add tabs

crates/data/Cargo.toml

@@ -14,6 +14,7 @@ gpui = { workspace = true, features = ["test-support"] }
 
 [features]
 default = ["full"]
-full = ["list", "tree"]
+full = ["list", "tabs", "tree"]
 list = []
+tabs = []
 tree = []

crates/data/src/lib.rs

@@ -4,5 +4,8 @@
 #[cfg(feature = "list")]
 pub mod list;
 
+#[cfg(feature = "tabs")]
+pub mod tabs;
+
 #[cfg(feature = "tree")]
 pub mod tree;

crates/data/src/tabs.rs

@@ -0,0 +1,299 @@
+use std::rc::Rc;
+
+use gpui::prelude::FluentBuilder as _;
+use gpui::{
+    AnyElement, App, ElementId, Hsla, InteractiveElement as _, IntoElement, KeyDownEvent,
+    ParentElement as _, Pixels, RenderOnce, Role, SharedString, StatefulInteractiveElement as _,
+    Styled as _, Window, div,
+};
+use gpui_native_icons::{IconRole, icon};
+use gpui_native_theme::ActiveTheme as _;
+
+/// The change reporter, fired with the next selected tab by pointer and keys.
+type ChangeHandler = Rc<dyn Fn(usize, &mut Window, &mut App)>;
+type TabsFn = Box<dyn Fn(&mut Window, &mut App) -> Vec<Tab>>;
+
+/// One tab of a [`Tabs`] strip.
+pub struct Tab {
+    label: SharedString,
+    icon: Option<IconRole>,
+    disabled: bool,
+}
+
+impl Tab {
+    /// Creates a tab with this label.
+    pub fn new<L>(label: L) -> Self
+    where
+        L: Into<SharedString>,
+    {
+        Self {
+            label: label.into(),
+            icon: None,
+            disabled: false,
+        }
+    }
+
+    /// Shows an icon leading the label.
+    pub fn icon(mut self, role: IconRole) -> Self {
+        self.icon = Some(role);
+        self
+    }
+
+    /// Renders the tab dimmed; clicks and keyboard skip it.
+    pub fn disabled(mut self, disabled: bool) -> Self {
+        self.disabled = disabled;
+        self
+    }
+}
+
+/// A tab strip.
+#[derive(IntoElement)]
+pub struct Tabs {
+    id: ElementId,
+    selected: usize,
+    a11y_label: Option<SharedString>,
+    on_change: Option<ChangeHandler>,
+    tabs: Option<TabsFn>,
+}
+
+impl Tabs {
+    /// Creates a strip selecting the first tab.
+    pub fn new<I>(id: I) -> Self
+    where
+        I: Into<ElementId>,
+    {
+        Self {
+            id: id.into(),
+            selected: 0,
+            a11y_label: None,
+            on_change: None,
+            tabs: None,
+        }
+    }
+
+    /// Sets the current selection.
+    pub fn selected(mut self, selected: usize) -> Self {
+        self.selected = selected;
+        self
+    }
+
+    /// Reports the next selected tab, from clicks and keys alike.
+    pub fn on_change<F>(mut self, handler: F) -> Self
+    where
+        F: Fn(usize, &mut Window, &mut App) + 'static,
+    {
+        self.on_change = Some(Rc::new(handler));
+        self
+    }
+
+    /// Sets the tabs, built fresh each render.
+    pub fn tabs<F>(mut self, tabs: F) -> Self
+    where
+        F: Fn(&mut Window, &mut App) -> Vec<Tab> + 'static,
+    {
+        self.tabs = Some(Box::new(tabs));
+        self
+    }
+
+    /// Overrides the accessibility label, which defaults to the id.
+    pub fn accessibility_label<L>(mut self, label: L) -> Self
+    where
+        L: Into<SharedString>,
+    {
+        self.a11y_label = Some(label.into());
+        self
+    }
+}
+
+struct TabsChrome {
+    foreground: Hsla,
+    muted: Hsla,
+    muted_foreground: Hsla,
+    primary: Hsla,
+    border: Hsla,
+    radius_sm: Pixels,
+    icon_size: Pixels,
+    text_size: Pixels,
+    /// The strip's selected index; re-selecting it reports nothing.
+    selected: usize,
+}
+
+impl RenderOnce for Tabs {
+    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
+        let chrome = {
+            let theme = cx.theme();
+            TabsChrome {
+                foreground: theme.colors.foreground,
+                muted: theme.colors.muted,
+                muted_foreground: theme.colors.muted_foreground,
+                primary: theme.ramps.primary.base,
+                border: theme.colors.border,
+                radius_sm: theme.radius.sm,
+                icon_size: theme.sizes.medium.icon_size,
+                text_size: theme.sizes.medium.text_size,
+                selected: self.selected,
+            }
+        };
+
+        let tabs = match self.tabs {
+            Some(build) => build(window, cx),
+            None => Vec::new(),
+        };
+
+        let selectable: Vec<usize> = tabs
+            .iter()
+            .enumerate()
+            .filter(|(_, tab)| !tab.disabled)
+            .map(|(index, _)| index)
+            .collect();
+
+        // Keyboard focus rides the strip across frames.
+        let focus_handle = window.with_element_namespace(self.id.clone(), |window| {
