 352                             void *data, int *got_frame,
 353                             AVPacket *avpkt)
 354 {
 355     AnsiContext *s = avctx->priv_data;
 356     uint8_t *buf = avpkt->data;
 357     int buf_size = avpkt->size;
 358     const uint8_t *buf_end   = buf+buf_size;
 359     int ret, i, count;
 360
 361     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
 362         return ret;
 363     if (!avctx->frame_number) {
 364         for (i=0; i<avctx->height; i++)
 365             memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);
 366         memset(s->frame->data[1], 0, AVPALETTE_SIZE);
 367     }
 368
 369     s->frame->pict_type           = AV_PICTURE_TYPE_I;
 370     s->frame->palette_has_changed = 1;
 371     set_palette((uint32_t *)s->frame->data[1]);
 372     if (!s->first_frame) {
 373         erase_screen(avctx);
 374         s->first_frame = 1;
 375     }
 376
 377     while(buf < buf_end) {
 378         switch(s->state) {
 379         case STATE_NORMAL:
 380             switch (buf[0]) {
 381             case 0x00: //NUL
 382             case 0x07: //BEL
 383             case 0x1A: //SUB
 384                 /* ignore */
 385                 break;
 386             case 0x08: //BS
 387                 s->x = FFMAX(s->x - 1, 0);
 388                 break;
 389             case 0x09: //HT
 390                 i = s->x / FONT_WIDTH;
 391                 count = ((i + 8) & ~7) - i;
 392                 for (i = 0; i < count; i++)
 393                     draw_char(avctx, ' ');
 394                 break;
 395             case 0x0A: //LF
 396                 hscroll(avctx);
 397             case 0x0D: //CR
 398                 s->x = 0;
 399                 break;
 400             case 0x0C: //FF
 401                 erase_screen(avctx);
 402                 break;
 403             case 0x1B: //ESC
 404                 s->state = STATE_ESCAPE;
 405                 break;
 406             default:
 407                 draw_char(avctx, buf[0]);
 408             }
 409             break;
 410         case STATE_ESCAPE:
 411             if (buf[0] == '[') {
 412                 s->state   = STATE_CODE;
 413                 s->nb_args = 0;
 414                 s->args[0] = -1;
 415             } else {
 416                 s->state = STATE_NORMAL;
 417                 draw_char(avctx, 0x1B);
 418                 continue;
 419             }
 420             break;
 421         case STATE_CODE:
 422             switch(buf[0]) {
 423             case '0': case '1': case '2': case '3': case '4':
 424             case '5': case '6': case '7': case '8': case '9':
 425                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)
 426                     s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
 427                 break;
 428             case ';':
 429                 s->nb_args++;
 430                 if (s->nb_args < MAX_NB_ARGS)
 431                     s->args[s->nb_args] = 0;
 432                 break;
 433             case 'M':
 434                 s->state = STATE_MUSIC_PREAMBLE;
 435                 break;
 436             case '=': case '?':
 437                 /* ignore */
 438                 break;
 439             default:
 440                 if (s->nb_args > MAX_NB_ARGS)
 441                     av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
 442                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
 443                     s->nb_args++;
 444                 if ((ret = execute_code(avctx, buf[0])) < 0)
 445                     return ret;
 446                 s->state = STATE_NORMAL;
 447             }
 448             break;
 449         case STATE_MUSIC_PREAMBLE:
 450             if (buf[0] == 0x0E || buf[0] == 0x1B)
 451                 s->state = STATE_NORMAL;
 452             /* ignore music data */
 453             break;
 454         }
 455         buf++;
 456     }
 457
 458     *got_frame = 1;
 459     if ((ret = av_frame_ref(data, s->frame)) < 0)
 460         return ret;
 461     return buf_size;
 462 }
 463
 464 static av_cold int decode_close(AVCodecContext *avctx)
 465 {
 466     AnsiContext *s = avctx->priv_data;
 467
 468     av_frame_free(&s->frame);
 469     return 0;
 470 }
 471
 472 AVCodec ff_ansi_decoder = {
 473     .name           = "ansi",
 474     .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
 475     .type           = AVMEDIA_TYPE_VIDEO,
 476     .id             = AV_CODEC_ID_ANSI,
 477     .priv_data_size = sizeof(AnsiContext),
 478     .init           = decode_init,
 479     .close          = decode_close,
 480     .decode         = decode_frame,
 481     .capabilities   = CODEC_CAP_DR1,
 482 };