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(otexstream &) 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                 pconverter_ = setConverter("lyxpreview");
 393 }
 394
 395
 396 PreviewLoader::Impl::~Impl()
 397 {
 398         InProgressProcesses::iterator ipit  = in_progress_.begin();
 399         InProgressProcesses::iterator ipend = in_progress_.end();
 400
 401         for (; ipit != ipend; ++ipit)
 402                 ipit->second.stop();
 403 }
 404
 405
 406 PreviewImage const *
 407 PreviewLoader::Impl::preview(string const & latex_snippet) const
 408 {
 409         Cache::const_iterator it = cache_.find(latex_snippet);
 410         return (it == cache_.end()) ? 0 : it->second.get();
 411 }
 412
 413
 414 namespace {
 415
 416 class FindSnippet {
 417 public:
 418         FindSnippet(string const & s) : snippet_(s) {}
 419         bool operator()(InProgressProcess const & process) const
 420         {
 421                 BitmapFile const & snippets = process.second.snippets;
 422                 BitmapFile::const_iterator beg  = snippets.begin();
 423                 BitmapFile::const_iterator end = snippets.end();
 424                 return find_if(beg, end, FindFirst(snippet_)) != end;
 425         }
 426
 427 private:
 428         string const snippet_;
 429 };
 430
 431 } // namespace anon
 432
 433 PreviewLoader::Status
 434 PreviewLoader::Impl::status(string const & latex_snippet) const
 435 {
 436         Cache::const_iterator cit = cache_.find(latex_snippet);
 437         if (cit != cache_.end())
 438                 return Ready;
 439
 440         PendingSnippets::const_iterator pit  = pending_.begin();
 441         PendingSnippets::const_iterator pend = pending_.end();
 442
 443         pit = find(pit, pend, latex_snippet);
 444         if (pit != pend)
 445                 return InQueue;
 446
 447         InProgressProcesses::const_iterator ipit  = in_progress_.begin();
 448         InProgressProcesses::const_iterator ipend = in_progress_.end();
 449
 450         ipit = find_if(ipit, ipend, FindSnippet(latex_snippet));
 451         if (ipit != ipend)
 452                 return Processing;
 453
 454         return NotFound;
 455 }
 456
 457
 458 void PreviewLoader::Impl::add(string const & latex_snippet)
 459 {
 460         if (!pconverter_ || status(latex_snippet) != NotFound)
 461                 return;
 462
 463         string const snippet = trim(latex_snippet);
 464         if (snippet.empty())
 465                 return;
 466
 467         LYXERR(Debug::GRAPHICS, "adding snippet:\n" << snippet);
 468
 469         pending_.push_back(snippet);
 470 }
 471
 472
 473 namespace {
 474
 475 class EraseSnippet {
 476 public:
 477         EraseSnippet(string const & s) : snippet_(s) {}
 478         void operator()(InProgressProcess & process)
 479         {
 480                 BitmapFile & snippets = process.second.snippets;
 481                 BitmapFile::iterator it  = snippets.begin();
 482                 BitmapFile::iterator end = snippets.end();
 483
 484                 it = find_if(it, end, FindFirst(snippet_));
 485                 if (it != end)
 486                         snippets.erase(it, it+1);
 487         }
 488
 489 private:
 490         string const & snippet_;
 491 };
 492
 493 } // namespace anon
 494
 495
 496 void PreviewLoader::Impl::remove(string const & latex_snippet)
 497 {
 498         Cache::iterator cit = cache_.find(latex_snippet);
 499         if (cit != cache_.end())
 500                 cache_.erase(cit);
 501
 502         PendingSnippets::iterator pit  = pending_.begin();
 503         PendingSnippets::iterator pend = pending_.end();
 504
 505         pending_.erase(std::remove(pit, pend, latex_snippet), pend);
 506
 507         InProgressProcesses::iterator ipit  = in_progress_.begin();
 508         InProgressProcesses::iterator ipend = in_progress_.end();
 509
 510         for_each(ipit, ipend, EraseSnippet(latex_snippet));
 511
 512         while (ipit != ipend) {
 513                 InProgressProcesses::iterator curr = ipit++;
 514                 if (curr->second.snippets.empty())
 515                         in_progress_.erase(curr);
 516         }
 517 }
 518
 519
 520 void PreviewLoader::Impl::startLoading(bool wait)
 521 {
 522         if (pending_.empty() || !pconverter_)
 523                 return;
 524
 525         // Only start the process off after the buffer is loaded from file.
