From 10b2b8fc694b60a17ccd2642f3a40c851e33b9da Mon Sep 17 00:00:00 2001
From: Dimitri van Heesch <doxygen@gmail.com>
Date: Wed, 12 Feb 2020 21:08:11 +0100
Subject: Improve formula handling and rendering.

Also added option HTML_FORMULA_FORMAT to generate SVG files for images (requires pdf2svg)
---
 src/commentscan.l      |  21 +--
 src/config.xml         |  11 ++
 src/docparser.cpp      |  12 +-
 src/doxygen.cpp        | 136 ++++----------
 src/doxygen.h          |   3 -
 src/formula.cpp        | 483 ++++++++++++++++++++++++++++++-------------------
 src/formula.h          |  58 +++---
 src/htmldocvisitor.cpp |  24 ++-
 src/portable.cpp       |   9 +
 src/portable.h         |   1 +
 10 files changed, 406 insertions(+), 352 deletions(-)

diff --git a/src/commentscan.l b/src/commentscan.l
index 411f5a7..597246e 100644
--- a/src/commentscan.l
+++ b/src/commentscan.l
@@ -17,6 +17,9 @@
 %option prefix="commentscanYY"
 %option reentrant
 %option extra-type="struct commentscanYY_state *"
+%top{
+#include <stdint.h>
+}
 
 %{
 
@@ -2862,21 +2865,9 @@ static QCString addFormula(yyscan_t yyscanner)
   struct yyguts_t *yyg = (struct yyguts_t*)yyscanner;
   QCString formLabel;
   QCString fText=yyextra->formulaText.simplifyWhiteSpace();
-  Formula *f=0;
-  if ((f=Doxygen::formulaDict->find(fText))==0)
-  {
-    f = new Formula(fText);
-    Doxygen::formulaList->append(f);
-    Doxygen::formulaDict->insert(fText,f);
-    formLabel.sprintf("\\_form#%d",f->getId());
-    Doxygen::formulaNameDict->insert(formLabel,f);
-  }
-  else
-  {
-    formLabel.sprintf("\\_form#%d",f->getId());
-  }
-  int i;
-  for (i=0;i<yyextra->formulaNewLines;i++) formLabel+="@_fakenl"; // add fake newlines to
+  int id = FormulaManager::instance().addFormula(fText);
+  formLabel.sprintf("\\_form#%d",id);
+  for (int i=0;i<yyextra->formulaNewLines;i++) formLabel+="@_fakenl"; // add fake newlines to
                                                          // keep the warnings 
                                                          // correctly aligned.
   return formLabel;
diff --git a/src/config.xml b/src/config.xml
index f40744d..fec21b6 100644
--- a/src/config.xml
+++ b/src/config.xml
@@ -2357,6 +2357,17 @@ The \c DOCSET_PUBLISHER_NAME tag identifies the documentation publisher.
 ]]>
       </docs>
     </option>
+    <option type='enum' id='HTML_FORMULA_FORMAT' defval='PNG' depends='GENERATE_HTML'>
+      <docs>
+<![CDATA[
+ If the \c HTML_FORMULA_FORMAT option is set to \c SVG, doxygen will use the pdf2svg
+ tool (see https://github.com/dawbarton/pdf2svg) to generate formulas as SVG images instead of
+ PNGs for the HTML output. These images will generally look nicer at scaled resolutions.
+]]>
+      </docs>
+      <value name="PNG" desc="The default"/>
+      <value name="SVG" desc="Looks nicer but requires the pdf2svg tool"/>
+    </option>
     <option type='int' id='FORMULA_FONTSIZE' minval='8' maxval='50' defval='10' depends='GENERATE_HTML'>
       <docs>
 <![CDATA[
diff --git a/src/docparser.cpp b/src/docparser.cpp
index 9348810..b3ae6bd 100644
--- a/src/docparser.cpp
+++ b/src/docparser.cpp
@@ -2223,15 +2223,13 @@ bool DocXRefItem::parse()
 DocFormula::DocFormula(DocNode *parent,int id) :
       m_relPath(g_relPath)
 {
-  m_parent = parent; 
-  QCString formCmd;
-  formCmd.sprintf("\\_form#%d",id);
-  Formula *formula=Doxygen::formulaNameDict->find(formCmd);
-  if (formula)
+  m_parent = parent;
+  QCString text = FormulaManager::instance().findFormula(id);
+  if (!text.isEmpty())
   {
-    m_id = formula->getId();
+    m_id = id;
     m_name.sprintf("form_%d",m_id);
-    m_text = formula->getFormulaText();
+    m_text = text;
   }
   else // wrong \_form#<n> command
   {
diff --git a/src/doxygen.cpp b/src/doxygen.cpp
index 49c4d5a..a36bf06 100644
--- a/src/doxygen.cpp
+++ b/src/doxygen.cpp
@@ -126,9 +126,6 @@ MemberNameSDict *Doxygen::functionNameSDict = 0;
 FileNameList    *Doxygen::inputNameList = 0;       // all input files
 FileNameDict    *Doxygen::inputNameDict = 0;
 GroupSDict      *Doxygen::groupSDict = 0;
-FormulaList     *Doxygen::formulaList = 0;       // all formulas
-FormulaDict     *Doxygen::formulaDict = 0;       // all formulas
-FormulaDict     *Doxygen::formulaNameDict = 0;   // the label name of all formulas
 PageSDict       *Doxygen::pageSDict = 0;
 PageSDict       *Doxygen::exampleSDict = 0;
 SectionDict     *Doxygen::sectionDict = 0;        // all page sections
@@ -197,7 +194,6 @@ void clearAll()
   Doxygen::pageSDict->clear();
   Doxygen::exampleSDict->clear();
   Doxygen::inputNameList->clear();
-  Doxygen::formulaList->clear();
   Doxygen::sectionDict->clear();
   Doxygen::inputNameDict->clear();
   Doxygen::includeNameDict->clear();
@@ -206,11 +202,10 @@ void clearAll()
   Doxygen::dotFileNameDict->clear();
   Doxygen::mscFileNameDict->clear();
   Doxygen::diaFileNameDict->clear();
-  Doxygen::formulaDict->clear();
-  Doxygen::formulaNameDict->clear();
   Doxygen::tagDestinationDict.clear();
   delete Doxygen::citeDict;
   delete Doxygen::mainPage; Doxygen::mainPage=0;
+  FormulaManager::instance().clear();
 }
 
