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 #include "texstream.h"
  29
  30 #include "frontends/Application.h" // hexName
  31
  32 #include "insets/Inset.h"
  33
  34 #include "support/convert.h"
  35 #include "support/debug.h"
  36 #include "support/FileName.h"
  37 #include "support/filetools.h"
  38 #include "support/ForkedCalls.h"
  39 #include "support/lstrings.h"
  40
  41 #include "support/bind.h"
  42 #include "support/TempFile.h"
  43
  44 #include <atomic>
  45 #include <fstream>
  46 #include <iomanip>
  47 #include <memory>
  48 #include <mutex>
  49 #include <sstream>
  50
  51 #include <QTimer>
  52
  53 using namespace std;
  54 using namespace lyx::support;
  55
  56
  57
  58 namespace {
  59
  60 typedef pair<string, FileName> SnippetPair;
  61
  62 // A list of all snippets to be converted to previews
  63 typedef list<string> PendingSnippets;
  64
  65 // Each item in the vector is a pair<snippet, image file name>.
  66 typedef vector<SnippetPair> BitmapFile;
  67
  68
  69 FileName const unique_tex_filename(FileName const & bufferpath)
  70 {
  71         TempFile tempfile(bufferpath, "lyxpreviewXXXXXX.tex");
  72         tempfile.setAutoRemove(false);
  73         return tempfile.name();
  74 }
  75
  76
  77 lyx::Converter const * setConverter(string const & from)
  78 {
  79         typedef vector<string> FmtList;
  80         typedef lyx::graphics::Cache GCache;
  81         FmtList const & loadableFormats = GCache::get().loadableFormats();
  82         FmtList::const_iterator it = loadableFormats.begin();
  83         FmtList::const_iterator const end = loadableFormats.end();
  84
  85         for (; it != end; ++it) {
  86                 string const to = *it;
  87                 if (from == to)
  88                         continue;
  89
  90                 lyx::Converter const * ptr = lyx::theConverters().getConverter(from, to);
  91                 if (ptr)
  92                         return ptr;
  93         }
  94
  95         // Show the error only once
  96 #ifdef LYX_USE_STD_CALL_ONCE
  97         // This is thread-safe.
  98         static once_flag flag;
  99         call_once(flag, [&](){
 100                         LYXERR0("PreviewLoader::startLoading()\n"
 101                                 << "No converter from \"" << from
 102                                 << "\" format has been defined.");
 103                 });
 104 #else
 105         // This is also thread-safe according to §6.7.4 of the C++11 standard.
 106         static bool first = true;
 107         if (first) {
 108                 first = false;
 109                 LYXERR0("PreviewLoader::startLoading()\n"
 110                         << "No converter from \"" << from
 111                         << "\" format has been defined.");
 112         }
 113 #endif
 114         return 0;
 115 }
 116
 117
 118 void setAscentFractions(vector<double> & ascent_fractions,
 119                         FileName const & metrics_file)
 120 {
 121         // If all else fails, then the images will have equal ascents and
 122         // descents.
 123         vector<double>::iterator it  = ascent_fractions.begin();
 124         vector<double>::iterator end = ascent_fractions.end();
 125         fill(it, end, 0.5);
 126
 127         ifstream in(metrics_file.toFilesystemEncoding().c_str());
 128         if (!in.good()) {
 129                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 130                         << "Unable to open file!");
 131                 return;
 132         }
 133
 134         bool error = false;
 135
 136         int snippet_counter = 1;
 137         while (!in.eof() && it != end) {
 138                 string snippet;
 139                 int id;
 140                 double ascent_fraction;
 141
 142                 in >> snippet >> id >> ascent_fraction;
 143
 144                 if (!in.good())
 145                         // eof after all
 146                         break;
 147
 148                 error = snippet != "Snippet";
 149                 if (error)
 150                         break;
 151
 152                 error = id != snippet_counter;
 153                 if (error)
 154                         break;
 155
 156                 *it = ascent_fraction;
 157
 158                 ++snippet_counter;
 159                 ++it;
 160         }
 161
 162         if (error) {
 163                 LYXERR(lyx::Debug::GRAPHICS, "setAscentFractions(" << metrics_file << ")\n"
 164                         << "Error reading file!\n");
 165         }
 166 }
 167
 168
 169 class FindFirst
 170 {
 171 public:
 172         FindFirst(string const & comp) : comp_(comp) {}
 173         bool operator()(SnippetPair const & sp) const { return sp.first == comp_; }
 174 private:
 175         string const comp_;
 176 };
 177
 178
 179 /// Store info on a currently executing, forked process.
