src/graphics/PreviewLoader.cpp

   1 /**
   2  * \file PreviewLoader.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Angus Leeming
   7  *
   8  * Full author contact details are available in file CREDITS.
   9  */
  10
  11 #include <config.h>
  12
  13 #include "PreviewLoader.h"
  14 #include "PreviewImage.h"
  15 #include "GraphicsCache.h"
  16
  17 #include "Buffer.h"
  18 #include "BufferParams.h"
  19 #include "Converter.h"
  20 #include "Encoding.h"
  21 #include "Format.h"
  22 #include "InsetIterator.h"
  23 #include "LaTeXFeatures.h"
  24 #include "LyXRC.h"
  25 #include "output.h"
  26 #include "OutputParams.h"
  27 #include "TexRow.h"
  28
  29 #include "frontends/Application.h" // hexName
  30
  31 #include "insets/Inset.h"
  32
  33 #include "support/convert.h"
  34 #include "support/debug.h"
  35 #include "support/FileName.h"
  36 #include "support/filetools.h"
  37 #include "support/ForkedCalls.h"
  38 #include "support/lstrings.h"
  39
  40 #include "support/bind.h"
  41
  42 #include <sstream>
  43 #include <fstream>
  44 #include <iomanip>
  45
  46 using namespace std;
  47 using namespace lyx::support;
  48
  49
  50
  51 namespace {
  52
  53 typedef pair<string, FileName> SnippetPair;
  54
  55 // A list of all snippets to be converted to previews
  56 typedef list<string> PendingSnippets;
  57
  58 // Each item in the vector is a pair<snippet, image file name>.
  59 typedef vector<SnippetPair> BitmapFile;
  60
  61
  62 string const unique_filename(string const & bufferpath)
  63 {
  64         static int theCounter = 0;
  65         string const filename = lyx::convert<string>(theCounter++) + "lyxpreview";
  66         return addName(bufferpath, filename);
  67 }
  68
  69
  70 lyx::Converter const * setConverter(string const from)
  71 {
  72         typedef vector<string> FmtList;
  73         typedef lyx::graphics::Cache GCache;
  74         FmtList const & loadableFormats = GCache::get().loadableFormats();
  75         FmtList::const_iterator it = loadableFormats.begin();
  76         FmtList::const_iterator const end = loadableFormats.end();
  77
  78         for (; it != end; ++it) {
  79                 string const to = *it;
  80                 if (from == to)
  81                         continue;
  82
  83                 lyx::Converter const * ptr = lyx::theConverters().getConverter(from, to);
  84                 if (ptr)
  85                         return ptr;
  86         }
  87
  88         static bool first = true;
  89         if (first) {
  90                 first = false;
  91                 LYXERR0("PreviewLoader::startLoading()\n"
  92                         << "No converter from \"" << from << "\" format has been defined.");
  93         }
  94         return 0;
  95 }
  96
  97
  98 void setAscentFractions(vector<double> & ascent_fractions,
  99                         FileName const & metrics_file)
 100 {
 101         // If all else fails, then the images will have equal ascents and
 102         // descents.
 103         vector<double>::iterator it  = ascent_fractions.begin();
 104         vector<double>::iterator end = ascent_fractions.end();
 105         fill(it, end, 0.5);
 106
 107         ifstream in(metrics_file.toFilesystemEncoding().c_str());
 108         if (!in.good()) {
 109                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 110                         << "Unable to open file!");
 111                 return;
 112         }
 113
 114         bool error = false;
 115
 116         int snippet_counter = 1;
 117         while (!in.eof() && it != end) {
 118                 string snippet;
 119                 int id;
 120                 double ascent_fraction;
 121
 122                 in >> snippet >> id >> ascent_fraction;
 123
 124                 if (!in.good())
 125                         // eof after all
 126                         break;
 127
 128                 error = snippet != "Snippet";
 129                 if (error)
 130                         break;
 131
 132                 error = id != snippet_counter;
 133                 if (error)
 134                         break;
 135
 136                 *it = ascent_fraction;
 137
 138                 ++snippet_counter;
 139                 ++it;
 140         }
 141
 142         if (error) {
 143                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 144                         << "Error reading file!\n");
 145         }
 146 }
 147
 148
 149 class FindFirst
 150 {
 151 public:
 152         FindFirst(string const & comp) : comp_(comp) {}
 153         bool operator()(SnippetPair const & sp) const { return sp.first == comp_; }
 154 private:
 155         string const comp_;
 156 };
 157
 158
 159 /// Store info on a currently executing, forked process.
