path: root/kdvi/dviRenderer.cpp

//
// Class: dviRenderer
//
// Class for rendering TeX DVI files.
// Part of KDVI- A previewer for TeX DVI files.
//
// (C) 2001-2005 Stefan Kebekus
// Distributed under the GPL
//

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <tqcheckbox.h>
#include <tqclipboard.h>
#include <tqcursor.h>
#include <tqlabel.h>
#include <tqfileinfo.h>
#include <tqlayout.h>
#include <tqmessagebox.h>
#include <tqpaintdevice.h>
#include <tqpainter.h>
#include <tqptrstack.h>
#include <tqregexp.h>
#include <tqurl.h>
#include <tqvbox.h>

#include <kapplication.h>
#include <kmessagebox.h>
#include <kmimemagic.h>
#include <kglobal.h>
#include <kdebug.h>
#include <keditcl.h>
#include <kfiledialog.h>
#include <kio/job.h>
#include <kio/netaccess.h>
#include <klocale.h>
#include <kprinter.h>
#include <kprocess.h>
#include <kprogress.h>
#include <kstandarddirs.h>
#include <kstdguiitem.h>

#include "documentWidget.h"
#include "dviFile.h"
#include "dviRenderer.h"
#include "fontpool.h"
#include "fontprogress.h"
#include "hyperlink.h"
#include "infodialog.h"
#include "kdvi_multipage.h"
#include "performanceMeasurement.h"
#include "prebookmark.h"
#include "psgs.h"
#include "xdvi.h"
#include "zoomlimits.h"
#include "dvisourcesplitter.h"
#include "renderedDviPagePixmap.h"

//#define DEBUG_DVIRENDERER

TQPainter *foreGroundPainter; // TQPainter used for text


//------ now comes the dviRenderer class implementation ----------

dviRenderer::dviRenderer(TQWidget *par)
  : DocumentRenderer(par), info(new infoDialog(par))
{
#ifdef DEBUG_DVIRENDERER
  kdDebug(4300) << "dviRenderer( parent=" << par << " )" << endl;
#endif

  // initialize the dvi machinery
  dviFile                = 0;

  connect(&font_pool, TQT_SIGNAL( setStatusBarText( const TQString& ) ), this, TQT_SIGNAL( setStatusBarText( const TQString& ) ) );

  parentWidget = par;
  shrinkfactor = 3;
  current_page = 0;
  resolutionInDPI = 0.0;

  connect( &clearStatusBarTimer, TQT_SIGNAL(timeout()), this, TQT_SLOT(clearStatusBar()) );

  currentlyDrawnPage = 0;
  editorCommand         = "";

  PostScriptOutPutString = NULL;
  HTML_href              = NULL;
  _postscript            = 0;

  // Storage used for dvips and friends, i.e. for the "export" functions.
  proc                   = 0;
  progress               = 0;
  export_printer         = 0;
  export_fileName        = "";
  export_tmpFileName     = "";
  export_errorString     = "";

  PS_interface           = new ghostscript_interface();
  // pass status bar messages through
  connect(PS_interface, TQT_SIGNAL( setStatusBarText( const TQString& ) ), this, TQT_SIGNAL( setStatusBarText( const TQString& ) ) );
}


dviRenderer::~dviRenderer()
{
#ifdef DEBUG_DVIRENDERER
  kdDebug(4300) << "~dviRenderer" << endl;
#endif

  mutex.lock();
  mutex.unlock();

  delete PS_interface;
  delete proc;
  delete dviFile;
  // Don't delete the export printer. This is owned by the
  // kdvi_multipage.
  export_printer = 0;
}


void dviRenderer::setPrefs(bool flag_showPS, const TQString &str_editorCommand, bool useFontHints )
{
  TQMutexLocker locker(&mutex);
  _postscript = flag_showPS;
  editorCommand = str_editorCommand;
  font_pool.setParameters( useFontHints );
  emit(documentIsChanged());
}


void dviRenderer::showInfo()
{
  mutex.lock();
  info->setDVIData(dviFile);
  info->show();
  mutex.unlock();
}