 180 class InProgress {
 181 public:
 182         ///
 183         InProgress() : pid(0) {}
 184         ///
 185         InProgress(string const & filename_base,
 186                    PendingSnippets const & pending,
 187                    string const & to_format);
 188         /// Remove any files left lying around and kill the forked process.
 189         void stop() const;
 190
 191         ///
 192         pid_t pid;
 193         ///
 194         string command;
 195         ///
 196         FileName metrics_file;
 197         ///
 198         BitmapFile snippets;
 199 };
 200
 201 typedef map<pid_t, InProgress>  InProgressProcesses;
 202
 203 typedef InProgressProcesses::value_type InProgressProcess;
 204
 205 } // namespace anon
 206
 207
 208
 209 namespace lyx {
 210 namespace graphics {
 211
 212 class PreviewLoader::Impl : public boost::signals2::trackable {
 213 public:
 214         ///
 215         Impl(PreviewLoader & p, Buffer const & b);
 216         /// Stop any InProgress items still executing.
 217         ~Impl();
 218         ///
 219         PreviewImage const * preview(string const & latex_snippet) const;
 220         ///
 221         PreviewLoader::Status status(string const & latex_snippet) const;
 222         ///
 223         void add(string const & latex_snippet);
 224         ///
 225         void remove(string const & latex_snippet);
 226         /// \p wait whether to wait for the process to complete or, instead,
 227         /// to do it in the background.
 228         void startLoading(bool wait = false);
 229         ///
 230         void refreshPreviews();
 231
 232         /// Emit this signal when an image is ready for display.
 233         boost::signals2::signal<void(PreviewImage const &)> imageReady;
 234
 235         Buffer const & buffer() const { return buffer_; }
 236
 237 private:
 238         /// Called by the ForkedCall process that generated the bitmap files.
 239         void finishedGenerating(pid_t, int);
 240         ///
 241         void dumpPreamble(otexstream &, OutputParams::FLAVOR) const;
 242         ///
 243         void dumpData(odocstream &, BitmapFile const &) const;
 244
 245         /** cache_ allows easy retrieval of already-generated images
 246          *  using the LaTeX snippet as the identifier.
 247          */
 248         typedef std::shared_ptr<PreviewImage> PreviewImagePtr;
 249         ///
 250         typedef map<string, PreviewImagePtr> Cache;
 251         ///
 252         Cache cache_;
 253
 254         /** pending_ stores the LaTeX snippets in anticipation of them being
 255          *  sent to the converter.
 256          */
 257         PendingSnippets pending_;
 258
 259         /** in_progress_ stores all forked processes so that we can proceed
 260          *  thereafter.
 261             The map uses the conversion commands as its identifiers.
 262          */
 263         InProgressProcesses in_progress_;
 264
 265         ///
 266         PreviewLoader & parent_;
 267         ///
 268         Buffer const & buffer_;
 269         ///
 270         mutable int font_scaling_factor_;
 271         ///
 272         mutable int fg_color_;
 273         ///
 274         mutable int bg_color_;
 275         ///
 276         QTimer * delay_refresh_;
 277         ///
 278         bool finished_generating_;
 279
 280         /// We don't own this
 281         static lyx::Converter const * pconverter_;
 282 };
 283
 284
 285 lyx::Converter const * PreviewLoader::Impl::pconverter_;
 286
 287
 288 //
 289 // The public interface, defined in PreviewLoader.h
 290 //
 291
 292 PreviewLoader::PreviewLoader(Buffer const & b)
 293         : pimpl_(new Impl(*this, b))
 294 {}
 295
 296
 297 PreviewLoader::~PreviewLoader()
 298 {
 299         delete pimpl_;
 300 }
 301
 302
 303 PreviewImage const * PreviewLoader::preview(string const & latex_snippet) const
 304 {
 305         return pimpl_->preview(latex_snippet);
 306 }
 307
 308
 309 PreviewLoader::Status PreviewLoader::status(string const & latex_snippet) const
 310 {
 311         return pimpl_->status(latex_snippet);
 312 }
 313
 314
 315 void PreviewLoader::add(string const & latex_snippet) const
 316 {
 317         pimpl_->add(latex_snippet);
 318 }
 319
 320
 321 void PreviewLoader::remove(string const & latex_snippet) const
 322 {
 323         pimpl_->remove(latex_snippet);
 324 }
 325
 326
 327 void PreviewLoader::startLoading(bool wait) const
 328 {
 329         pimpl_->startLoading(wait);
