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 #include "support/TempFile.h"
  42
  43 #include <sstream>
  44 #include <fstream>
  45 #include <iomanip>
  46
  47 #include <QTimer>
  48
  49 using namespace std;
  50 using namespace lyx::support;
  51
  52
  53
  54 namespace {
  55
  56 typedef pair<string, FileName> SnippetPair;
  57
  58 // A list of all snippets to be converted to previews
  59 typedef list<string> PendingSnippets;
  60
  61 // Each item in the vector is a pair<snippet, image file name>.
  62 typedef vector<SnippetPair> BitmapFile;
  63
  64
  65 FileName const unique_tex_filename(FileName const & bufferpath)
  66 {
  67         TempFile tempfile(bufferpath, "lyxpreviewXXXXXX.tex");
  68         tempfile.setAutoRemove(false);
  69         return tempfile.name();
  70 }
  71
  72
  73 lyx::Converter const * setConverter(string const & from)
  74 {
  75         typedef vector<string> FmtList;
  76         typedef lyx::graphics::Cache GCache;
  77         FmtList const & loadableFormats = GCache::get().loadableFormats();
  78         FmtList::const_iterator it = loadableFormats.begin();
  79         FmtList::const_iterator const end = loadableFormats.end();
  80
  81         for (; it != end; ++it) {
  82                 string const to = *it;
  83                 if (from == to)
  84                         continue;
  85
  86                 lyx::Converter const * ptr = lyx::theConverters().getConverter(from, to);
  87                 if (ptr)
  88                         return ptr;
  89         }
  90
  91         // FIXME THREAD
  92         static bool first = true;
  93         if (first) {
  94                 first = false;
  95                 LYXERR0("PreviewLoader::startLoading()\n"
  96                         << "No converter from \"" << from << "\" format has been defined.");
  97         }
  98         return 0;
  99 }
 100
 101
 102 void setAscentFractions(vector<double> & ascent_fractions,
 103                         FileName const & metrics_file)
 104 {
 105         // If all else fails, then the images will have equal ascents and
 106         // descents.
 107         vector<double>::iterator it  = ascent_fractions.begin();
 108         vector<double>::iterator end = ascent_fractions.end();
 109         fill(it, end, 0.5);
 110
 111         ifstream in(metrics_file.toFilesystemEncoding().c_str());
 112         if (!in.good()) {
 113                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 114                         << "Unable to open file!");
 115                 return;
 116         }
 117
 118         bool error = false;
 119
 120         int snippet_counter = 1;
 121         while (!in.eof() && it != end) {
 122                 string snippet;
 123                 int id;
 124                 double ascent_fraction;
 125
 126                 in >> snippet >> id >> ascent_fraction;
 127
 128                 if (!in.good())
 129                         // eof after all
 130                         break;
 131
 132                 error = snippet != "Snippet";
 133                 if (error)
 134                         break;
 135
 136                 error = id != snippet_counter;
 137                 if (error)
 138                         break;
 139
 140                 *it = ascent_fraction;
 141
 142                 ++snippet_counter;
 143                 ++it;
 144         }
 145
 146         if (error) {
 147                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 148                         << "Error reading file!\n");
 149         }
 150 }
 151
 152
 153 class FindFirst
 154 {
 155 public:
 156         FindFirst(string const & comp) : comp_(comp) {}
 157         bool operator()(SnippetPair const & sp) const { return sp.first == comp_; }
 158 private:
 159         string const comp_;
 160 };
 161
 162
 163 /// Store info on a currently executing, forked process.
 164 class InProgress {
 165 public:
 166         ///
 167         InProgress() : pid(0) {}
 168         ///
 169         InProgress(string const & filename_base,
 170                    PendingSnippets const & pending,
 171                    string const & to_format);
 172         /// Remove any files left lying around and kill the forked process.
