QComboBox to show Qt::PenStyle

Hello!


I'ld like to create a QComboBox-based class to show exactly the thing found on the image:

Attachment 10026

I tried to find a free one on the web, but I couldn't. Essentially, so, how could I put the line styles inside the QComboBox like that?


Thanks,

Momergil

That is pretty straight forward:

1) have a loop that iterates over the value range of pen style
2) in the loop create a QPixmap, fill it white (or whatever background color you'd like)
3) create a painter on the pixmap, set the pen style, draw a line
4) add the pixmap as an item on the combobox.

For (4) I would suggest to additionally set the pen style as the userData, so you can easily retrieve it in the slot reacting to currenIndexChanged()

Cheers,
_

Thanks anda,

but I'm having quite a trouble to work with the QPainter. I receive:

Code:

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QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::setPen: Painter not active
QPainter::end: Painter not active, aborted

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from this:

Code:

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for (int aaa = Qt::SolidLine; aaa < Qt::CustomDashLine; aaa++)
    {
        QPixmap pix;
        pix.fill();
 
        QPainter painter;
 
        painter.begin(&pix);
        painter.setPen((Qt::PenStyle)aaa);
        painter.drawLine(2,2,6,6); //temporary values
        painter.end();
 
        newComboBox->addItem("",pix);
    }

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Notice that not only I'm having problem with setting the QPainter to the pixmap, but also I couldn't find any suitable addItem method to insert the pixmap inside the QComboBox; both of them don't seem to accept that. :x

QPixmap's default constructor creates a null pixmap.
I am pretty sure you want your pixmap to be larger than 0 pixels right?

And yes, there is no addItem() that takes a QPixmap, however there is one that takes a QIcon and, drumroll, there is QIcon constructor that takes a QPixmap.

Cheers,
_

So here is the final work, for now:

Code:

---

//![1] Begins
    drawConfigBar = new QToolBar(QToolBar::tr("Draw Configuration Bar"),this);
    drawConfigBar->setOrientation(Qt::Vertical);
    drawConfigBar->setMovable(true);
    drawConfigBar->setFloatable(true);
 
    //![2]
    QAction* newAction = NULL;
    QComboBox* newComboBox = NULL;
 
    //Pen Style
    newComboBox = new QComboBox(drawConfigBar);
    newComboBox->setToolTip(newComboBox->tr("Line style"));
    newComboBox->setEditable(false);
    newComboBox->setIconSize(QSize(80,14));
    newComboBox->setMinimumWidth(80);
    connect(newComboBox,SIGNAL(currentIndexChanged(int)),this,SLOT(slotLineStyleSelected(int)));
 
    for (aaa = Qt::SolidLine; aaa < Qt::CustomDashLine; aaa++)
    {
        QPixmap pix(80,14);
        pix.fill(Qt::white);
 
        QBrush brush(Qt::black);
        QPen pen(brush,2.5,(Qt::PenStyle)aaa);
 
        QPainter painter(&pix);
        painter.setPen(pen);
        painter.drawLine(2,7,78,7);
 
        newComboBox->addItem(QIcon(pix),"");
    }    
 
    newComboBox->setCurrentIndex((int)Qt::SolidLine - 1);
 
    drawConfigBar->addWidget(newComboBox);
 
    //Pen width
    newComboBox = new QComboBox(drawConfigBar);
    newComboBox->setToolTip(newComboBox->tr("Line width"));
    newComboBox->setEditable(false);
    newComboBox->setIconSize(QSize(80,14));
    newComboBox->setMinimumWidth(80);
    connect(newComboBox,SIGNAL(currentIndexChanged(int)),this,SLOT(slotLineThicknessSelected(int)));
 
    for (aaa = 1; aaa < 6; aaa++)
    {
        QPixmap pix(80,14);
        pix.fill(Qt::white);
 
        QBrush brush(Qt::black);
        QPen pen(brush,(double)aaa,Qt::SolidLine);
 
        QPainter painter(&pix);
        painter.setPen(pen);
        painter.drawLine(2,7,78,7);
 
        newComboBox->addItem(QIcon(pix),"");
    }
 
    newComboBox->setCurrentIndex(0);
 
    drawConfigBar->addWidget(newComboBox);

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If you extend your addItem calls to contain the actual value

Code:

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newComboBox->addItem(QIcon(pix), QString(), QVariant(aaa));

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then you can get the value again in the slot

Code:

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void YourClass::slotCurrentIndexChanged(int index)
{
    int value = comboBox->itemData(index).toInt();
}

---

Cheers,
_