 330 }
 331
 332
 333 void PreviewLoader::refreshPreviews()
 334 {
 335         pimpl_->refreshPreviews();
 336 }
 337
 338
 339 boost::signals2::connection PreviewLoader::connect(slot_type const & slot) const
 340 {
 341         return pimpl_->imageReady.connect(slot);
 342 }
 343
 344
 345 void PreviewLoader::emitSignal(PreviewImage const & pimage) const
 346 {
 347         pimpl_->imageReady(pimage);
 348 }
 349
 350
 351 Buffer const & PreviewLoader::buffer() const
 352 {
 353         return pimpl_->buffer();
 354 }
 355
 356 } // namespace graphics
 357 } // namespace lyx
 358
 359
 360 // The details of the Impl
 361 // =======================
 362
 363 namespace {
 364
 365 class IncrementedFileName {
 366 public:
 367         IncrementedFileName(string const & to_format,
 368                             string const & filename_base)
 369                 : to_format_(to_format), base_(filename_base), counter_(1)
 370         {}
 371
 372         SnippetPair const operator()(string const & snippet)
 373         {
 374                 ostringstream os;
 375                 os << base_ << counter_++ << '.' << to_format_;
 376                 string const file = os.str();
 377
 378                 return make_pair(snippet, FileName(file));
 379         }
 380
 381 private:
 382         string const & to_format_;
 383         string const & base_;
 384         int counter_;
 385 };
 386
 387
 388 InProgress::InProgress(string const & filename_base,
 389                        PendingSnippets const & pending,
 390                        string const & to_format)
 391         : pid(0),
 392           metrics_file(filename_base + ".metrics"),
 393           snippets(pending.size())
 394 {
 395         PendingSnippets::const_iterator pit  = pending.begin();
 396         PendingSnippets::const_iterator pend = pending.end();
 397         BitmapFile::iterator sit = snippets.begin();
 398
 399         transform(pit, pend, sit,
 400                        IncrementedFileName(to_format, filename_base));
 401 }
 402
 403
 404 void InProgress::stop() const
 405 {
 406         if (pid)
 407                 ForkedCallsController::kill(pid, 0);
 408
 409         if (!metrics_file.empty())
 410                 metrics_file.removeFile();
 411
 412         BitmapFile::const_iterator vit  = snippets.begin();
 413         BitmapFile::const_iterator vend = snippets.end();
 414         for (; vit != vend; ++vit) {
 415                 if (!vit->second.empty())
 416                         vit->second.removeFile();
 417         }
 418 }
 419
 420 } // namespace anon
 421
 422
 423 namespace lyx {
 424 namespace graphics {
 425
 426 PreviewLoader::Impl::Impl(PreviewLoader & p, Buffer const & b)
 427         : parent_(p), buffer_(b), finished_generating_(true)
 428 {
 429         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 430         if (theApp()) {
 431                 fg_color_ = strtol(theApp()->hexName(foregroundColor()).c_str(), 0, 16);
 432                 bg_color_ = strtol(theApp()->hexName(backgroundColor()).c_str(), 0, 16);
 433         } else {
 434                 fg_color_ = 0x0;
 435                 bg_color_ = 0xffffff;
 436         }
 437         if (!pconverter_)
 438                 pconverter_ = setConverter("lyxpreview");
 439
 440         delay_refresh_ = new QTimer(&parent_);
 441         delay_refresh_->setSingleShot(true);
 442         QObject::connect(delay_refresh_, SIGNAL(timeout()),
 443                          &parent_, SLOT(refreshPreviews()));
 444 }
 445
 446
 447 PreviewLoader::Impl::~Impl()
 448 {
 449         delete delay_refresh_;
 450
 451         InProgressProcesses::iterator ipit  = in_progress_.begin();
 452         InProgressProcesses::iterator ipend = in_progress_.end();
 453
 454         for (; ipit != ipend; ++ipit)
 455                 ipit->second.stop();
 456 }
 457
 458
 459 PreviewImage const *
 460 PreviewLoader::Impl::preview(string const & latex_snippet) const
 461 {
 462         int fs = int(buffer_.fontScalingFactor());
 463         int fg = 0x0;
 464         int bg = 0xffffff;
 465         if (theApp()) {
 466                 fg = strtol(theApp()->hexName(foregroundColor()).c_str(), 0, 16);
 467                 bg = strtol(theApp()->hexName(backgroundColor()).c_str(), 0, 16);
 468         }
 469         if (font_scaling_factor_ != fs || fg_color_ != fg || bg_color_ != bg) {
 470                 // Schedule refresh of all previews on zoom or color changes.