 160 class InProgress {
 161 public:
 162         ///
 163         InProgress() : pid(0) {}
 164         ///
 165         InProgress(string const & filename_base,
 166                    PendingSnippets const & pending,
 167                    string const & to_format);
 168         /// Remove any files left lying around and kill the forked process.
 169         void stop() const;
 170
 171         ///
 172         pid_t pid;
 173         ///
 174         string command;
 175         ///
 176         FileName metrics_file;
 177         ///
 178         BitmapFile snippets;
 179 };
 180
 181 typedef map<pid_t, InProgress>  InProgressProcesses;
 182
 183 typedef InProgressProcesses::value_type InProgressProcess;
 184
 185 } // namespace anon
 186
 187
 188
 189 namespace lyx {
 190 namespace graphics {
 191
 192 class PreviewLoader::Impl : public boost::signals::trackable {
 193 public:
 194         ///
 195         Impl(PreviewLoader & p, Buffer const & b);
 196         /// Stop any InProgress items still executing.
 197         ~Impl();
 198         ///
 199         PreviewImage const * preview(string const & latex_snippet) const;
 200         ///
 201         PreviewLoader::Status status(string const & latex_snippet) const;
 202         ///
 203         void add(string const & latex_snippet);
 204         ///
 205         void remove(string const & latex_snippet);
 206         /// \p wait whether to wait for the process to complete or, instead,
 207         /// to do it in the background.
 208         void startLoading(bool wait = false);
 209
 210         /// Emit this signal when an image is ready for display.
 211         boost::signal<void(PreviewImage const &)> imageReady;
 212
 213         Buffer const & buffer() const { return buffer_; }
 214
 215 private:
 216         /// Called by the ForkedCall process that generated the bitmap files.
 217         void finishedGenerating(pid_t, int);
 218         ///
 219         void dumpPreamble(odocstream &) const;
 220         ///
 221         void dumpData(odocstream &, BitmapFile const &) const;
 222
 223         /** cache_ allows easy retrieval of already-generated images
 224          *  using the LaTeX snippet as the identifier.
 225          */
 226         typedef shared_ptr<PreviewImage> PreviewImagePtr;
 227         ///
 228         typedef map<string, PreviewImagePtr> Cache;
 229         ///
 230         Cache cache_;
 231
 232         /** pending_ stores the LaTeX snippets in anticipation of them being
 233          *  sent to the converter.
 234          */
 235         PendingSnippets pending_;
 236
 237         /** in_progress_ stores all forked processes so that we can proceed
 238          *  thereafter.
 239             The map uses the conversion commands as its identifiers.
 240          */
 241         InProgressProcesses in_progress_;
 242
 243         ///
 244         PreviewLoader & parent_;
 245         ///
 246         Buffer const & buffer_;
 247
 248         /// We don't own this
 249         static lyx::Converter const * pconverter_;
 250 };
 251
 252
 253 lyx::Converter const * PreviewLoader::Impl::pconverter_;
 254
 255
 256 //
 257 // The public interface, defined in PreviewLoader.h
 258 //
 259
 260 PreviewLoader::PreviewLoader(Buffer const & b)
 261         : pimpl_(new Impl(*this, b))
 262 {}
 263
 264
 265 PreviewLoader::~PreviewLoader()
 266 {
 267         delete pimpl_;
 268 }
 269
 270
 271 PreviewImage const * PreviewLoader::preview(string const & latex_snippet) const
 272 {
 273         return pimpl_->preview(latex_snippet);
 274 }
 275
 276
 277 PreviewLoader::Status PreviewLoader::status(string const & latex_snippet) const
 278 {
 279         return pimpl_->status(latex_snippet);
 280 }
 281
 282
 283 void PreviewLoader::add(string const & latex_snippet) const
 284 {
 285         pimpl_->add(latex_snippet);
 286 }
 287
 288
 289 void PreviewLoader::remove(string const & latex_snippet) const
 290 {
 291         pimpl_->remove(latex_snippet);
 292 }
 293
 294
