src/frontends/qt/LaTeXHighlighter.cpp

   1 /**
   2  * \file LaTeXHighlighter.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Bo Peng
   7  *
   8  * Full author contact details are available in file CREDITS.
   9  */
  10
  11 #include <config.h>
  12
  13 #include "LaTeXHighlighter.h"
  14 #include "qt_helpers.h"
  15
  16 #include <QString>
  17 #include <QTextDocument>
  18
  19 namespace lyx {
  20 namespace frontend {
  21
  22
  23 LaTeXHighlighter::LaTeXHighlighter(QTextDocument * parent, bool at_letter)
  24         : QSyntaxHighlighter(parent), at_letter_(at_letter)
  25 {
  26         auto blend = [](QColor color1, QColor color2) {
  27                 int r = 0.5 * (color1.red() + color2.red());
  28                 int g = 0.5 * (color1.green() + color2.green());
  29                 int b = 0.5 * (color1.blue() + color2.blue());
  30                 return QColor(r, g, b);
  31         };
  32         QPalette palette = QPalette();
  33         QColor text_color = palette.color(QPalette::Active, QPalette::Text);
  34         keywordFormat.setForeground(blend(Qt::blue, text_color));
  35         keywordFormat.setFontWeight(QFont::Bold);
  36         commentFormat.setForeground(palette.color(QPalette::Disabled,
  37                                                   QPalette::Text));
  38         mathFormat.setForeground(blend(Qt::red, text_color));
  39         warningFormat.setForeground(Qt::red);
  40         warningFormat.setFontWeight(QFont::Bold);
  41 }
  42
  43
  44 void LaTeXHighlighter::highlightBlock(QString const & text)
  45 {
  46         // $ $
  47         static const QRegExp exprMath("\\$[^\\$]*\\$");
  48         int index = exprMath.indexIn(text);
  49         while (index >= 0) {
  50                 int length = exprMath.matchedLength();
  51                 setFormat(index, length, mathFormat);
  52                 index = exprMath.indexIn(text, index + length);
  53         }
  54         // [ ]
  55         static const QRegExp exprStartDispMath("(\\\\\\[|"
  56                 "\\\\begin\\{equation\\**\\}|"
  57                 "\\\\begin\\{eqnarray\\**\\}|"
  58                 "\\\\begin\\{align(ed|at)*\\**\\}|"
  59                 "\\\\begin\\{flalign\\**\\}|"
  60                 "\\\\begin\\{gather\\**\\}|"
  61                 "\\\\begin\\{multline\\**\\}|"
  62                 "\\\\begin\\{array\\**\\}|"
  63                 "\\\\begin\\{cases\\**\\}"
  64                 ")");
  65         static const QRegExp exprEndDispMath("(\\\\\\]|"
  66                 "\\\\end\\{equation\\**\\}|"
  67                 "\\\\end\\{eqnarray\\**\\}|"
  68                 "\\\\end\\{align(ed|at)*\\**\\}|"
  69                 "\\\\end\\{flalign\\**\\}|"
  70                 "\\\\end\\{gather\\**\\}|"
  71                 "\\\\end\\{multline\\**\\}|"
  72                 "\\\\end\\{array\\**\\}|"
  73                 "\\\\end\\{cases\\**\\}"
  74                 ")");
  75         int startIndex = 0;
  76         // if previous block was in 'disp math'
  77         // start search from 0 (for end disp math)
  78         // otherwise, start search from 'begin disp math'
  79         if (previousBlockState() != 1)
  80                 startIndex = exprStartDispMath.indexIn(text);
  81         while (startIndex >= 0) {
  82                 int endIndex = exprEndDispMath.indexIn(text, startIndex);
  83                 int length;
  84                 if (endIndex == -1) {
  85                         setCurrentBlockState(1);
  86                         length = text.length() - startIndex;
  87                 } else {
  88                         length = endIndex - startIndex + exprEndDispMath.matchedLength();
  89                 }
  90                 setFormat(startIndex, length, mathFormat);
  91                 startIndex = exprStartDispMath.indexIn(text, startIndex + length);
  92         }
  93         // \whatever
  94         static const QRegExp exprKeywordAtOther("\\\\[A-Za-z]+");
  95         // \wh@tever
  96         static const QRegExp exprKeywordAtLetter("\\\\[A-Za-z@]+");
  97         QRegExp const & exprKeyword = at_letter_ ? exprKeywordAtLetter
  98                                                  : exprKeywordAtOther;
  99         index = exprKeyword.indexIn(text);
 100         while (index >= 0) {
 101                 int length = exprKeyword.matchedLength();
 102                 setFormat(index, length, keywordFormat);
 103                 index = exprKeyword.indexIn(text, index + length);
 104         }
 105         // %comment
 106         // Treat a line as a comment starting at a percent sign
 107         // * that is the first character in a line
 108         // * that is preceded by
 109         // ** an even number of backslashes
 110         // ** any character other than a backslash
 111         QRegExp exprComment("(?:^|[^\\\\])(?:\\\\\\\\)*(%).*$");
 112         exprComment.indexIn(text);
 113         index = exprComment.pos(1);
 114         while (index >= 0) {
 115                 int const length = exprComment.matchedLength()
 116                                  - (index - exprComment.pos(0));
 117                 setFormat(index, length, commentFormat);
 118                 exprComment.indexIn(text, index + length);
 119                 index = exprComment.pos(1);
 120         }
 121         // <LyX Warning: ...>
 122         QString lyxwarn = qt_("LyX Warning: ");
 123         QRegExp exprWarning("<" + lyxwarn + "[^<]*>");
 124         index = exprWarning.indexIn(text);
 125         while (index >= 0) {
 126                 int length = exprWarning.matchedLength();
 127                 setFormat(index, length, warningFormat);
 128                 index = exprWarning.indexIn(text, index + length);
 129         }
 130 }
 131
 132 } // namespace frontend
 133 } // namespace lyx