 173         void stop() const;
 174
 175         ///
 176         pid_t pid;
 177         ///
 178         string command;
 179         ///
 180         FileName metrics_file;
 181         ///
 182         BitmapFile snippets;
 183 };
 184
 185 typedef map<pid_t, InProgress>  InProgressProcesses;
 186
 187 typedef InProgressProcesses::value_type InProgressProcess;
 188
 189 } // namespace anon
 190
 191
 192
 193 namespace lyx {
 194 namespace graphics {
 195
 196 class PreviewLoader::Impl : public boost::signals::trackable {
 197 public:
 198         ///
 199         Impl(PreviewLoader & p, Buffer const & b);
 200         /// Stop any InProgress items still executing.
 201         ~Impl();
 202         ///
 203         PreviewImage const * preview(string const & latex_snippet) const;
 204         ///
 205         PreviewLoader::Status status(string const & latex_snippet) const;
 206         ///
 207         void add(string const & latex_snippet);
 208         ///
 209         void remove(string const & latex_snippet);
 210         /// \p wait whether to wait for the process to complete or, instead,
 211         /// to do it in the background.
 212         void startLoading(bool wait = false);
 213         ///
 214         void refreshPreviews();
 215
 216         /// Emit this signal when an image is ready for display.
 217         boost::signal<void(PreviewImage const &)> imageReady;
 218
 219         Buffer const & buffer() const { return buffer_; }
 220
 221 private:
 222         /// Called by the ForkedCall process that generated the bitmap files.
 223         void finishedGenerating(pid_t, int);
 224         ///
 225         void dumpPreamble(otexstream &, OutputParams::FLAVOR) const;
 226         ///
 227         void dumpData(odocstream &, BitmapFile const &) const;
 228
 229         /** cache_ allows easy retrieval of already-generated images
 230          *  using the LaTeX snippet as the identifier.
 231          */
 232         typedef shared_ptr<PreviewImage> PreviewImagePtr;
 233         ///
 234         typedef map<string, PreviewImagePtr> Cache;
 235         ///
 236         Cache cache_;
 237
 238         /** pending_ stores the LaTeX snippets in anticipation of them being
 239          *  sent to the converter.
 240          */
 241         PendingSnippets pending_;
 242
 243         /** in_progress_ stores all forked processes so that we can proceed
 244          *  thereafter.
 245             The map uses the conversion commands as its identifiers.
 246          */
 247         InProgressProcesses in_progress_;
 248
 249         ///
 250         PreviewLoader & parent_;
 251         ///
 252         Buffer const & buffer_;
 253         ///
 254         mutable int font_scaling_factor_;
 255         ///
 256         QTimer * delay_refresh_;
 257         ///
 258         bool finished_generating_;
 259
 260         /// We don't own this
 261         static lyx::Converter const * pconverter_;
 262 };
 263
 264
 265 lyx::Converter const * PreviewLoader::Impl::pconverter_;
 266
 267
 268 //
 269 // The public interface, defined in PreviewLoader.h
 270 //
 271
 272 PreviewLoader::PreviewLoader(Buffer const & b)
 273         : pimpl_(new Impl(*this, b))
 274 {}
 275
 276
 277 PreviewLoader::~PreviewLoader()
 278 {
 279         delete pimpl_;
 280 }
 281
 282
 283 PreviewImage const * PreviewLoader::preview(string const & latex_snippet) const
 284 {
 285         return pimpl_->preview(latex_snippet);
 286 }
 287
 288
 289 PreviewLoader::Status PreviewLoader::status(string const & latex_snippet) const
 290 {
 291         return pimpl_->status(latex_snippet);
 292 }
 293
 294
 295 void PreviewLoader::add(string const & latex_snippet) const
 296 {
 297         pimpl_->add(latex_snippet);
 298 }
 299
 300
 301 void PreviewLoader::remove(string const & latex_snippet) const
 302 {
 303         pimpl_->remove(latex_snippet);
 304 }
 305
 306
 307 void PreviewLoader::startLoading(bool wait) const
 308 {
