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1 /* 2 * libcaca Colour ASCII-Art library 3 * Copyright © 2002—2018 Sam Hocevar <sam@hocevar.net> 4 * All Rights Reserved 5 * 6 * This library is free software. It comes without any warranty, to 7 * the extent permitted by applicable law. You can redistribute it 8 * and/or modify it under the terms of the Do What the Fuck You Want 9 * to Public License, Version 2, as published by Sam Hocevar. See 10 * http://www.wtfpl.net/ for more details. 11 */ 12 13 /* 14 * This file contains functions for attribute management and colourspace 15 * conversions. 16 */ 17 18 #include "config.h" 19 20 #include "caca.h" 21 #include "caca_internals.h" 22 23 static uint8_t nearest_ansi(uint16_t); 24 25 /* RGB colours for the ANSI palette. There is no real standard, so we 26 * use the same values as gnome-terminal. The 7th colour (brown) is a bit 27 * special: 0xfa50 instead of 0xfaa0. */ 28 static const uint16_t ansitab16[16] = 29 { 30 0xf000, 0xf00a, 0xf0a0, 0xf0aa, 0xfa00, 0xfa0a, 0xfa50, 0xfaaa, 31 0xf555, 0xf55f, 0xf5f5, 0xf5ff, 0xff55, 0xff5f, 0xfff5, 0xffff, 32 }; 33 34 /* Same table, except on 14 bits (3-4-4-3) */ 35 static const uint16_t ansitab14[16] = 36 { 37 0x3800, 0x3805, 0x3850, 0x3855, 0x3d00, 0x3d05, 0x3d28, 0x3d55, 38 0x3aaa, 0x3aaf, 0x3afa, 0x3aff, 0x3faa, 0x3faf, 0x3ffa, 0x3fff, 39 }; 40 41 /** \brief Get the text attribute at the given coordinates. 42 * 43 * Get the internal \e libcaca attribute value of the character at the 44 * given coordinates. The attribute value has 32 significant bits, 45 * organised as follows from MSB to LSB: 46 * - 3 bits for the background alpha 47 * - 4 bits for the background red component 48 * - 4 bits for the background green component 49 * - 3 bits for the background blue component 50 * - 3 bits for the foreground alpha 51 * - 4 bits for the foreground red component 52 * - 4 bits for the foreground green component 53 * - 3 bits for the foreground blue component 54 * - 4 bits for the bold, italics, underline and blink flags 55 * 56 * If the coordinates are outside the canvas boundaries, the current 57 * attribute is returned. 58 * 59 * This function never fails. 60 * 61 * \param cv A handle to the libcaca canvas. 62 * \param x X coordinate. 63 * \param y Y coordinate. 64 * \return The requested attribute. 65 */ 66 uint32_t caca_get_attr(caca_canvas_t const *cv, int x, int y) 67 { 68 if(x < 0 || x >= (int)cv->width || y < 0 || y >= (int)cv->height) 69 return cv->curattr; 70 71 return cv->attrs[x + y * cv->width]; 72 } 73 74 /** \brief Set the default character attribute. 75 * 76 * Set the default character attribute for drawing. Attributes define 77 * foreground and background colour, transparency, bold, italics and 78 * underline styles, as well as blink. String functions such as 79 * caca_printf() and graphical primitive functions such as caca_draw_line() 80 * will use this attribute. 81 * 82 * The value of \e attr is either: 83 * - a 32-bit integer as returned by caca_get_attr(), in which case it 84 * also contains colour information, 85 * - a combination (bitwise OR) of style values (\e CACA_UNDERLINE, 86 * \e CACA_BLINK, \e CACA_BOLD and \e CACA_ITALICS), in which case 87 * setting the attribute does not modify the current colour information. 88 * 89 * To retrieve the current attribute value, use caca_get_attr(-1,-1). 90 * 91 * This function never fails. 92 * 93 * \param cv A handle to the libcaca canvas. 94 * \param attr The requested attribute value. 