Keyboard focus about slint HOT 5 CLOSED

I think we need something like active_focus the moment we introduce focus scopes. For consistency with has_focus I suggest to call the property wants_focus.

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I think we need something like active_focus the moment we introduce focus scopes. For consistency with has_focus I suggest to call the property wants_focus.

What's the use case for having these different properties. It must not be confusing and the semantic must be clear.

The use case i have in mind for focus property looks like this:

Foo {
     // 1. Binding on focus to control the appearence if the object is focussed
     color: focus ? red: blue;

     on_something {
            // 2. manually sets the focus to an item, eg, when entering a page or something.
           some_item.focus = true;
     }

    // 3. When this window/tab/sub-region aquire the focus, 
    // this is the particular widget which aquire the focus
    focus: true;

    // The focus is set based on a condition: does that make sense?
    focus: some_settings.sholuld_have_focus;
}

I think it only make sense to show the active focus. Or is there use case where we are interested on a different kind of focus in binding expression?

As for setting the focus, in my experience, one almost always want to set the active focus.

For the last use-case of setting the focus with focus:, this is indeed a more local focus which is not the active focus. I guess we can make the compiler understand that when setting the focus in a .60 file is the default default focus on a region.

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I agree about those 3 use-cases (reading focus property, programmatically setting focus and expressing desire to receive focus when window/tab/sub-region acquires).

I think (1) and (2) are well covered with a single property, ideally called focus indeed. That is simple and readable.

It's (3) that kind of ruins it :-) and I think it goes hand-in-hand with the question: How do you define these sub-regions? If, for example, we address (3) rather by means of declaring a "forwarding", then perhaps we can just stay with one "focus" property. I'd like that.

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A styled LineEdit could perhaps serve as example:

LineEdit := Rectangle {
    border_color: root.has_focus ? #556884 : #ffffff;
    forward_focus: input;
    // ...
    GridLayout {
        padding: 3lx;
        input := TextInput {
           ...
        }
    }
}

Let's say we allow defining a forward_focus property. That could perhaps also create a focus alias to the forwarded element (property <bool> focus; focus <=> input.focus in the above example`).

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The basic focus handling is implemented now, with TextInput as the only element supporting keyboard events right now. has_focus is the visible property for reading, someitem.focus() can be called to explicitly focus an element and initial_focus: some_item; can be used to point to an item that either shall receive the initial focus or by itself forwards using another initial_focus binding.

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