Qt Mdi Area get size not including scroll area

haris123

I have some issue with Qt MdiArea where I created a sub-window which fit inside MdiArea, and then I check the size of MdiArea got correct result. But if I move the window to the end of MdiArea which will make scroll bar appear, and check the MdiArea size again, but getting the same size as window without scrollbar. I think the scroll area not considering while getting size, but only the viewport size returning.

How I can get the total size including scrollable area of the MdiArea.

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->mdiArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    ui->mdiArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    ui->mdiArea->setOption(QMdiArea::DontMaximizeSubWindowOnActivation);

    // Set Mdi Area as the central widget
    setCentralWidget(ui->mdiArea);


    QWidget *widget = new QWidget(ui->mdiArea);
    QMdiSubWindow *w1 = ui->mdiArea->addSubWindow(widget);
    w1->resize(320, 240);
    // And show the widget
    widget->show();
}


void MainWindow::wheelEvent(QWheelEvent *event)
{
    qDebug()<<"mdiArea size: "<<ui->mdiArea->size();


}

Correct Result without scroll bar.
alt text

Wrong Result with scroll bar.
alt text

Chris Kawa

ui->mdiArea->size() is the size of the entire widget, including all its children and scrollbars are just children.
What you probably want is the size of the scroll area viewport - the widget that hosts the actual contents of the area, so ui->mdiArea->viewport()->size().

haris123

@Chris-Kawa said in Qt Mdi Area get size not including scroll area:

ui->mdiArea->viewport()->size()

I tried that too, but got the same result.

qDebug()<<"mdiArea size: "<<ui->mdiArea->size();
qDebug()<<"mdiArea -> viewport size: "<<ui->mdiArea->viewport()->size();

Print the same result when scroll bar there and not there.

mdiArea size: QSize(982, 662)
mdiArea -> viewport size: QSize(982, 645)

And I got it solved by,

   QScrollBar  *h_bar = ui->mdiArea->horizontalScrollBar();
   QScrollBar  *v_bar = ui->mdiArea->verticalScrollBar();

   int total_width = h_bar->maximum()-h_bar->minimum()+ui->mdiArea->width();
   int total_height = v_bar->maximum()-v_bar->minimum()+ui->mdiArea->height();

Seems working for me.

Chris Kawa

Oh, I misunderstood what you want. I thought you wanted the viewport size but you want the actual viewport contents size. QScrollArea has a widget() method that lets you get the content widget and its size, but unfortunately QMdiArea doesn't seem to have similar option, so your solution might be ok.