QGraphicsViews: how to arrange items using QGraphicsLinearLayout (or other layout)

Hi!

I'm developing a class that must contain like "products for sale list" in the form of graphics (QPixmap). So, I've chose QGraphicsView (for a similiar situation, in the past I've used QScrollArea and a QGridLayout to manage widgets buts is slow when you use to many widgets). The problem is that I've never used it.

What I plan to do is: having a way to arrange QPixmaps items inside QGraphicsView, so my question is: Do I need a layout to handle pixmaps in a easy way? Having in mind that items can be added and deleted so I must re-arrange items.

I've reading how QGraphicsViews works, the scene and such, but I don't have clear how to work with a layout and pixmaps items inside this.

Can anyone supply a small example code?

I will be very grateful.

Thanks in advance.

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I'm developing a class that must contain like "products for sale list" in the form of graphics (QPixmap). So, I've chose QGraphicsView (for a similiar situation, in the past I've used QScrollArea and a QGridLayout to manage widgets buts is slow when you use to many widgets).

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How many widgets are there?

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What I plan to do is: having a way to arrange QPixmaps items inside QGraphicsView, so my question is: Do I need a layout to handle pixmaps in a easy way? Having in mind that items can be added and deleted so I must re-arrange items.

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One easy way is to use QGraphicsWidget and QGraphicsLayout. If you want to use QGraphicsPixmapItem then you have take care to layout yourself.

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I've reading how QGraphicsViews works, the scene and such, but I don't have clear how to work with a layout and pixmaps items inside this.

Can anyone supply a small example code?

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This is an example to use QGraphicsWidget

Code:

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int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QGraphicsView view;
    QGraphicsScene scene;
    QGraphicsWidget * widget = new QGraphicsWidget;
    QGraphicsLinearLayout *layout = new QGraphicsLinearLayout(Qt::Vertical);
 
    for(int i = 0; i < 10; i++)
    {
        QLabel * label = new QLabel;
        label->setPixmap(QPixmap("C:/image.jpg"));
        QGraphicsWidget * w = scene.addWidget(label);
        layout->addItem(w);
    }
 
    widget->setLayout(layout);
    scene.addItem(widget);
    view.setScene(&scene);
    view.show();
 
    return a.exec();
}

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Thanks for reply! yesterdays after reading, which you said the same, in some forums i got the conclusion about QGraphicsPixmapItem about the layout. So, I use QLabel to achieve this, plus using QGraphicsLinearLayout :)

Thanks!, now I will test things over this :)

Cheers.

Well, here is the basic example of how it looks the test code: Attachment 9739

I use QLabel but with setText() and using HTML code, so I can display both Pixmap and Text :)

Cheers.

Santosh Reddy: I have another dub: in this example I've subclassed QLabel, to implemente a focus "effect" (by using focusInEvent and focusOutEvent event, and stylesheet to change border color when selected). Now, how i do select multiple items/widgets in QGraphicsView?

Thanks.

Set QGraphicsItem::ItemIsSelectable flag for the QGraphicsWidget (subclassed QLabel). Note that you will have to draw the selection rectangle explicitly.

Yeah, already applied that flag (Python):

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graphicItem.setFlags(QGraphicsItem.ItemIsFocusable | QGraphicsItem.ItemIsSelectable)

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And for the subclassed QLabel, for focus i've added:

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def focusInEvent(self, event):
self.focusState.emit(True)
self.setStyleSheet("QLabel{background-color: transparent; border: 2px solid #90b6e2; border-radius: 5px;}")
return QLabel.focusInEvent(self, event)


def focusOutEvent(self, event):
self.focusState.emit(False)
self.setStyleSheet("QLabel{background-color: transparent; border: 2px solid transparent; border-radius: 5px;}")
return QLabel.focusInEvent(self, event)

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This last one, would be a problem for selecting more than one QLabel/widget at time? or is something that i must handle from QGraphicsView itself?