Add new file

codeeditor.h

+#ifndef CODEEDITOR_H
+#define CODEEDITOR_H
+
+#include <QWidget>
+#include <QPlainTextEdit>
+
+class CodeEditor : public QPlainTextEdit
+{
+    Q_OBJECT
+public:
+   CodeEditor(QWidget *parent = 0);
+
+   void lineNumberAreaPaintEvent(QPaintEvent* event);
+   int lineNumberAreaWidth();
+
+protected:
+   void resizeEvent(QResizeEvent* event) override;
+
+private slots:
+   void updateLineNumberAreaWidth(int newBlockCount);
+   void highlightCurrentLine();
+   void updateLineNumberArea(const QRect& rect, int dy);
+
+private:
+   QWidget *lineNumberArea;
+};
+
+#endif // CODEEDITOR_H
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