I changed my code because it seems impossible for me.
Now I created table using QTextTable.

Qt Code: 
  1. QTextDocument *document=new QTextDocument(this);
  2. QTextCursor cursor(document);
  3. cursor.movePosition(QTextCursor::Start);
  4.  
  5. QTextTableCellFormat cellFormat;
  6. cellFormat.setLeftPadding(7);
  7. cellFormat.setRightPadding(7);
  8.  
  9. QBrush blackBrush(Qt::SolidPattern);
  10. QTextTableFormat tableFormat;
  11. tableFormat.setAlignment(Qt::AlignLeft);
  12. tableFormat.setBorderBrush(blackBrush);
  13. tableFormat.setBorder(.5);
  14. tableFormat.setCellSpacing(0);
  15. tableFormat.setBorderStyle(QTextFrameFormat::BorderStyle_Solid);
  16. tableFormat.setAlignment(Qt::AlignLeft);
  17. tableFormat.setWidth(QTextLength(QTextLength::PercentageLength, 100));
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I noticed setColumnWidthConstraints function for column width. But cell width changes according to text.
Is there a way to get cell width in QTextTable?