Breadcrumb

A path through a hierarchy: folders, then the current resource. Segments with an action are links, and the last segment is the current one.

Import

use limn::{Breadcrumb, BreadcrumbItem, Component, Icon};

Usage

A breadcrumb takes an ID, its segments and the palette. A segment with an action reports UiAction::Clicked with that action’s ID; a segment without one is passive. The host supplies every label and action: the breadcrumb infers no navigation.

fn view(palette: ComponentPalette) -> Element {
    Breadcrumb::new(
        "path",
        vec![
            BreadcrumbItem::new("limn").action("crumb=root").icon(Icon::Folder),
            BreadcrumbItem::new("crates").action("crumb=crates"),
            BreadcrumbItem::new("empty.rs").tooltip("crates/limn/src/empty.rs"),
        ],
        palette,
    )
    .width(420.0)
    .render()
}

fn update(state: &mut State, action: &UiAction) {
    if let UiAction::Clicked { id } = action {
        if let Some(folder) = id.strip_prefix("crumb=") {
            state.open_folder(folder);
        }
    }
}

The bar is 320 wide and 28 tall by default; width and height change that, and the height is never less than 20.

Segments

BreadcrumbItem::new(label) takes action to make it a link, icon for a glyph before the label, and tooltip for the hint’s description, such as the segment’s full path.

A file path

Breadcrumb::from_path("file-path", "crates/limn/src/find_bar.rs", palette)
    .dirty(state.unsaved)
    .segment_action(|segment| Some(format!("open={segment}")))
    .width(420.0)
    .render()

from_path splits a file path into one segment per folder and the file last, with its file icon when the bar is at least 76 wide. Each segment’s tooltip is its own path. The segments are passive until segment_action gives them actions: it is called with each folder’s path from the root and, for the file, with the whole path as it was given, and returning None leaves that segment passive. dirty(true) marks unsaved changes with a dot after the file’s name.

Breadcrumb::from_path("file-path", path, palette)
    .item(BreadcrumbItem::new("render").action("symbol=render"))
    .render()

item adds one more segment after the last, such as a symbol inside the file. It becomes the current resource.

Collapsed segments

When the path does not fit, middle segments collapse into an ellipsis whose hint is the complete path. If one of the hidden segments has an action, the ellipsis opens a menu of them, and the host owns whether it is open:

Breadcrumb::new("path", items, palette)
    .overflow_open(state.path_menu_open)
    .render()

The ellipsis reports {id}:overflow_toggle, and dismissing the menu reports {id}:overflow_dismiss, where {id} is the breadcrumb’s ID. A choice in the menu reports the segment’s own action.

Search and editing

Breadcrumb::new("path", items, palette).search_action("path-search").render()
Breadcrumb::new("path", items, palette)
    .editing("path-input", &state.location, "Go to a path")
    .render()

search_action ends the bar with a search button that reports the action; the path gives up the button’s width, so the bar keeps its size. editing shows a one-line field in place of the path, for typing a location or a search. The host owns its text through InputChanged and Submitted for the input ID, and leaves this mode by not calling editing.

The button’s hint shows Ctrl+F; search_shortcut(keys) shows the keys the host binds instead, and an empty string none.

Disabled

BreadcrumbItem::new("archive").action("open=archive").enabled(state.can_open_archive)

A disabled segment with an action is text like one without, in muted ink even when it is the current resource, and a disabled row in the menu of collapsed segments. It keeps its place and its hint.

Actions

Accessibility

A segment with an action is a link named by its label; disabled, it is there and cannot be followed. A segment without one is text. The ellipsis is named by the full_path label and says whether its menu is expanded, and the search button is named by the search label.