 526         if (!buffer_.isFullyLoaded())
 527                 return;
 528
 529         LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()");
 530
 531         // As used by the LaTeX file and by the resulting image files
 532         string const directory = buffer_.temppath();
 533
 534         string const filename_base = unique_filename(directory);
 535
 536         // Create an InProgress instance to place in the map of all
 537         // such processes if it starts correctly.
 538         InProgress inprogress(filename_base, pending_, pconverter_->to);
 539
 540         // clear pending_, so we're ready to start afresh.
 541         pending_.clear();
 542
 543         // Output the LaTeX file.
 544         FileName const latexfile(filename_base + ".tex");
 545
 546         // we use the encoding of the buffer
 547         Encoding const & enc = buffer_.params().encoding();
 548         ofdocstream of;
 549         try { of.reset(enc.iconvName()); }
 550         catch (iconv_codecvt_facet_exception const & e) {
 551                 LYXERR0("Caught iconv exception: " << e.what()
 552                         << "\nUnable to create LaTeX file: " << latexfile);
 553                 return;
 554         }
 555
 556         TexRow texrow;
 557         otexstream os(of, texrow);
 558         OutputParams runparams(&enc);
 559         LaTeXFeatures features(buffer_, buffer_.params(), runparams);
 560
 561         if (!openFileWrite(of, latexfile))
 562                 return;
 563
 564         if (!of) {
 565                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 566                                         << "Unable to create LaTeX file\n" << latexfile);
 567                 return;
 568         }
 569         of << "\\batchmode\n";
 570         dumpPreamble(os);
 571         // handle inputenc etc.
 572         buffer_.params().writeEncodingPreamble(os, features);
 573         of << "\n\\begin{document}\n";
 574         dumpData(of, inprogress.snippets);
 575         of << "\n\\end{document}\n";
 576         of.close();
 577         if (of.fail()) {
 578                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 579                                          << "File was not closed properly.");
 580                 return;
 581         }
 582
 583         double const font_scaling_factor =
 584                 buffer_.isExporting() ? 75.0 * buffer_.params().html_math_img_scale
 585                         : 0.01 * lyxrc.dpi * lyxrc.zoom * lyxrc.preview_scale_factor;
 586
 587         // The conversion command.
 588         ostringstream cs;
 589         cs << pconverter_->command
 590            << " " << quoteName(latexfile.toFilesystemEncoding())
 591            << " --dpi " << int(font_scaling_factor);
 592
 593         // FIXME XHTML
 594         // The colors should be customizable.
 595         if (!buffer_.isExporting()) {
 596                 ColorCode const fg = PreviewLoader::foregroundColor();
 597                 ColorCode const bg = PreviewLoader::backgroundColor();
 598                 cs << " --fg " << theApp()->hexName(fg)
 599                    << " --bg " << theApp()->hexName(bg);
 600         }
 601
 602         // FIXME what about LuaTeX?
 603         if (buffer_.params().useNonTeXFonts)
 604                 cs << " --latex=xelatex";
 605         if (buffer_.params().encoding().package() == Encoding::japanese)
 606                 cs << " --latex=platex";
 607         if (buffer_.params().bibtex_command != "default")
 608                 cs << " --bibtex=" << quoteName(buffer_.params().bibtex_command);
 609         else if (buffer_.params().encoding().package() == Encoding::japanese)
 610                 cs << " --bibtex=" << quoteName(lyxrc.jbibtex_command);
 611         else
 612                 cs << " --bibtex=" << quoteName(lyxrc.bibtex_command);
 613         if (buffer_.params().bufferFormat() == "lilypond-book")
 614                 cs << " --lilypond";
 615
 616         string const command = libScriptSearch(cs.str());
 617
 618         if (wait) {
 619                 ForkedCall call(buffer_.filePath());
 620                 int ret = call.startScript(ForkedProcess::Wait, command);
 621                 static int fake = (2^20) + 1;
 622                 int pid = fake++;
 623                 inprogress.pid = pid;
 624                 inprogress.command = command;
 625                 in_progress_[pid] = inprogress;
 626                 finishedGenerating(pid, ret);
 627                 return;
 628         }
 629
 630         // Initiate the conversion from LaTeX to bitmap images files.
 631         ForkedCall::SignalTypePtr
 632                 convert_ptr(new ForkedCall::SignalType);
 633         convert_ptr->connect(bind(&Impl::finishedGenerating, this, _1, _2));
 634
 635         ForkedCall call(buffer_.filePath());
 636         int ret = call.startScript(command, convert_ptr);
 637
 638         if (ret != 0) {
 639                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 640                                         << "Unable to start process\n" << command);
 641                 return;
 642         }
 643
 644         // Store the generation process in a list of all such processes
 645         inprogress.pid = call.pid();
 646         inprogress.command = command;
 647         in_progress_[inprogress.pid] = inprogress;
 648 }
 649
 650
 651 void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 652 {
 653         // Paranoia check!