 class Statistics
@@ -281,10 +276,6 @@ void statistics()
   fprintf(stderr,"--- typedefDict stats ----\n");
   fprintf(stderr,"--- namespaceAliasDict stats ----\n");
   Doxygen::namespaceAliasDict.statistics();
-  fprintf(stderr,"--- formulaDict stats ----\n");
-  Doxygen::formulaDict->statistics();
-  fprintf(stderr,"--- formulaNameDict stats ----\n");
-  Doxygen::formulaNameDict->statistics();
   fprintf(stderr,"--- tagDestinationDict stats ----\n");
   Doxygen::tagDestinationDict.statistics();
   fprintf(stderr,"--- g_compoundKeywordDict stats ----\n");
@@ -9576,66 +9567,6 @@ int readFileOrDirectory(const char *s,
 
 //----------------------------------------------------------------------------
 
-void readFormulaRepository(QCString dir, bool cmp)
-{
-  static int current_repository = 0; 
-  int new_repository = 0; 
-  QFile f(dir+"/formula.repository");
-  if (f.open(IO_ReadOnly)) // open repository
-  {
-    msg("Reading formula repository...\n");
-    QTextStream t(&f);
-    QCString line;
-    Formula *f;
-    while (!t.eof())
-    {
-      line=t.readLine().utf8();
-      int se=line.find(':'); // find name and text separator.
-      if (se==-1)
-      {
-        warn_uncond("formula.repository is corrupted!\n");
-        break;
-      }
-      else
-      {
-        QCString formName = line.left(se);
-        QCString formText = line.right(line.length()-se-1);
-        if (cmp)
-        {
-          if ((f=Doxygen::formulaDict->find(formText))==0)
-          {
-            term("discrepancy between formula repositories! Remove "
-                "formula.repository and from_* files from output directories.");
-          }
-          QCString formLabel;
-          formLabel.sprintf("\\_form#%d",f->getId());
-          if (formLabel != formName)
-          {
-            term("discrepancy between formula repositories! Remove "
-                "formula.repository and from_* files from output directories.");
-          }
-          new_repository++;
-        }
-        else
-        {
-          f=new Formula(formText);
-          Doxygen::formulaList->append(f);
-          Doxygen::formulaDict->insert(formText,f);
-          Doxygen::formulaNameDict->insert(formName,f);
-          current_repository++;
-        }
-      }
-    }
-  }
-  if (cmp && (current_repository != new_repository))
-  {
-    term("size discrepancy between formula repositories! Remove "
-        "formula.repository and from_* files from output directories.");
-  }
-}
-
-//----------------------------------------------------------------------------
-
 static void expandAliases()
 {
   QDictIterator<QCString> adi(Doxygen::aliasDict);
@@ -9935,10 +9866,6 @@ void initDoxygen()
   Doxygen::citeDict = new CiteDict(257);
   Doxygen::genericsDict = new GenericsSDict;
   Doxygen::indexList = new IndexList;
-  Doxygen::formulaList = new FormulaList;
-  Doxygen::formulaList->setAutoDelete(TRUE);
-  Doxygen::formulaDict = new FormulaDict(1009);
-  Doxygen::formulaNameDict = new FormulaDict(1009);
   Doxygen::sectionDict = new SectionDict(257);
   Doxygen::sectionDict->setAutoDelete(TRUE);
 
@@ -9968,10 +9895,9 @@ void initDoxygen()
 
 void cleanUpDoxygen()
 {
+  FormulaManager::instance().clear();
+
   delete Doxygen::sectionDict;
-  delete Doxygen::formulaNameDict;
-  delete Doxygen::formulaDict;
-  delete Doxygen::formulaList;
   delete Doxygen::indexList;
   delete Doxygen::genericsDict;
   delete Doxygen::inputNameDict;
@@ -11036,18 +10962,22 @@ void parseInput()
 
   if (Config_getBool(GENERATE_HTML) && !Config_getBool(USE_MATHJAX))
   {
-    readFormulaRepository(Config_getString(HTML_OUTPUT));
+    FormulaManager::instance().readFormulas(Config_getString(HTML_OUTPUT));
   }
   if (Config_getBool(GENERATE_RTF))
   {
     // in case GENERRATE_HTML is set we just have to compare, both repositories should be identical
-    readFormulaRepository(Config_getString(RTF_OUTPUT),Config_getBool(GENERATE_HTML) && !Config_getBool(USE_MATHJAX));
+    FormulaManager::instance().readFormulas(Config_getString(RTF_OUTPUT),
+                              Config_getBool(GENERATE_HTML) &&
+                              !Config_getBool(USE_MATHJAX));
   }
   if (Config_getBool(GENERATE_DOCBOOK))
   {
     // in case GENERRATE_HTML is set we just have to compare, both repositories should be identical
-    readFormulaRepository(Config_getString(DOCBOOK_OUTPUT),
-                         (Config_getBool(GENERATE_HTML) && !Config_getBool(USE_MATHJAX)) || Config_getBool(GENERATE_RTF));
+    FormulaManager::instance().readFormulas(Config_getString(DOCBOOK_OUTPUT),
+                         (Config_getBool(GENERATE_HTML) &&
+                         !Config_getBool(USE_MATHJAX)) ||
+                         Config_getBool(GENERATE_RTF));
   }
 
