0.9.1-alpha.41

Patch Changes

• 277a713: Tabs — List · Trigger · Label · Indicator · Content

  The indicator is one node sliding, not a border on each tab appearing and disappearing. The triggers publish their rectangles on layout, the root keeps them, and the indicator springs between them on the UI thread — so it keeps travelling while whatever the new tab shows is mounting.

  Softer than the chevron's spring: damping 20 against stiffness 220 at mass 0.6. That one turns 180 degrees and must not overshoot; this one slides a few dozen points, and a touch of overshoot is what makes it feel attached to the press. Its first placement jumps rather than springing — animating it would slide the pill in from the start of the row on mount, which reads as the tab bar arranging itself rather than as a control at rest.

  Tabs.Indicator is written by the caller, inside the list. Leaving it out is a legitimate bar, where the label's colour is the only thing saying which tab is chosen, and that is why it is a slot rather than something the list conjures.

  Three shapes, not three emphases. primary is the segmented control — a pill inside a filled track; secondary is the underline; light is neither, with no track and no rule and nothing but the chosen tab's label going to the accent. Different affordances rather than the same one louder, which is why the union is three rather than the usual four. All three read the same roles, so a tint lands on any of them through the same names — painting a pill, a rule or a word.

  light names no bg and no bgSelected, and that is how it has no track and no rule rather than an omission: paint resolves both to nothing, so the list stays transparent and the indicator, with no fill and no compound to give it a size, draws nothing even when a caller leaves <Tabs.Indicator /> in place. Its chosen label goes to the accent rather than the foreground, because with nothing else moving the colour is the whole signal, and a tab merely darker than its neighbours is not chosen — it is just darker.

  A tab is named, not numbered. The legacy component took an activeIndex, which breaks the moment a tab is inserted.

  A panel is mounted only while its tab is chosen. A tab bar over four screens of content should not have four screens of content mounted; a panel that must keep its state across a switch is one the caller holds the state for, which is the same trade every router makes.

  No xs: a tab is a target before it is a label, and at that height there is nothing left of it.

  A scrollable list and Tabs.Separator are not here. Centring the chosen tab when the bar overflows means the indicator has to account for a scroll offset the triggers' own layout does not report, which is worth its own change.