//------ this function calls the dvi interpreter ----------


void dviRenderer::drawPage(double resolution, RenderedDocumentPage *page)
{
#ifdef DEBUG_DVIRENDERER
  kdDebug(4300) << "dviRenderer::drawPage(documentPage *) called, page number " << page->getPageNumber() << endl;
#endif
  
  // Paranoid safety checks
  if (page == 0) {
    kdError(4300) << "dviRenderer::drawPage(documentPage *) called with argument == 0" << endl; 
    return;
  }
  if (page->getPageNumber() == 0) {
    kdError(4300) << "dviRenderer::drawPage(documentPage *) called for a documentPage with page number 0" << endl;
    return;
  }

  mutex.lock();
  if ( dviFile == 0 ) {
    kdError(4300) << "dviRenderer::drawPage(documentPage *) called, but no dviFile class allocated." << endl;
    page->clear();
    mutex.unlock();
    return;
  }
  if (page->getPageNumber() > dviFile->total_pages) {
    kdError(4300) << "dviRenderer::drawPage(documentPage *) called for a documentPage with page number " << page->getPageNumber() 
		  << " but the current dviFile has only " << dviFile->total_pages << " pages." << endl;
    mutex.unlock();
    return;
  }
  if ( dviFile->dvi_Data() == 0 ) {
    kdError(4300) << "dviRenderer::drawPage(documentPage *) called, but no dviFile is loaded yet." << endl;
    page->clear();
    mutex.unlock();
    return;
  }
 
  if (resolution != resolutionInDPI)
    setResolution(resolution);
  
  currentlyDrawnPage     = page;
  shrinkfactor           = 1200/resolutionInDPI;
  current_page           = page->getPageNumber()-1;
  
  
  // Reset colors
  colorStack.clear();
  globalColor = Qt::black;

  TQApplication::setOverrideCursor( waitCursor );
  foreGroundPainter = page->getPainter();
  if (foreGroundPainter != 0) {
    errorMsg = TQString::null;
    draw_page();
    page->returnPainter(foreGroundPainter);
  }
  TQApplication::restoreOverrideCursor();
  
  page->isEmpty = false;
  if (errorMsg.isEmpty() != true) {
    KMessageBox::detailedError(parentWidget,
			       i18n("<qt><strong>File corruption!</strong> KDVI had trouble interpreting your DVI file. Most "
				    "likely this means that the DVI file is broken.</qt>"),
			       errorMsg, i18n("DVI File Error"));
    errorMsg = TQString::null;
    currentlyDrawnPage = 0;
    mutex.unlock();
    return;
  }
  
  // Tell the user (once) if the DVI file contains source specials
  // ... we don't want our great feature to go unnoticed.
  RenderedDviPagePixmap* currentDVIPage = dynamic_cast<RenderedDviPagePixmap*>(currentlyDrawnPage);
  if (currentDVIPage)
  {
    if ((dviFile->sourceSpecialMarker == true) && (currentDVIPage->sourceHyperLinkList.size() > 0)) {
      dviFile->sourceSpecialMarker = false;
      // Show the dialog as soon as event processing is finished, and
      // the program is idle
      TQTimer::singleShot( 0, this, TQT_SLOT(showThatSourceInformationIsPresent()) );
    }
  }
  
  currentlyDrawnPage = 0;
  mutex.unlock();
}


void dviRenderer::getText(RenderedDocumentPage* page)
{
  bool postscriptBackup = _postscript;
  // Disable postscript-specials temporarely to speed up text extraction.
  _postscript = false;

  drawPage(100.0, page);

  _postscript = postscriptBackup;
}


void dviRenderer::showThatSourceInformationIsPresent()
{
  // In principle, we should use a KMessagebox here, but we want to
  // add a button "Explain in more detail..." which opens the
  // Helpcenter. Thus, we practically re-implement the KMessagebox
  // here. Most of the code is stolen from there.
  