   /**************************************************************************
@@ -11477,6 +11407,29 @@ void generateOutput()
   }
   g_s.end();
 
+  const FormulaManager &fm = FormulaManager::instance();
+  if (fm.hasFormulas() && generateHtml
+      && !Config_getBool(USE_MATHJAX))
+  {
+    g_s.begin("Generating images for formulas in HTML...\n");
+    fm.generateImages(Config_getString(HTML_OUTPUT), Config_getEnum(HTML_FORMULA_FORMAT)=="SVG" ?
+        FormulaManager::Format::Vector : FormulaManager::Format::Bitmap, FormulaManager::HighDPI::On);
+    g_s.end();
+  }
+  if (fm.hasFormulas() && generateRtf)
+  {
+    g_s.begin("Generating images for formulas in RTF...\n");
+    fm.generateImages(Config_getString(RTF_OUTPUT),FormulaManager::Format::Bitmap);
+    g_s.end();
+  }
+
+  if (fm.hasFormulas() && generateDocbook)
+  {
+    g_s.begin("Generating images for formulas in Docbook...\n");
+    fm.generateImages(Config_getString(DOCBOOK_OUTPUT),FormulaManager::Format::Bitmap);
+    g_s.end();
+  }
+
   g_s.begin("Generating example documentation...\n");
   generateExampleDocs();
   g_s.end();
@@ -11516,27 +11469,6 @@ void generateOutput()
   generateDirDocs(*g_outputList);
   g_s.end();
 
-  if (Doxygen::formulaList->count()>0 && generateHtml
-      && !Config_getBool(USE_MATHJAX))
-  {
-    g_s.begin("Generating bitmaps for formulas in HTML...\n");
-    Doxygen::formulaList->generateBitmaps(Config_getString(HTML_OUTPUT));
-    g_s.end();
-  }
-  if (Doxygen::formulaList->count()>0 && generateRtf)
-  {
-    g_s.begin("Generating bitmaps for formulas in RTF...\n");
-    Doxygen::formulaList->generateBitmaps(Config_getString(RTF_OUTPUT));
-    g_s.end();
-  }
-
-  if (Doxygen::formulaList->count()>0 && generateDocbook)
-  {
-    g_s.begin("Generating bitmaps for formulas in Docbook...\n");
-    Doxygen::formulaList->generateBitmaps(Config_getString(DOCBOOK_OUTPUT));
-    g_s.end();
-  }
-
   if (Config_getBool(SORT_GROUP_NAMES))
   {
     Doxygen::groupSDict->sort();
diff --git a/src/doxygen.h b/src/doxygen.h
index b93ab27..19136c3 100644
--- a/src/doxygen.h
+++ b/src/doxygen.h
@@ -116,9 +116,6 @@ class Doxygen
     static StringDict                namespaceAliasDict;
     static GroupSDict               *groupSDict;
     static NamespaceSDict           *namespaceSDict;
-    static FormulaList              *formulaList;
-    static FormulaDict              *formulaDict;
-    static FormulaDict              *formulaNameDict;
     static StringDict                tagDestinationDict;
     static StringDict                aliasDict;
     static QIntDict<MemberGroupInfo> memGrpInfoDict;
diff --git a/src/formula.cpp b/src/formula.cpp
index 01a96b3..063684e 100644
--- a/src/formula.cpp
+++ b/src/formula.cpp
@@ -1,7 +1,6 @@
 /******************************************************************************
- * 
  *
- * Copyright (C) 1997-2015 by Dimitri van Heesch.
+ * Copyright (C) 1997-2020 by Dimitri van Heesch.
  *
  * Permission to use, copy, modify, and distribute this software and its
  * documentation under the terms of the GNU General Public License is hereby 
@@ -14,41 +13,135 @@
  *
  */
 
-#include <stdlib.h>
-#include <qfile.h>
-#include <qfileinfo.h>
-#include <qtextstream.h>
-#include <qdir.h>
-
 #include "formula.h"
-#include "image.h"
-#include "util.h"
 #include "message.h"
 #include "config.h"
-#include "portable.h"
-#include "index.h"
-#include "doxygen.h"
 #include "ftextstream.h"
+#include "util.h"
+#include "portable.h"
+#include "image.h"
+
+#include <qfile.h>
+#include <qtextstream.h>
+#include <qdir.h>
+
+#include <map>
+#include <vector>
+#include <string>
+#include <utility>
 