 295 void PreviewLoader::startLoading(bool wait) const
 296 {
 297         pimpl_->startLoading(wait);
 298 }
 299
 300
 301 boost::signals::connection PreviewLoader::connect(slot_type const & slot) const
 302 {
 303         return pimpl_->imageReady.connect(slot);
 304 }
 305
 306
 307 void PreviewLoader::emitSignal(PreviewImage const & pimage) const
 308 {
 309         pimpl_->imageReady(pimage);
 310 }
 311
 312
 313 Buffer const & PreviewLoader::buffer() const
 314 {
 315         return pimpl_->buffer();
 316 }
 317
 318 } // namespace graphics
 319 } // namespace lyx
 320
 321
 322 // The details of the Impl
 323 // =======================
 324
 325 namespace {
 326
 327 class IncrementedFileName {
 328 public:
 329         IncrementedFileName(string const & to_format,
 330                             string const & filename_base)
 331                 : to_format_(to_format), base_(filename_base), counter_(1)
 332         {}
 333
 334         SnippetPair const operator()(string const & snippet)
 335         {
 336                 ostringstream os;
 337                 os << base_ << counter_++ << '.' << to_format_;
 338                 string const file = os.str();
 339
 340                 return make_pair(snippet, FileName(file));
 341         }
 342
 343 private:
 344         string const & to_format_;
 345         string const & base_;
 346         int counter_;
 347 };
 348
 349
 350 InProgress::InProgress(string const & filename_base,
 351                        PendingSnippets const & pending,
 352                        string const & to_format)
 353         : pid(0),
 354           metrics_file(filename_base + ".metrics"),
 355           snippets(pending.size())
 356 {
 357         PendingSnippets::const_iterator pit  = pending.begin();
 358         PendingSnippets::const_iterator pend = pending.end();
 359         BitmapFile::iterator sit = snippets.begin();
 360
 361         transform(pit, pend, sit,
 362                        IncrementedFileName(to_format, filename_base));
 363 }
 364
 365
 366 void InProgress::stop() const
 367 {
 368         if (pid)
 369                 ForkedCallsController::kill(pid, 0);
 370
 371         if (!metrics_file.empty())
 372                 metrics_file.removeFile();
 373
 374         BitmapFile::const_iterator vit  = snippets.begin();
 375         BitmapFile::const_iterator vend = snippets.end();
 376         for (; vit != vend; ++vit) {
 377                 if (!vit->second.empty())
 378                         vit->second.removeFile();
 379         }
 380 }
 381
 382 } // namespace anon
 383
 384
 385 namespace lyx {
 386 namespace graphics {
 387
 388 PreviewLoader::Impl::Impl(PreviewLoader & p, Buffer const & b)
 389         : parent_(p), buffer_(b)
 390 {
 391         if (!pconverter_){
 392                 if (b.params().encoding().package() == Encoding::japanese)
 393                         pconverter_ = setConverter("lyxpreview-platex");
 394                 else
 395                         pconverter_ = setConverter("lyxpreview");
 396         }
 397 }
 398
 399
 400 PreviewLoader::Impl::~Impl()
 401 {
 402         InProgressProcesses::iterator ipit  = in_progress_.begin();
 403         InProgressProcesses::iterator ipend = in_progress_.end();
 404
 405         for (; ipit != ipend; ++ipit)
 406                 ipit->second.stop();
 407 }
 408
 409
 410 PreviewImage const *
 411 PreviewLoader::Impl::preview(string const & latex_snippet) const
 412 {
 413         Cache::const_iterator it = cache_.find(latex_snippet);
 414         return (it == cache_.end()) ? 0 : it->second.get();
 415 }
 416
 417
 418 namespace {
 419
 420 class FindSnippet {
 421 public:
 422         FindSnippet(string const & s) : snippet_(s) {}
 423         bool operator()(InProgressProcess const & process) const
 424         {
 425                 BitmapFile const & snippets = process.second.snippets;
 426                 BitmapFile::const_iterator beg  = snippets.begin();
 427                 BitmapFile::const_iterator end = snippets.end();