  // Check if the 'Don't show again' feature was used
  KConfig *config = kapp->config();
  KConfigGroupSaver saver( config, "Notification Messages" );
  bool showMsg = config->readBoolEntry( "KDVI-info_on_source_specials", true);
  
  if (showMsg) {
    KDialogBase *dialog= new KDialogBase(i18n("KDVI: Information"), KDialogBase::Yes, KDialogBase::Yes, KDialogBase::Yes,
					 parentWidget, "information", true, true,KStdGuiItem::ok() );
    
    TQVBox *topcontents = new TQVBox (dialog);
    topcontents->setSpacing(KDialog::spacingHint()*2);
    topcontents->setMargin(KDialog::marginHint()*2);
    
    TQWidget *contents = new TQWidget(topcontents);
    TQHBoxLayout * lay = new TQHBoxLayout(contents);
    lay->setSpacing(KDialog::spacingHint()*2);
    
    lay->addStretch(1);
    TQLabel *label1 = new TQLabel( contents);
    label1->setPixmap(TQMessageBox::standardIcon(TQMessageBox::Information));
    lay->add( label1 );
    TQLabel *label2 = new TQLabel( i18n("<qt>This DVI file contains source file information. You may click into the text with the "
				      "middle mouse button, and an editor will open the TeX-source file immediately.</qt>"),
				 contents);
    label2->setMinimumSize(label2->sizeHint());
    lay->add( label2 );
    lay->addStretch(1);
    TQSize extraSize = TQSize(50,30);
    TQCheckBox *checkbox = new TQCheckBox(i18n("Do not show this message again"), topcontents);
    extraSize = TQSize(50,0);
    dialog->setHelpLinkText(i18n("Explain in more detail..."));
    dialog->setHelp("inverse-search", "kdvi");
    dialog->enableLinkedHelp(true);
    dialog->setMainWidget(topcontents);
    dialog->enableButtonSeparator(false);
    dialog->incInitialSize( extraSize );
    dialog->exec();
    delete dialog;
    
    showMsg = !checkbox->isChecked();
    if (!showMsg) {
      KConfigGroupSaver saver( config, "Notification Messages" );
      config->writeEntry( "KDVI-info_on_source_specials", showMsg);
    }
    config->sync();
  }
}


void dviRenderer::embedPostScript()
{
#ifdef DEBUG_DVIRENDERER
  kdDebug(4300) << "dviRenderer::embedPostScript()" << endl;
#endif

  if (!dviFile)
    return;

  embedPS_progress = new KProgressDialog(parentWidget, "embedPSProgressDialog",
					 i18n("Embedding PostScript Files"), TQString::null, true);
  if (!embedPS_progress)
    return;
  embedPS_progress->setAllowCancel(false);
  embedPS_progress->showCancelButton(false);
  embedPS_progress->setMinimumDuration(400);
  embedPS_progress->progressBar()->setTotalSteps(dviFile->numberOfExternalPSFiles);
  embedPS_progress->progressBar()->setProgress(0);
  embedPS_numOfProgressedFiles = 0;


  Q_UINT16 currPageSav = current_page;
  errorMsg = TQString::null;
  for(current_page=0; current_page < dviFile->total_pages; current_page++) {
    if (current_page < dviFile->total_pages) {
      command_pointer = dviFile->dvi_Data() + dviFile->page_offset[current_page];
      end_pointer     = dviFile->dvi_Data() + dviFile->page_offset[current_page+1];
    } else
      command_pointer = end_pointer = 0;

    memset((char *) &currinf.data, 0, sizeof(currinf.data));
    currinf.fonttable = &(dviFile->tn_table);
    currinf._virtual  = NULL;
    prescan(&dviRenderer::prescan_embedPS);
  }

  delete embedPS_progress;

  if (!errorMsg.isEmpty()) {
    errorMsg = "<qt>" + errorMsg + "</qt>";
    KMessageBox::detailedError(parentWidget, "<qt>" + i18n("Not all PostScript files could be embedded into your document.") + "</qt>", errorMsg);
    errorMsg = TQString::null;
  } else
    KMessageBox::information(parentWidget, "<qt>" + i18n("All external PostScript files were embedded into your document. You "
						 "will probably want to save the DVI file now.") + "</qt>",
			     TQString::null, "embeddingDone");

