fontpool.cpp

okular

// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; c-brace-offset: 0; -*-
//
// fontpool.cpp
//
// (C) 2001-2005 Stefan Kebekus
// Distributed under the GPL

#include <config.h>

#include "fontpool.h"
#include "kvs_debug.h"
#include "TeXFont.h"

#include <klocale.h>
#include <kmessagebox.h>

#include <QApplication>
#include <QPainter>

#include <cmath>

//#define DEBUG_FONTPOOL


// List of permissible MetaFontModes which are supported by kdvi.

//const char *MFModes[]       = { "cx", "ljfour", "lexmarks" };
//const char *MFModenames[]   = { "Canon CX", "LaserJet 4", "Lexmark S" };
//const int   MFResolutions[] = { 300, 600, 1200 };

#ifdef PERFORMANCE_MEASUREMENT
QTime fontPoolTimer;
bool fontPoolTimerFlag;
#endif

fontPool::fontPool()
  :  progress("fontgen",  // Chapter in the documentation for help.
              i18n("KDVI is currently generating bitmap fonts..."),
              i18n("Aborts the font generation. Don't do this."),
              i18n("KDVI is currently generating bitmap fonts which are needed to display your document. "
                   "For this, KDVI uses a number of external programs, such as MetaFont. You can find "
                   "the output of these programs later in the document info dialog."),
              i18n("KDVI is generating fonts. Please wait."),
              0)
{
#ifdef DEBUG_FONTPOOL
  kDebug(kvs::dvi) << "fontPool::fontPool() called" << endl;
#endif

  setObjectName("Font Pool");

  displayResolution_in_dpi = 100.0; // A not-too-bad-default
  useFontHints             = true;
  CMperDVIunit             = 0;
  extraSearchPath          = QString::null;
  fontList.setAutoDelete(true);

#ifdef HAVE_FREETYPE
  // Initialize the Freetype Library
  if ( FT_Init_FreeType( &FreeType_library ) != 0 ) {
    kError(kvs::dvi) << "Cannot load the FreeType library. KDVI proceeds without FreeType support." << endl;
    FreeType_could_be_loaded = false;
  } else
    FreeType_could_be_loaded = true;
#endif

  // If PK fonts are generated, the kpsewhich command will re-route
  // the output of MetaFont into its stderr. Here we make sure this
  // output is intercepted and parsed.
  connect(&kpsewhich_, SIGNAL(readyReadStandardError()),
          this, SLOT(mf_output_receiver()));

  // Check if the QT library supports the alpha channel of
  // QImages. Experiments show that --depending of the configuration
  // of QT at compile and runtime or the availability of the XFt
  // extension, alpha channels are either supported, or silently
  // ignored.
  QImage start(1, 1, QImage::Format_ARGB32); // Generate a 1x1 image, black with alpha=0x10
  quint32 *destScanLine = (quint32 *)start.scanLine(0);
  *destScanLine = 0x80000000;
  QPixmap intermediate = QPixmap::fromImage(start);
  QPixmap dest(1,1);
  dest.fill(Qt::white);
  QPainter paint( &dest );
  paint.drawPixmap(0, 0, intermediate);
  paint.end();
  start = dest.toImage().convertToFormat(QImage::Format_ARGB32);
  quint8 result = *(start.scanLine(0)) & 0xff;

  if ((result == 0xff) || (result == 0x00)) {
#ifdef DEBUG_FONTPOOL
    kDebug(kvs::dvi) << "fontPool::fontPool(): QPixmap does not support the alpha channel" << endl;
#endif
    QPixmapSupportsAlpha = false;
  } else {
#ifdef DEBUG_FONTPOOL
    kDebug(kvs::dvi) << "fontPool::fontPool(): QPixmap supports the alpha channel" << endl;
#endif
    QPixmapSupportsAlpha = true;
  }
}


fontPool::~fontPool()
{
#ifdef DEBUG_FONTPOOL
  kDebug(kvs::dvi) << "fontPool::~fontPool() called" << endl;
#endif

#ifdef HAVE_FREETYPE
  if (FreeType_could_be_loaded == true)
    FT_Done_FreeType( FreeType_library );
#endif
}


void fontPool::setParameters( bool _useFontHints )
{
  // Check if glyphs need to be cleared
  if (_useFontHints != useFontHints) {
    double displayResolution = displayResolution_in_dpi;
    TeXFontDefinition *fontp = fontList.first();
    while(fontp != 0 ) {
      fontp->setDisplayResolution(displayResolution * fontp->enlargement);
      fontp=fontList.next();
    }
  }

  useFontHints = _useFontHints;
}


TeXFontDefinition* fontPool::appendx(const QString& fontname, quint32 checksum, quint32 scale, double enlargement)
{
  // Reuse font if possible: check if a font with that name and
  // natural resolution is already in the fontpool, and use that, if
  // possible.
  TeXFontDefinition *fontp = fontList.first();
  while( fontp != 0 ) {
    if ((fontname == fontp->fontname) && ( (int)(enlargement*1000.0+0.5)) == (int)(fontp->enlargement*1000.0+0.5)) {
      // if font is already in the list
      fontp->mark_as_used();
      return fontp;
    }
    fontp=fontList.next();
  }

