Add LatexRenderer class

CMakeLists.txt

@@ -152,6 +152,7 @@ set(okularpart_SRCS
    ui/formwidgets.cpp
    ui/guiutils.cpp
    ui/ktreeviewsearchline.cpp
+   ui/latexrenderer.cpp
    ui/minibar.cpp
    ui/pageitemdelegate.cpp
    ui/pagepainter.cpp

ui/latexrenderer.cpp

@@ -0,0 +1,195 @@
+/***************************************************************************
+ *   Copyright (C) 2004 by Duncan Mac-Vicar Prett <duncan@kde.org>         *
+ *   Copyright (C) 2004-2005 by Olivier Goffart <ogoffart@kde.org>         *
+ *   Copyright (C) 2011 by Niels Ole Salscheider                           *
+ *                         <niels_ole@salscheider-online.de>               *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ ***************************************************************************/
+
+#include "latexrenderer.h"
+
+#include <QtGui>
+#include <kstandarddirs.h>
+#include <kprocess.h>
+#include <ktemporaryfile.h>
+
+namespace GuiUtils
+{
+
+LatexRenderer::LatexRenderer()
+{
+    m_filelist = new QVector<QString>();
+}
+
+LatexRenderer::~LatexRenderer()
+{
+    while (!m_filelist->isEmpty())
+    {
+        QFile::remove(m_filelist->last());
+        m_filelist->pop_back();
+    }
+
+    delete m_filelist;
+}
+
+
+LatexRenderer::Error LatexRenderer::renderLatexInHtml( QString& html, const QColor& textColor, int fontSize, int resolution, QString& latexOutput )
+{
+    if( !html.contains("$$"))
+        return NoError;
+
+    // this searches for $$formula$$ 
+    QRegExp rg("\\$\\$.+\\$\\$");
+    rg.setMinimal(true);
+
+    int pos = 0;
+
+    QMap<QString, QString> replaceMap;
+    while (pos >= 0 && pos < html.length())
+    {
+        pos = rg.indexIn(html, pos);
+
+        if (pos >= 0 )
+        {
+            const QString match = rg.cap(0);
+            pos += rg.matchedLength();
+
+            QString formul=match;
+            // first remove the $$ delimiters on start and end
+            formul.remove("$$");
+            // then trim the result, so we can skip totally empty/whitespace-only formulas
+            formul = formul.trimmed();
+            if (formul.isEmpty() || !securityCheck(formul))
+                continue;
+
+            QString fileName;
+            Error returnCode = handleLatex(fileName, formul, textColor, fontSize, resolution, latexOutput);
+            if (returnCode != NoError)
+                return returnCode;
+
+            replaceMap[match] = fileName;
+        }
+    }
+    
+    if(replaceMap.isEmpty()) //we haven't found any LaTeX strings
+        return NoError;
+    
+    int imagePxWidth,imagePxHeight;
+    for (QMap<QString,QString>::ConstIterator it = replaceMap.constBegin(); it != replaceMap.constEnd(); ++it)
+    {
+        QImage theImage(*it);
+        if(theImage.isNull())
+            continue;
+        imagePxWidth = theImage.width();
+        imagePxHeight = theImage.height();
+        QString escapedLATEX=Qt::escape(it.key()).replace('\"',"&quot;");  //we need  the escape quotes because that string will be in a title="" argument, but not the \n
+        html.replace(Qt::escape(it.key()), " <img width=\"" + QString::number(imagePxWidth) + "\" height=\"" + QString::number(imagePxHeight) + "\" align=\"middle\" src=\"" + (*it) + "\"  alt=\"" + escapedLATEX +"\" title=\"" + escapedLATEX +"\"  /> ");
+    }
+    return NoError;
+}
+
+bool LatexRenderer::mightContainLatex (const QString& text)
+{
+    if( !text.contains("$$"))
+        return false;
+
+    // this searches for $$formula$$ 
+    QRegExp rg("\\$\\$.+\\$\\$");
+    rg.setMinimal(true);
+    if( rg.lastIndexIn(text) == -1 )
+        return false;
+
+    return true;
+}
+
+LatexRenderer::Error LatexRenderer::handleLatex( QString& fileName, const QString& latexFormula, const QColor& textColor, int fontSize, int resolution, QString& latexOutput )
+{
+    KProcess latexProc;
+    KProcess dvipngProc;
+
+    KTemporaryFile *tempFile = new KTemporaryFile();
+    tempFile->setPrefix("kdelatex-");
+    tempFile->setSuffix(".tex");
+    tempFile->open();
+    QString tempFileName = tempFile->fileName();
+    QFileInfo *tempFileInfo = new QFileInfo(tempFileName);
+    QString tempFileNameNS = tempFileInfo->absolutePath() + QDir::separator() + tempFileInfo->baseName();
+    QString tempFilePath = tempFileInfo->absolutePath();
+    delete tempFileInfo;
+    QTextStream tempStream(tempFile);
+
+    tempStream << "\
+\\documentclass[" << fontSize << "pt]{article} \
+\\usepackage{color} \
+\\usepackage{amsmath,latexsym,amsfonts,amssymb,ulem} \
+\\pagestyle{empty} \
+\\begin{document} \
+{\\color[rgb]{" << textColor.redF() << "," << textColor.greenF() << "," << textColor.blueF() << "} \
+\\begin{eqnarray*} \
+" << latexFormula << " \
+\\end{eqnarray*}} \
+\\end{document}";
+
+    tempFile->close();
+    QString latexExecutable = KStandardDirs::findExe("latex");
+    if (latexExecutable.isEmpty())
+    {
+        qDebug() << "Could not find latex!";
+        delete tempFile;
+        fileName = QString("");
+        return LatexNotFound;
+    }
+    latexProc << latexExecutable << "-interaction=nonstopmode" << "-halt-on-error" << QString("-output-directory=%1").arg(tempFilePath) << tempFile->fileName();
+    latexProc.setOutputChannelMode( KProcess::MergedChannels );
+    latexProc.execute();
+    latexOutput = latexProc.readAll();
+    tempFile->remove();
+
+    QFile::remove(tempFileNameNS + QString(".log"));
+    QFile::remove(tempFileNameNS + QString(".aux"));
+    delete tempFile;
+
+    if (!QFile::exists(tempFileNameNS + QString(".dvi")))
+    {
+        fileName = QString("");
+        return LatexFailed;
+    }
+
+    QString dvipngExecutable = KStandardDirs::findExe("dvipng");
+    if (dvipngExecutable.isEmpty())
+    {
+        qDebug() << "Could not find dvipng!";
+        fileName = QString("");
+        return DvipngNotFound;
+    }
+
+    dvipngProc << dvipngExecutable << QString("-o%1").arg(tempFileNameNS + QString(".png")) << "-Ttight" << "-bgTransparent" << QString("-D %1").arg(resolution) << QString("%1").arg(tempFileNameNS + QString(".dvi"));
+    dvipngProc.setOutputChannelMode( KProcess::MergedChannels );
+    dvipngProc.execute();
+
+    QFile::remove(tempFileNameNS + QString(".dvi"));
+    
+    if (!QFile::exists(tempFileNameNS + QString(".png")))
+    {
+        fileName = QString("");
+        return DvipngFailed;
+    }
+
+    m_filelist->append(tempFileNameNS + QString(".png"));    
+    fileName = tempFileNameNS + QString(".png");
+    return NoError;
+}
+
+bool LatexRenderer::securityCheck( const QString &latexFormula )
+{
+    return !latexFormula.contains(QRegExp("\\\\(def|let|futurelet|newcommand|renewcomment|else|fi|write|input|include"
+    "|chardef|catcode|makeatletter|noexpand|toksdef|every|errhelp|errorstopmode|scrollmode|nonstopmode|batchmode"
+    "|read|csname|newhelp|relax|afterground|afterassignment|expandafter|noexpand|special|command|loop|repeat|toks"
+    "|output|line|mathcode|name|item|section|mbox|DeclareRobustCommand)[^a-zA-Z]"));
+}
+
+}