 471                 // The previews are regenerated only after the zoom factor
 472                 // has not been changed for about 1 second.
 473                 fg_color_ = fg;
 474                 bg_color_ = bg;
 475                 delay_refresh_->start(1000);
 476         }
 477         // Don't try to access the cache until we are done.
 478         if (delay_refresh_->isActive() || !finished_generating_)
 479                 return 0;
 480         Cache::const_iterator it = cache_.find(latex_snippet);
 481         return (it == cache_.end()) ? 0 : it->second.get();
 482 }
 483
 484
 485 void PreviewLoader::Impl::refreshPreviews()
 486 {
 487         font_scaling_factor_ = int(buffer_.fontScalingFactor());
 488         // Reschedule refresh until the previous process completed.
 489         if (!finished_generating_) {
 490                 delay_refresh_->start(1000);
 491                 return;
 492         }
 493         Cache::const_iterator cit = cache_.begin();
 494         Cache::const_iterator cend = cache_.end();
 495         while (cit != cend)
 496                 parent_.remove((cit++)->first);
 497         finished_generating_ = false;
 498         buffer_.updatePreviews();
 499 }
 500
 501
 502 namespace {
 503
 504 class FindSnippet {
 505 public:
 506         FindSnippet(string const & s) : snippet_(s) {}
 507         bool operator()(InProgressProcess const & process) const
 508         {
 509                 BitmapFile const & snippets = process.second.snippets;
 510                 BitmapFile::const_iterator beg  = snippets.begin();
 511                 BitmapFile::const_iterator end = snippets.end();
 512                 return find_if(beg, end, FindFirst(snippet_)) != end;
 513         }
 514
 515 private:
 516         string const snippet_;
 517 };
 518
 519 } // namespace anon
 520
 521 PreviewLoader::Status
 522 PreviewLoader::Impl::status(string const & latex_snippet) const
 523 {
 524         Cache::const_iterator cit = cache_.find(latex_snippet);
 525         if (cit != cache_.end())
 526                 return Ready;
 527
 528         PendingSnippets::const_iterator pit  = pending_.begin();
 529         PendingSnippets::const_iterator pend = pending_.end();
 530
 531         pit = find(pit, pend, latex_snippet);
 532         if (pit != pend)
 533                 return InQueue;
 534
 535         InProgressProcesses::const_iterator ipit  = in_progress_.begin();
 536         InProgressProcesses::const_iterator ipend = in_progress_.end();
 537
 538         ipit = find_if(ipit, ipend, FindSnippet(latex_snippet));
 539         if (ipit != ipend)
 540                 return Processing;
 541
 542         return NotFound;
 543 }
 544
 545
 546 void PreviewLoader::Impl::add(string const & latex_snippet)
 547 {
 548         if (!pconverter_ || status(latex_snippet) != NotFound)
 549                 return;
 550
 551         string const snippet = trim(latex_snippet);
 552         if (snippet.empty())
 553                 return;
 554
 555         LYXERR(Debug::GRAPHICS, "adding snippet:\n" << snippet);
 556
 557         pending_.push_back(snippet);
 558 }
 559
 560
 561 namespace {
 562
 563 class EraseSnippet {
 564 public:
 565         EraseSnippet(string const & s) : snippet_(s) {}
 566         void operator()(InProgressProcess & process)
 567         {
 568                 BitmapFile & snippets = process.second.snippets;
 569                 BitmapFile::iterator it  = snippets.begin();
 570                 BitmapFile::iterator end = snippets.end();
 571
 572                 it = find_if(it, end, FindFirst(snippet_));
 573                 if (it != end)
 574                         snippets.erase(it, it+1);
 575         }
 576
 577 private:
 578         string const & snippet_;
 579 };
 580
 581 } // namespace anon
 582
 583
 584 void PreviewLoader::Impl::remove(string const & latex_snippet)
 585 {
 586         Cache::iterator cit = cache_.find(latex_snippet);
 587         if (cit != cache_.end())
 588                 cache_.erase(cit);
 589
 590         PendingSnippets::iterator pit  = pending_.begin();
 591         PendingSnippets::iterator pend = pending_.end();
 592
 593         pending_.erase(std::remove(pit, pend, latex_snippet), pend);
 594
 595         InProgressProcesses::iterator ipit  = in_progress_.begin();
 596         InProgressProcesses::iterator ipend = in_progress_.end();
 597
 598         for_each(ipit, ipend, EraseSnippet(latex_snippet));
 599
 600         while (ipit != ipend) {
 601                 InProgressProcesses::iterator curr = ipit++;
