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 "LyXRC.h"
  23 #include "output.h"
  24 #include "OutputParams.h"
  25 #include "TexRow.h"
  26 #include "texstream.h"
  27
  28 #include "frontends/Application.h" // hexName
  29
  30 #include "support/convert.h"
  31 #include "support/debug.h"
  32 #include "support/FileName.h"
  33 #include "support/filetools.h"
  34 #include "support/ForkedCalls.h"
  35 #include "support/lstrings.h"
  36 #include "support/os.h"
  37
  38 #include "support/TempFile.h"
  39
  40 #include <atomic>
  41 #include <fstream>
  42 #include <iomanip>
  43 #include <memory>
  44 #include <mutex>
  45 #include <sstream>
  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 void setAscentFractions(vector<double> & ascent_fractions,
  74                         FileName const & metrics_file)
  75 {
  76         // If all else fails, then the images will have equal ascents and
  77         // descents.
  78         vector<double>::iterator it  = ascent_fractions.begin();
  79         vector<double>::iterator end = ascent_fractions.end();
  80         fill(it, end, 0.5);
  81
  82         ifstream in(metrics_file.toFilesystemEncoding().c_str());
  83         if (!in.good()) {
  84                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
  85                         << "Unable to open file!");
  86                 return;
  87         }
  88
  89         bool error = false;
  90
  91         int snippet_counter = 1;
  92         while (!in.eof() && it != end) {
  93                 string snippet;
  94                 int id;
  95                 double ascent_fraction;
  96
  97                 in >> snippet >> id >> ascent_fraction;
  98
  99                 if (!in.good())
 100                         // eof after all
 101                         break;
 102
 103                 error = snippet != "Snippet";
 104                 if (error)
 105                         break;
 106
 107                 error = id != snippet_counter;
 108                 if (error)
 109                         break;
 110
 111                 *it = ascent_fraction;
 112
 113                 ++snippet_counter;
 114                 ++it;
 115         }
 116
 117         if (error) {
 118                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 119                         << "Error reading file!\n");
 120         }
 121 }
 122
 123
 124 std::function <bool (SnippetPair const &)> FindFirst(string const & comp)
 125 {
 126         return [&comp](SnippetPair const & sp) { return sp.first == comp; };
 127 }
 128
 129
 130 /// Store info on a currently executing, forked process.
 131 class InProgress {
 132 public:
 133         ///
 134         InProgress() : pid(0) {}
 135         ///
 136         InProgress(string const & filename_base,
 137                    PendingSnippets const & pending,
 138                    string const & to_format);
 139         /// Remove any files left lying around and kill the forked process.
 140         void stop() const;
 141
 142         ///
 143         string command;
 144         ///
 145         FileName metrics_file;
 146         ///
 147         BitmapFile snippets;
 148         ///
 149         pid_t pid;
 150 };
 151
 152 typedef map<pid_t, InProgress>  InProgressProcesses;
 153
 154 typedef InProgressProcesses::value_type InProgressProcess;
 155
 156 } // namespace
 157
 158
 159 namespace lyx {
 160 namespace graphics {
 161
 162 class PreviewLoader::Impl {
 163 public:
 164         ///
 165         Impl(PreviewLoader & p, Buffer const & b);
 166         /// Stop any InProgress items still executing.
 167         ~Impl();
 168         ///
 169         PreviewImage const * preview(string const & latex_snippet) const;
 170         ///
 171         PreviewLoader::Status status(string const & latex_snippet) const;
 172         ///
 173         void add(string const & latex_snippet);
 174         ///
 175         void remove(string const & latex_snippet);
 176         /// \p wait whether to wait for the process to complete or, instead,
 177         /// to do it in the background.
 178         void startLoading(bool wait = false);
 179         ///
 180         void refreshPreviews();
 181
 182         /// Emit this signal when an image is ready for display.
