Slint MenuBar shortcuts when MenuBar is invisible/disabled

[npwoods]

I'm really liking the new menu shortcuts... good work!

I am running into one thing however. How would I go about having menu shortcuts that are active even if the menu is disabled?

The only way I can figure out how to do this is by replicating menu shortcuts in a FocusScope. Is there a better way to do this? I can't really envision a way to do this that involves keeping the MenuBar object live, as I realize that in the below example the MenuBar is nonexistant if show-menu-bar is false.

Perhaps MenuBar could have a visible property that if false, would make the menu bar invisible but keep the shortcuts active?

import {
    VerticalBox,
} from "std-widgets.slint";

export component Example inherits Window {
    preferred-width: 230px;
    preferred-height: 200px;
    property <bool> show-menu-bar: true;
    property <int> alpha: 0;
    property <int> bravo: 0;
    property <int> charlie: 0;
    if show-menu-bar: MenuBar {
        Menu {
            title: @tr("Menu");
            MenuItem {
                title: "Alpha";
                shortcut: @keys(Control + "1");
                activated => {
                    root.alpha = root.alpha + 1;
                }
            }

            MenuItem {
                title: "Bravo";
                shortcut: @keys(Control + "2");
                activated => {
                    root.bravo = root.bravo + 1;
                }
            }

            MenuItem {
                title: "Charlie";
                shortcut: @keys(Control + "3");
                activated => {
                    root.charlie = root.charlie + 1;
                }
            }

            MenuItem {
                title: "Toggle";
                shortcut: @keys(Control + "4");
                activated => {
                    show-menu-bar = !show-menu-bar;
                }
            }
        }
    }
    FocusScope {
        key-pressed(event) => {
            if (!show-menu-bar && event.modifiers.control && event.text == "1") {
                root.alpha = root.alpha + 1;
                accept
            } else if (!show-menu-bar && event.modifiers.control && event.text == "2") {
                root.bravo = root.bravo + 1;
                accept
            } else if (!show-menu-bar && event.modifiers.control && event.text == "3") {
                root.charlie = root.charlie + 1;
                accept
            } else if (!show-menu-bar && event.modifiers.control && event.text == "4") {
                show-menu-bar = !show-menu-bar;
                accept
            } else {
                reject
            }
        }
        VerticalBox {
            Text {
                text: root.alpha;
            }

            Text {
                text: root.bravo;
            }

            Text {
                text: root.charlie;
            }
        }
    }
}

[npwoods]

I tried my hand at this, and have a draft PR. It was surprisingly straight forward to do this for non-native menus but I was not able to do the required plumbing for muda support. Details in the PR.

[ogoffart]

I see the value in having the shortcut active when the menu bar is hidden.
I'm wondering if visible is the right approach though. Maybe it would b possible to make them work even if the if <condition>: MenuBar is false, but that would also be strange as this is not what if: does for other things. But also visible for normal widget hides them but keep them in the layout. So either way there would be inconsistency.

[LeonMatthes]

Note: For the moment, using the approach with a focus scope and key binding elements is the correct way to work around this until we have a proper solution.

[LeonMatthes]

Hi, thank you for the question. I think Olivier's answer goes in the right direction here. I just changed the title because I first thought you meant the "disabled" property on the menu item:
https://docs.slint.dev/latest/docs/slint/reference/window/contextmenuarea/#enabled-2

[npwoods]

But also visible for normal widget hides them but keep them in the layout. So either way there would be inconsistency.

My first thought on this is that arguably the menu lowering process arguably creates inconsistency by its very nature. This is why in my draft PR, the lowered form has a menubar-visible property distinct from the normal visible property.

Note: For the moment, using the approach with a focus scope and key binding elements is the correct way to work around this until we have a proper solution.

Understood, thanks!

In any case if it is decided that my PR is on the right track, I would be fine doing the dirty work if I got some advice about how to properly plumb things to the muda logic in the winit back end.

[npwoods]

After some hacking, I have found that another approach that seems to work is to:

1. Add condition: extern "C" fn(VRef<MenuVTable>) -> bool, to MenuVTable
2. Implement Menu::condition() on MenuFromItemTree by checking the condition member variable
3. Remove the check on condition from MenuFromItemTree::update_shadow_tree()
4. Change the muda logic to check condition() when calling rebuild_menus()

Of course, this is not complete, and given the lack of consensus about how to do this, it seems premature to submit a PR.

[LeonMatthes]

Hey @npwoods,
thank you for the updates 👍

@ogoffart and I just had another chat about this.

We especially discussed whether this should use the if condition or a visible property.
As currently the behavior of an if statement is to fully remove items from the item tree, having shortcuts on a menu bar is still active if it has been entirely removed by an if does not make sense.

However, a visible property would be okay for this because that would suggest that the menu bar still exists but it's just not visible anymore.

I think overall you can continue with your current approach, just make sure to use a visible property instead of the if condition (if one exists).

This will also need documentation that unlike most other items, a menu bar that is invisible will also be of zero size.
Also, having an invisible menu bar on macOS doesn't make a lot of sense. I think the semantics of it are still okay if we just show an empty menu bar if it is invisible. We will need to document this and suggest to users to always show the menu bar on macOS.

In a sense, all of this is sort of working around the fact that we currently do not have Action items that the menu bar could refer to.
So we could also consider moving to that approach in the future, but that is not likely to land soon.

[npwoods]

I just committed changes to my PR that adds the visible property to MenuVTable and honors it within the muda code.

I briefly tried adding visible as a parameter to MenuFromItemTree::new() and MenuFromItemTree::new_with_condition() (side note - IMHO these two functions should be one function that takes condition as an Option), but I found the plumbing challenging and would like some guidance. Some questions:

• Should visible really be Option<Pin<Box<Property<bool>>>> so that the muda code can poll the latest value?
• Or should visible not be a member of MenuFromItemTree and instead queried from the item_tree or something else? What is the incantation to make this happen?
• Am I completely off base?