htmlhighlighter.h

#ifndef HTMLHIGHLIGHTER_H
#define HTMLHIGHLIGHTER_H

#include <QSyntaxHighlighter>

class HTMLHighlighter : public QSyntaxHighlighter {
    Q_OBJECT

public:
    explicit HTMLHighlighter(QTextDocument* parent = nullptr);

protected:
    void highlightBlock(const QString& text) Q_DECL_OVERRIDE;

private:
    // Status highlighting, which is a text box at the time of its closure
    enum States {
        None,
        Tag,
        Comment,
        Quote
    };

    struct HighlightingRule {
        QRegExp pattern;
        QTextCharFormat format;
    };
    QVector<HighlightingRule> m_startTagRules;    // Formatting rules for opening tag
    QVector<HighlightingRule> m_endTagRules;      // Formatting rules for closing tags

    QRegExp m_openTag;                            // opening tag symbol - "<"
    QRegExp m_closeTag;                           // closing symbol tag - ">"
    QTextCharFormat m_edgeTagFormat;              // character formatting of openTag and closeTag
    QTextCharFormat m_insideTagFormat;            // Formatting text inside the tag

    QRegExp m_commentStartExpression;             // Regular expression of start comment
    QRegExp m_commentEndExpression;               // Redular expression of end comment
    QTextCharFormat m_multiLineCommentFormat;     // Format text inside a comment

    QRegExp m_quotes;                             // Regular Expression for text in quotes inside the tag
    QTextCharFormat m_quotationFormat;            // Formatting text in quotes inside the tag
    QTextCharFormat m_tagsFormat;                 // Formatting tags themselves
};

#endif // HTMLHIGHLIGHTER_H