Setting font to QLabel failled

[H_V_]

Hi,
I have a widget with a QLabel and a QLineEdit and I want to be able to modify the font of the QLineEdit without affecting the QLabel font. So I reimplemented the setFont of the widget. I've first try to only apply the new font to the line edit, but if I don't call the base class implementation (QWidget::setFont()) it bugs and nothing is displayed (neither QLabel, neither QLineEdit).
So I've change to call the base class implementation in my implementation, which makes both QLineEdit and QLabel font change.
So I saved the QLabel original font before and reapply it after... It does'nt work neither. But if I specify a static font it works.
Code exemple:

class MyWidget: public QWidget
{
  virtual void setFont(const QFont& font);
private:
  QLineEdit* lineedit;
  QLabel* label;
}

first case:

void MyWidget::setFont(const QFont& newFont)
{
   lineedit->setFont(newFont);
}//nothing is displayed

second case:

void MyWidget::setFont(const QFont& newFont)
{
   QFont f = label.font();                //storing label font
   QWidget::setFont(font);           //applying new font to the whole widget
   label->setFont(f);                      //applying back its original font to label
}//label font is set to newFont and not to f

third case:

void MyWidget::setFont(const QFont& newFont)
{
   QFont f("Times", 8);                   //creating a local variable font
   QWidget::setFont(font);           //applying new font to the whole widget
   label->setFont(f);                      //applying the local font to label
}//label font is set to  f

this is working in the third case, but I would like to keep the original font of label and not code it in a static way in case the general style of the application change.
Any idea?

[VRonin]

You overcomplicated the issue a lot. just call lineedit->setStyleSheet("font: bold italic large "Times New Roman");

[J.Hilk]

@VRonin said in Setting font to QLabel failled:

You overcomplicated the issue a lot. just call lineedit->setStyleSheet("font: bold italic large "Times New Roman");

I personally am not a fan of setting fonts via stylesheet.

For example, what if you want an option to change the font size in your app via a QSpinbox, so the elderly can read your texts too :-)

You have to create a StyleSheet as a QString, insert the new fontsize into it, and apply it to all effected Objects/Widgets.

Or am I wrong here?

[SGaist]

Hi and welcome to devnet,

Just a side note, the setFont method is not virtual so your code is hiding the base class implementation thus you won't have the results you expect.

[joeQ]

@H_V_ Just In case, my customize function name first character is capitalized. like Class::SetFont(...). qt inner function Class::setFont(...);

[H_V_]

@VRonin How can i set a stylesheet that depend on a font that is choose by the user? Because your solution seems a bit static to me...

[H_V_]

@SGaist I agree, that's why I call the QWidget::setFont

[VRonin]

How can i set a stylesheet that depend on a font that is choose by the user?

#include <QStringBuilder>
    QString fontStyleString(const QFont& fnt){
        const QString baseStr= QStringLiteral("font-family: \"") % fnt.family()
                % QStringLiteral("\";font-weight: ") % (fnt.bold() ? QStringLiteral("bold") : QStringLiteral("normal"))
                 % QStringLiteral(";font-size: ") % QString::number(fnt.pointSizeF(),'f') % "pt"
                % QStringLiteral(";font-style: ");
        switch (fnt.style()){
        case QFont::StyleItalic:
            return baseStr % QStringLiteral("italic");
        case QFont::StyleOblique:
            return baseStr % QStringLiteral("oblique");
        default:
            return baseStr % QStringLiteral("normal");
        }
    }

[H_V_]

@VRonin Thanks, it works perfectly.
But I'm a bit curious on why my method works with the local variable and not with the stored value. If someone has an explaination I would be grateful...

[VRonin]

@H_V_ said in Setting font to QLabel failled:

But I'm a bit curious on why my method works with the local variable and not with the stored value. If someone has an explaination I would be grateful...

strange indeed. funnily enough this works:

const QString f = label->font().toString();                //storing label font
   QWidget::setFont(font);           //applying new font to the whole widget
QFont tmpFont;
tmpFont.fromString(f);
   label->setFont(tmpFont);  

[H_V_]

Ok, I'm so sorry guys, I think I was clearly not awake enough.
After more investigation, it appears that the first described case works perfectly when you don't forget to clean your project :-s :

void MyWidget::setFont(const QFont& newFont)
{
lineedit->setFont(newFont);
}

So sorry for wasting your time and thanks a lot for all your replies

[H_V_]

@VRonin said in Setting font to QLabel failled:

@H_V_ said in Setting font to QLabel failled:

But I'm a bit curious on why my method works with the local variable and not with the stored value. If someone has an explaination I would be grateful...

strange indeed. funnily enough this works:

const QString f = label->font().toString();                //storing label font
   QWidget::setFont(font);           //applying new font to the whole widget
QFont tmpFont;
tmpFont.fromString(f);
   label->setFont(tmpFont);  

Despite I found the solution, I'm still curious about that strange behavior (that appears even stranger after your post)... Have you found any explaination?