 309         pimpl_->startLoading(wait);
 310 }
 311
 312
 313 void PreviewLoader::refreshPreviews()
 314 {
 315         pimpl_->refreshPreviews();
 316 }
 317
 318
 319 boost::signals::connection PreviewLoader::connect(slot_type const & slot) const
 320 {
 321         return pimpl_->imageReady.connect(slot);
 322 }
 323
 324
 325 void PreviewLoader::emitSignal(PreviewImage const & pimage) const
 326 {
 327         pimpl_->imageReady(pimage);
 328 }
 329
 330
 331 Buffer const & PreviewLoader::buffer() const
 332 {
 333         return pimpl_->buffer();
 334 }
 335
 336 } // namespace graphics
 337 } // namespace lyx
 338
 339
 340 // The details of the Impl
 341 // =======================
 342
 343 namespace {
 344
 345 class IncrementedFileName {
 346 public:
 347         IncrementedFileName(string const & to_format,
 348                             string const & filename_base)
 349                 : to_format_(to_format), base_(filename_base), counter_(1)
 350         {}
 351
 352         SnippetPair const operator()(string const & snippet)
 353         {
 354                 ostringstream os;
 355                 os << base_ << counter_++ << '.' << to_format_;
 356                 string const file = os.str();
 357
 358                 return make_pair(snippet, FileName(file));
 359         }
 360
 361 private:
 362         string const & to_format_;
 363         string const & base_;
 364         int counter_;
 365 };
 366
 367
 368 InProgress::InProgress(string const & filename_base,
 369                        PendingSnippets const & pending,
 370                        string const & to_format)
 371         : pid(0),
 372           metrics_file(filename_base + ".metrics"),
 373           snippets(pending.size())
 374 {
 375         PendingSnippets::const_iterator pit  = pending.begin();
 376         PendingSnippets::const_iterator pend = pending.end();
 377         BitmapFile::iterator sit = snippets.begin();
 378
 379         transform(pit, pend, sit,
 380                        IncrementedFileName(to_format, filename_base));
 381 }
 382
 383
 384 void InProgress::stop() const
 385 {
 386         if (pid)
 387                 ForkedCallsController::kill(pid, 0);
 388
 389         if (!metrics_file.empty())
 390                 metrics_file.removeFile();
 391
 392         BitmapFile::const_iterator vit  = snippets.begin();
 393         BitmapFile::const_iterator vend = snippets.end();
 394         for (; vit != vend; ++vit) {
 395                 if (!vit->second.empty())
 396                         vit->second.removeFile();
 397         }
 398 }
 399
 400 } // namespace anon
 401
 402
 403 namespace lyx {
 404 namespace graphics {
 405
 406 PreviewLoader::Impl::Impl(PreviewLoader & p, Buffer const & b)
 407         : parent_(p), buffer_(b), finished_generating_(true)
 408 {
 409         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 410         if (!pconverter_)
 411                 pconverter_ = setConverter("lyxpreview");
 412
 413         delay_refresh_ = new QTimer(&parent_);
 414         delay_refresh_->setSingleShot(true);
 415         QObject::connect(delay_refresh_, SIGNAL(timeout()),
 416                          &parent_, SLOT(refreshPreviews()));
 417 }
 418
 419
 420 PreviewLoader::Impl::~Impl()
 421 {
 422         delete delay_refresh_;
 423
 424         InProgressProcesses::iterator ipit  = in_progress_.begin();
 425         InProgressProcesses::iterator ipend = in_progress_.end();
 426
 427         for (; ipit != ipend; ++ipit)
 428                 ipit->second.stop();
 429 }
 430
 431
 432 PreviewImage const *
 433 PreviewLoader::Impl::preview(string const & latex_snippet) const
 434 {
 435         int fs = int(buffer_.fontScalingFactor());
 436         if (font_scaling_factor_ != fs) {
 437                 // Schedule refresh of all previews on zoom changes.
 438                 // The previews are regenerated only after the zoom factor
 439                 // has not been changed for about 1 second.