+            window.use_keyed_state("tabs-focus", cx, |_, cx| cx.focus_handle())
+        });
+        let focus = focus_handle.read(cx).clone();
+
+        let label = self
+            .a11y_label
+            .clone()
+            .unwrap_or_else(|| SharedString::from(self.id.to_string()));
+
+        let strip: Vec<AnyElement> = tabs
+            .iter()
+            .enumerate()
+            .map(|(index, tab)| {
+                render_tab(
+                    tab,
+                    index,
+                    self.selected == index,
+                    &chrome,
+                    &self.on_change,
+                    &focus,
+                )
+            })
+            .collect();
+
+        div()
+            .id(self.id)
+            .flex()
+            .gap_1()
+            .border_b_1()
+            .border_color(chrome.border)
+            .text_size(chrome.text_size)
+            .track_focus(&focus)
+            .focusable()
+            .tab_stop(true)
+            .role(Role::TabList)
+            .aria_label(label)
+            .on_key_down({
+                let selected = self.selected;
+                let on_change = self.on_change.clone();
+                move |event: &KeyDownEvent, window, cx| {
+                    let target = match event.keystroke.key.as_str() {
+                        "right" => adjacent(&selectable, selected, true),
+                        "left" => adjacent(&selectable, selected, false),
+                        "home" => selectable.first().copied(),
+                        "end" => selectable.last().copied(),
+                        _ => return,
+                    };
+                    if let Some(next) = target
+                        && next != selected
+                        && let Some(on_change) = &on_change
+                    {
+                        on_change(next, window, cx);
+                    }
+                    cx.stop_propagation();
+                }
+            })
+            .children(strip)
+    }
+}
+
+fn render_tab(
+    tab: &Tab,
+    index: usize,
+    selected: bool,
+    chrome: &TabsChrome,
+    on_change: &Option<ChangeHandler>,
+    focus: &gpui::FocusHandle,
+) -> AnyElement {
+    let label_color = if tab.disabled {
+        chrome.muted_foreground
+    } else if selected {
+        chrome.primary
+    } else {
+        chrome.foreground
+    };
+
+    let mut strip_tab = div()
+        .id(("tab", index))
+        .flex()
+        .items_center()
+        .gap_1p5()
+        .px_2()
+        .py_1()
+        .rounded_tl(chrome.radius_sm)
+        .rounded_tr(chrome.radius_sm)
+        .role(Role::Tab)
+        .aria_selected(selected)
+        .text_color(label_color)
+        .when(selected, |strip_tab| {
+            // The underline sits on the strip's hairline, marking the active
+            // tab the way a native tab bar does.
+            strip_tab.border_b_2().border_color(chrome.primary)
+        })
+        .when(!tab.disabled && !selected, |strip_tab| {
+            strip_tab.hover(|strip_tab| strip_tab.bg(chrome.muted))
+        })
+        .child(
+            div()
+                .flex_none()
+                .pb_0p5()
+                .when_some(tab.icon, |strip_tab, role| {
+                    strip_tab.child(icon(role).size(chrome.icon_size * 0.75).color(label_color))
+                }),
+        )
+        .child(strip_tab_label(tab.label.clone(), selected, chrome));
+
+    if !tab.disabled {
+        let selected_index = chrome.selected;
+        strip_tab = strip_tab.cursor_pointer().on_click({
+            let on_change = on_change.clone();
+            let focus = focus.clone();
+            move |_, window, cx| {
+                window.focus(&focus, cx);
+                if index != selected_index
+                    && let Some(on_change) = &on_change
+                {
+                    on_change(index, window, cx);
+                }
+            }
+        });
+    }
+
+    strip_tab.into_any_element()
+}
+
+fn strip_tab_label(label: SharedString, selected: bool, chrome: &TabsChrome) -> AnyElement {
+    div()
+        .text_color(if selected {
+            chrome.primary
+        } else {
+            chrome.foreground
+        })
+        .child(label)
+        .into_any_element()
+}
+
+/// The next selectable tab in the direction.
+fn adjacent(selectable: &[usize], selected: usize, forward: bool) -> Option<usize> {
+    if forward {
+        selectable.iter().copied().find(|index| *index > selected)
+    } else {
+        selectable
+            .iter()
+            .copied()
+            .rev()
+            .find(|index| *index < selected)
+    }
+}