95 * \return This function always returns 0. 96 */ 97 int caca_set_attr(caca_canvas_t *cv, uint32_t attr) 98 { 99 if(attr < 0x00000010) 100 attr = (cv->curattr & 0xfffffff0) | attr; 101 102 cv->curattr = attr; 103 104 return 0; 105 } 106 107 /** \brief Unset flags in the default character attribute. 108 * 109 * Unset flags in the default character attribute for drawing. Attributes 110 * define foreground and background colour, transparency, bold, italics and 111 * underline styles, as well as blink. String functions such as 112 * caca_printf() and graphical primitive functions such as caca_draw_line() 113 * will use this attribute. 114 * 115 * The value of \e attr is a combination (bitwise OR) of style values 116 * (\e CACA_UNDERLINE, \e CACA_BLINK, \e CACA_BOLD and \e CACA_ITALICS). 117 * Unsetting these attributes does not modify the current colour information. 118 * 119 * To retrieve the current attribute value, use caca_get_attr(-1,-1). 120 * 121 * This function never fails. 122 * 123 * \param cv A handle to the libcaca canvas. 124 * \param attr The requested attribute values to unset. 125 * \return This function always returns 0. 126 */ 127 int caca_unset_attr(caca_canvas_t *cv, uint32_t attr) 128 { 129 cv->curattr &= ~(attr & 0x0000000f); 130 131 return 0; 132 } 133 134 /** \brief Toggle flags in the default character attribute. 135 * 136 * Toggle flags in the default character attribute for drawing. Attributes 137 * define foreground and background colour, transparency, bold, italics and 138 * underline styles, as well as blink. String functions such as 139 * caca_printf() and graphical primitive functions such as caca_draw_line() 140 * will use this attribute. 141 * 142 * The value of \e attr is a combination (bitwise OR) of style values 143 * (\e CACA_UNDERLINE, \e CACA_BLINK, \e CACA_BOLD and \e CACA_ITALICS). 144 * Toggling these attributes does not modify the current colour information. 145 * 146 * To retrieve the current attribute value, use caca_get_attr(-1,-1). 147 * 148 * This function never fails. 149 * 150 * \param cv A handle to the libcaca canvas. 151 * \param attr The requested attribute values to toggle. 152 * \return This function always returns 0. 153 */ 154 int caca_toggle_attr(caca_canvas_t *cv, uint32_t attr) 155 { 156 cv->curattr ^= attr & 0x0000000f; 157 158 return 0; 159 } 160 161 /** \brief Set the character attribute at the given coordinates. 162 * 163 * Set the character attribute, without changing the character's value. If 164 * the character at the given coordinates is a fullwidth character, both 165 * cells' attributes are replaced. 166 * 167 * The value of \e attr is either: 168 * - a 32-bit integer as returned by caca_get_attr(), in which case it 169 * also contains colour information, 170 * - a combination (bitwise OR) of style values (\e CACA_UNDERLINE, 171 * \e CACA_BLINK, \e CACA_BOLD and \e CACA_ITALICS), in which case 172 * setting the attribute does not modify the current colour information. 173 * 174 * This function never fails. 175 * 176 * \param cv A handle to the libcaca canvas. 177 * \param x X coordinate. 178 * \param y Y coordinate. 179 * \param attr The requested attribute value. 180 * \return This function always returns 0. 