 602                 if (curr->second.snippets.empty())
 603                         in_progress_.erase(curr);
 604         }
 605 }
 606
 607
 608 void PreviewLoader::Impl::startLoading(bool wait)
 609 {
 610         if (pending_.empty() || !pconverter_)
 611                 return;
 612
 613         // Only start the process off after the buffer is loaded from file.
 614         if (!buffer_.isFullyLoaded())
 615                 return;
 616
 617         LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()");
 618
 619         // As used by the LaTeX file and by the resulting image files
 620         FileName const directory(buffer_.temppath());
 621
 622         FileName const latexfile = unique_tex_filename(directory);
 623         string const filename_base = removeExtension(latexfile.absFileName());
 624
 625         // Create an InProgress instance to place in the map of all
 626         // such processes if it starts correctly.
 627         InProgress inprogress(filename_base, pending_, pconverter_->to());
 628
 629         // clear pending_, so we're ready to start afresh.
 630         pending_.clear();
 631
 632         // Output the LaTeX file.
 633         // we use the encoding of the buffer
 634         Encoding const & enc = buffer_.params().encoding();
 635         ofdocstream of;
 636         try { of.reset(enc.iconvName()); }
 637         catch (iconv_codecvt_facet_exception const & e) {
 638                 LYXERR0("Caught iconv exception: " << e.what()
 639                         << "\nUnable to create LaTeX file: " << latexfile);
 640                 return;
 641         }
 642
 643         otexstream os(of);
 644         OutputParams runparams(&enc);
 645         LaTeXFeatures features(buffer_, buffer_.params(), runparams);
 646
 647         if (!openFileWrite(of, latexfile))
 648                 return;
 649
 650         if (!of) {
 651                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 652                                         << "Unable to create LaTeX file\n" << latexfile);
 653                 return;
 654         }
 655         of << "\\batchmode\n";
 656
 657         // Set \jobname of previews to the document name (see bug 9627)
 658         of << "\\def\\jobname{"
 659            << from_utf8(changeExtension(buffer_.latexName(true), ""))
 660            << "}\n";
 661
 662         LYXERR(Debug::LATEX, "Format = " << buffer_.params().getDefaultOutputFormat());
 663         string latexparam = "";
 664         bool docformat = !buffer_.params().default_output_format.empty()
 665                         && buffer_.params().default_output_format != "default";
 666         // Use LATEX flavor if the document does not specify a specific
 667         // output format (see bug 9371).
 668         OutputParams::FLAVOR flavor = docformat
 669                                         ? buffer_.params().getOutputFlavor()
 670                                         : OutputParams::LATEX;
 671         if (buffer_.params().encoding().package() == Encoding::japanese) {
 672                 latexparam = " --latex=platex";
 673                 flavor = OutputParams::LATEX;
 674         }
 675         else if (buffer_.params().useNonTeXFonts) {
 676                 if (flavor == OutputParams::LUATEX)
 677                         latexparam = " --latex=lualatex";
 678                 else {
 679                         flavor = OutputParams::XETEX;
 680                         latexparam = " --latex=xelatex";
 681                 }
 682         }
 683         else {
 684                 switch (flavor) {
 685                         case OutputParams::PDFLATEX:
 686                                 latexparam = " --latex=pdflatex";
 687                                 break;
 688                         case OutputParams::XETEX:
 689                                 latexparam = " --latex=xelatex";
 690                                 break;
 691                         case OutputParams::LUATEX:
 692                                 latexparam = " --latex=lualatex";
 693                                 break;
 694                         case OutputParams::DVILUATEX:
 695                                 latexparam = " --latex=dvilualatex";
 696                                 break;
 697                         default:
 698                                 flavor = OutputParams::LATEX;
 699                 }
 700         }
 701         dumpPreamble(os, flavor);
 702         // handle inputenc etc.