  // Prescan phase starts here
#ifdef PERFORMANCE_MEASUREMENT
  kdDebug(4300) << "Time elapsed till prescan phase starts " << performanceTimer.elapsed() << "ms" << endl;
  TQTime preScanTimer;
  preScanTimer.start();
#endif
  dviFile->numberOfExternalPSFiles = 0;
  prebookmarks.clear();
  for(current_page=0; current_page < dviFile->total_pages; current_page++) {
    PostScriptOutPutString = new TQString();

    if (current_page < dviFile->total_pages) {
      command_pointer = dviFile->dvi_Data() + dviFile->page_offset[current_page];
      end_pointer     = dviFile->dvi_Data() + dviFile->page_offset[current_page+1];
    } else
      command_pointer = end_pointer = 0;

    memset((char *) &currinf.data, 0, sizeof(currinf.data));
    currinf.fonttable = &(dviFile->tn_table);
    currinf._virtual  = NULL;

    prescan(&dviRenderer::prescan_parseSpecials);

    if (!PostScriptOutPutString->isEmpty())
      PS_interface->setPostScript(current_page, *PostScriptOutPutString);
    delete PostScriptOutPutString;
  }
  PostScriptOutPutString = NULL;


#ifdef PERFORMANCE_MEASUREMENT
  kdDebug(4300) << "Time required for prescan phase: " << preScanTimer.restart() << "ms" << endl;
#endif
  current_page = currPageSav;
  _isModified = true;
}


bool dviRenderer::isValidFile(const TQString& filename) const
{
  TQFile f(filename);
  if (!f.open(IO_ReadOnly))
    return false;

  unsigned char test[4];
  if ( f.readBlock( (char *)test,2)<2 || test[0] != 247 || test[1] != 2 )
    return false;

  int n = f.size();
  if ( n < 134 )	// Too short for a dvi file
    return false;
  f.at( n-4 );

  unsigned char trailer[4] = { 0xdf,0xdf,0xdf,0xdf };

  if ( f.readBlock( (char *)test, 4 )<4 || strncmp( (char *)test, (char *) trailer, 4 ) )
    return false;
  // We suppose now that the dvi file is complete and OK
  return true;
}


bool dviRenderer::setFile(const TQString &fname, const KURL &base)
{
#ifdef DEBUG_DVIRENDERER
  kdDebug(4300) << "dviRenderer::setFile( fname='" << fname << "', ref='" << ref << "', sourceMarker=" << sourceMarker << " )" << endl;
#endif

  TQMutexLocker lock(&mutex);

  TQFileInfo fi(fname);
  TQString   filename = fi.absFilePath();

  // If fname is the empty string, then this means: "close". Delete
  // the dvifile and the pixmap.
  if (fname.isEmpty()) {
    // Delete DVI file
    info->setDVIData(0);
    delete dviFile;
    dviFile = 0;
    return true;
  }
  
  
  // Make sure the file actually exists.
  if (!fi.exists() || fi.isDir()) {
    KMessageBox::error( parentWidget,
			i18n("<qt><strong>File error.</strong> The specified file '%1' does not exist. "
			     "KDVI already tried to add the ending '.dvi'.</qt>").arg(filename),
			i18n("File Error!"));
    return false;
  }
  
  // Check if we are really loading a DVI file, and complain about the
  // mime type, if the file is not DVI. Perhaps we should move the
  // procedure later to the kviewpart, instead of the implementaton in
  // the multipage.
  TQString mimetype( KMimeMagic::self()->findFileType( fname )->mimeType() );
  if (mimetype != "application/x-dvi") {
    KMessageBox::sorry( parentWidget,
			i18n( "<qt>Could not open file <nobr><strong>%1</strong></nobr> which has "
			      "type <strong>%2</strong>. KDVI can only load DVI (.dvi) files.</qt>" )
			.arg( fname )
			.arg( mimetype ) );
    return false;
  }
  