 183         signal<void(PreviewImage const &)> imageReady;
 184
 185         Buffer const & buffer() const { return buffer_; }
 186
 187         lyx::Converter const * setConverter(string const & from);
 188
 189 private:
 190         /// Called by the ForkedCall process that generated the bitmap files.
 191         void finishedGenerating(pid_t, int);
 192         ///
 193         void dumpPreamble(otexstream &, Flavor) const;
 194         ///
 195         void dumpData(odocstream &, BitmapFile const &) const;
 196
 197         /** cache_ allows easy retrieval of already-generated images
 198          *  using the LaTeX snippet as the identifier.
 199          */
 200         typedef std::shared_ptr<PreviewImage> PreviewImagePtr;
 201         ///
 202         typedef map<string, PreviewImagePtr> Cache;
 203         ///
 204         Cache cache_;
 205
 206         /** pending_ stores the LaTeX snippets in anticipation of them being
 207          *  sent to the converter.
 208          */
 209         PendingSnippets pending_;
 210
 211         /** in_progress_ stores all forked processes so that we can proceed
 212          *  thereafter.
 213          */
 214         InProgressProcesses in_progress_;
 215
 216         ///
 217         PreviewLoader & parent_;
 218         ///
 219         Buffer const & buffer_;
 220         ///
 221         mutable int font_scaling_factor_;
 222         ///
 223         mutable int fg_color_;
 224         ///
 225         mutable int bg_color_;
 226         ///
 227         QTimer * delay_refresh_;
 228         ///
 229         bool finished_generating_;
 230
 231         /// We don't own this
 232         static lyx::Converter const * pconverter_;
 233
 234 };
 235
 236
 237 lyx::Converter const * PreviewLoader::Impl::pconverter_;
 238
 239
 240 //
 241 // The public interface, defined in PreviewLoader.h
 242 //
 243
 244 PreviewLoader::PreviewLoader(Buffer const & b)
 245         : pimpl_(make_shared<Impl>(*this, b))
 246 {}
 247
 248
 249 PreviewImage const * PreviewLoader::preview(string const & latex_snippet) const
 250 {
 251         return pimpl_->preview(latex_snippet);
 252 }
 253
 254
 255 PreviewLoader::Status PreviewLoader::status(string const & latex_snippet) const
 256 {
 257         return pimpl_->status(latex_snippet);
 258 }
 259
 260
 261 void PreviewLoader::add(string const & latex_snippet) const
 262 {
 263         pimpl_->add(latex_snippet);
 264 }
 265
 266
 267 void PreviewLoader::remove(string const & latex_snippet) const
 268 {
 269         pimpl_->remove(latex_snippet);
 270 }
 271
 272
 273 void PreviewLoader::startLoading(bool wait) const
 274 {
 275         pimpl_->startLoading(wait);
 276 }
 277
 278
 279 void PreviewLoader::refreshPreviews()
 280 {
 281         pimpl_->refreshPreviews();
 282 }
 283
 284
 285 connection PreviewLoader::connect(slot const & slot) const
 286 {
 287         return pimpl_->imageReady.connect(slot);
 288 }
 289
 290
 291 void PreviewLoader::emitSignal(PreviewImage const & pimage) const
 292 {
 293         pimpl_->imageReady(pimage);
 294 }
 295
 296
 297 Buffer const & PreviewLoader::buffer() const
 298 {
 299         return pimpl_->buffer();
 300 }
 301
 302 } // namespace graphics
 303 } // namespace lyx
 304
 305
 306 // The details of the Impl
 307 // =======================
 308
 309 namespace {
 310
 311 class IncrementedFileName {
 312 public:
 313         IncrementedFileName(string const & to_format,
 314                             string const & filename_base)
 315                 : to_format_(to_format), base_(filename_base), counter_(1)
 316         {}
 317
 318         SnippetPair const operator()(string const & snippet)
 319         {
 320                 ostringstream os;
 321                 os << base_ << counter_++ << '.' << to_format_;
 322                 string const file_name = os.str();
 323                 return make_pair(snippet, FileName(file_name));
 324         }