181 */ 182 int caca_put_attr(caca_canvas_t *cv, int x, int y, uint32_t attr) 183 { 184 uint32_t *curattr, *curchar; 185 int xmin, xmax; 186 187 if(x < 0 || x >= (int)cv->width || y < 0 || y >= (int)cv->height) 188 return 0; 189 190 xmin = xmax = x; 191 192 curchar = cv->chars + x + y * cv->width; 193 curattr = cv->attrs + x + y * cv->width; 194 195 if(attr < 0x00000010) 196 curattr[0] = (curattr[0] & 0xfffffff0) | attr; 197 else 198 curattr[0] = attr; 199 200 if(x && curchar[0] == CACA_MAGIC_FULLWIDTH) 201 { 202 curattr[-1] = curattr[0]; 203 xmin--; 204 } 205 else if(x + 1 < (int)cv->width && curchar[1] == CACA_MAGIC_FULLWIDTH) 206 { 207 curattr[1] = curattr[0]; 208 xmax++; 209 } 210 211 if(!cv->dirty_disabled) 212 caca_add_dirty_rect(cv, xmin, y, xmax - xmin + 1, 1); 213 214 return 0; 215 } 216 217 /** \brief Set the default colour pair for text (ANSI version). 218 * 219 * Set the default ANSI colour pair for text drawing. String functions such 220 * as caca_printf() and graphical primitive functions such as caca_draw_line() 221 * will use these attributes. 222 * 223 * Color values are those defined in caca.h, such as CACA_RED 224 * or CACA_TRANSPARENT. 225 * 226 * If an error occurs, -1 is returned and \b errno is set accordingly: 227 * - \c EINVAL At least one of the colour values is invalid. 228 * 229 * \param cv A handle to the libcaca canvas. 230 * \param fg The requested ANSI foreground colour. 231 * \param bg The requested ANSI background colour. 232 * \return 0 in case of success, -1 if an error occurred. 233 */ 234 int caca_set_color_ansi(caca_canvas_t *cv, uint8_t fg, uint8_t bg) 235 { 236 uint32_t attr; 237 238 if(fg > 0x20 || bg > 0x20) 239 { 240 seterrno(EINVAL); 241 return -1; 242 } 243 244 attr = ((uint32_t)(bg | 0x40) << 18) | ((uint32_t)(fg | 0x40) << 4); 245 cv->curattr = (cv->curattr & 0x0000000f) | attr; 246 247 return 0; 248 } 249 250 /** \brief Set the default colour pair for text (truecolor version). 251 * 252 * Set the default ARGB colour pair for text drawing. String functions such 253 * as caca_printf() and graphical primitive functions such as caca_draw_line() 254 * will use these attributes. 255 * 256 * Colors are 16-bit ARGB values, each component being coded on 4 bits. For 257 * instance, 0xf088 is solid dark cyan (A=15 R=0 G=8 B=8), and 0x8fff is 258 * white with 50% alpha (A=8 R=15 G=15 B=15). 259 * 260 * This function never fails. 261 * 262 * \param cv A handle to the libcaca canvas. 263 * \param fg The requested ARGB foreground colour. 264 * \param bg The requested ARGB background colour. 265 * \return This function always returns 0. 266 */ 267 int caca_set_color_argb(caca_canvas_t *cv, uint16_t fg, uint16_t bg) 268 { 269 uint32_t attr; 270 271 if(fg < 0x100) 272 fg += 0x100; 273 274 if(bg < 0x100) 275 bg += 0x100; 276 277 fg = ((fg >> 1) & 0x7ff) | ((fg >> 13) << 11); 278 bg = ((bg >> 1) & 0x7ff) | ((bg >> 13) << 11); 279 280 attr = ((uint32_t)bg << 18) | ((uint32_t)fg << 4); 281 cv->curattr = (cv->curattr & 0x0000000f) | attr; 282 283 return 0; 284 } 285 286 /** \brief Get DOS ANSI information from attribute. 287 * 288 * Get the ANSI colour pair for a given attribute. The returned value is 289 * an 8-bit value whose higher 4 bits are the background colour and lower 290 * 4 bits are the foreground colour. 291 * 292 * If the attribute has ARGB colours, the nearest colour is used. Special 293 * attributes such as \e CACA_DEFAULT and \e CACA_TRANSPARENT are not 294 * handled and are both replaced with \e CACA_LIGHTGRAY for the foreground 295 * colour and \e CACA_BLACK for the background colour. 296 * 297 * This function never fails. If the attribute value is outside the expected 298 * 32-bit range, higher order bits are simply ignored. 299 * 300 * \param attr The requested attribute value. 301 * \return The corresponding DOS ANSI value. 