-Formula::Formula(const char *text)
+// TODO: remove these dependencies
+#include "doxygen.h" // for Doxygen::indexList
+#include "index.h"   // for Doxygen::indexList
+
+// Remove the temporary files
+#define RM_TMP_FILES (true)
+//#define RM_TMP_FILES (false)
+
+struct FormulaManager::Private
+{
+  void storeDisplaySize(int id,int w,int h)
+  {
+    displaySizeMap.insert(std::make_pair(id,DisplaySize(w,h)));
+  }
+  DisplaySize getDisplaySize(int id)
+  {
+    auto it = displaySizeMap.find(id);
+    if (it!=displaySizeMap.end())
+    {
+      return it->second;
+    }
+    return DisplaySize(-1,-1);
+  }
+  std::vector<std::string>  formulas;
+  std::map<std::string,int> formulaMap;
+  std::map<int,DisplaySize> displaySizeMap;
+};
+
+FormulaManager::FormulaManager() : p(new Private)
 {
-  static int count=0;
-  number = count++;
-  form=text;
 }
 
-Formula::~Formula()
+FormulaManager &FormulaManager::instance()
 {
+  static FormulaManager fm;
+  return fm;
 }
 
-int Formula::getId()
+void FormulaManager::readFormulas(const char *dir,bool doCompare)
 {
-  return number;
+  QFile f(QCString(dir)+"/formula.repository");
+  if (f.open(IO_ReadOnly)) // open repository
+  {
+    int formulaCount=0;
+    msg("Reading formula repository...\n");
+    QTextStream t(&f);
+    QCString line;
+    int lineNr=1;
+    while (!t.eof())
+    {
+      line=t.readLine().utf8();
+      // old format: \_form#<digits>:formula
+      // new format: \_form#<digits>=<digits>x<digits>:formula
+      int hi=line.find('#');
+      int ei=line.find('=');
+      int se=line.find(':'); // find name and text separator.
+      if (hi==-1 || se==-1 || hi>se)
+      {
+        warn_uncond("%s/formula.repository is corrupted at line %d!\n",dir,lineNr);
+        break;
+      }
+      else
+      {
+        QCString formName = line.left(se);
+        QCString formText = line.right(line.length()-se-1);
+        int w=-1,h=-1;
+        if (ei!=-1 && ei>hi && ei<se) // new format
+        {
+          int xi=formName.find('x',hi);
+          if (xi!=-1)
+          {
+            w=formName.mid(hi+1,xi-hi-1).toInt();
+            h=formName.mid(xi+1).toInt();
+          }
+          formName = formName.left(ei);
+        }
+        else
+        {
+          ei=formName.length();
+        }
+        if (doCompare)
+        {
+          int formId = formName.mid(hi+1,ei-hi-1).toInt();
+          QCString storedFormText = FormulaManager::instance().findFormula(formId);
+          if (storedFormText!=formText)
+          {
+            term("discrepancy between formula repositories! Remove "
+                "formula.repository and from_* files from output directories.\n");
+          }
+          formulaCount++;
+        }
+        else
+        {
+          int id = addFormula(formText);
+          if (w!=-1 && h!=-1)
+          {
+            p->storeDisplaySize(id,w,h);
+          }
+        }
+      }
+      lineNr++;
+    }
+    if (doCompare && formulaCount!=p->formulas.size())
+    {
+      term("size discrepancy between formula repositories! Remove "
+           "formula.repository and from_* files from output directories.\n");
+    }
+  }
 }
 