  // Check if the file is a valid DVI file.
  if (!isValidFile(filename))
  {
    KMessageBox::sorry( parentWidget,
                        i18n("<qt>File corruption! KDVI had trouble interpreting your DVI file. Most "
                             "likely this means that the DVI file is broken.</qt>")
                        .arg( fname ) );
    return false;
  }

  TQApplication::setOverrideCursor( waitCursor );
  dvifile *dviFile_new = new dvifile(filename, &font_pool);
  
  if ((dviFile == 0) || (dviFile->filename != filename))
    dviFile_new->sourceSpecialMarker = true;
  else
    dviFile_new->sourceSpecialMarker = false;
  
  if ((dviFile_new->dvi_Data() == NULL)||(dviFile_new->errorMsg.isEmpty() != true)) {
    TQApplication::restoreOverrideCursor();
    if (dviFile_new->errorMsg.isEmpty() != true)
      KMessageBox::detailedError(parentWidget,
				 i18n("<qt>File corruption! KDVI had trouble interpreting your DVI file. Most "
				      "likely this means that the DVI file is broken.</qt>"),
				 dviFile_new->errorMsg, i18n("DVI File Error"));
    delete dviFile_new;
    return false;
  }
  
  delete dviFile;
  dviFile = dviFile_new;
  numPages = dviFile->total_pages;
  info->setDVIData(dviFile);
  _isModified = false;
  baseURL = base;
  
  font_pool.setExtraSearchPath( fi.dirPath(true) );
  font_pool.setCMperDVIunit( dviFile->getCmPerDVIunit() );
  
  // Extract PostScript from the DVI file, and store the PostScript
  // specials in PostScriptDirectory, and the headers in the
  // PostScriptHeaderString.
  PS_interface->clear();
  
  // If the DVI file comes from a remote URL (e.g. downloaded from a
  // web server), we limit the PostScript files that can be accessed
  // by this file to the download directory, in order to limit the
  // possibilities of a denial of service attack.
  TQString includePath;
  if (!baseURL.isLocalFile()) {
    includePath = filename;
    includePath.truncate(includePath.findRev('/'));
  }
  PS_interface->setIncludePath(includePath);
  
  // We will also generate a list of hyperlink-anchors and source-file
  // anchors in the document. So declare the existing lists empty.
  anchorList.clear();
  sourceHyperLinkAnchors.clear();
  bookmarks.clear();
  prebookmarks.clear();
  
  if (dviFile->page_offset.isEmpty() == true)
    return false;
  
  // Locate fonts.
  font_pool.locateFonts();
  
  // Update the list of fonts in the info window
  if (info != 0)
    info->setFontInfo(&font_pool);
  
  // We should pre-scan the document now (to extract embedded,
  // PostScript, Hyperlinks, ets).
  
  // PRESCAN STARTS HERE
#ifdef PERFORMANCE_MEASUREMENT
  kdDebug(4300) << "Time elapsed till prescan phase starts " << performanceTimer.elapsed() << "ms" << endl;
  TQTime preScanTimer;
  preScanTimer.start();
#endif
  dviFile->numberOfExternalPSFiles = 0;
  Q_UINT16 currPageSav = current_page;
  prebookmarks.clear();
  
  for(current_page=0; current_page < dviFile->total_pages; current_page++) {
    PostScriptOutPutString = new TQString();
    
    if (current_page < dviFile->total_pages) {
      command_pointer = dviFile->dvi_Data() + dviFile->page_offset[current_page];
      end_pointer     = dviFile->dvi_Data() + dviFile->page_offset[current_page+1];
    } else
      command_pointer = end_pointer = 0;
    
    memset((char *) &currinf.data, 0, sizeof(currinf.data));
    currinf.fonttable = &(dviFile->tn_table);
    currinf._virtual  = NULL;
    prescan(&dviRenderer::prescan_parseSpecials);
    
    if (!PostScriptOutPutString->isEmpty())
      PS_interface->setPostScript(current_page, *PostScriptOutPutString);
    delete PostScriptOutPutString;
  }
  PostScriptOutPutString = NULL;
  
