box renderer: Allow for shapes with radius bigger than box width (or height)

[peter-ha]

Problem: I have a box with relative radius 100%:

Now when the width of the box gets smaller, I want the radius still be of the same size, but it gets squeezed:

We have this use case for the new Material sliders (#413).

I wonder if there is a way to introduce a mode where the radius stays the same, even if it exceeds the width (or height) of the box. I haven't looked at the box renderer code yet whether this is feasible...

[peter-ha]

This is how I reproduced it:

#include "QskBox.h"
#include "QskBoxShapeMetrics.h"
#include "QskLinearBox.h"
#include "QskWindow.h"

#include <SkinnyShortcut.h>
#include <SkinnyNamespace.h>

#include <QDebug>
#include <QGuiApplication>
#include <QTimer>
#include <qnamespace.h>

int main( int argc, char* argv[] )
{
    QGuiApplication app( argc, argv );

    SkinnyShortcut::enable( SkinnyShortcut::AllShortcuts );

    QskWindow window;

    auto* l = new QskLinearBox(window.contentItem());

    auto* box = new QskBox(l);
    box->setPanel(true);
    box->setGradientHint(QskBox::Panel, Qt::magenta);
    box->setFixedSize(150,50);
    box->setBoxShapeHint(QskBox::Panel, {25, 25, 25, 25});

    auto* t = new QTimer(&app);
    QObject::connect(t, &QTimer::timeout, box, [box]()
    {
        static qreal w = 150;
        static bool shrink = true;
        if((w<=0 && shrink) || (w>=150 && !shrink))
        {
            shrink = !shrink;
        }

        w = shrink ? w-5 : w+5;
        box->setFixedWidth(w);
    });
    t->start(50);

    window.resize( 150, 50 );
    window.show();

    return app.exec();
}