src/VSpace.cpp

   1 /**
   2  * \file VSpace.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Matthias Ettrich
   7  *
   8  * Full author contact details are available in file CREDITS.
   9  */
  10
  11 #include <config.h>
  12
  13 #include "VSpace.h"
  14
  15 #include "Buffer.h"
  16 #include "BufferParams.h"
  17 #include "BufferView.h"
  18 #include "support/gettext.h"
  19 #include "Length.h"
  20 #include "Text.h"
  21 #include "TextMetrics.h" // for defaultRowHeight()
  22
  23 #include "support/convert.h"
  24 #include "support/lstrings.h"
  25
  26 #include "support/lassert.h"
  27
  28 #include <cstring>
  29
  30 using namespace std;
  31 using namespace lyx::support;
  32
  33
  34 namespace lyx {
  35
  36 namespace {
  37
  38 /// used to return numeric values in parsing vspace
  39 double number[4] = { 0, 0, 0, 0 };
  40
  41 /// used to return unit types in parsing vspace
  42 Length::UNIT unit[4] = {
  43         Length::UNIT_NONE,
  44         Length::UNIT_NONE,
  45         Length::UNIT_NONE,
  46         Length::UNIT_NONE
  47 };
  48
  49 /// the current position in the number array
  50 int number_index;
  51 /// the current position in the unit array
  52 int unit_index;
  53
  54 /// skip n characters of input
  55 inline void lyx_advance(string & data, size_t n)
  56 {
  57         data.erase(0, n);
  58 }
  59
  60
  61 /// return true when the input is at the end
  62 inline bool isEndOfData(string const & data)
  63 {
  64         return ltrim(data).empty();
  65 }
  66
  67
  68 /**
  69  * nextToken -  return the next token in the input
  70  * @param data input string
  71  * @return a char representing the type of token returned
  72  *
  73  * The possible return values are :
  74  *      +       stretch indicator for glue length
  75  *      -       shrink indicator for glue length
  76  *      n       a numeric value (stored in number array)
  77  *      u       a unit type (stored in unit array)
  78  *      E       parse error
  79  */
  80 char nextToken(string & data)
  81 {
  82         data = ltrim(data);
  83
  84         if (data.empty())
  85                 return '\0';
  86
  87         if (data[0] == '+') {
  88                 lyx_advance(data, 1);
  89                 return '+';
  90         }
  91
  92         if (prefixIs(data, "plus")) {
  93                 lyx_advance(data, 4);
  94                 return '+';
  95         }
  96
  97         if (data[0] == '-') {
  98                 lyx_advance(data, 1);
  99                 return '-';
 100         }
 101
 102         if (prefixIs(data, "minus")) {
 103                 lyx_advance(data, 5);
 104                 return '-';
 105         }
 106
 107         size_t i = data.find_first_not_of("0123456789.");
 108
 109         if (i != 0) {
 110                 if (number_index > 3)
 111                         return 'E';
 112
 113                 string buffer;
 114
 115                 // we have found some number
 116                 if (i == string::npos) {
 117                         buffer = data;
 118                         i = data.size() + 1;
 119                 } else {
 120                         buffer = data.substr(0, i);
 121                 }
 122
 123                 lyx_advance(data, i);
 124
 125                 if (isStrDbl(buffer)) {
 126                         number[number_index] = convert<double>(buffer);
 127                         ++number_index;
 128                         return 'n';
 129                 }
 130                 return 'E';
 131         }
 132
 133         i = data.find_first_not_of("abcdefghijklmnopqrstuvwxyz%");
 134         if (i != 0) {
 135                 if (unit_index > 3)
 136                         return 'E';
 137
 138                 string buffer;
 139
 140                 // we have found some alphabetical string
 141                 if (i == string::npos) {
 142                         buffer = data;
 143                         i = data.size() + 1;
 144                 } else {
 145                         buffer = data.substr(0, i);
 146                 }
 147
 148                 // possibly we have "mmplus" string or similar
 149                 if (buffer.size() > 5 &&
 150                                 (buffer.substr(2, 4) == string("plus") ||
 151                                  buffer.substr(2, 5) == string("minus")))
 152                 {
 153                         lyx_advance(data, 2);
 154                         unit[unit_index] = unitFromString(buffer.substr(0, 2));
 155                 } else {
 156                         lyx_advance(data, i);