  // Generate the list of bookmarks
  bookmarks.clear();
  TQPtrStack<Bookmark> stack;
  stack.setAutoDelete (false);
  TQValueVector<PreBookmark>::iterator it;
  for( it = prebookmarks.begin(); it != prebookmarks.end(); ++it ) {
    Bookmark *bmk = new Bookmark((*it).title, findAnchor((*it).anchorName));
    if (stack.isEmpty())
      bookmarks.append(bmk);
    else {
      stack.top()->subordinateBookmarks.append(bmk);
      stack.remove();
    }
    for(int i=0; i<(*it).noOfChildren; i++)
      stack.push(bmk);
  }
  prebookmarks.clear();
  
  
#ifdef PERFORMANCE_MEASUREMENT
  kdDebug(4300) << "Time required for prescan phase: " << preScanTimer.restart() << "ms" << endl;
#endif
  current_page = currPageSav;
  // PRESCAN ENDS HERE
  
  
  pageSizes.resize(0);
  if (dviFile->suggestedPageSize != 0) {
    // Fill the vector pageSizes with total_pages identical entries
    pageSizes.resize(dviFile->total_pages, *(dviFile->suggestedPageSize));
  }
  
  TQApplication::restoreOverrideCursor();
  return true;
}


Anchor dviRenderer::parseReference(const TQString &reference)
{
  mutex.lock();
  
#ifdef DEBUG_DVIRENDERER
  kdError(4300) << "dviRenderer::parseReference( " << reference << " ) called" << endl;
#endif

  if (dviFile == 0) {
    mutex.unlock();
    return Anchor();
  }    

  // case 1: The reference is a number, which we'll interpret as a
  // page number.
  bool ok;
  int page = reference.toInt ( &ok );
  if (ok == true) {
    if (page < 0)
      page = 0;
    if (page > dviFile->total_pages)
      page = dviFile->total_pages;

    mutex.unlock();
    return Anchor(page, Length() );
  }
  
  // case 2: The reference is of form "src:1111Filename", where "1111"
  // points to line number 1111 in the file "Filename". KDVI then
  // looks for source specials of the form "src:xxxxFilename", and
  // tries to find the special with the biggest xxxx
  if (reference.find("src:",0,false) == 0) {
  
    // Extract the file name and the numeral part from the reference string
    DVI_SourceFileSplitter splitter(reference, dviFile->filename);
    Q_UINT32 refLineNumber = splitter.line();
    TQString  refFileName   = splitter.filePath();
    
    if (sourceHyperLinkAnchors.isEmpty()) {
      KMessageBox::sorry(parentWidget, i18n("<qt>You have asked KDVI to locate the place in the DVI file which corresponds to "
				    "line %1 in the TeX-file <strong>%2</strong>. It seems, however, that the DVI file "
				    "does not contain the necessary source file information. "
				    "We refer to the manual of KDVI for a detailed explanation on how to include this "
				    "information. Press the F1 key to open the manual.</qt>").arg(refLineNumber).arg(refFileName),
			 i18n("Could Not Find Reference"));
      mutex.unlock();
      return Anchor();
    }

    // Go through the list of source file anchors, and find the anchor
    // whose line number is the biggest among those that are smaller
    // than the refLineNumber. That way, the position in the DVI file
    // which is highlighted is always a little further up than the
    // position in the editor, e.g. if the DVI file contains
    // positional information at the beginning of every paragraph,
    // KDVI jumps to the beginning of the paragraph that the cursor is
    // in, and never to the next paragraph. If source file anchors for
    // the refFileName can be found, but none of their line numbers is
    // smaller than the refLineNumber, the reason is most likely, that
    // the cursor in the editor stands somewhere in the preamble of
    // the LaTeX file. In that case, we jump to the beginning of the
    // document.
    bool anchorForRefFileFound = false; // Flag that is set if source file anchors for the refFileName could be found at all
    