-void FormulaList::generateBitmaps(const char *path)
+void FormulaManager::generateImages(const char *path,Format format,HighDPI hd) const
 {
-  int x1,y1,x2,y2;
   QDir d(path);
   // store the original directory
   if (!d.exists())
@@ -70,10 +163,7 @@ void FormulaList::generateBitmaps(const char *path)
   QDir thisDir;
   // generate a latex file containing one formula per page.
   QCString texName="_formulas.tex";
-  QList<int> pagesToGenerate;
-  pagesToGenerate.setAutoDelete(TRUE);
-  FormulaListIterator fli(*this);
-  Formula *formula;
+  std::vector<int> formulasToGenerate;
   QFile f(texName);
   bool formulaError=FALSE;
   if (f.open(IO_WriteOnly))
@@ -93,32 +183,32 @@ void FormulaList::generateBitmaps(const char *path)
     }
     t << "\\pagestyle{empty}" << endl; 
     t << "\\begin{document}" << endl;
-    int page=0;
-    for (fli.toFirst();(formula=fli.current());++fli)
+    for (int i=0; i<(int)p->formulas.size(); i++)
     {
       QCString resultName;
-      resultName.sprintf("form_%d.png",formula->getId());
+      resultName.sprintf("form_%d.%s",i,format==Format::Vector?"svg":"png");
       // only formulas for which no image exists are generated
       QFileInfo fi(resultName);
       if (!fi.exists())
       {
         // we force a pagebreak after each formula
-        t << formula->getFormulaText() << endl << "\\pagebreak\n\n";
-        pagesToGenerate.append(new int(page));
+        t << p->formulas[i].c_str() << endl << "\\pagebreak\n\n";
+        formulasToGenerate.push_back(i);
       }
       Doxygen::indexList->addImageFile(resultName);
-      page++;
     }
     t << "\\end{document}" << endl;
     f.close();
   }
-  if (pagesToGenerate.count()>0) // there are new formulas
+  if (!formulasToGenerate.empty()) // there are new formulas
   {
     //printf("Running latex...\n");
     //system("latex _formulas.tex </dev/null >/dev/null");
     QCString latexCmd = "latex";
     Portable::sysTimerStart();
-    if (Portable::system(latexCmd,"_formulas.tex")!=0)
+    char args[4096];
+    sprintf(args,"-interaction=batchmode _formulas.tex >%s",Portable::devNull());
+    if (Portable::system(latexCmd,args)!=0)
     {
       err("Problems running latex. Check your installation or look "
           "for typos in _formulas.tex and check _formulas.log!\n");
@@ -127,23 +217,18 @@ void FormulaList::generateBitmaps(const char *path)
     }
     Portable::sysTimerStop();
     //printf("Running dvips...\n");
-    QListIterator<int> pli(pagesToGenerate);
-    int *pagePtr;
     int pageIndex=1;
-    for (;(pagePtr=pli.current());++pli,++pageIndex)
+    for (int pageNum : formulasToGenerate)
     {
-      int pageNum=*pagePtr;
       msg("Generating image form_%d.png for formula\n",pageNum);
-      char dviArgs[4096];
-      char psArgs[4096];
       QCString formBase;
       formBase.sprintf("_form%d",pageNum);
       // run dvips to convert the page with number pageIndex to an
       // postscript file.
-      sprintf(dviArgs,"-q -D 600 -n 1 -p %d -o %s_tmp.ps _formulas.dvi",
+      sprintf(args,"-q -D 600 -n 1 -p %d -o %s_tmp.ps _formulas.dvi",
           pageIndex,formBase.data());
       Portable::sysTimerStart();
-      if (Portable::system("dvips",dviArgs)!=0)
+      if (Portable::system("dvips",args)!=0)
       {
         err("Problems running dvips. Check your installation!\n");
         Portable::sysTimerStop();
@@ -151,179 +236,171 @@ void FormulaList::generateBitmaps(const char *path)
         return;
       }
       Portable::sysTimerStop();
-      // run eps2eps to convert to an encapsulated postscript file with
-      // boundingbox (dvips with -E has some problems here).
-      sprintf(psArgs,"%s_tmp.ps %s.eps",formBase.data(),formBase.data()); 
+
+      // extract the bounding box for the postscript file
+      sprintf(args,"-q -dBATCH -dNOPAUSE -P- -dNOSAFER -sDEVICE=bbox %s_tmp.ps 2>%s_tmp.epsi",
+          formBase.data(),formBase.data());
       Portable::sysTimerStart();
-      if (Portable::system("eps2eps",psArgs)!=0)
+      if (Portable::system(Portable::ghostScriptCommand(),args)!=0)
       {
-        err("Problems running eps2eps. Check your installation!\n");
+        err("Problems running %s. Check your installation!\n",Portable::ghostScriptCommand());
         Portable::sysTimerStop();
         QDir::setCurrent(oldDir);
         return;
       }
       Portable::sysTimerStop();
-      // now we read the generated postscript file to extract the bounding box
-      QFileInfo fi(formBase+".eps");
+
+      // extract the bounding box info from the generate .epsi file
+      int x1=0,y1=0,x2=0,y2=0;
+      QFileInfo fi(formBase+"_tmp.epsi");
       if (fi.exists())
       {
-        QCString eps = fileToString(formBase+".eps");
-        int i=eps.find("%%BoundingBox:");
+        QString eps = fileToString(formBase+"_tmp.epsi");
+        int i = eps.find("%%BoundingBox:");
         if (i!=-1)
         {
           sscanf(eps.data()+i,"%%%%BoundingBox:%d %d %d %d",&x1,&y1,&x2,&y2);
         }
         else
         {
-          err("Couldn't extract bounding box!\n");
+          err("Couldn't extract bounding box from %s_tmp.epsi",formBase.data());
         }
-      } 
-      // next we generate a postscript file which contains the eps
-      // and displays it in the right colors and the right bounding box
-      f.setName(formBase+".ps");
-      if (f.open(IO_WriteOnly))
-      {
-        FTextStream t(&f);
-        t << "1 1 1 setrgbcolor" << endl;  // anti-alias to white background
-        t << "newpath" << endl;
-        t << "-1 -1 moveto" << endl;
-        t << (x2-x1+2) << " -1 lineto" << endl;
-        t << (x2-x1+2) << " " << (y2-y1+2) << " lineto" << endl;
-        t << "-1 " << (y2-y1+2) << " lineto" <<endl;
-        t << "closepath" << endl;
-        t << "fill" << endl;
-        t << -x1 << " " << -y1 << " translate" << endl;
-        t << "0 0 0 setrgbcolor" << endl;
-        t << "(" << formBase << ".eps) run" << endl;
-        f.close();
       }
-      // scale the image so that it is four times larger than needed.
-      // and the sizes are a multiple of four.
-      double scaleFactor = 16.0/3.0; 
+      //printf("Bounding box [%d %d %d %d]\n",x1,y1,x2,y2);
+
+      // convert the corrected EPS to a bitmap
+      double scaleFactor = 1.25;
       int zoomFactor = Config_getInt(FORMULA_FONTSIZE);
       if (zoomFactor<8 || zoomFactor>50) zoomFactor=10;
       scaleFactor *= zoomFactor/10.0;
-      int gx = (((int)((x2-x1)*scaleFactor))+3)&~1;
-      int gy = (((int)((y2-y1)*scaleFactor))+3)&~1;
-      // Then we run ghostscript to convert the postscript to a pixmap
-      // The pixmap is a truecolor image, where only black and white are
-      // used.  
 