 440                 delay_refresh_->start(1000);
 441         }
 442         // Don't try to access the cache until we are done.
 443         if (delay_refresh_->isActive() || !finished_generating_)
 444                 return 0;
 445         Cache::const_iterator it = cache_.find(latex_snippet);
 446         return (it == cache_.end()) ? 0 : it->second.get();
 447 }
 448
 449
 450 void PreviewLoader::Impl::refreshPreviews()
 451 {
 452         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 453         // Reschedule refresh until the previous process completed.
 454         if (!finished_generating_) {
 455                 delay_refresh_->start(1000);
 456                 return;
 457         }
 458         Cache::const_iterator cit = cache_.begin();
 459         Cache::const_iterator cend = cache_.end();
 460         while (cit != cend)
 461                 parent_.remove((cit++)->first);
 462         finished_generating_ = false;
 463         buffer_.updatePreviews();
 464 }
 465
 466
 467 namespace {
 468
 469 class FindSnippet {
 470 public:
 471         FindSnippet(string const & s) : snippet_(s) {}
 472         bool operator()(InProgressProcess const & process) const
 473         {
 474                 BitmapFile const & snippets = process.second.snippets;
 475                 BitmapFile::const_iterator beg  = snippets.begin();
 476                 BitmapFile::const_iterator end = snippets.end();
 477                 return find_if(beg, end, FindFirst(snippet_)) != end;
 478         }
 479
 480 private:
 481         string const snippet_;
 482 };
 483
 484 } // namespace anon
 485
 486 PreviewLoader::Status
 487 PreviewLoader::Impl::status(string const & latex_snippet) const
 488 {
 489         Cache::const_iterator cit = cache_.find(latex_snippet);
 490         if (cit != cache_.end())
 491                 return Ready;
 492
 493         PendingSnippets::const_iterator pit  = pending_.begin();
 494         PendingSnippets::const_iterator pend = pending_.end();
 495
 496         pit = find(pit, pend, latex_snippet);
 497         if (pit != pend)
 498                 return InQueue;
 499
 500         InProgressProcesses::const_iterator ipit  = in_progress_.begin();
 501         InProgressProcesses::const_iterator ipend = in_progress_.end();
 502
 503         ipit = find_if(ipit, ipend, FindSnippet(latex_snippet));
 504         if (ipit != ipend)
 505                 return Processing;
 506
 507         return NotFound;
 508 }
 509
 510
 511 void PreviewLoader::Impl::add(string const & latex_snippet)
 512 {
 513         if (!pconverter_ || status(latex_snippet) != NotFound)
 514                 return;
 515
 516         string const snippet = trim(latex_snippet);
 517         if (snippet.empty())
 518                 return;
 519
 520         LYXERR(Debug::GRAPHICS, "adding snippet:\n" << snippet);
 521
 522         pending_.push_back(snippet);
 523 }
 524
 525
 526 namespace {
 527
 528 class EraseSnippet {
 529 public:
 530         EraseSnippet(string const & s) : snippet_(s) {}
 531         void operator()(InProgressProcess & process)
 532         {
 533                 BitmapFile & snippets = process.second.snippets;
 534                 BitmapFile::iterator it  = snippets.begin();
 535                 BitmapFile::iterator end = snippets.end();
 536
 537                 it = find_if(it, end, FindFirst(snippet_));
 538                 if (it != end)
 539                         snippets.erase(it, it+1);
 540         }
 541
 542 private:
 543         string const & snippet_;
 544 };
 545
 546 } // namespace anon
 547
 548
 549 void PreviewLoader::Impl::remove(string const & latex_snippet)
 550 {
 551         Cache::iterator cit = cache_.find(latex_snippet);
 552         if (cit != cache_.end())
 553                 cache_.erase(cit);
 554
 555         PendingSnippets::iterator pit  = pending_.begin();
 556         PendingSnippets::iterator pend = pending_.end();
 557
 558         pending_.erase(std::remove(pit, pend, latex_snippet), pend);
 559
 560         InProgressProcesses::iterator ipit  = in_progress_.begin();
 561         InProgressProcesses::iterator ipend = in_progress_.end();
 562
 563         for_each(ipit, ipend, EraseSnippet(latex_snippet));
 564
 565         while (ipit != ipend) {
 566                 InProgressProcesses::iterator curr = ipit++;
 567                 if (curr->second.snippets.empty())
 568                         in_progress_.erase(curr);
 569         }
 570 }
 571
 572
 573 void PreviewLoader::Impl::startLoading(bool wait)
 574 {
 575         if (pending_.empty() || !pconverter_)
 576                 return;
 577
 578         // Only start the process off after the buffer is loaded from file.