 428                 return find_if(beg, end, FindFirst(snippet_)) != end;
 429         }
 430
 431 private:
 432         string const snippet_;
 433 };
 434
 435 } // namespace anon
 436
 437 PreviewLoader::Status
 438 PreviewLoader::Impl::status(string const & latex_snippet) const
 439 {
 440         Cache::const_iterator cit = cache_.find(latex_snippet);
 441         if (cit != cache_.end())
 442                 return Ready;
 443
 444         PendingSnippets::const_iterator pit  = pending_.begin();
 445         PendingSnippets::const_iterator pend = pending_.end();
 446
 447         pit = find(pit, pend, latex_snippet);
 448         if (pit != pend)
 449                 return InQueue;
 450
 451         InProgressProcesses::const_iterator ipit  = in_progress_.begin();
 452         InProgressProcesses::const_iterator ipend = in_progress_.end();
 453
 454         ipit = find_if(ipit, ipend, FindSnippet(latex_snippet));
 455         if (ipit != ipend)
 456                 return Processing;
 457
 458         return NotFound;
 459 }
 460
 461
 462 void PreviewLoader::Impl::add(string const & latex_snippet)
 463 {
 464         if (!pconverter_ || status(latex_snippet) != NotFound)
 465                 return;
 466
 467         string const snippet = trim(latex_snippet);
 468         if (snippet.empty())
 469                 return;
 470
 471         LYXERR(Debug::GRAPHICS, "adding snippet:\n" << snippet);
 472
 473         pending_.push_back(snippet);
 474 }
 475
 476
 477 namespace {
 478
 479 class EraseSnippet {
 480 public:
 481         EraseSnippet(string const & s) : snippet_(s) {}
 482         void operator()(InProgressProcess & process)
 483         {
 484                 BitmapFile & snippets = process.second.snippets;
 485                 BitmapFile::iterator it  = snippets.begin();
 486                 BitmapFile::iterator end = snippets.end();
 487
 488                 it = find_if(it, end, FindFirst(snippet_));
 489                 if (it != end)
 490                         snippets.erase(it, it+1);
 491         }
 492
 493 private:
 494         string const & snippet_;
 495 };
 496
 497 } // namespace anon
 498
 499
 500 void PreviewLoader::Impl::remove(string const & latex_snippet)
 501 {
 502         Cache::iterator cit = cache_.find(latex_snippet);
 503         if (cit != cache_.end())
 504                 cache_.erase(cit);
 505
 506         PendingSnippets::iterator pit  = pending_.begin();
 507         PendingSnippets::iterator pend = pending_.end();
 508
 509         pending_.erase(std::remove(pit, pend, latex_snippet), pend);
 510
 511         InProgressProcesses::iterator ipit  = in_progress_.begin();
 512         InProgressProcesses::iterator ipend = in_progress_.end();
 513
 514         for_each(ipit, ipend, EraseSnippet(latex_snippet));
 515
 516         while (ipit != ipend) {
 517                 InProgressProcesses::iterator curr = ipit++;
 518                 if (curr->second.snippets.empty())
 519                         in_progress_.erase(curr);
 520         }
 521 }
 522
 523
 524 void PreviewLoader::Impl::startLoading(bool wait)
 525 {
 526         if (pending_.empty() || !pconverter_)
 527                 return;
 528
 529         // Only start the process off after the buffer is loaded from file.
 530         if (!buffer_.isFullyLoaded())
 531                 return;
 532
 533         LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()");
 534
 535         // As used by the LaTeX file and by the resulting image files
 536         string const directory = buffer_.temppath();
 537
 538         string const filename_base = unique_filename(directory);
 539
 540         // Create an InProgress instance to place in the map of all
 541         // such processes if it starts correctly.
 542         InProgress inprogress(filename_base, pending_, pconverter_->to);
 543
 544         // clear pending_, so we're ready to start afresh.
 545         pending_.clear();
 546
 547         // Output the LaTeX file.
