Pass Qt::green like function argument

[yczo]

Hello and thank you very much for all.
I would like to create a setter to update the color of a QPainter Object...

this is my idea...
void ampel::updateColor(){ <----- how to pass here Qt::green

cColor->setColor(Qt::green);

}

but, how can I pass the Qt::green like a variable, which type of variable, musst I use? Is needed a special #include in the MainWindow, for Qt:green like valour use?

Greetings

[Chris Kawa]

Well Qt::green is one of the values of a Qt::GlobalColor enum type, so your function signature would be

void ampel::updateColor(Qt::GlobalColor color)

but this is not a good idea.

It's not a good idea because it limits your colors to the predefined constants, and that limitation is artificial. What you really want to do is pass any color and Qt has a QColor class for that. This is also the argument of setColor so matching signature of your surrounding function could potentially mean one conversion less.
So I propose you give it the following signature:

void ampel::updateColor(const QColor& color)

Thanks to the multiple constructors of QColor and the rules of implicit conversion of c++ this can be then called in any of these ways:

   ampel foo;
   foo.updateColor(Qt::green);
   foo.updateColor(QColor(0,255,0));
   foo.updateColor("green");
   foo.updateColor("#00FF00");
   foo.updateColor(0x00FF00);

The include you need for that is <QColor>.

[yczo]

Thank you very much