 579         if (!buffer_.isFullyLoaded())
 580                 return;
 581
 582         LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()");
 583
 584         // As used by the LaTeX file and by the resulting image files
 585         FileName const directory(buffer_.temppath());
 586
 587         FileName const latexfile = unique_tex_filename(directory);
 588         string const filename_base = removeExtension(latexfile.absFileName());
 589
 590         // Create an InProgress instance to place in the map of all
 591         // such processes if it starts correctly.
 592         InProgress inprogress(filename_base, pending_, pconverter_->to());
 593
 594         // clear pending_, so we're ready to start afresh.
 595         pending_.clear();
 596
 597         // Output the LaTeX file.
 598         // we use the encoding of the buffer
 599         Encoding const & enc = buffer_.params().encoding();
 600         ofdocstream of;
 601         try { of.reset(enc.iconvName()); }
 602         catch (iconv_codecvt_facet_exception const & e) {
 603                 LYXERR0("Caught iconv exception: " << e.what()
 604                         << "\nUnable to create LaTeX file: " << latexfile);
 605                 return;
 606         }
 607
 608         TexRow texrow;
 609         otexstream os(of, texrow);
 610         OutputParams runparams(&enc);
 611         LaTeXFeatures features(buffer_, buffer_.params(), runparams);
 612
 613         if (!openFileWrite(of, latexfile))
 614                 return;
 615
 616         if (!of) {
 617                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 618                                         << "Unable to create LaTeX file\n" << latexfile);
 619                 return;
 620         }
 621         of << "\\batchmode\n";
 622
 623         LYXERR(Debug::LATEX, "Format = " << buffer_.params().getDefaultOutputFormat());
 624         string latexparam = "";
 625         bool docformat = !buffer_.params().default_output_format.empty()
 626                         && buffer_.params().default_output_format != "default";
 627         // Use LATEX flavor if the document does not specify a specific
 628         // output format (see bug 9371).
 629         OutputParams::FLAVOR flavor = docformat
 630                                         ? buffer_.params().getOutputFlavor()
 631                                         : OutputParams::LATEX;
 632         if (buffer_.params().encoding().package() == Encoding::japanese) {
 633                 latexparam = " --latex=platex";
 634                 flavor = OutputParams::LATEX;
 635         }
 636         else if (buffer_.params().useNonTeXFonts) {
 637                 if (flavor == OutputParams::LUATEX)
 638                         latexparam = " --latex=lualatex";
 639                 else {
 640                         flavor = OutputParams::XETEX;
 641                         latexparam = " --latex=xelatex";
 642                 }
 643         }
 644         else {
 645                 switch (flavor) {
 646                         case OutputParams::PDFLATEX:
 647                                 latexparam = " --latex=pdflatex";
 648                                 break;
 649                         case OutputParams::XETEX:
 650                                 latexparam = " --latex=xelatex";
 651                                 break;
 652                         case OutputParams::LUATEX:
 653                                 latexparam = " --latex=lualatex";
 654                                 break;
 655                         case OutputParams::DVILUATEX:
 656                                 latexparam = " --latex=dvilualatex";
 657                                 break;
 658                         default:
 659                                 flavor = OutputParams::LATEX;
 660                 }
 661         }
 662         dumpPreamble(os, flavor);
 663         // handle inputenc etc.
