FFmpeg: libavcodec/ansi.c Source File

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libavcodec

ansi.c

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1 /*

2 * ASCII/ANSI art decoder

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 */

22 /**

23 * @file

24 * ASCII/ANSI art decoder

25 */

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"

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) */

42 #define DEFAULT_FG_COLOR 7 /**< CGA color index */

43 #define DEFAULT_BG_COLOR 0

44 #define DEFAULT_SCREEN_MODE 3 /**< 80x25 */

46 #define FONT_WIDTH 8 /**< Font width */

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 };

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;

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;

78 static av_cold int decode_init(AVCodecContext *avctx)

79 {

80 AnsiContext *s = avctx->priv_data;

81 avctx->pix_fmt = AV_PIX_FMT_PAL8;

83 s->frame = av_frame_alloc();

84 if (!s->frame)

85 return AVERROR(ENOMEM);

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;

93 if (!avctx->width || !avctx->height)

94 avcodec_set_dimensions(avctx, 80<<3, 25<<4);

96 return 0;

97 }

99 static 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

114 static 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

134 static 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

143 static 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 */

155 static 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 */

182 static int execute_code(AVCodecContext * avctx, int c)

183 {

184 AnsiContext *s = avctx->priv_data;

185 int ret, i, width, height;

186 switch(c) {

187 case 'A': //Cursor Up

188 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);

189 break;

190 case 'B': //Cursor Down

191 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);

192 break;

193 case 'C': //Cursor Right

194 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);

195 break;

196 case 'D': //Cursor Left

197 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);

198 break;

199 case 'H': //Cursor Position

200 case 'f': //Horizontal and Vertical Position

201 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;

202 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;

203 break;

204 case 'h': //set creen mode

205 case 'l': //reset screen mode

206 if (s->nb_args < 2)

207 s->args[0] = DEFAULT_SCREEN_MODE;

208 width = avctx->width;

209 height = avctx->height;

210 switch(s->args[0]) {

211 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)

212 s->font = avpriv_cga_font;

213 s->font_height = 8;

214 width = 40<<3;

215 height = 25<<3;

216 break;

217 case 2: case 3: //640x400 (25 rows)

218 s->font = avpriv_vga16_font;

219 s->font_height = 16;

220 width = 80<<3;

221 height = 25<<4;

222 break;

223 case 6: case 14: //640x200 (25 rows)

224 s->font = avpriv_cga_font;

225 s->font_height = 8;

226 width = 80<<3;

227 height = 25<<3;

228 break;

229 case 7: //set line wrapping

230 break;

231 case 15: case 16: //640x350 (43 rows)

232 s->font = avpriv_cga_font;

233 s->font_height = 8;

234 width = 80<<3;

235 height = 43<<3;

236 break;

237 case 17: case 18: //640x480 (60 rows)

238 s->font = avpriv_cga_font;

239 s->font_height = 8;

240 width = 80<<3;

241 height = 60<<4;

242 break;

243 default:

244 avpriv_request_sample(avctx, "Unsupported screen mode");

245 }

246 s->x = av_clip(s->x, 0, width - FONT_WIDTH);

247 s->y = av_clip(s->y, 0, height - s->font_height);

248 if (width != avctx->width || height != avctx->height) {

249 av_frame_unref(s->frame);

250 avcodec_set_dimensions(avctx, width, height);

251 if ((ret = ff_get_buffer(avctx, s->frame,

252 AV_GET_BUFFER_FLAG_REF)) < 0)

253 return ret;

254 s->frame->pict_type = AV_PICTURE_TYPE_I;

255 s->frame->palette_has_changed = 1;

256 set_palette((uint32_t *)s->frame->data[1]);

257 erase_screen(avctx);

258 } else if (c == 'l') {

259 erase_screen(avctx);

260 }

261 break;

262 case 'J': //Erase in Page

263 switch (s->args[0]) {

264 case 0:

265 erase_line(avctx, s->x, avctx->width - s->x);

266 if (s->y < avctx->height - s->font_height)

267 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],

268 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);

269 break;

270 case 1:

271 erase_line(avctx, 0, s->x);

272 if (s->y > 0)

273 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);

274 break;

275 case 2:

276 erase_screen(avctx);

277 }

278 break;

279 case 'K': //Erase in Line

280 switch(s->args[0]) {

281 case 0:

282 erase_line(avctx, s->x, avctx->width - s->x);

283 break;

284 case 1:

285 erase_line(avctx, 0, s->x);

286 break;

287 case 2:

288 erase_line(avctx, 0, avctx->width);

289 }

290 break;

291 case 'm': //Select Graphics Rendition

292 if (s->nb_args == 0) {

293 s->nb_args = 1;

294 s->args[0] = 0;

295 }

296 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {

297 int m = s->args[i];

298 if (m == 0) {

299 s->attributes = 0;

300 s->fg = DEFAULT_FG_COLOR;

301 s->bg = DEFAULT_BG_COLOR;

302 } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {

303 s->attributes |= 1 << (m - 1);

304 } else if (m >= 30 && m <= 37) {

305 s->fg = ansi_to_cga[m - 30];

306 } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {

307 int index = s->args[i + 2];

308 s->fg = index < 16 ? ansi_to_cga[index] : index;