 157                         unit[unit_index] = unitFromString(buffer);
 158                 }
 159
 160                 if (unit[unit_index] != Length::UNIT_NONE) {
 161                         ++unit_index;
 162                         return 'u';
 163                 }
 164                 return 'E';  // Error
 165         }
 166         return 'E';  // Error
 167 }
 168
 169
 170 /// latex representation of a vspace
 171 struct LaTeXLength {
 172         char const * pattern;
 173         int  plus_val_index;
 174         int  minus_val_index;
 175         int  plus_uni_index;
 176         int  minus_uni_index;
 177 };
 178
 179
 180 /// the possible formats for a vspace string
 181 LaTeXLength table[] = {
 182         { "nu",       0, 0, 0, 0 },
 183         { "nu+nu",    2, 0, 2, 0 },
 184         { "nu+nu-nu", 2, 3, 2, 3 },
 185         { "nu+-nu",   2, 2, 2, 2 },
 186         { "nu-nu",    0, 2, 0, 2 },
 187         { "nu-nu+nu", 3, 2, 3, 2 },
 188         { "nu-+nu",   2, 2, 2, 2 },
 189         { "n+nu",     2, 0, 1, 0 },
 190         { "n+n-nu",   2, 3, 1, 1 },
 191         { "n+-nu",    2, 2, 1, 1 },
 192         { "n-nu",     0, 2, 0, 1 },
 193         { "n-n+nu",   3, 2, 1, 1 },
 194         { "n-+nu",    2, 2, 1, 1 },
 195         { "",         0, 0, 0, 0 }   // sentinel, must be empty
 196 };
 197
 198
 199 } // namespace anon
 200
 201 const char * stringFromUnit(int unit)
 202 {
 203         if (unit < 0 || unit > num_units)
 204                 return 0;
 205         return unit_name[unit];
 206 }
 207
 208
 209 bool isValidGlueLength(string const & data, GlueLength * result)
 210 {
 211         // This parser is table-driven.  First, it constructs a "pattern"
 212         // that describes the sequence of tokens in "data".  For example,
 213         // "n-nu" means: number, minus sign, number, unit.  As we go along,
 214         // numbers and units are stored into static arrays.  Then, "pattern"
 215         // is searched in the "table".  If it is found, the associated
 216         // table entries tell us which number and unit should go where
 217         // in the Length structure.  Example: if "data" has the "pattern"
 218         // "nu+nu-nu", the associated table entries are "2, 3, 2, 3".
 219         // That means, "plus_val" is the second number that was seen
 220         // in the input, "minus_val" is the third number, and "plus_uni"
 221         // and "minus_uni" are the second and third units, respectively.
 222         // ("val" and "uni" are always the first items seen in "data".)
 223         // This is the most elegant solution I could find -- a straight-
 224         // forward approach leads to very long, tedious code that would be
 225         // much harder to understand and maintain. (AS)
 226
 227         if (data.empty())
 228                 return true;
 229         string buffer = ltrim(data);
 230
 231         // To make isValidGlueLength recognize negative values as
 232         // the first number this little hack is needed:
 233         int val_sign = 1; // positive as default
 234         switch (buffer[0]) {
 235         case '-':
 236                 lyx_advance(buffer, 1);
 237                 val_sign = -1;
 238                 break;
 239         case '+':
 240                 lyx_advance(buffer, 1);
 241                 break;
 242         default:
 243                 break;
 244         }
 245         // end of hack
 246
 247         int  pattern_index = 0;
 248         int  table_index = 0;
 249         char pattern[20];
 250
 251         number_index = 1;
 252         unit_index = 1;  // entries at index 0 are sentinels
 253
 254         // construct "pattern" from "data"
 255         while (!isEndOfData(buffer)) {
 256                 if (pattern_index > 20)
 257                         return false;
 258                 pattern[pattern_index] = nextToken(buffer);
 259                 if (pattern[pattern_index] == 'E')
 260                         return false;
 261                 ++pattern_index;
 262         }
 263         pattern[pattern_index] = '\0';
 264
 265         // search "pattern" in "table"
 266         table_index = 0;
 267         while (strcmp(pattern, table[table_index].pattern)) {
 268                 ++table_index;
 269                 if (!*table[table_index].pattern)
 270                         return false;
 271         }
 272
 273         // Get the values from the appropriate places.  If an index
 274         // is zero, the corresponding array value is zero or UNIT_NONE,
 275         // so we needn't check this.