    TQValueVector<DVI_SourceFileAnchor>::iterator bestMatch = sourceHyperLinkAnchors.end();
    TQValueVector<DVI_SourceFileAnchor>::iterator it;
    for( it = sourceHyperLinkAnchors.begin(); it != sourceHyperLinkAnchors.end(); ++it )
      if (refFileName.stripWhiteSpace() == it->fileName.stripWhiteSpace()
      || refFileName.stripWhiteSpace() == it->fileName.stripWhiteSpace() + ".tex"
      ) {
	anchorForRefFileFound = true;
	
	if ( (it->line <= refLineNumber) &&
	     ( (bestMatch == sourceHyperLinkAnchors.end()) || (it->line > bestMatch->line) ) )
	  bestMatch = it;
      }
    
    if (bestMatch != sourceHyperLinkAnchors.end()) {
      mutex.unlock();
      return Anchor(bestMatch->page, bestMatch->distance_from_top);
    } else
      if (anchorForRefFileFound == false)
	KMessageBox::sorry(parentWidget, i18n("<qt>KDVI was not able to locate the place in the DVI file which corresponds to "
					      "line %1 in the TeX-file <strong>%2</strong>.</qt>").arg(refLineNumber).arg(refFileName),
			   i18n( "Could Not Find Reference" ));
      else {
	mutex.unlock();
	return Anchor();
      }
    mutex.unlock();
    return Anchor();
  }
  mutex.unlock();
  return Anchor();
}


void dviRenderer::setResolution(double resolution_in_DPI)
{
  // Ignore minute changes. The difference to the current value would
  // hardly be visible anyway. That saves a lot of re-painting,
  // e.g. when the user resizes the window, and a flickery mouse
  // changes the window size by 1 pixel all the time.
  if (fabs(resolutionInDPI-resolution_in_DPI) < 1)
    return;

  resolutionInDPI = resolution_in_DPI;
  
  // Pass the information on to the font pool. 
  font_pool.setDisplayResolution( resolutionInDPI );
  shrinkfactor = 1200/resolutionInDPI;
  return;
}


void dviRenderer::clearStatusBar()
{
  emit setStatusBarText( TQString::null );
}


void dviRenderer::handleSRCLink(const TQString &linkText, TQMouseEvent *e, DocumentWidget *win)
{
#ifdef DEBUG_SPECIAL
  RenderedDviPagePixmap* currentDVIPage = dynamic_cast<RenderedDviPagePixmap*> currentlyDrawnPage;
  if (currentDVIPage)
  {
    kdDebug(4300) << "Source hyperlink to " << currentDVIPage->sourceHyperLinkList[i].linkText << endl;
  }
#endif

  DVI_SourceFileSplitter splitter(linkText, dviFile->filename);
  TQString TeXfile = splitter.filePath();
  if ( ! splitter.fileExists() )
  {
      KMessageBox::sorry(parentWidget, TQString("<qt>") +
			 i18n("The DVI-file refers to the TeX-file "
			      "<strong>%1</strong> which could not be found.").arg(KShellProcess::quote(TeXfile)) +
			 TQString("</qt>"),
			 i18n( "Could Not Find File" ));
      return;
  }
  
  TQString command = editorCommand;
  if (command.isEmpty() == true) {
    int r = KMessageBox::warningContinueCancel(parentWidget, TQString("<qt>") +
					       i18n("You have not yet specified an editor for inverse search. "
						    "Please choose your favorite editor in the "
						    "<strong>DVI options dialog</strong> "
						    "which you will find in the <strong>Settings</strong>-menu.") +
					       TQString("</qt>"),
					       i18n("Need to Specify Editor"),
					       i18n("Use KDE's Editor Kate for Now"));
    if (r == KMessageBox::Continue)
      command = "kate %f";
    else
      return;
  }
  command = command.replace( "%l", TQString::number(splitter.line()) ).replace( "%f", KShellProcess::quote(TeXfile) );
  
