Tabs

Containers · interactive

A strip of tabs.

Import

#include "gbui/widgets/tabs.hpp"

Example

Tabs

tabs · Containers · interactive

Nothing is downloaded until you press it.

std::optional<std::size_t> tabs(Ui& ui, const Interaction& input, std::string_view id, const std::vector<TabItem>& items, std::size_t selected, const TabsOptions& options = {});

Draws the strip and reports which tab the user chose, or nothing. Stateless like everything else: the caller owns the selected index and hands it in. The strip is one focusable stop — the ARIA "roving tabindex" pattern — so Tab moves past the whole strip rather than through every tab in it, and the arrow keys move between them once it has the keyboard. Not built yet, and named rather than half-done: an overflow menu for when the tabs do not fit (they currently shrink and elide), a close affordance, and reordering by drag.

TabPanels

tabPanels · Containers

Nothing is downloaded until you press it.

void tabPanels(Ui& ui, std::size_t selected, const std::vector<std::function<void(Ui&)>>& panels, const TabPanelsOptions& options = {});

Builds the panel bodies for a tab strip. Separate from tabs because the two are rarely siblings: a vertical strip sits beside its panels and a horizontal one above them, and a caller often puts a toolbar or a splitter between them. An unselected panel is built inside a box of no height that clips, so it takes part in nothing the reader can see while still being there — which is the whole difference lazy turns off.

API

TabsOptions

Option	Type	Default	What it does
orientation	TabsOrientation Horizontal · Vertical	TabsOrientation::Horizontal	A strip along the top or a rail down the side. Both arrow pairs step it either way, so the keys do not change when the layout does.
thickness	float	36.0f	The strip's thickness: its height when horizontal, its width when vertical.
itemHeight	float	34.0f	Vertical only — how tall each row is. Horizontal takes its tab height from thickness.
gap	float	2.0f
indicator	bool	true	The moving bar marking the active tab: under it when horizontal, down its leading edge when vertical. It slides between tabs when an animator is present and simply appears on the new one when there is not.
indicatorWidth	float	2.0f
indicatorInset	float	0.0f	How far the indicator sits from the strip's trailing edge — under a horizontal strip, beside a vertical one. Zero puts it hard against the edge, which is what a strip with a rule under it wants: the bar and the rule are then the same line, one of them lit. A strip without a rule usually wants a pixel or two of air, or the bar reads as an underline attached to the word rather than as a marker under the tab.
itemPadding optional	std::optional<Edges>		The space inside each tab. Unset takes a default that fits the orientation: horizontal tabs get room under the label so the indicator clears its descenders, and vertical rows keep a lane free on the leading edge so the label does not shift sideways when a tab becomes the active one. Here for the same reason Style::padding is on every node — a caller who disagrees with the spacing should be able to say so rather than work around it — and it is the one piece of a tab strip's spacing the caller could not reach.
rule	bool	true	A rule along the whole strip — under it, or beside it — so the strip reads as an edge rather than as floating text.

TabPanelsOptions

Option	Type	Default	What it does
lazy	bool	false	Build only the selected panel, and skip the rest entirely. Off by default, which is what a hidden <div> does on the web: it is still in the document, so anything that measures it or looks it up finds it. Turning it on is cheaper — an unbuilt panel costs nothing to lay out or paint — and the price is that everything about the panels the reader is not looking at stops existing: input.frameOf on a control inside one returns nothing, and any component that places itself from last frame's geometry starts from scratch when its tab comes back. For a handful of pages the difference is not worth thinking about. For a window whose tabs each hold a table of fifty thousand rows it is the difference between usable and not.