 276         if (result) {
 277                 result->len_.value  (number[1] * val_sign);
 278                 result->len_.unit   (unit[1]);
 279                 result->plus_.value (number[table[table_index].plus_val_index]);
 280                 result->plus_.unit  (unit  [table[table_index].plus_uni_index]);
 281                 result->minus_.value(number[table[table_index].minus_val_index]);
 282                 result->minus_.unit (unit  [table[table_index].minus_uni_index]);
 283         }
 284         return true;
 285 }
 286
 287
 288 bool isValidLength(string const & data, Length * result)
 289 {
 290         // This is a trimmed down version of isValidGlueLength.
 291         // The parser may seem overkill for lengths without
 292         // glue, but since we already have it, using it is
 293         // easier than writing something from scratch.
 294         if (data.empty())
 295                 return true;
 296
 297         string   buffer = data;
 298         int      pattern_index = 0;
 299         char     pattern[3];
 300
 301         // To make isValidLength recognize negative values
 302         // this little hack is needed:
 303         int val_sign = 1; // positive as default
 304         switch (buffer[0]) {
 305         case '-':
 306                 lyx_advance(buffer, 1);
 307                 val_sign = -1;
 308                 break;
 309         case '+':
 310                 lyx_advance(buffer, 1);
 311                 // fall through
 312         default:
 313                 // no action
 314                 break;
 315         }
 316         // end of hack
 317
 318         number_index = unit_index = 1;  // entries at index 0 are sentinels
 319
 320         // construct "pattern" from "data"
 321         while (!isEndOfData(buffer)) {
 322                 if (pattern_index > 2)
 323                         return false;
 324                 pattern[pattern_index] = nextToken(buffer);
 325                 if (pattern[pattern_index] == 'E')
 326                         return false;
 327                 ++pattern_index;
 328         }
 329         pattern[pattern_index] = '\0';
 330
 331         // only the most basic pattern is accepted here
 332         if (strcmp(pattern, "nu") != 0)
 333                 return false;
 334
 335         // It _was_ a correct length string.
 336         // Store away the values we found.
 337         if (result) {
 338                 result->val_  = number[1] * val_sign;
 339                 result->unit_ = unit[1];
 340         }
 341         return true;
 342 }
 343
 344
 345 //
 346 //  VSpace class
 347 //
 348
 349 VSpace::VSpace()
 350         : kind_(DEFSKIP), len_(), keep_(false)
 351 {}
 352
 353
 354 VSpace::VSpace(VSpaceKind k)
 355         : kind_(k), len_(), keep_(false)
 356 {}
 357
 358
 359 VSpace::VSpace(Length const & l)
 360         : kind_(LENGTH), len_(l), keep_(false)
 361 {}
 362
 363
 364 VSpace::VSpace(GlueLength const & l)
 365         : kind_(LENGTH), len_(l), keep_(false)
 366 {}
 367
 368
 369 VSpace::VSpace(string const & data)
 370         : kind_(DEFSKIP), len_(), keep_(false)
 371 {
 372         if (data.empty())
 373                 return;
 374
 375         string input = rtrim(data);
 376
 377         size_t const length = input.length();
 378
 379         if (length > 1 && input[length - 1] == '*') {
 380                 keep_ = true;
 381                 input.erase(length - 1);
 382         }
 383
 384         if (prefixIs(input, "defskip"))
 385                 kind_ = DEFSKIP;
 386         else if (prefixIs(input, "smallskip"))
 387                 kind_ = SMALLSKIP;
 388         else if (prefixIs(input, "medskip"))
 389                 kind_ = MEDSKIP;
 390         else if (prefixIs(input, "bigskip"))
 391                 kind_ = BIGSKIP;
 392         else if (prefixIs(input, "vfill"))
 393                 kind_ = VFILL;
 394         else if (isValidGlueLength(input, &len_))
 395                 kind_ = LENGTH;
 396         else if (isStrDbl(input)) {
 397                 // This last one is for reading old .lyx files
 398                 // without units in added_space_top/bottom.
 399                 // Let unit default to centimeters here.