#ifdef DEBUG_SPECIAL
  kdDebug(4300) << "Calling program: " << command << endl;
#endif
  
  // There may still be another program running. Since we don't
  // want to mix the output of several programs, we will
  // henceforth dimiss the output of the older programm. "If it
  // hasn't failed until now, we don't care."
  if (proc != 0) {
    qApp->disconnect(proc, TQT_SIGNAL(receivedStderr(KProcess *, char *, int)), 0, 0);
    qApp->disconnect(proc, TQT_SIGNAL(receivedStdout(KProcess *, char *, int)), 0, 0);
    proc = 0;
  }
  
  // Set up a shell process with the editor command.
  proc = new KShellProcess();
  if (proc == 0) {
    kdError(4300) << "Could not allocate ShellProcess for the editor command." << endl;
    return;
  }
  qApp->connect(proc, TQT_SIGNAL(receivedStderr(KProcess *, char *, int)), this, TQT_SLOT(dvips_output_receiver(KProcess *, char *, int)));
  qApp->connect(proc, TQT_SIGNAL(receivedStdout(KProcess *, char *, int)), this, TQT_SLOT(dvips_output_receiver(KProcess *, char *, int)));
  qApp->connect(proc, TQT_SIGNAL(processExited(KProcess *)), this, TQT_SLOT(editorCommand_terminated(KProcess *)));
  // Merge the editor-specific editor message here.
  export_errorString = i18n("<qt>The external program<br><br><tt><strong>%1</strong></tt><br/><br/>which was used to call the editor "
			    "for inverse search, reported an error. You might wish to look at the <strong>document info "
			    "dialog</strong> which you will find in the File-Menu for a precise error report. The "
			    "manual for KDVI contains a detailed explanation how to set up your editor for use with KDVI, "
			    "and a list of common problems.</qt>").arg(command);
  
  info->clear(i18n("Starting the editor..."));
  
  int flashOffset      = e->y(); // Heuristic correction. Looks better.
  win->flash(flashOffset);
  
  
  proc->clearArguments();
  *proc << command;
  proc->closeStdin();
  if (proc->start(KProcess::NotifyOnExit, KProcess::AllOutput) == false) {
    kdError(4300) << "Editor failed to start" << endl;
    return;
  }
}


TQString dviRenderer::PDFencodingToQString(const TQString& _pdfstring)
{
  // This method locates special PDF characters in a string and
  // replaces them by UTF8. See Section 3.2.3 of the PDF reference
  // guide for information.
  TQString pdfstring = _pdfstring;
  pdfstring = pdfstring.replace("\\n", "\n");
  pdfstring = pdfstring.replace("\\r", "\n");
  pdfstring = pdfstring.replace("\\t", "\t");
  pdfstring = pdfstring.replace("\\f", "\f");
  pdfstring = pdfstring.replace("\\(", "(");
  pdfstring = pdfstring.replace("\\)", ")");
  pdfstring = pdfstring.replace("\\\\", "\\");
  
  // Now replace octal character codes with the characters they encode
  int pos;
  TQRegExp rx( "(\\\\)(\\d\\d\\d)" );  // matches "\xyz" where x,y,z are numbers
  while((pos = rx.search( pdfstring )) != -1) {
    pdfstring = pdfstring.replace(pos, 4, TQChar(rx.cap(2).toInt(0,8)));
  }
  rx.setPattern( "(\\\\)(\\d\\d)" );  // matches "\xy" where x,y are numbers
  while((pos = rx.search( pdfstring )) != -1) {
    pdfstring = pdfstring.replace(pos, 3, TQChar(rx.cap(2).toInt(0,8)));
  }
  rx.setPattern( "(\\\\)(\\d)" );  // matches "\x" where x is a number
  while((pos = rx.search( pdfstring )) != -1) {
    pdfstring = pdfstring.replace(pos, 4, TQChar(rx.cap(2).toInt(0,8)));
  }
  return pdfstring;
}


#include "dviRenderer.moc"