 703         // I think, this is already hadled by dumpPreamble(): Kornel
 704         // buffer_.params().writeEncodingPreamble(os, features);
 705         of << "\n\\begin{document}\n";
 706         dumpData(of, inprogress.snippets);
 707         of << "\n\\end{document}\n";
 708         of.close();
 709         if (of.fail()) {
 710                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 711                                          << "File was not closed properly.");
 712                 return;
 713         }
 714
 715         // The conversion command.
 716         ostringstream cs;
 717         cs << pconverter_->command()
 718            << " " << quoteName(latexfile.toFilesystemEncoding())
 719            << " --dpi " << font_scaling_factor_;
 720
 721         // FIXME XHTML
 722         // The colors should be customizable.
 723         if (!buffer_.isExporting()) {
 724                 ColorCode const fg = PreviewLoader::foregroundColor();
 725                 ColorCode const bg = PreviewLoader::backgroundColor();
 726                 cs << " --fg " << theApp()->hexName(fg)
 727                    << " --bg " << theApp()->hexName(bg);
 728         }
 729
 730         cs << latexparam;
 731         if (buffer_.params().bibtex_command != "default")
 732                 cs << " --bibtex=" << quoteName(buffer_.params().bibtex_command);
 733         else if (buffer_.params().encoding().package() == Encoding::japanese)
 734                 cs << " --bibtex=" << quoteName(lyxrc.jbibtex_command);
 735         else
 736                 cs << " --bibtex=" << quoteName(lyxrc.bibtex_command);
 737         if (buffer_.params().bufferFormat() == "lilypond-book")
 738                 cs << " --lilypond";
 739
 740         string const command = cs.str();
 741
 742         if (wait) {
 743                 ForkedCall call(buffer_.filePath(), buffer_.layoutPos());
 744                 int ret = call.startScript(ForkedProcess::Wait, command);
 745                 static atomic_int fake((2^20) + 1);
 746                 int pid = fake++;
 747                 inprogress.pid = pid;
 748                 inprogress.command = command;
 749                 in_progress_[pid] = inprogress;
 750                 finishedGenerating(pid, ret);
 751                 return;
 752         }
 753
 754         // Initiate the conversion from LaTeX to bitmap images files.
 755         ForkedCall::SignalTypePtr
 756                 convert_ptr(new ForkedCall::SignalType);
 757         convert_ptr->connect(bind(&Impl::finishedGenerating, this, _1, _2));
 758
 759         ForkedCall call(buffer_.filePath());
 760         int ret = call.startScript(command, convert_ptr);
 761
 762         if (ret != 0) {
 763                 LYXERR(Debug::GRAPHICS, "PreviewLoader::startLoading()\n"
 764                                         << "Unable to start process\n" << command);
 765                 return;
 766         }
 767
 768         // Store the generation process in a list of all such processes
 769         inprogress.pid = call.pid();
 770         inprogress.command = command;
 771         in_progress_[inprogress.pid] = inprogress;
 772 }
 773
 774
 775 double PreviewLoader::displayPixelRatio() const
 776 {
 777         return buffer().params().display_pixel_ratio;
 778 }
 779
 780 void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 781 {
 782         // Paranoia check!
 783         InProgressProcesses::iterator git = in_progress_.find(pid);
 784         if (git == in_progress_.end()) {
 785                 lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 786                         "data for PID " << pid << endl;
 787                 finished_generating_ = true;
 788                 return;
 789         }
 790
 791         string const command = git->second.command;
 792         string const status = retval > 0 ? "failed" : "succeeded";
 793         LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 794                                 << retval << "): processing " << status
 795                                 << " for " << command);
 796         if (retval > 0) {
 797                 in_progress_.erase(git);
 798                 finished_generating_ = true;
 799                 return;
 800         }
 801
 802         // Read the metrics file, if it exists
 803         vector<double> ascent_fractions(git->second.snippets.size());
 804         setAscentFractions(ascent_fractions, git->second.metrics_file);
 805
 806         // Add these newly generated bitmap files to the cache and
 807         // start loading them into LyX.