 664         // I think, this is already hadled by dumpPreamble(): Kornel
 665         // buffer_.params().writeEncodingPreamble(os, features);
 666         of << "\n\\begin{document}\n";
 667         dumpData(of, inprogress.snippets);
 668         of << "\n\\end{document}\n";
 669         of.close();
 670         if (of.fail()) {
 671                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 672                                          << "File was not closed properly.");
 673                 return;
 674         }
 675
 676         // The conversion command.
 677         ostringstream cs;
 678         cs << pconverter_->command()
 679            << " " << quoteName(latexfile.toFilesystemEncoding())
 680            << " --dpi " << font_scaling_factor_;
 681
 682         // FIXME XHTML
 683         // The colors should be customizable.
 684         if (!buffer_.isExporting()) {
 685                 ColorCode const fg = PreviewLoader::foregroundColor();
 686                 ColorCode const bg = PreviewLoader::backgroundColor();
 687                 cs << " --fg " << theApp()->hexName(fg)
 688                    << " --bg " << theApp()->hexName(bg);
 689         }
 690
 691         cs << latexparam;
 692         if (buffer_.params().bibtex_command != "default")
 693                 cs << " --bibtex=" << quoteName(buffer_.params().bibtex_command);
 694         else if (buffer_.params().encoding().package() == Encoding::japanese)
 695                 cs << " --bibtex=" << quoteName(lyxrc.jbibtex_command);
 696         else
 697                 cs << " --bibtex=" << quoteName(lyxrc.bibtex_command);
 698         if (buffer_.params().bufferFormat() == "lilypond-book")
 699                 cs << " --lilypond";
 700
 701         string const command = cs.str();
 702
 703         if (wait) {
 704                 ForkedCall call(buffer_.filePath(), buffer_.layoutPos());
 705                 int ret = call.startScript(ForkedProcess::Wait, command);
 706                 // FIXME THREAD
 707                 static int fake = (2^20) + 1;
 708                 int pid = fake++;
 709                 inprogress.pid = pid;
 710                 inprogress.command = command;
 711                 in_progress_[pid] = inprogress;
 712                 finishedGenerating(pid, ret);
 713                 return;
 714         }
 715
 716         // Initiate the conversion from LaTeX to bitmap images files.
 717         ForkedCall::SignalTypePtr
 718                 convert_ptr(new ForkedCall::SignalType);
 719         convert_ptr->connect(bind(&Impl::finishedGenerating, this, _1, _2));
 720
 721         ForkedCall call(buffer_.filePath());
 722         int ret = call.startScript(command, convert_ptr);
 723
 724         if (ret != 0) {
 725                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 726                                         << "Unable to start process\n" << command);
 727                 return;
 728         }
 729
 730         // Store the generation process in a list of all such processes
 731         inprogress.pid = call.pid();
 732         inprogress.command = command;
 733         in_progress_[inprogress.pid] = inprogress;
 734 }
 735
 736
 737 double PreviewLoader::displayPixelRatio() const
 738 {
 739         return buffer().params().display_pixel_ratio;
 740 }
 741
 742 void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 743 {
 744         // Paranoia check!
 745         InProgressProcesses::iterator git = in_progress_.find(pid);
 746         if (git == in_progress_.end()) {
 747                 lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 748                         "data for PID " << pid << endl;
 749                 finished_generating_ = true;
 750                 return;
 751         }
 752
 753         string const command = git->second.command;
 754         string const status = retval > 0 ? "failed" : "succeeded";
 755         LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 756                                 << retval << "): processing " << status
 757                                 << " for " << command);
 758         if (retval > 0) {
 759                 in_progress_.erase(git);
 760                 finished_generating_ = true;
 761                 return;
 762         }
 763
 764         // Read the metrics file, if it exists
 765         vector<double> ascent_fractions(git->second.snippets.size());
 766         setAscentFractions(ascent_fractions, git->second.metrics_file);
 767
 768         // Add these newly generated bitmap files to the cache and
 769         // start loading them into LyX.