 325
 326 private:
 327         string const & to_format_;
 328         string const & base_;
 329         int counter_;
 330 };
 331
 332
 333 InProgress::InProgress(string const & filename_base,
 334                        PendingSnippets const & pending,
 335                        string const & to_format)
 336         : metrics_file(filename_base + ".metrics"),
 337           snippets(pending.size()), pid(0)
 338 {
 339         PendingSnippets::const_iterator pit  = pending.begin();
 340         PendingSnippets::const_iterator pend = pending.end();
 341         BitmapFile::iterator sit = snippets.begin();
 342
 343         transform(pit, pend, sit,
 344                        IncrementedFileName(to_format, filename_base));
 345 }
 346
 347
 348 void InProgress::stop() const
 349 {
 350         if (pid)
 351                 ForkedCallsController::kill(pid, 0);
 352
 353         if (!metrics_file.empty())
 354                 metrics_file.removeFile();
 355
 356         BitmapFile::const_iterator vit  = snippets.begin();
 357         BitmapFile::const_iterator vend = snippets.end();
 358         for (; vit != vend; ++vit) {
 359                 if (!vit->second.empty())
 360                         vit->second.removeFile();
 361         }
 362 }
 363
 364 } // namespace
 365
 366
 367 namespace lyx {
 368 namespace graphics {
 369
 370 PreviewLoader::Impl::Impl(PreviewLoader & p, Buffer const & b)
 371         : parent_(p), buffer_(b), finished_generating_(true)
 372 {
 373         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 374         if (theApp()) {
 375                 fg_color_ = convert(theApp()->hexName(foregroundColor()), 16);
 376                 bg_color_ = convert(theApp()->hexName(backgroundColor()), 16);
 377         } else {
 378                 fg_color_ = 0x0;
 379                 bg_color_ = 0xffffff;
 380         }
 381         if (!pconverter_)
 382                 pconverter_ = setConverter("lyxpreview");
 383
 384         delay_refresh_ = new QTimer(&parent_);
 385         delay_refresh_->setSingleShot(true);
 386         QObject::connect(delay_refresh_, SIGNAL(timeout()),
 387                          &parent_, SLOT(refreshPreviews()));
 388 }
 389
 390
 391 lyx::Converter const * PreviewLoader::Impl::setConverter(string const & from)
 392 {
 393         typedef vector<string> FmtList;
 394         FmtList const & loadableFormats = graphics::Cache::get().loadableFormats();
 395         FmtList::const_iterator it = loadableFormats.begin();
 396         FmtList::const_iterator const end = loadableFormats.end();
 397
 398         for (; it != end; ++it) {
 399                 string const to = *it;
 400                 if (from == to)
 401                         continue;
 402
 403                 lyx::Converter const * ptr = lyx::theConverters().getConverter(from, to);
 404                 if (ptr)
 405                         return ptr;
 406         }
 407
 408         // Show the error only once. This is thread-safe.
 409         static nullptr_t no_conv = [&]{
 410                 LYXERR0("PreviewLoader::startLoading()\n"
 411                         << "No converter from \"" << from
 412                         << "\" format has been defined.");
 413                 return nullptr;
 414         } ();
 415
 416         return no_conv;
 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         int fg = 0x0;
 437         int bg = 0xffffff;
 438         if (theApp()) {
 439                 fg = convert(theApp()->hexName(foregroundColor()), 16);
 440                 bg = convert(theApp()->hexName(backgroundColor()), 16);
 441         }
 442         if (font_scaling_factor_ != fs || fg_color_ != fg || bg_color_ != bg) {
 443                 // Schedule refresh of all previews on zoom or color changes.
 444                 // The previews are regenerated only after the zoom factor
 445                 // has not been changed for about 1 second.
