Precision of QFontMetrics

Dummie1138

Hi. I have the following two QLabels.

The top one has been resized using QFontMetrics, like so:

        QFontMetrics fm(QFont("DejaVu Sans", 12));    
        //Line that stores QFont's size   
        QString labelStyle = "color: navy; font: 12px \"DejaVu Sans\"; background: transparent; alignment: center";    
    
        //Build the main line.    
        QFrame *frontLine = new QFrame(this);    
        frontLine->setStyleSheet("border: 10px solid #000080;");    
        frontLine->setGeometry(X, Y, SPLITLINEWIDTH, SPLITLINEHEIGHT);    
        QString labelText = "Initial Temp";    
    
        QLabel *iniTemp = new QLabel(this);    
        iniTemp->setText(labelText);
        iniTemp->setStyleSheet(labelStyle);    
        iniTemp->resize(fm.horizontalAdvance(labelText), LABELHEIGHT);    
        //iniTemp->setFrameShadow(QFrame::Raised);    
        iniTemp->setFrameStyle(QFrame::Panel);    
        iniTemp->setLineWidth(2);
        qDebug() << (iniTemp->width());
        iniTemp->move(X - (iniTemp->width())/2, Y+SPLITLINEHEIGHT+LABELDISTANCE);

The bottom one has not been altered.

    QFontMetrics fm(QFont("DejaVu Sans", 12));
    //Line that stores QFont's size
    QString labelStyle = "color: navy; font: 12px \"DejaVu Sans\"; background: transparent; alignment: center";

    //Build the main line.
    QFrame *frontLine = new QFrame(this);
    frontLine->setStyleSheet("border: 10px solid #000080;");
    frontLine->setGeometry(X, Y, SPLITLINEWIDTH, SPLITLINEHEIGHT);
    QString labelText = "Initial Temp";

    QLabel *iniTemp = new QLabel(this);
    iniTemp->setText(labelText);
    iniTemp->setStyleSheet(labelStyle);
    //iniTemp->resize(fm.horizontalAdvance(labelText), LABELHEIGHT);
    //iniTemp->setFrameShadow(QFrame::Raised);
    iniTemp->setFrameStyle(QFrame::Panel);
    iniTemp->setLineWidth(2);
    qDebug() << (iniTemp->width());
    iniTemp->move(X - (iniTemp->width())/2, Y+SPLITLINEHEIGHT+LABELDISTANCE);

How precise is QFontMetrics ususally? I wanna know this because I believe my fonts are correctly labelled unless I've misunderstood something. Please let me know if more information is required.

mrjj

@Dummie1138

Hi
Well in that case it should be pretty much on spot. At least in win 7/10.

Do note that sometimes mixing Stylesheets and Fonts might give surprises. :)

mrjj

Hi
Normally QFontMetrics is pretty precise, and horizontalAdvance even more so than the old Width function but
it also depends on the OS.

Dummie1138

@mrjj Thank you for your response. I am currently operating on Windows 10, is that enough additional information?

mrjj

@Dummie1138

Hi
Well in that case it should be pretty much on spot. At least in win 7/10.

Do note that sometimes mixing Stylesheets and Fonts might give surprises. :)

Dummie1138

@mrjj I see, thanks. In that case, what are some other ways I can control the font size of the text in QLabel? I haven't been able to find any within the QLabel documentation.

mpergand

@Dummie1138 said in Precision of QFontMetrics:

what are some other ways I can control the font size of the text in QLabel?

    auto label=new QLabel("Hello Wolrd");
    auto font=label->font();    // default font
    font.setPointSize(font.pointSize()+2);
    label->setFont(font);
    label->show();