302 */ 303 uint8_t caca_attr_to_ansi(uint32_t attr) 304 { 305 uint8_t fg = nearest_ansi((attr >> 4) & 0x3fff); 306 uint8_t bg = nearest_ansi(attr >> 18); 307 308 return (fg < 0x10 ? fg : CACA_LIGHTGRAY) 309 | ((bg < 0x10 ? bg : CACA_BLACK) << 4); 310 } 311 312 /** \brief Get ANSI foreground information from attribute. 313 * 314 * Get the ANSI foreground colour value for a given attribute. The returned 315 * value is either one of the \e CACA_RED, \e CACA_BLACK etc. predefined 316 * colours, or the special value \e CACA_DEFAULT meaning the media's 317 * default foreground value, or the special value \e CACA_TRANSPARENT. 318 * 319 * If the attribute has ARGB colours, the nearest colour is returned. 320 * 321 * This function never fails. If the attribute value is outside the expected 322 * 32-bit range, higher order bits are simply ignored. 323 * 324 * \param attr The requested attribute value. 325 * \return The corresponding ANSI foreground value. 326 */ 327 uint8_t caca_attr_to_ansi_fg(uint32_t attr) 328 { 329 return nearest_ansi((attr >> 4) & 0x3fff); 330 } 331 332 /** \brief Get ANSI background information from attribute. 333 * 334 * Get the ANSI background colour value for a given attribute. The returned 335 * value is either one of the \e CACA_RED, \e CACA_BLACK etc. predefined 336 * colours, or the special value \e CACA_DEFAULT meaning the media's 337 * default background value, or the special value \e CACA_TRANSPARENT. 338 * 339 * If the attribute has ARGB colours, the nearest colour is returned. 340 * 341 * This function never fails. If the attribute value is outside the expected 342 * 32-bit range, higher order bits are simply ignored. 343 * 344 * \param attr The requested attribute value. 345 * \return The corresponding ANSI background value. 346 */ 347 uint8_t caca_attr_to_ansi_bg(uint32_t attr) 348 { 349 return nearest_ansi(attr >> 18); 350 } 351 352 /** \brief Get 12-bit RGB foreground information from attribute. 353 * 354 * Get the 12-bit foreground colour value for a given attribute. The returned 355 * value is a native-endian encoded integer with each red, green and blue 356 * values encoded on 8 bits in the following order: 357 * - 8-11 most significant bits: red 358 * - 4-7 most significant bits: green 359 * - least significant bits: blue 360 * 361 * This function never fails. If the attribute value is outside the expected 362 * 32-bit range, higher order bits are simply ignored. 363 * 364 * \param attr The requested attribute value. 365 * \return The corresponding 12-bit RGB foreground value. 366 */ 367 uint16_t caca_attr_to_rgb12_fg(uint32_t attr) 368 { 369 uint16_t fg = (attr >> 4) & 0x3fff; 370 371 if(fg < (0x10 | 0x40)) 372 return ansitab16[fg ^ 0x40] & 0x0fff; 373 374 if(fg == (CACA_DEFAULT | 0x40)) 375 return ansitab16[CACA_LIGHTGRAY] & 0x0fff; 376 377 if(fg == (CACA_TRANSPARENT | 0x40)) 378 return ansitab16[CACA_LIGHTGRAY] & 0x0fff; 379 380 return (fg << 1) & 0x0fff; 381 } 382 383 /** \brief Get 12-bit RGB background information from attribute. 384 * 385 * Get the 12-bit background colour value for a given attribute. The returned 386 * value is a native-endian encoded integer with each red, green and blue 387 * values encoded on 8 bits in the following order: 388 * - 8-11 most significant bits: red 389 * - 4-7 most significant bits: green 390 * - least significant bits: blue 391 * 392 * This function never fails. If the attribute value is outside the expected 393 * 32-bit range, higher order bits are simply ignored. 