 446                 fg_color_ = fg;
 447                 bg_color_ = bg;
 448                 delay_refresh_->start(1000);
 449         }
 450         // Don't try to access the cache until we are done.
 451         if (delay_refresh_->isActive() || !finished_generating_)
 452                 return nullptr;
 453
 454         Cache::const_iterator it = cache_.find(latex_snippet);
 455         return (it == cache_.end()) ? nullptr : it->second.get();
 456 }
 457
 458
 459 void PreviewLoader::Impl::refreshPreviews()
 460 {
 461         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 462         // Reschedule refresh until the previous process completed.
 463         if (!finished_generating_) {
 464                 delay_refresh_->start(1000);
 465                 return;
 466         }
 467         Cache::const_iterator cit = cache_.begin();
 468         Cache::const_iterator cend = cache_.end();
 469         while (cit != cend)
 470                 parent_.remove((cit++)->first);
 471         finished_generating_ = false;
 472         buffer_.updatePreviews();
 473 }
 474
 475
 476 namespace {
 477
 478 std::function<bool (InProgressProcess const &)> FindSnippet(string const & s)
 479 {
 480         return [&s](InProgressProcess const & process) {
 481                 BitmapFile const & snippets = process.second.snippets;
 482                 BitmapFile::const_iterator beg  = snippets.begin();
 483                 BitmapFile::const_iterator end = snippets.end();
 484                 return find_if(beg, end, FindFirst(s)) != end;
 485         };
 486 }
 487
 488 } // namespace
 489
 490 PreviewLoader::Status
 491 PreviewLoader::Impl::status(string const & latex_snippet) const
 492 {
 493         Cache::const_iterator cit = cache_.find(latex_snippet);
 494         if (cit != cache_.end())
 495                 return Ready;
 496
 497         PendingSnippets::const_iterator pit  = pending_.begin();
 498         PendingSnippets::const_iterator pend = pending_.end();
 499
 500         pit = find(pit, pend, latex_snippet);
 501         if (pit != pend)
 502                 return InQueue;
 503
 504         InProgressProcesses::const_iterator ipit  = in_progress_.begin();
 505         InProgressProcesses::const_iterator ipend = in_progress_.end();
 506
 507         ipit = find_if(ipit, ipend, FindSnippet(latex_snippet));
 508         if (ipit != ipend)
 509                 return Processing;
 510
 511         return NotFound;
 512 }
 513
 514
 515 void PreviewLoader::Impl::add(string const & latex_snippet)
 516 {
 517         if (!pconverter_ || status(latex_snippet) != NotFound)
 518                 return;
 519
 520         string const snippet = trim(latex_snippet);
 521         if (snippet.empty())
 522                 return;
 523
 524         LYXERR(Debug::GRAPHICS, "adding snippet:\n" << snippet);
 525
 526         pending_.push_back(snippet);
 527 }
 528
 529
 530 namespace {
 531
 532 std::function<void (InProgressProcess &)> EraseSnippet(string const & s)
 533 {
 534         return [&s](InProgressProcess & process) {
 535                 BitmapFile & snippets = process.second.snippets;
 536                 BitmapFile::iterator it  = snippets.begin();
 537                 BitmapFile::iterator end = snippets.end();
 538
 539                 it = find_if(it, end, FindFirst(s));
 540                 if (it != end)
 541                         snippets.erase(it, it+1);
 542         };
 543 }
 544
 545 } // namespace
 546
 547
 548 void PreviewLoader::Impl::remove(string const & latex_snippet)
 549 {
 550         Cache::iterator cit = cache_.find(latex_snippet);
 551         if (cit != cache_.end())
 552                 cache_.erase(cit);
 553
 554         PendingSnippets::iterator pit  = pending_.begin();
 555         PendingSnippets::iterator pend = pending_.end();
 556
 557         pending_.erase(std::remove(pit, pend, latex_snippet), pend);
 558
 559         InProgressProcesses::iterator ipit  = in_progress_.begin();
 560         InProgressProcesses::iterator ipend = in_progress_.end();
 561
 562         for_each(ipit, ipend, EraseSnippet(latex_snippet));
 563
 564         while (ipit != ipend) {
 565                 InProgressProcesses::iterator curr = ipit++;
 566                 if (curr->second.snippets.empty())
 567                         in_progress_.erase(curr);
 568         }
 569 }
 570
 571
 572 void PreviewLoader::Impl::startLoading(bool wait)
 573 {
 574         if (pending_.empty() || !pconverter_)
 575                 return;
 576
 577         // Only start the process off after the buffer is loaded from file.
