0018. TabStrip can show an icon on each tab, with or without its title

Date: 2026-10-17

Status

Proposed. The user asked for app icons in the Patina desktop bar's window list, which is a TabStrip (ADR-0012), with a setting for icons only, titles only, or both. The API is my design.

Context

A tab only showed its title. The desktop bar's tabs are open windows, and an app's icon tells them apart faster than a title. With many windows open, icon-only tabs also take a fraction of the room. Other apps may want the same: a browser shows site icons, a messenger shows chat avatars.

Decision

Two builder options. Without them nothing changes:

• .icons(&[Option<TextureId>]) gives each tab an icon, drawn 18 px square before the title and centred with it. The caller loads the textures. A tab whose icon is None, because it isn't loaded yet or there isn't one, shows its title's first letter in a small filled square in the icon's place. That keeps the tabs lined up and fills them as icons arrive.
• .label(TabLabel) picks what a tab shows: Title (the default), Icon or IconAndTitle. Without .icons it's always the title.
• Icon-only tabs are a fixed 44 px wide and show their title on hover. They have no close cross, because it would cover the icon. A middle click and the tab's menu still close them.

Consequences

• Existing callers are unchanged.
• Icon lookup (themes, .desktop files) stays with the caller. Patina doesn't read the file system for icons.
• Icon-only tabs can't be closed by a plain left click anywhere. That's the trade for not covering the icon.