  // If font doesn't exist yet, we have to generate a new font.

  double displayResolution = displayResolution_in_dpi;

  fontp = new TeXFontDefinition(fontname, displayResolution*enlargement, checksum, scale, this, enlargement);
  if (fontp == 0) {
    kError(kvs::dvi) << i18n("Could not allocate memory for a font structure") << endl;
    exit(0);
  }
  fontList.append(fontp);

#ifdef PERFORMANCE_MEASUREMENT
  fontPoolTimer.start();
  fontPoolTimerFlag = false;
#endif

  // Now start kpsewhich/MetaFont, etc. if necessary
  return fontp;
}


QString fontPool::status()
{
#ifdef DEBUG_FONTPOOL
  kDebug(kvs::dvi) << "fontPool::status() called" << endl;
#endif

  QString       text;
  QStringList   tmp;

  if (fontList.isEmpty())
    return i18n("The fontlist is currently empty.");

  text.append("<table WIDTH=\"100%\" NOSAVE >");
  text.append( QString("<tr><td><b>%1</b></td> <td><b>%2</b></td> <td><b>%3</b></td> <td><b>%4</b> <td><b>%5</b></td> <td><b>%6</b></td></tr>")
               .arg(i18n("TeX Name"))
               .arg(i18n("Family"))
               .arg(i18n("Zoom"))
               .arg(i18n("Type"))
               .arg(i18n("Encoding"))
               .arg(i18n("Comment")) );

 TeXFontDefinition *fontp = fontList.first();
  while ( fontp != 0 ) {
    QString errMsg, encoding;

    if (!(fontp->flags & TeXFontDefinition::FONT_VIRTUAL)) {
#ifdef HAVE_FREETYPE
      encoding = fontp->getFullEncodingName();
#endif
      if (fontp->font != 0)
        errMsg = fontp->font->errorMessage;
      else
        errMsg = i18n("Font file not found");
    }

#ifdef HAVE_FREETYPE
    tmp << QString ("<tr><td>%1</td> <td>%2</td> <td>%3%</td> <td>%4</td> <td>%5</td> <td>%6</td></tr>")
      .arg(fontp->fontname)
      .arg(fontp->getFullFontName())
      .arg((int)(fontp->enlargement*100 + 0.5))
      .arg(fontp->getFontTypeName())
      .arg(encoding)
      .arg(errMsg);
#endif

    fontp=fontList.next();
  }

  tmp.sort();
  text.append(tmp.join("\n"));
  text.append("</table>");

  return text;
}


bool fontPool::areFontsLocated()
{
#ifdef DEBUG_FONTPOOL
  kDebug(kvs::dvi) << "fontPool::areFontsLocated() called" << endl;
#endif

  // Is there a font whose name we did not try to find out yet?
  TeXFontDefinition *fontp = fontList.first();
  while( fontp != 0 ) {
    if ( !fontp->isLocated() )
      return false;
    fontp=fontList.next();
  }

#ifdef DEBUG_FONTPOOL
  kDebug(kvs::dvi) << "... yes, all fonts are located (but not necessarily loaded)." << endl;
#endif
  return true; // That says that all fonts are located.
}


void fontPool::locateFonts()
{
  kpsewhichOutput = QString::null;

  // First, we try and find those fonts which exist on disk
  // already. If virtual fonts are found, they will add new fonts to
  // the list of fonts whose font files need to be located, so that we
  // repeat the lookup.
  bool vffound;
  do {
    vffound = false;
    locateFonts(false, false, &vffound);
  } while(vffound);

  // If still not all fonts are found, look again, this time with
  // on-demand generation of PK fonts enabled.
  if (!areFontsLocated())
    locateFonts(true, false);

  // If still not all fonts are found, we look for TFM files as a last
  // resort, so that we can at least draw filled rectangles for
  // characters.
  if (!areFontsLocated())
    locateFonts(false, true);

  // If still not all fonts are found, we give up. We mark all fonts
  // as 'located', so that we won't look for them any more, and
  // present an error message to the user.
  if (!areFontsLocated()) {
    markFontsAsLocated();
    QString details = QString("<qt><p><b>PATH:</b> %1</p>%2</qt>").arg(getenv("PATH")).arg(kpsewhichOutput);
    KMessageBox::detailedError( 0, i18n("<qt><p>KDVI was not able to locate all the font files "
                                        "which are necessary to display the current DVI file. "
                                        "Your document might be unreadable.</p></qt>"),
                                details,
                                i18n("Not All Font Files Found") );
  }
}


void fontPool::locateFonts(bool makePK, bool locateTFMonly, bool *virtualFontsFound)