394 * 395 * \param attr The requested attribute value. 396 * \return The corresponding 12-bit RGB background value. 397 */ 398 uint16_t caca_attr_to_rgb12_bg(uint32_t attr) 399 { 400 uint16_t bg = attr >> 18; 401 402 if(bg < (0x10 | 0x40)) 403 return ansitab16[bg ^ 0x40] & 0x0fff; 404 405 if(bg == (CACA_DEFAULT | 0x40)) 406 return ansitab16[CACA_BLACK] & 0x0fff; 407 408 if(bg == (CACA_TRANSPARENT | 0x40)) 409 return ansitab16[CACA_BLACK] & 0x0fff; 410 411 return (bg << 1) & 0x0fff; 412 } 413 414 /** \brief Get 64-bit ARGB information from attribute. 415 * 416 * Get the 64-bit colour and alpha values for a given attribute. The values 417 * are written as 8-bit integers in the \e argb array in the following order: 418 * - \e argb[0]: background alpha value 419 * - \e argb[1]: background red value 420 * - \e argb[2]: background green value 421 * - \e argb[3]: background blue value 422 * - \e argb[4]: foreground alpha value 423 * - \e argb[5]: foreground red value 424 * - \e argb[6]: foreground green value 425 * - \e argb[7]: foreground blue value 426 * 427 * This function never fails. If the attribute value is outside the expected 428 * 32-bit range, higher order bits are simply ignored. 429 * 430 * \param attr The requested attribute value. 431 * \param argb An array of 8-bit integers. 432 */ 433 void caca_attr_to_argb64(uint32_t attr, uint8_t argb[8]) 434 { 435 uint16_t fg = (attr >> 4) & 0x3fff; 436 uint16_t bg = attr >> 18; 437 438 if(bg < (0x10 | 0x40)) 439 bg = ansitab16[bg ^ 0x40]; 440 else if(bg == (CACA_DEFAULT | 0x40)) 441 bg = ansitab16[CACA_BLACK]; 442 else if(bg == (CACA_TRANSPARENT | 0x40)) 443 bg = 0x0fff; 444 else 445 bg = ((bg << 2) & 0xf000) | ((bg << 1) & 0x0fff); 446 447 argb[0] = bg >> 12; 448 argb[1] = (bg >> 8) & 0xf; 449 argb[2] = (bg >> 4) & 0xf; 450 argb[3] = bg & 0xf; 451 452 if(fg < (0x10 | 0x40)) 453 fg = ansitab16[fg ^ 0x40]; 454 else if(fg == (CACA_DEFAULT | 0x40)) 455 fg = ansitab16[CACA_LIGHTGRAY]; 456 else if(fg == (CACA_TRANSPARENT | 0x40)) 457 fg = 0x0fff; 458 else 459 fg = ((fg << 2) & 0xf000) | ((fg << 1) & 0x0fff); 460 461 argb[4] = fg >> 12; 462 argb[5] = (fg >> 8) & 0xf; 463 argb[6] = (fg >> 4) & 0xf; 464 argb[7] = fg & 0xf; 465 } 466 467 /* 468 * XXX: the following functions are local 469 */ 470 471 static uint8_t nearest_ansi(uint16_t argb14) 472 { 473 unsigned int i, best, dist; 474 475 if(argb14 < (0x10 | 0x40)) 476 return argb14 ^ 0x40; 477 478 if(argb14 == (CACA_DEFAULT | 0x40) || argb14 == (CACA_TRANSPARENT | 0x40)) 479 return argb14 ^ 0x40; 480 481 if(argb14 < 0x0fff) /* too transparent */ 482 return CACA_TRANSPARENT; 483 484 best = CACA_DEFAULT; 485 dist = 0x3fff; 486 for(i = 0; i < 16; i++) 487 { 488 unsigned int d = 0; 489 int a, b; 490 491 a = (ansitab14[i] >> 7) & 0xf; 492 b = (argb14 >> 7) & 0xf; 493 d += (a - b) * (a - b); 494 495 a = (ansitab14[i] >> 3) & 0xf; 496 b = (argb14 >> 3) & 0xf; 497 d += (a - b) * (a - b); 498 499 a = (ansitab14[i] << 1) & 0xf; 500 b = (argb14 << 1) & 0xf; 501 d += (a - b) * (a - b); 502 503 if(d < dist) 504 { 505 dist = d; 506 best = i; 507 } 508 } 509 510 return best; 511 } 512 513 #define RGB12TO24(i) \ 514 (((uint32_t)((i & 0xf00) >> 8) * 0x110000) \ 515 | ((uint32_t)((i & 0x0f0) >> 4) * 0x001100) \ 516 | ((uint32_t)(i & 0x00f) * 0x000011)) 517 518 uint32_t _caca_attr_to_rgb24fg(uint32_t attr) 519 { 520 return RGB12TO24(caca_attr_to_rgb12_fg(attr)); 521 } 522 523 uint32_t _caca_attr_to_rgb24bg(uint32_t attr) 524 { 525 return RGB12TO24(caca_attr_to_rgb12_bg(attr)); 526 } 527