 578         if (!buffer_.isFullyLoaded())
 579                 return;
 580
 581         LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()");
 582
 583         // As used by the LaTeX file and by the resulting image files
 584         FileName const directory(buffer_.temppath());
 585
 586         FileName const latexfile = unique_tex_filename(directory);
 587         string const filename_base = removeExtension(latexfile.absFileName());
 588
 589         // Create an InProgress instance to place in the map of all
 590         // such processes if it starts correctly.
 591         InProgress inprogress(filename_base, pending_, pconverter_->to());
 592
 593         // clear pending_, so we're ready to start afresh.
 594         pending_.clear();
 595
 596         // Output the LaTeX file.
 597         // we use the encoding of the buffer
 598         Encoding const & enc = buffer_.params().encoding();
 599         ofdocstream of;
 600         try { of.reset(enc.iconvName()); }
 601         catch (iconv_codecvt_facet_exception const & e) {
 602                 LYXERR0("Caught iconv exception: " << e.what()
 603                         << "\nUnable to create LaTeX file: " << latexfile);
 604                 return;
 605         }
 606
 607         otexstream os(of);
 608         if (!openFileWrite(of, latexfile))
 609                 return;
 610
 611         if (!of) {
 612                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 613                                         << "Unable to create LaTeX file\n" << latexfile);
 614                 return;
 615         }
 616         of << "\\batchmode\n";
 617
 618         LYXERR(Debug::OUTFILE, "Format = " << buffer_.params().getDefaultOutputFormat());
 619         string latexparam = "";
 620         bool docformat = !buffer_.params().default_output_format.empty()
 621                         && buffer_.params().default_output_format != "default";
 622         // Use LATEX flavor if the document does not specify a specific
 623         // output format (see bug 9371).
 624         Flavor flavor = docformat
 625                                         ? buffer_.params().getOutputFlavor()
 626                                         : Flavor::LaTeX;
 627         if (buffer_.params().encoding().package() == Encoding::japanese) {
 628                 latexparam = " --latex=platex";
 629                 flavor = Flavor::LaTeX;
 630         }
 631         else if (buffer_.params().useNonTeXFonts) {
 632                 if (flavor == Flavor::LuaTeX)
 633                         latexparam = " --latex=lualatex";
 634                 else {
 635                         flavor = Flavor::XeTeX;
 636                         latexparam = " --latex=xelatex";
 637                 }
 638         }
 639         else {
 640                 switch (flavor) {
 641                         case Flavor::PdfLaTeX:
 642                                 latexparam = " --latex=pdflatex";
 643                                 break;
 644                         case Flavor::XeTeX:
 645                                 latexparam = " --latex=xelatex";
 646                                 break;
 647                         case Flavor::LuaTeX:
 648                                 latexparam = " --latex=lualatex";
 649                                 break;
 650                         case Flavor::DviLuaTeX:
 651                                 latexparam = " --latex=dvilualatex";
 652                                 break;
 653                         default:
 654                                 flavor = Flavor::LaTeX;
 655                 }
 656         }
 657         dumpPreamble(os, flavor);
 658         // handle inputenc etc.