 548         FileName const latexfile(filename_base + ".tex");
 549
 550         // we use the encoding of the buffer
 551         Encoding const & enc = buffer_.params().encoding();
 552         ofdocstream of;
 553         try { of.reset(enc.iconvName()); }
 554         catch (iconv_codecvt_facet_exception & e) {
 555                 LYXERR0("Caught iconv exception: " << e.what()
 556                         << "\nUnable to create LaTeX file: " << latexfile);
 557                 return;
 558         }
 559
 560         TexRow texrow;
 561         OutputParams runparams(&enc);
 562         LaTeXFeatures features(buffer_, buffer_.params(), runparams);
 563
 564         if (!openFileWrite(of, latexfile))
 565                 return;
 566
 567         if (!of) {
 568                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 569                                         << "Unable to create LaTeX file\n" << latexfile);
 570                 return;
 571         }
 572         of << "\\batchmode\n";
 573         dumpPreamble(of);
 574         // handle inputenc etc.
 575         buffer_.params().writeEncodingPreamble(of, features, texrow);
 576         of << "\n\\begin{document}\n";
 577         dumpData(of, inprogress.snippets);
 578         of << "\n\\end{document}\n";
 579         of.close();
 580         if (of.fail()) {
 581                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 582                                          << "File was not closed properly.");
 583                 return;
 584         }
 585
 586         double const font_scaling_factor =
 587                 buffer_.isExporting() ? 75.0 * buffer_.params().html_math_img_scale
 588                         : 0.01 * lyxrc.dpi * lyxrc.zoom * lyxrc.preview_scale_factor;
 589
 590         // FIXME XHTML
 591         // The colors should be customizable.
 592         ColorCode const bg = buffer_.isExporting()
 593                        ? Color_white : PreviewLoader::backgroundColor();
 594         ColorCode const fg = buffer_.isExporting()
 595                        ? Color_black : PreviewLoader::foregroundColor();
 596         // The conversion command.
 597         ostringstream cs;
 598         cs << pconverter_->command << ' ' << pconverter_->to << ' '
 599            << quoteName(latexfile.toFilesystemEncoding()) << ' '
 600            << int(font_scaling_factor) << ' '
 601            << theApp()->hexName(fg) << ' '
 602            << theApp()->hexName(bg);
 603         if (buffer_.params().useXetex)
 604                 cs << " xelatex";
 605
 606         string const command = libScriptSearch(cs.str());
 607
 608         if (wait) {
 609                 ForkedCall call;
 610                 int ret = call.startScript(ForkedProcess::Wait, command);
 611                 static int fake = (2^20) + 1;
 612                 int pid = fake++;
 613                 inprogress.pid = pid;
 614                 inprogress.command = command;
 615                 in_progress_[pid] = inprogress;
 616                 finishedGenerating(pid, ret);
 617                 return;
 618         }
 619
 620         // Initiate the conversion from LaTeX to bitmap images files.
 621         ForkedCall::SignalTypePtr
 622                 convert_ptr(new ForkedCall::SignalType);
 623         convert_ptr->connect(bind(&Impl::finishedGenerating, this, _1, _2));
 624
 625         ForkedCall call;
 626         int ret = call.startScript(command, convert_ptr);
 627
 628         if (ret != 0) {
 629                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 630                                         << "Unable to start process\n" << command);
 631                 return;
 632         }
 633
 634         // Store the generation process in a list of all such processes
 635         inprogress.pid = call.pid();
 636         inprogress.command = command;
 637         in_progress_[inprogress.pid] = inprogress;
 638 }
 639
 640
 641 void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 642 {
 643         // Paranoia check!
 644         InProgressProcesses::iterator git = in_progress_.find(pid);
 645         if (git == in_progress_.end()) {
 646                 lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 647                         "data for PID " << pid << endl;
 648                 return;
 649         }
 650
 651         string const command = git->second.command;
 652         string const status = retval > 0 ? "failed" : "succeeded";
 653         LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 654                                 << retval << "): processing " << status
 655                                 << " for " << command);
 656         if (retval > 0)
 657                 return;
 658
 659         // Read the metrics file, if it exists
 660         vector<double> ascent_fractions(git->second.snippets.size());
 661         setAscentFractions(ascent_fractions, git->second.metrics_file);
 662
 663         // Add these newly generated bitmap files to the cache and
 664         // start loading them into LyX.