crates/data/tests/tabs.rs

@@ -0,0 +1,112 @@
+use std::{cell::RefCell, rc::Rc};
+
+use gpui::{
+    Context, IntoElement, Modifiers, MouseButton, ParentElement as _, Render, Styled as _,
+    TestAppContext, VisualTestContext, Window, div, point, px,
+};
+use gpui_native_data::tabs::{Tab, Tabs};
+use gpui_native_theme::Theme;
+
+type Changes = Rc<RefCell<Vec<usize>>>;
+
+struct Harness {
+    selected: usize,
+    changes: Changes,
+}
+
+impl Render for Harness {
+    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let changes = self.changes.clone();
+        let view = cx.entity();
+        div().size_full().child(
+            Tabs::new("test-tabs")
+                .selected(self.selected)
+                .on_change(move |next, _, cx| {
+                    changes.borrow_mut().push(next);
+                    view.update(cx, |harness, cx| {
+                        harness.selected = next;
+                        cx.notify();
+                    });
+                })
+                .tabs(|_, _| {
+                    vec![
+                        Tab::new("One"),
+                        Tab::new("Two"),
+                        Tab::new("Off").disabled(true),
+                        Tab::new("End"),
+                    ]
+                }),
+        )
+    }
+}
+
+/// Same-length labels keep the strip's geometry predictable: each tab is
+/// roughly 40 px wide with a 4 px gap, so clicks at `(20/62/104/146, 12)`
+/// land on One / Two / the disabled Off / End.
+fn tabs_window() -> (TestAppContext, VisualTestContext, Changes) {
+    let mut cx = TestAppContext::single();
+    cx.update(Theme::init);
+    let changes = Rc::new(RefCell::new(Vec::new()));
+    let harness_changes = changes.clone();
+    let window = cx.add_window(move |_, _| Harness {
+        selected: 0,
+        changes: harness_changes,
+    });
+    let mut visual = VisualTestContext::from_window(window.into(), &cx);
+    visual.update(|window, cx| {
+        window.draw(cx).clear(cx);
+    });
+    (cx, visual, changes)
+}
+
+fn click(visual: &mut VisualTestContext, position: gpui::Point<gpui::Pixels>) {
+    visual.simulate_mouse_down(position, MouseButton::Left, Modifiers::default());
+    visual.simulate_mouse_up(position, MouseButton::Left, Modifiers::default());
+}
+
+#[test]
+fn clicking_a_tab_selects_it_and_hands_the_strip_the_keyboard() {
+    let (_cx, mut visual, changes) = tabs_window();
+
+    // Tab 0 is already selected; selecting it again reports nothing.
+    click(&mut visual, point(px(20.), px(12.)));
+    assert!(changes.borrow().is_empty());
+
+    // The click focused the strip, so the arrows switch from here.
+    visual.simulate_keystrokes("right");
+    assert_eq!(*changes.borrow(), vec![1]);
+}
+
+#[test]
+fn clicking_a_disabled_tab_reports_nothing() {
+    let (_cx, mut visual, changes) = tabs_window();
+
+    click(&mut visual, point(px(104.), px(12.)));
+    assert!(changes.borrow().is_empty());
+}
+
+#[test]
+fn arrow_keys_skip_disabled_tabs_and_never_wrap() {
+    let (_cx, mut visual, changes) = tabs_window();
+
+    click(&mut visual, point(px(20.), px(12.))); // One: already selected, no report
+    visual.simulate_keystrokes("right"); // Two
+    visual.simulate_keystrokes("right"); // over the disabled tab → End
+    visual.simulate_keystrokes("right"); // last; no wrap
+    assert_eq!(*changes.borrow(), vec![1, 3]);
+
+    visual.simulate_keystrokes("left"); // over the disabled tab → Two
+    visual.simulate_keystrokes("home"); // One
+    visual.simulate_keystrokes("end"); // End
+    assert_eq!(*changes.borrow(), vec![1, 3, 1, 0, 3]);
+}
+
+#[test]
+fn clicking_a_different_tab_reports_once() {
+    let (_cx, mut visual, changes) = tabs_window();
+
+    click(&mut visual, point(px(20.), px(12.))); // One: no change, just focus
+    click(&mut visual, point(px(62.), px(12.))); // Two
+    click(&mut visual, point(px(62.), px(12.))); // Two again: no change
+    assert_eq!(*changes.borrow(), vec![1]);
+}