Diff between QBrush and QPen

[wagmare]

hi friends,
i try to send the QPen value as argument like
in lineitem.h

class LineItem : public QObject, public QGraphicsLineItem
{
        Q_OBJECT
public:
        LineItem(const QLineF &rect, const QPen &pen);
private:
        int xvalue, yvalue;
        QPen pen;
}

class LineItem : public QObject, public QGraphicsLineItem
{
        Q_OBJECT
public:
        LineItem(const QLineF &rect, const QPen &pen);
private:
        int xvalue, yvalue;
        QPen pen;
}

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in lineitem.cpp

LineItem::LineItem(const QLineF &line, const QPen &pen)
    : QGraphicsLineItem(line),
      pen(pen)
{
void LineItem ::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
{
 painter->setPen(pen);
         painter->drawLine(line());
 
}

LineItem::LineItem(const QLineF &line, const QPen &pen)
    : QGraphicsLineItem(line),
      pen(pen)
{
void LineItem ::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
{
 painter->setPen(pen);
         painter->drawLine(line());

}

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in graphicsview

line1 = new LineItem(QLineF(2,4, 2 ,30), Qt::green);
  line1->setPos(100,550);
 scene->addItem(line1);

line1 = new LineItem(QLineF(2,4, 2 ,30), Qt::green);
  line1->setPos(100,550);
 scene->addItem(line1);

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its giving error as
dualmon.cpp:93: error: no matching function for call to ‘LineItem::LineItem(QLineF, Qt::GlobalColor)’
lineitem.h:13: note: candidates are: LineItem::LineItem(const QLineF&, const QPen&)
lineitem.h:8: note: LineItem::LineItem(const LineItem&)
or as

but if the same QPen i replace with QBrush its running perfectly ...
i can send color as argument for QBrush but not for QPen why?

please help




}

[talk2amulya]

the color u gave is a Qt::GlobalColor , when u use QBrush instead of QPen, the following constructor is used(since the second argument is default and first is already given)

QBrush ( Qt::GlobalColor color, Qt::BrushStyle style = Qt::SolidPattern )

for QPen, there is no such constructor

[wagmare]

thanks .. so i have to send QColor instead of QPen ...

[Lykurg]

thanks .. so i have to send QColor instead of QPen ...

If you want to sent a QColor why you define a constructor expecting a QPen? What's about defining:

...
LineItem(const QLineF &rect, const QPen &pen);
LineItem(const QLineF &rect, const QColor &color);
LineItem(const QLineF &rect, const Qt::GlobalColor color);

...
LineItem(const QLineF &rect, const QPen &pen);
LineItem(const QLineF &rect, const QColor &color);
LineItem(const QLineF &rect, const Qt::GlobalColor color);

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with for example:

LineItem(const QLineF &rect, const Qt::GlobalColor color)
   : QGraphicsLineItem(line)
{
  pen = QPen(QColor(color));
}

LineItem(const QLineF &rect, const Qt::GlobalColor color)
   : QGraphicsLineItem(line)
{
  pen = QPen(QColor(color));
}

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then you will be save.

[wagmare]

no just i am telling i cant send GlobalColor to QPen .. just send the color value to the constructor .. from the value i will set it to QPen

[Lykurg]

Well, you can set up a QPen from a GlobalColor. The only thing is that Qt does this not for you. So just do it by yourself by transforming the GlobalColor to a QColor and set this to the QPen.