 654         InProgressProcesses::iterator git = in_progress_.find(pid);
 655         if (git == in_progress_.end()) {
 656                 lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 657                         "data for PID " << pid << endl;
 658                 return;
 659         }
 660
 661         string const command = git->second.command;
 662         string const status = retval > 0 ? "failed" : "succeeded";
 663         LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 664                                 << retval << "): processing " << status
 665                                 << " for " << command);
 666         if (retval > 0)
 667                 return;
 668
 669         // Read the metrics file, if it exists
 670         vector<double> ascent_fractions(git->second.snippets.size());
 671         setAscentFractions(ascent_fractions, git->second.metrics_file);
 672
 673         // Add these newly generated bitmap files to the cache and
 674         // start loading them into LyX.
 675         BitmapFile::const_iterator it  = git->second.snippets.begin();
 676         BitmapFile::const_iterator end = git->second.snippets.end();
 677
 678         list<PreviewImagePtr> newimages;
 679
 680         int metrics_counter = 0;
 681         for (; it != end; ++it, ++metrics_counter) {
 682                 string const & snip = it->first;
 683                 FileName const & file = it->second;
 684                 double af = ascent_fractions[metrics_counter];
 685
 686                 // Add the image to the cache only if it's actually present
 687                 if (file.isReadableFile()) {
 688                         PreviewImagePtr ptr(new PreviewImage(parent_, snip, file, af));
 689                         cache_[snip] = ptr;
 690
 691                         newimages.push_back(ptr);
 692                 }
 693
 694         }
 695
 696         // Remove the item from the list of still-executing processes.
 697         in_progress_.erase(git);
 698
 699         // Tell the outside world
 700         list<PreviewImagePtr>::const_reverse_iterator
 701                 nit  = newimages.rbegin();
 702         list<PreviewImagePtr>::const_reverse_iterator
 703                 nend = newimages.rend();
 704         for (; nit != nend; ++nit) {
 705                 imageReady(*nit->get());
 706         }
 707 }
 708
 709
 710 void PreviewLoader::Impl::dumpPreamble(otexstream & os) const
 711 {
 712         // Dump the preamble only.
 713         OutputParams runparams(&buffer_.params().encoding());
 714         if (buffer_.params().useNonTeXFonts)
 715                 runparams.flavor = OutputParams::XETEX;
 716         else
 717                 runparams.flavor = OutputParams::LATEX;
 718         runparams.nice = true;
 719         runparams.moving_arg = true;
 720         runparams.free_spacing = true;
 721         buffer_.writeLaTeXSource(os, buffer_.filePath(), runparams, Buffer::OnlyPreamble);
 722
 723         // FIXME! This is a HACK! The proper fix is to control the 'true'
 724         // passed to WriteStream below:
 725         // int InsetMathNest::latex(Buffer const &, odocstream & os,
 726         //                          OutputParams const & runparams) const
 727         // {
 728         //      WriteStream wi(os, runparams.moving_arg, true);
 729         //      par_->write(wi);
 730         //      return wi.line();
 731         // }
 732         os << "\n"
 733            << "\\def\\lyxlock{}\n"
 734            << "\n";
 735
 736         // All equation labels appear as "(#)" + preview.sty's rendering of
 737         // the label name
 738         if (lyxrc.preview_hashed_labels)
 739                 os << "\\renewcommand{\\theequation}{\\#}\n";
 740
 741         // Use the preview style file to ensure that each snippet appears on a
 742         // fresh page.
 743         // Also support PDF output (automatically generated e.g. when
 744         // \usepackage[pdftex]{hyperref} is used and XeTeX.
 745         os << "\n"
 746            << "\\usepackage[active,delayed,showlabels,lyx]{preview}\n"
 747            << "\n";
 748 }
 749
 750
 751 void PreviewLoader::Impl::dumpData(odocstream & os,
 752                                    BitmapFile const & vec) const
 753 {
 754         if (vec.empty())
 755                 return;
 756
 757         BitmapFile::const_iterator it  = vec.begin();
 758         BitmapFile::const_iterator end = vec.end();
 759
 760         for (; it != end; ++it) {
 761                 // FIXME UNICODE
 762                 os << "\\begin{preview}\n"
 763                    << from_utf8(it->first)
 764                    << "\n\\end{preview}\n\n";
 765         }
 766 }
 767
 768 } // namespace graphics
 769 } // namespace lyx