 665         BitmapFile::const_iterator it  = git->second.snippets.begin();
 666         BitmapFile::const_iterator end = git->second.snippets.end();
 667
 668         list<PreviewImagePtr> newimages;
 669
 670         int metrics_counter = 0;
 671         for (; it != end; ++it, ++metrics_counter) {
 672                 string const & snip = it->first;
 673                 FileName const & file = it->second;
 674                 double af = ascent_fractions[metrics_counter];
 675
 676                 PreviewImagePtr ptr(new PreviewImage(parent_, snip, file, af));
 677                 cache_[snip] = ptr;
 678
 679                 newimages.push_back(ptr);
 680         }
 681
 682         // Remove the item from the list of still-executing processes.
 683         in_progress_.erase(git);
 684
 685         // Tell the outside world
 686         list<PreviewImagePtr>::const_reverse_iterator
 687                 nit  = newimages.rbegin();
 688         list<PreviewImagePtr>::const_reverse_iterator
 689                 nend = newimages.rend();
 690         for (; nit != nend; ++nit) {
 691                 imageReady(*nit->get());
 692         }
 693 }
 694
 695
 696 void PreviewLoader::Impl::dumpPreamble(odocstream & os) const
 697 {
 698         // Dump the preamble only.
 699         OutputParams runparams(&buffer_.params().encoding());
 700         runparams.flavor = OutputParams::LATEX;
 701         runparams.nice = true;
 702         runparams.moving_arg = true;
 703         runparams.free_spacing = true;
 704         buffer_.writeLaTeXSource(os, buffer_.filePath(), runparams, true, false);
 705
 706         // FIXME! This is a HACK! The proper fix is to control the 'true'
 707         // passed to WriteStream below:
 708         // int InsetMathNest::latex(Buffer const &, odocstream & os,
 709         //                          OutputParams const & runparams) const
 710         // {
 711         //      WriteStream wi(os, runparams.moving_arg, true);
 712         //      par_->write(wi);
 713         //      return wi.line();
 714         // }
 715         os << "\n"
 716            << "\\def\\lyxlock{}\n"
 717            << "\n";
 718
 719         // All equation labels appear as "(#)" + preview.sty's rendering of
 720         // the label name
 721         if (lyxrc.preview_hashed_labels)
 722                 os << "\\renewcommand{\\theequation}{\\#}\n";
 723
 724         // Use the preview style file to ensure that each snippet appears on a
 725         // fresh page.
 726         // Also support PDF output (automatically generated e.g. when
 727         // \usepackage[pdftex]{hyperref} is used and XeTeX.
 728         os << "\n"
 729            << "\\newif\\ifxetex\n"
 730            << "\\expandafter\\ifx\\csname XeTeXrevision\\endcsname\\relax\n"
 731            << "   \\xetexfalse\n"
 732            << "\\else\n"
 733            << "    \\xetextrue\n"
 734            << "\\fi\n"
 735            << "\\newif\\ifpdf\n"
 736            << "\\ifx\\pdfoutput\\undefined\n"
 737            << "\\else\\ifx\\pdfoutput\\relax\n"
 738            << "\\else\\ifnum0=\\pdfoutput\n"
 739            << "\\else\\pdftrue\\fi\\fi\\fi\n"
 740            << "\\ifxetex\n"
 741            << "  \\usepackage[active,delayed,tightpage,showlabels,lyx,xetex]{preview}\n"
 742            << "\\else\n"
 743            << "\\ifpdf\n"
 744            << "  \\usepackage[active,delayed,tightpage,showlabels,lyx,pdftex]{preview}\n"
 745            << "\\else\n"
 746            << "  \\usepackage[active,delayed,showlabels,lyx,dvips]{preview}\n"
 747            << "\\fi\n"
 748            << "\\fi\n"
 749            << "\n";
 750 }
 751
 752
 753 void PreviewLoader::Impl::dumpData(odocstream & os,
 754                                    BitmapFile const & vec) const
 755 {
 756         if (vec.empty())
 757                 return;
 758
 759         BitmapFile::const_iterator it  = vec.begin();
 760         BitmapFile::const_iterator end = vec.end();
 761
 762         for (; it != end; ++it) {
 763                 // FIXME UNICODE
 764                 os << "\\begin{preview}\n"
 765                    << from_utf8(it->first)
 766                    << "\n\\end{preview}\n\n";
 767         }
 768 }
 769
 770 } // namespace graphics
 771 } // namespace lyx