ui/latexrenderer.h

@@ -0,0 +1,51 @@
+/***************************************************************************
+ *   Copyright (C) 2004 by Duncan Mac-Vicar Prett <duncan@kde.org>         *
+ *   Copyright (C) 2004-2005 by Olivier Goffart <ogoffart@kde.org>         *
+ *   Copyright (C) 2011 by Niels Ole Salscheider                           *
+ *                         <niels_ole@salscheider-online.de>               *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ ***************************************************************************/
+
+#ifndef LATEXRENDERER_H
+#define LATEXRENDERER_H
+#include "guiutils.h"
+
+#include <QVector>
+class QString;
+class QColor;
+
+namespace GuiUtils
+{
+
+class LatexRenderer
+{
+
+public:
+    enum Error {
+        NoError,
+        LatexNotFound,
+        DvipngNotFound,
+        LatexFailed,
+        DvipngFailed
+    };
+
+    LatexRenderer();
+    virtual ~LatexRenderer();
+
+    Error renderLatexInHtml( QString& html, const QColor &textColor, int fontSize, int resolution, QString &latexOutput );
+    static bool mightContainLatex ( const QString& text );
+
+private:
+    Error handleLatex( QString &fileName, const QString &latexFormula, const QColor &textColor, int fontSize, int resolution, QString &latexOutput );
+    static bool securityCheck( const QString &latexFormula );
+
+    QVector<QString> *m_filelist;
+};
+
+}
+
+#endif // LATEXRENDERER_H