QT textedit宽度自适应内容

 QTextDocument *document = m_pTextEditMessage->document();
    int dEditWidth = 450;
    document->adjustSize();
    double dHeight = document->size().height() + 1;
    double dWidth = document->size().width()+1;
    document->documentLayout();
    QTextBlock textBlock = document->begin();
    int lineCount = textBlock.layout()->lineCount();
    if (dWidth * lineCount < dEditWidth)
    {
        m_pTextEditMessage->setMinimumWidth(dWidth * lineCount);
        m_pTextEditMessage->setMaximumWidth(dWidth * lineCount);
        document->setTextWidth(dWidth * lineCount);
    }
    else
    {
      m_pTextEditMessage->setMinimumWidth(dEditWidth);
      m_pTextEditMessage->setMaximumWidth(dEditWidth);
      document->setTextWidth(dEditWidth);
    }