codeeditor.h

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#ifndef CODEEDITOR_H
#define CODEEDITOR_H
 
#include <QPlainTextEdit>
 
QT_BEGIN_NAMESPACE
class QPaintEvent;
class QResizeEvent;
class QSize;
class QWidget;
QT_END_NAMESPACE
 
class LineNumberArea;
 
 
class CodeEditor : public QPlainTextEdit {
  Q_OBJECT
 
public:
  CodeEditor(QWidget* parent = nullptr);
 
  void lineNumberAreaPaintEvent(QPaintEvent* event);
  int lineNumberAreaWidth();
  QString getText() const { return toPlainText(); }
  void loadText(const QString& text);
 
protected:
  void resizeEvent(QResizeEvent* event) override;
 
private slots:
  void updateLineNumberAreaWidth(int newBlockCount);
  void highlightCurrentLine();
  void updateLineNumberArea(const QRect& rect, int dy);
 
private:
  QWidget* lineNumberArea;
};
 
 
class LineNumberArea : public QWidget {
public:
  LineNumberArea(CodeEditor* editor) : QWidget(editor), codeEditor(editor) {}
 
  QSize sizeHint() const override {
    return QSize(codeEditor->lineNumberAreaWidth(), 0);
  }
 
protected:
  void paintEvent(QPaintEvent* event) override {
    codeEditor->lineNumberAreaPaintEvent(event);
  }
 
private:
  CodeEditor* codeEditor;
};
 
 
#endif