-      char gsArgs[4096];
-      sprintf(gsArgs,"-q -g%dx%d -r%dx%d -sDEVICE=ppmraw "
-                    "-sOutputFile=%s.pnm -dNOPAUSE -dBATCH -dNOSAFER %s.ps",
-                    gx,gy,(int)(scaleFactor*72),(int)(scaleFactor*72),
-                    formBase.data(),formBase.data()
-             );
-      Portable::sysTimerStart();
-      if (Portable::system(Portable::ghostScriptCommand(),gsArgs)!=0)
+      int width  = (int)((x2-x1)*scaleFactor+0.5f);
+      int height = (int)((y2-y1)*scaleFactor+0.5f);
+      p->storeDisplaySize(pageNum,width,height);
+
+      if (format==Format::Vector)
       {
-        err("Problem running ghostscript %s %s. Check your installation!\n",Portable::ghostScriptCommand(),gsArgs);
+        // crop the image to its bounding box
+        sprintf(args,"-q -dBATCH -dNOPAUSE -P- -dNOSAFER -sDEVICE=pdfwrite"
+                     " -o %s_tmp.pdf -c \"[/CropBox [%d %d %d %d] /PAGES pdfmark\" -f %s_tmp.ps",
+                     formBase.data(),x1,y1,x2,y2,formBase.data());
+        Portable::sysTimerStart();
+        if (Portable::system(Portable::ghostScriptCommand(),args)!=0)
+        {
+          err("Problems running %s. Check your installation!\n",Portable::ghostScriptCommand());
+          Portable::sysTimerStop();
+          QDir::setCurrent(oldDir);
+          return;
+        }
         Portable::sysTimerStop();
-        QDir::setCurrent(oldDir);
-        return;
+
+        sprintf(args,"%s_tmp.pdf form_%d.svg",formBase.data(),pageNum);
+        Portable::sysTimerStart();
+        if (Portable::system("pdf2svg",args)!=0)
+        {
+          err("Problems running pdf2svg. Check your installation!\n");
+          Portable::sysTimerStop();
+          QDir::setCurrent(oldDir);
+          return;
+        }
+        Portable::sysTimerStop();
+        if (RM_TMP_FILES) thisDir.remove(formBase+"_tmp.pdf");
       }
-      Portable::sysTimerStop();
-      f.setName(formBase+".pnm");
-      uint imageX=0,imageY=0;
-      // we read the generated image again, to obtain the pixel data.
-      if (f.open(IO_ReadOnly))
+      else // format==Format::Bitmap
       {
-        QTextStream t(&f);
-        QCString s;
-        if (!t.eof())
-          s=t.readLine().utf8();
-        if (s.length()<2 || s.left(2)!="P6")
-          err("ghostscript produced an illegal image format!");
-        else
+        // crop the image to its bounding box
+        sprintf(args,"-q -dBATCH -dNOPAUSE -P- -dNOSAFER -sDEVICE=eps2write"
+                     " -o %s_tmp.eps -f %s_tmp.ps",formBase.data(),formBase.data());
+        Portable::sysTimerStart();
+        if (Portable::system(Portable::ghostScriptCommand(),args)!=0)
         {
-          // assume the size is after the first line that does not start with
-          // # excluding the first line of the file.
-          while (!t.eof() && (s=t.readLine().utf8()) && !s.isEmpty() && s.at(0)=='#') { }
-          sscanf(s,"%d %d",&imageX,&imageY);
+          err("Problems running %s. Check your installation!\n",Portable::ghostScriptCommand());
+          Portable::sysTimerStop();
+          QDir::setCurrent(oldDir);
+          return;
         }
-        if (imageX>0 && imageY>0)
+
+        // read back %s_tmp.eps and replace
+        // bounding box values with x1,y1,x2,y2 and remove the HiResBoundingBox
+        QFile epsIn(formBase+"_tmp.eps");
+        QFile epsOut(formBase+"_tmp_corr.eps");
+        if (epsIn.open(IO_ReadOnly) && epsOut.open(IO_WriteOnly))
         {
-          //printf("Converting image...\n");
-          char *data = new char[imageX*imageY*3]; // rgb 8:8:8 format
-          uint i,x,y,ix,iy;
-          f.readBlock(data,imageX*imageY*3);
-          Image srcImage(imageX,imageY),
-                filteredImage(imageX,imageY),
-                dstImage(imageX/4,imageY/4);
-          uchar *ps=srcImage.getData();
-          // convert image to black (1) and white (0) index.
-          for (i=0;i<imageX*imageY;i++) *ps++= (data[i*3]==0 ? 1 : 0);
-          // apply a simple box filter to the image 
-          static int filterMask[]={1,2,1,2,8,2,1,2,1};
-          for (y=0;y<srcImage.getHeight();y++)
+          int maxLineLen=100*1024;
+          while (!epsIn.atEnd())
           {
-            for (x=0;x<srcImage.getWidth();x++)
+            QCString buf(maxLineLen);
+            FTextStream t(&epsOut);
+            int numBytes = epsIn.readLine(buf.rawData(),maxLineLen);
+            if (numBytes>0)
             {
-              int s=0;
-              for (iy=0;iy<2;iy++)
+              buf.resize(numBytes+1);
+              if (buf.startsWith("%%BoundingBox"))
               {
-                for (ix=0;ix<2;ix++)
-                {
-                  s+=srcImage.getPixel(x+ix-1,y+iy-1)*filterMask[iy*3+ix];
-                }
+                t << "%%BoundingBox: " << x1 << " " << y1 << " " << x2 << " " << y2 << endl;
+              }
+              else if (buf.startsWith("%%HiResBoundingBox")) // skip this one
+              {
+              }
+              else