309 i += 2;

310 } else if (m == 39) {

311 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];

312 } else if (m >= 40 && m <= 47) {

313 s->bg = ansi_to_cga[m - 40];

314 } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {

315 int index = s->args[i + 2];

316 s->bg = index < 16 ? ansi_to_cga[index] : index;

317 i += 2;

318 } else if (m == 49) {

319 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];

320 } else {

321 avpriv_request_sample(avctx, "Unsupported rendition parameter");

322 }

323 }

324 break;

325 case 'n': //Device Status Report

326 case 'R': //report current line and column

327 /* ignore */

328 break;

329 case 's': //Save Cursor Position

330 s->sx = s->x;

331 s->sy = s->y;

332 break;

333 case 'u': //Restore Cursor Position

334 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);

335 s->y = av_clip(s->sy, 0, avctx->height - s->font_height);

336 break;

337 default:

338 avpriv_request_sample(avctx, "Unknown escape code");

339 break;

340 }

341 s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH);

342 s->y = av_clip(s->y, 0, avctx->height - s->font_height);

343 return 0;

344 }

345

346 static int decode_frame(AVCodecContext *avctx,

347 void *data, int *got_frame,

348 AVPacket *avpkt)

349 {

350 AnsiContext *s = avctx->priv_data;

351 uint8_t *buf = avpkt->data;

352 int buf_size = avpkt->size;

353 const uint8_t *buf_end = buf+buf_size;

354 int ret, i, count;

355

356 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)

357 return ret;

358 if (!avctx->frame_number) {

359 for (i=0; i<avctx->height; i++)

360 memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);

361 memset(s->frame->data[1], 0, AVPALETTE_SIZE);

362 }

363

364 s->frame->pict_type = AV_PICTURE_TYPE_I;

365 s->frame->palette_has_changed = 1;

366 set_palette((uint32_t *)s->frame->data[1]);

367 if (!s->first_frame) {

368 erase_screen(avctx);

369 s->first_frame = 1;

370 }

371

372 while(buf < buf_end) {

373 switch(s->state) {

374 case STATE_NORMAL:

375 switch (buf[0]) {

376 case 0x00: //NUL

377 case 0x07: //BEL

378 case 0x1A: //SUB

379 /* ignore */

380 break;

381 case 0x08: //BS

382 s->x = FFMAX(s->x - 1, 0);

383 break;

384 case 0x09: //HT

385 i = s->x / FONT_WIDTH;

386 count = ((i + 8) & ~7) - i;

387 for (i = 0; i < count; i++)

388 draw_char(avctx, ' ');

389 break;

390 case 0x0A: //LF

391 hscroll(avctx);

392 case 0x0D: //CR

393 s->x = 0;

394 break;

395 case 0x0C: //FF

396 erase_screen(avctx);

397 break;

398 case 0x1B: //ESC

399 s->state = STATE_ESCAPE;

400 break;

401 default:

402 draw_char(avctx, buf[0]);

403 }

404 break;

405 case STATE_ESCAPE:

406 if (buf[0] == '[') {

407 s->state = STATE_CODE;

408 s->nb_args = 0;

409 s->args[0] = -1;

410 } else {

411 s->state = STATE_NORMAL;

412 draw_char(avctx, 0x1B);

413 continue;

414 }

415 break;

416 case STATE_CODE:

417 switch(buf[0]) {

418 case '0': case '1': case '2': case '3': case '4':

419 case '5': case '6': case '7': case '8': case '9':

420 if (s->nb_args < MAX_NB_ARGS)

421 s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';

422 break;

423 case ';':

424 s->nb_args++;

425 if (s->nb_args < MAX_NB_ARGS)

426 s->args[s->nb_args] = 0;

427 break;

428 case 'M':

429 s->state = STATE_MUSIC_PREAMBLE;

430 break;

431 case '=': case '?':

432 /* ignore */

433 break;

434 default:

435 if (s->nb_args > MAX_NB_ARGS)

436 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);

437 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)

438 s->nb_args++;

439 if ((ret = execute_code(avctx, buf[0])) < 0)

440 return ret;

441 s->state = STATE_NORMAL;

442 }

443 break;

444 case STATE_MUSIC_PREAMBLE:

445 if (buf[0] == 0x0E || buf[0] == 0x1B)

446 s->state = STATE_NORMAL;

447 /* ignore music data */

448 break;

449 }

450 buf++;

451 }

452

453 *got_frame = 1;

454 if ((ret = av_frame_ref(data, s->frame)) < 0)

455 return ret;

456 return buf_size;

457 }

458

459 static av_cold int decode_close(AVCodecContext *avctx)

460 {

461 AnsiContext *s = avctx->priv_data;

462

463 av_frame_free(&s->frame);

464 return 0;

465 }

466

467 AVCodec ff_ansi_decoder = {

468 .name = "ansi",

469 .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),

470 .type = AVMEDIA_TYPE_VIDEO,

471 .id = AV_CODEC_ID_ANSI,

472 .priv_data_size = sizeof(AnsiContext),

473 .init = decode_init,

474 .close = decode_close,

475 .decode = decode_frame,

476 .capabilities = CODEC_CAP_DR1,

477 };

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