 659         // I think this is already handled by dumpPreamble(): Kornel
 660         // buffer_.params().writeEncodingPreamble(os, features);
 661         of << "\n\\begin{document}\n";
 662         dumpData(of, inprogress.snippets);
 663         of << "\n\\end{document}\n";
 664         of.close();
 665         if (of.fail()) {
 666                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 667                                          << "File was not closed properly.");
 668                 return;
 669         }
 670
 671         // The conversion command.
 672         ostringstream cs;
 673         cs << subst(pconverter_->command(), "$${python}", os::python())
 674            << " " << quoteName(latexfile.toFilesystemEncoding())
 675            << " --dpi " << font_scaling_factor_;
 676
 677         // FIXME XHTML
 678         // The colors should be customizable.
 679         if (!buffer_.isExporting()) {
 680                 ColorCode const fg = PreviewLoader::foregroundColor();
 681                 ColorCode const bg = PreviewLoader::backgroundColor();
 682                 cs << " --fg " << theApp()->hexName(fg)
 683                    << " --bg " << theApp()->hexName(bg);
 684         }
 685
 686         cs << latexparam;
 687         cs << " --bibtex=" << quoteName(buffer_.params().bibtexCommand());
 688         if (buffer_.params().bufferFormat() == "lilypond-book")
 689                 cs << " --lilypond";
 690
 691         string const command = cs.str();
 692
 693         if (wait) {
 694                 ForkedCall call(buffer_.filePath(), buffer_.layoutPos());
 695                 int ret = call.startScript(ForkedProcess::Wait, command);
 696                 // PID_MAX_LIMIT is 2^22 so we start one after that
 697                 static atomic_int fake((1 << 22) + 1);
 698                 int pid = fake++;
 699                 inprogress.pid = pid;
 700                 inprogress.command = command;
 701                 in_progress_[pid] = inprogress;
 702                 finishedGenerating(pid, ret);
 703                 return;
 704         }
 705
 706         // Initiate the conversion from LaTeX to bitmap images files.
 707         ForkedCall::sigPtr convert_ptr = make_shared<ForkedCall::sig>();
 708         weak_ptr<PreviewLoader::Impl> this_ = parent_.pimpl_;
 709         convert_ptr->connect([this_](pid_t pid, int retval){
 710                         if (auto p = this_.lock()) {
 711                                 p->finishedGenerating(pid, retval);
 712                         }
 713                 });
 714
 715         ForkedCall call(buffer_.filePath());
 716         int ret = call.startScript(command, convert_ptr);
 717
 718         if (ret != 0) {
 719                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 720                                         << "Unable to start process\n" << command);
 721                 return;
 722         }
 723
 724         // Store the generation process in a list of all such processes
 725         inprogress.pid = call.pid();
 726         inprogress.command = command;
 727         in_progress_[inprogress.pid] = inprogress;
 728 }
 729
 730
 731 double PreviewLoader::displayPixelRatio() const
 732 {
 733         return buffer().params().display_pixel_ratio;
 734 }
 735
 736 void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 737 {
 738         // Paranoia check!
 739         InProgressProcesses::iterator git = in_progress_.find(pid);
 740         if (git == in_progress_.end()) {
 741                 lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 742                         "data for PID " << pid << endl;
 743                 finished_generating_ = true;
 744                 return;
 745         }
 746
 747         string const command = git->second.command;
 748         string const status = retval > 0 ? "failed" : "succeeded";
 749         LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 750                                 << retval << "): processing " << status
 751                                 << " for " << command);
 752         if (retval > 0) {
 753                 in_progress_.erase(git);
 754                 finished_generating_ = true;
 755                 return;
 756         }
 757
 758         // Read the metrics file, if it exists
 759         vector<double> ascent_fractions(git->second.snippets.size());
 760         setAscentFractions(ascent_fractions, git->second.metrics_file);
 761
 762         // Add these newly generated bitmap files to the cache and
 763         // start loading them into LyX.