 770         BitmapFile::const_iterator it  = git->second.snippets.begin();
 771         BitmapFile::const_iterator end = git->second.snippets.end();
 772
 773         list<PreviewImagePtr> newimages;
 774
 775         int metrics_counter = 0;
 776         for (; it != end; ++it, ++metrics_counter) {
 777                 string const & snip = it->first;
 778                 FileName const & file = it->second;
 779                 double af = ascent_fractions[metrics_counter];
 780
 781                 // Add the image to the cache only if it's actually present
 782                 // and not empty (an empty image is signaled by af < 0)
 783                 if (af >= 0 && file.isReadableFile()) {
 784                         PreviewImagePtr ptr(new PreviewImage(parent_, snip, file, af));
 785                         cache_[snip] = ptr;
 786
 787                         newimages.push_back(ptr);
 788                 }
 789
 790         }
 791
 792         // Remove the item from the list of still-executing processes.
 793         in_progress_.erase(git);
 794
 795         // Tell the outside world
 796         list<PreviewImagePtr>::const_reverse_iterator
 797                 nit  = newimages.rbegin();
 798         list<PreviewImagePtr>::const_reverse_iterator
 799                 nend = newimages.rend();
 800         for (; nit != nend; ++nit) {
 801                 imageReady(*nit->get());
 802         }
 803         finished_generating_ = true;
 804 }
 805
 806
 807 void PreviewLoader::Impl::dumpPreamble(otexstream & os, OutputParams::FLAVOR flavor) const
 808 {
 809         // Dump the preamble only.
 810         LYXERR(Debug::LATEX, "dumpPreamble, flavor == " << flavor);
 811         OutputParams runparams(&buffer_.params().encoding());
 812         runparams.flavor = flavor;
 813         runparams.nice = true;
 814         runparams.moving_arg = true;
 815         runparams.free_spacing = true;
 816         runparams.is_child = buffer_.parent();
 817         buffer_.writeLaTeXSource(os, buffer_.filePath(), runparams, Buffer::OnlyPreamble);
 818
 819         // FIXME! This is a HACK! The proper fix is to control the 'true'
 820         // passed to WriteStream below:
 821         // int InsetMathNest::latex(Buffer const &, odocstream & os,
 822         //                          OutputParams const & runparams) const
 823         // {
 824         //      WriteStream wi(os, runparams.moving_arg, true);
 825         //      par_->write(wi);
 826         //      return wi.line();
 827         // }
 828         os << "\n"
 829            << "\\def\\lyxlock{}\n"
 830            << "\n";
 831
 832         // All equation labels appear as "(#)" + preview.sty's rendering of
 833         // the label name
 834         if (lyxrc.preview_hashed_labels)
 835                 os << "\\renewcommand{\\theequation}{\\#}\n";
 836
 837         // Use the preview style file to ensure that each snippet appears on a
 838         // fresh page.
 839         // Also support PDF output (automatically generated e.g. when
 840         // \usepackage[pdftex]{hyperref} is used and XeTeX.
 841         os << "\n"
 842            << "\\usepackage[active,delayed,showlabels,lyx]{preview}\n"
 843            << "\n";
 844 }
 845
 846
 847 void PreviewLoader::Impl::dumpData(odocstream & os,
 848                                    BitmapFile const & vec) const
 849 {
 850         if (vec.empty())
 851                 return;
 852
 853         BitmapFile::const_iterator it  = vec.begin();
 854         BitmapFile::const_iterator end = vec.end();
 855
 856         for (; it != end; ++it) {
 857                 // FIXME UNICODE
 858                 os << "\\begin{preview}\n"
 859                    << from_utf8(it->first)
 860                    << "\n\\end{preview}\n\n";
 861         }
 862 }
 863
 864 } // namespace graphics
 865 } // namespace lyx
 866
 867 #include "moc_PreviewLoader.cpp"