c++qtlayoutqgraphicswidget

QGraphicsWidget and QGraphicsLayout spacing and sizes

I use QGraphicsWidget and QGraphics[Linear]Layout inside a QGraphicsScene to create a Node like "Widget". Each Node has a Header, multiple IOGraphicsWidgets and a Footer.

The code Structure:

Code structure

The wanted layout:

Node layout

The result of the current code:

Current result

As you can see the NodeGraphicsWidget (the red rectangle behind the HeaderWidget) is not resized to contain all items added to it. The spacing between the LayoutItems is also huge and m_centerWidgetLayout->setSpacing(0) changed nothing. Right now I'm thinking of writing all the layouts myself, but I hope there is a better way that I can use the standard qt.

NodeGraphicsWidget:addIOWidget(AbstractIOGraphicsWidget *ioWidget) just adds the given AbstractIOGraphicsWidget to the m_centerWidgetLayout.

The Constructor of NodeGraphicsWidget:

NodeGraphicsWidget::NodeGraphicsWidget(NodeGraphicsWidget::WidgetCreationFunction headerCreationFunc, NodeGraphicsWidget::WidgetCreationFunction footerCreationFunc, QGraphicsItem *parent, Qt::WindowFlags wFlags):
    QGraphicsWidget(parent, wFlags)
{
    m_headerWidget = new QGraphicsWidget(this);
    m_centerWidget = new QGraphicsWidget(this);
    m_centerWidgetLayout = new QGraphicsLinearLayout(Qt::Orientation::Vertical, m_centerWidget);
    m_centerWidgetLayout->setSpacing(0);
    m_centerWidget->setLayout(m_centerWidgetLayout);
    m_footerWidget = new QGraphicsWidget(this);


    headerCreationFunc(this, m_headerWidget);
    if(footerCreationFunc != nullptr){
        footerCreationFunc(this, m_footerWidget);
    }

    setAutoFillBackground(true);

    QPalette pal;

    pal.setColor(QPalette::Window, QColor(Qt::red));

    this->setPalette(pal);

}

To see the full sourcecode visit: https://github.com/nidomiro/QtNodes/tree/f5426c154a4938481f00031f031507499cc0e183/src

Solution

  • I found the solution to my problem myself. First I forgot the root-layout of NodeGraphicsWidget but that didn't fix the whole issue. The main issue, the spacing between the items, wasn't the real problem. The real problem was that every QGraphicsLinearLayout has an margin by default and AbstractIOGraphicsWidget root-layout had those margins. layout->setContentsMargins(0,0,0,0) solved the issue.