 400                 kind_ = LENGTH;
 401                 len_  = GlueLength(Length(convert<double>(input), Length::CM));
 402         }
 403 }
 404
 405
 406 bool VSpace::operator==(VSpace const & other) const
 407 {
 408         if (kind_ != other.kind_)
 409                 return false;
 410
 411         if (kind_ != LENGTH)
 412                 return this->keep_ == other.keep_;
 413
 414         if (len_ != other.len_)
 415                 return false;
 416
 417         return keep_ == other.keep_;
 418 }
 419
 420
 421 string const VSpace::asLyXCommand() const
 422 {
 423         string result;
 424         switch (kind_) {
 425         case DEFSKIP:   result = "defskip";      break;
 426         case SMALLSKIP: result = "smallskip";    break;
 427         case MEDSKIP:   result = "medskip";      break;
 428         case BIGSKIP:   result = "bigskip";      break;
 429         case VFILL:     result = "vfill";        break;
 430         case LENGTH:    result = len_.asString(); break;
 431         }
 432         if (keep_)
 433                 result += '*';
 434         return result;
 435 }
 436
 437
 438 string const VSpace::asLatexCommand(BufferParams const & params) const
 439 {
 440         switch (kind_) {
 441         case DEFSKIP:
 442                 return params.getDefSkip().asLatexCommand(params);
 443
 444         case SMALLSKIP:
 445                 return keep_ ? "\\vspace*{\\smallskipamount}" : "\\smallskip{}";
 446
 447         case MEDSKIP:
 448                 return keep_ ? "\\vspace*{\\medskipamount}" : "\\medskip{}";
 449
 450         case BIGSKIP:
 451                 return keep_ ? "\\vspace*{\\bigskipamount}" : "\\bigskip{}";
 452
 453         case VFILL:
 454                 return keep_ ? "\\vspace*{\\fill}" : "\\vfill{}";
 455
 456         case LENGTH:
 457                 return keep_ ? "\\vspace*{" + len_.asLatexString() + '}'
 458                         : "\\vspace{" + len_.asLatexString() + '}';
 459
 460         default:
 461                 LASSERT(false, /**/);
 462                 return string();
 463         }
 464 }
 465
 466
 467 docstring const VSpace::asGUIName() const
 468 {
 469         docstring result;
 470         switch (kind_) {
 471         case DEFSKIP:
 472                 result = _("Default skip");
 473                 break;
 474         case SMALLSKIP:
 475                 result = _("Small skip");
 476                 break;
 477         case MEDSKIP:
 478                 result = _("Medium skip");
 479                 break;
 480         case BIGSKIP:
 481                 result = _("Big skip");
 482                 break;
 483         case VFILL:
 484                 result = _("Vertical fill");
 485                 break;
 486         case LENGTH:
 487                 result = from_ascii(len_.asString());
 488                 break;
 489         }
 490         if (keep_)
 491                 result += ", " + _("protected");
 492         return result;
 493 }
 494
 495
 496 string VSpace::asHTMLLength() const
 497 {
 498         string result;
 499         switch (kind_) {
 500                 case DEFSKIP:   result = "2ex"; break;
 501                 case SMALLSKIP: result = "1ex"; break;
 502                 case MEDSKIP:   result = "3ex"; break;
 503                 case BIGSKIP:   result = "5ex"; break;
 504                 case LENGTH: {
 505                         Length tmp = len_.len();
 506                         if (tmp.value() > 0)
 507                                 result = tmp.asHTMLString();
 508                 }
 509                 case VFILL:     break;
 510         }
 511         return result;
 512 }
 513
 514 int VSpace::inPixels(BufferView const & bv) const
 515 {
 516         // Height of a normal line in pixels (zoom factor considered)
 517         int const default_height = defaultRowHeight();
 518
 519         switch (kind_) {
 520
 521         case DEFSKIP:
 522                 return bv.buffer().params().getDefSkip().inPixels(bv);
 523
 524         // This is how the skips are normally defined by LateX.
 525         // But there should be some way to change this per document.
 526         case SMALLSKIP:
 527                 return default_height / 4;
 528
 529         case MEDSKIP:
 530                 return default_height / 2;
 531
 532         case BIGSKIP:
 533                 return default_height;
 534
 535         case VFILL:
 536                 // leave space for the vfill symbol
 537                 return 3 * default_height;
 538
 539         case LENGTH:
 540                 return len_.len().inPixels(bv.workWidth());
 541
 542         default:
 543                 LASSERT(false, /**/);
 544                 return 0;
 545         }
 546 }
 547
 548
 549 } // namespace lyx