[Development] QML Rectangle corner radius API for Qt 6.7

[Tor Arne Vestbø]

> On 22 Dec 2023, at 13:20, Giuseppe D'Angelo via Development <development at qt-project.org> wrote:
> 
> Il 22/12/23 11:15, André Somers ha scritto:
>> I can see two options. The simplest option is to have a `radii`
>> property, which is a grouped property containing the `topLeft`,
>> `topRight`, `bottomLeft` and `bottomRight` properties as a floating
>> point value as we have now. I think that would be cleaner than the
>> current state of things.
> 
> While at it, it should be aptly named `cornersRadii` or similar.
> 
> `radius` has always violated Qt API guidelines. A rectangle doesn't have a radius. We shouldn't be doing the same mistake again.

Radius is a well established term for this in Qt, and other UI frameworks. A key principle in Qt’s API design is familiarity and consistency.

We can change the `radius` property from a qreal into a group property with left/rigth/top/bottom, similar to anchors. We can detect in the setRadius setter if the incoming argument is a real, and apply that to all of the corners. That would be backwards compatible, and give a more granular API for those that need it.

Tor Arne