 808         BitmapFile::const_iterator it  = git->second.snippets.begin();
 809         BitmapFile::const_iterator end = git->second.snippets.end();
 810
 811         list<PreviewImagePtr> newimages;
 812
 813         int metrics_counter = 0;
 814         for (; it != end; ++it, ++metrics_counter) {
 815                 string const & snip = it->first;
 816                 FileName const & file = it->second;
 817                 double af = ascent_fractions[metrics_counter];
 818
 819                 // Add the image to the cache only if it's actually present
 820                 // and not empty (an empty image is signaled by af < 0)
 821                 if (af >= 0 && file.isReadableFile()) {
 822                         PreviewImagePtr ptr(new PreviewImage(parent_, snip, file, af));
 823                         cache_[snip] = ptr;
 824
 825                         newimages.push_back(ptr);
 826                 }
 827
 828         }
 829
 830         // Remove the item from the list of still-executing processes.
 831         in_progress_.erase(git);
 832
 833         // Tell the outside world
 834         list<PreviewImagePtr>::const_reverse_iterator
 835                 nit  = newimages.rbegin();
 836         list<PreviewImagePtr>::const_reverse_iterator
 837                 nend = newimages.rend();
 838         for (; nit != nend; ++nit) {
 839                 imageReady(*nit->get());
 840         }
 841         finished_generating_ = true;
 842 }
 843
 844
 845 void PreviewLoader::Impl::dumpPreamble(otexstream & os, OutputParams::FLAVOR flavor) const
 846 {
 847         // Dump the preamble only.
 848         LYXERR(Debug::LATEX, "dumpPreamble, flavor == " << flavor);
 849         OutputParams runparams(&buffer_.params().encoding());
 850         runparams.flavor = flavor;
 851         runparams.nice = true;
 852         runparams.moving_arg = true;
 853         runparams.free_spacing = true;
 854         runparams.is_child = buffer_.parent();
 855         buffer_.writeLaTeXSource(os, buffer_.filePath(), runparams, Buffer::OnlyPreamble);
 856
 857         // FIXME! This is a HACK! The proper fix is to control the 'true'
 858         // passed to WriteStream below:
 859         // int InsetMathNest::latex(Buffer const &, odocstream & os,
 860         //                          OutputParams const & runparams) const
 861         // {
 862         //      WriteStream wi(os, runparams.moving_arg, true);
 863         //      par_->write(wi);
 864         //      return wi.line();
 865         // }
 866         os << "\n"
 867            << "\\def\\lyxlock{}\n"
 868            << "\n";
 869
 870         // All equation labels appear as "(#)" + preview.sty's rendering of
 871         // the label name
 872         if (lyxrc.preview_hashed_labels)
 873                 os << "\\renewcommand{\\theequation}{\\#}\n";
 874
 875         // Use the preview style file to ensure that each snippet appears on a
 876         // fresh page.
 877         // Also support PDF output (automatically generated e.g. when
 878         // \usepackage[pdftex]{hyperref} is used and XeTeX.
 879         os << "\n"
 880            << "\\usepackage[active,delayed,showlabels,lyx]{preview}\n"
 881            << "\n";
 882 }
 883
 884
 885 void PreviewLoader::Impl::dumpData(odocstream & os,
 886                                    BitmapFile const & vec) const
 887 {
 888         if (vec.empty())
 889                 return;
 890
 891         BitmapFile::const_iterator it  = vec.begin();
 892         BitmapFile::const_iterator end = vec.end();
 893
 894         for (; it != end; ++it) {
 895                 // FIXME UNICODE
 896                 os << "\\begin{preview}\n"
 897                    << from_utf8(it->first)
 898                    << "\n\\end{preview}\n\n";
 899         }
 900 }
 901
 902 } // namespace graphics
 903 } // namespace lyx
 904
 905 #include "moc_PreviewLoader.cpp"