 764         BitmapFile::const_iterator it  = git->second.snippets.begin();
 765         BitmapFile::const_iterator end = git->second.snippets.end();
 766
 767         list<PreviewImagePtr> newimages;
 768
 769         size_t metrics_counter = 0;
 770         for (; it != end; ++it, ++metrics_counter) {
 771                 string const & snip = it->first;
 772                 FileName const & file = it->second;
 773                 double af = ascent_fractions[metrics_counter];
 774
 775                 // Add the image to the cache only if it's actually present
 776                 // and not empty (an empty image is signaled by af < 0)
 777                 if (af >= 0 && file.isReadableFile()) {
 778                         PreviewImagePtr ptr(new PreviewImage(parent_, snip, file, af));
 779                         cache_[snip] = ptr;
 780
 781                         newimages.push_back(ptr);
 782                 }
 783
 784         }
 785
 786         // Remove the item from the list of still-executing processes.
 787         in_progress_.erase(git);
 788
 789         // Tell the outside world
 790         list<PreviewImagePtr>::const_reverse_iterator
 791                 nit  = newimages.rbegin();
 792         list<PreviewImagePtr>::const_reverse_iterator
 793                 nend = newimages.rend();
 794         for (; nit != nend; ++nit) {
 795                 imageReady(*nit->get());
 796         }
 797         finished_generating_ = true;
 798         buffer_.scheduleRedrawWorkAreas();
 799 }
 800
 801
 802 void PreviewLoader::Impl::dumpPreamble(otexstream & os, Flavor flavor) const
 803 {
 804         // Dump the preamble only.
 805         LYXERR(Debug::OUTFILE, "dumpPreamble, flavor == " << static_cast<int>(flavor));
 806         OutputParams runparams(&buffer_.params().encoding());
 807         runparams.flavor = flavor;
 808         runparams.nice = true;
 809         runparams.moving_arg = true;
 810         runparams.free_spacing = true;
 811         runparams.is_child = buffer_.parent();
 812         buffer_.writeLaTeXSource(os, buffer_.filePath(), runparams, Buffer::OnlyPreamble);
 813
 814         // FIXME! This is a HACK! The proper fix is to control the 'true'
 815         // passed to TeXMathStream below:
 816         // int InsetMathNest::latex(Buffer const &, odocstream & os,
 817         //                          OutputParams const & runparams) const
 818         // {
 819         //      TeXMathStream wi(os, runparams.moving_arg, true);
 820         //      par_->write(wi);
 821         //      return wi.line();
 822         // }
 823         os << "\n"
 824            << "\\def\\lyxlock{}\n"
 825            << "\n";
 826
 827         // All equation labels appear as "(#)" + preview.sty's rendering of
 828         // the label name
 829         if (lyxrc.preview_hashed_labels)
 830                 os << "\\renewcommand{\\theequation}{\\#}\n";
 831
 832         // Use the preview style file to ensure that each snippet appears on a
 833         // fresh page.
 834         // Also support PDF output (automatically generated e.g. when
 835         // \usepackage[pdftex]{hyperref} is used and XeTeX.
 836         os << "\n"
 837            << "\\usepackage[active,delayed,showlabels,lyx]{preview}\n"
 838            << "\n";
 839 }
 840
 841
 842 void PreviewLoader::Impl::dumpData(odocstream & os,
 843                                    BitmapFile const & vec) const
 844 {
 845         if (vec.empty())
 846                 return;
 847
 848         BitmapFile::const_iterator it  = vec.begin();
 849         BitmapFile::const_iterator end = vec.end();
 850
 851         for (; it != end; ++it) {
 852                 // FIXME UNICODE
 853                 os << "\\begin{preview}\n"
 854                    << from_utf8(it->first)
 855                    << "\n\\end{preview}\n\n";
 856         }
 857 }
 858
 859 } // namespace graphics
 860 } // namespace lyx
 861
 862 #include "moc_PreviewLoader.cpp"