+              {
+                t << buf;
               }
-              filteredImage.setPixel(x,y,s);
-            }
-          }
-          // down-sample the image to 1/16th of the area using 16 gray scale
-          // colors.
-          // TODO: optimize this code.
-          for (y=0;y<dstImage.getHeight();y++)
-          {
-            for (x=0;x<dstImage.getWidth();x++)
-            {
-              int xp=x<<2;
-              int yp=y<<2;
-              int c=filteredImage.getPixel(xp+0,yp+0)+
-                    filteredImage.getPixel(xp+1,yp+0)+
-                    filteredImage.getPixel(xp+2,yp+0)+
-                    filteredImage.getPixel(xp+3,yp+0)+
-                    filteredImage.getPixel(xp+0,yp+1)+
-                    filteredImage.getPixel(xp+1,yp+1)+
-                    filteredImage.getPixel(xp+2,yp+1)+
-                    filteredImage.getPixel(xp+3,yp+1)+
-                    filteredImage.getPixel(xp+0,yp+2)+
-                    filteredImage.getPixel(xp+1,yp+2)+
-                    filteredImage.getPixel(xp+2,yp+2)+
-                    filteredImage.getPixel(xp+3,yp+2)+
-                    filteredImage.getPixel(xp+0,yp+3)+
-                    filteredImage.getPixel(xp+1,yp+3)+
-                    filteredImage.getPixel(xp+2,yp+3)+
-                    filteredImage.getPixel(xp+3,yp+3);
-              // here we scale and clip the color value so the
-              // resulting image has a reasonable contrast
-              dstImage.setPixel(x,y,QMIN(15,(c*15)/(16*10)));
             }
           }
-          // save the result as a bitmap
-          QCString resultName;
-          resultName.sprintf("form_%d.png",pageNum);
-          // the option parameter 1 is used here as a temporary hack
-          // to select the right color palette! 
-          dstImage.save(resultName,1);
-          delete[] data;
+          epsIn.close();
+          epsOut.close();
+        }
+        else
+        {
+          err("Problems correcting the eps files from %s_tmp.eps to %s_tmp_corr.eps\n",
+              formBase.data(),formBase.data());
+          QDir::setCurrent(oldDir);
+          return;
+        }
+
+        if (hd==HighDPI::On) // for high DPI display it looks much better if the
+                             // image resolution is higher than the display resolution
+        {
+          scaleFactor*=2;
+        }
+
+        Portable::sysTimerStop();
+        sprintf(args,"-q -dNOSAFER -dBATCH -dNOPAUSE -dEPSCrop -sDEVICE=pnggray -dGraphicsAlphaBits=4 -dTextAlphaBits=4 "
+            "-r%d -sOutputFile=form_%d.png %s_tmp_corr.eps",(int)(scaleFactor*72),pageNum,formBase.data());
+        Portable::sysTimerStart();
+        if (Portable::system(Portable::ghostScriptCommand(),args)!=0)
+        {
+          err("Problems running %s. Check your installation!\n",Portable::ghostScriptCommand());
+          Portable::sysTimerStop();
+          QDir::setCurrent(oldDir);
+          return;
         }
-        f.close();
-      } 
+        Portable::sysTimerStop();
+
+        thisDir.remove(formBase+"_tmp.eps");
+        thisDir.remove(formBase+"_tmp_corr.eps");
+      }
+
       // remove intermediate image files
-      thisDir.remove(formBase+"_tmp.ps");
-      thisDir.remove(formBase+".eps");
-      thisDir.remove(formBase+".pnm");
-      thisDir.remove(formBase+".ps");
+      if (RM_TMP_FILES)
+      {
+        thisDir.remove(formBase+"_tmp.ps");
+        thisDir.remove(formBase+"_tmp.epsi");
+      }
+      pageIndex++;
     }
     // remove intermediate files produced by latex
-    thisDir.remove("_formulas.dvi");
-    if (!formulaError) thisDir.remove("_formulas.log"); // keep file in case of errors
-    thisDir.remove("_formulas.aux");
+    if (RM_TMP_FILES)
+    {
+      thisDir.remove("_formulas.dvi");
+      if (!formulaError) thisDir.remove("_formulas.log"); // keep file in case of errors
+      thisDir.remove("_formulas.aux");
+    }
   }
   // remove the latex file itself
-  if (!formulaError) thisDir.remove("_formulas.tex");
+  if (RM_TMP_FILES && !formulaError) thisDir.remove("_formulas.tex");
+
   // write/update the formula repository so we know what text the 
   // generated images represent (we use this next time to avoid regeneration
   // of the images, and to avoid forcing the user to delete all images in order
@@ -332,9 +409,15 @@ void FormulaList::generateBitmaps(const char *path)
   if (f.open(IO_WriteOnly))
   {
     FTextStream t(&f);
-    for (fli.toFirst();(formula=fli.current());++fli)
+    for (int i=0; i<(int)p->formulas.size(); i++)
     {
-      t << "\\_form#" << formula->getId() << ":" << formula->getFormulaText() << endl;
+      DisplaySize size = p->getDisplaySize(i);
+      t << "\\_form#" << i;
+      if (size.width!=-1 && size.height!=-1)
+      {
+        t << "=" << size.width << "x" << size.height;
+      }
+      t << ":" << p->formulas[i].c_str() << endl;
     }
     f.close();
   }
@@ -342,15 +425,43 @@ void FormulaList::generateBitmaps(const char *path)
   QDir::setCurrent(oldDir);
 }
 
+void FormulaManager::clear()
+{
+  p->formulas.clear();
+  p->formulaMap.clear();
+}
+
+int FormulaManager::addFormula(const char *formulaText)
+{
+  std::string key = std::string(formulaText);
+  auto it = p->formulaMap.find(key);
+  if (it!=p->formulaMap.end()) // already stored
+  {
+    return it->second;
+  }
+  // store new formula
+  int id = p->formulas.size();
+  p->formulaMap.insert(std::pair<std::string,int>(key,id));
+  p->formulas.push_back(key);
+  return id;
+}
+
+QCString FormulaManager::findFormula(int formulaId) const
+{
+  if (formulaId>=0 && formulaId<(int)p->formulas.size())
+  {
+    return p->formulas[formulaId].c_str();
+  }
+  return QCString();
+}
+
+bool FormulaManager::hasFormulas() const
+{
+  return !p->formulas.empty();
+}
 
-#ifdef FORMULA_TEST
-int main()
+FormulaManager::DisplaySize FormulaManager::displaySize(int formulaId) const
 {
-  FormulaList fl;
-  fl.append(new Formula("$x^2$"));
-  fl.append(new Formula("$y^2$"));
-  fl.append(new Formula("$\\sqrt{x_0^2+x_1^2+x_2^2}$"));
-  fl.generateBitmaps("dest");
-  return 0;
+  return p->getDisplaySize(formulaId);
 }
-#endif
+
diff --git a/src/formula.h b/src/formula.h
index 422030c..4bd90af 100644
--- a/src/formula.h
+++ b/src/formula.h
@@ -18,45 +18,33 @@
 #ifndef FORMULA_H
 #define FORMULA_H
 
-#include <qlist.h>
-#include <qdict.h>
+#include <memory>
+#include <qcstring.h>
 
-/** Class representing a formula in the output. */
-class Formula
+/*! Manager class to handle formulas */
+class FormulaManager
 {
   public:
-    Formula(const char *text);
-   ~Formula();
-    int getId();
-    QCString getFormulaText() const { return form; }
-    
+    struct DisplaySize
+    {
+      DisplaySize(int w,int h) : width(w), height(h) {}
+      int width;
+      int height;
+    };
+    enum class Format { Bitmap, Vector };
+    enum class HighDPI { On, Off };
+    static FormulaManager &instance();
+    void readFormulas(const char *dir,bool doCompare=false);
+    void clear();
+    int addFormula(const char *formulaText);
+    void generateImages(const char *outputDir,Format format,HighDPI hd = HighDPI::Off) const;
+    QCString findFormula(int formulaId) const;
+    bool hasFormulas() const;
+    DisplaySize displaySize(int formulaId) const;
   private:
-    int number;
-    QCString form;
-};
-
-/** A list of Formula objects. */
-class FormulaList : public QList<Formula>
-{
-  public:
-    void generateBitmaps(const char *path);
-};
-
-/** Iterator for Formula objects in a FormulaList. */
-class FormulaListIterator : public QListIterator<Formula>
-{
-  public:
-    FormulaListIterator(const FormulaList &l) : 
-      QListIterator<Formula>(l) {}
-};
-
-/** Unsorted dictionary of Formula objects. */
-class FormulaDict : public QDict<Formula>
-{
-  public:
-    FormulaDict(uint size) : 
-      QDict<Formula>(size) {}
-   ~FormulaDict() {}
+    FormulaManager();
+    struct Private;
+    std::unique_ptr<Private> p;
 };
 
 #endif
diff --git a/src/htmldocvisitor.cpp b/src/htmldocvisitor.cpp
index aff838e..5c17198 100644
--- a/src/htmldocvisitor.cpp
+++ b/src/htmldocvisitor.cpp
@@ -36,6 +36,7 @@
 #include "htmlentity.h"
 #include "emoji.h"
 #include "plantuml.h"
+#include "formula.h"
 
 static const int NUM_HTML_LIST_TYPES = 4;
 static const char types[][NUM_HTML_LIST_TYPES] = {"1", "a", "i", "A"};
@@ -888,10 +889,25 @@ void HtmlDocVisitor::visit(DocFormula *f)
     m_t << "\" alt=\"";
     filterQuotedCdataAttr(f->text());
     m_t << "\"";
-    // TODO: cache image dimensions on formula generation and give height/width
-    // for faster preloading and better rendering of the page
-    m_t << " src=\"" << f->relPath() << f->name() << ".png\"/>";
-
+    m_t << " src=\"" << f->relPath() << f->name();
+    if (Config_getEnum(HTML_FORMULA_FORMAT)=="SVG")
+    {
+      m_t << ".svg";
+    }
+    else
+    {
+      m_t << ".png";
+    }
+    FormulaManager::DisplaySize size = FormulaManager::instance().displaySize(f->id());
+    if (size.width!=-1)
+    {
+      m_t << "\" width=\"" << size.width;
+    }
+    if (size.height!=-1)
+    {
+      m_t << "\" height=\"" << size.height;
+    }
+    m_t << "\"/>";
   }
   if (bDisplay)
   {
diff --git a/src/portable.cpp b/src/portable.cpp
index 403b0ea..8ceb7d6 100644
--- a/src/portable.cpp
+++ b/src/portable.cpp
@@ -567,3 +567,12 @@ const char *Portable::strnstr(const char *haystack, const char *needle, size_t h
   }
   return 0;
 }
+
+const char *Portable::devNull()
+{
+#if defined(_WIN32) && !defined(__CYGWIN__)
+  return "NUL";
+#else
+  return "/dev/null";
+#endif
+}
diff --git a/src/portable.h b/src/portable.h
index 771108e..956ae41 100644
--- a/src/portable.h
+++ b/src/portable.h
@@ -43,6 +43,7 @@ namespace Portable
   void           correct_path(void);
   void           setShortDir(void);
   const char *   strnstr(const char *haystack, const char *needle, size_t haystack_len);
+  const char *   devNull();
 }
 
 
-- 
cgit v0.12