func (p TabViewPainter) PaintTabBar(canvas widget.Canvas, ps tabview.PaintState) {
	if ps.Bounds.IsEmpty() {
		return
	}

	colors := ps.ColorScheme
	if colors == (tabview.TabColorScheme{}) {
		colors = p.resolveColors()
	}

	// Tab bar background.
	canvas.DrawRect(ps.Bounds, colors.Background)

	// Draw each tab.
	for i := range ps.Tabs {
		ts := &ps.Tabs[i]
		flPaintTab(canvas, ts, colors)
	}

	// Selected indicator.
	if ps.SelectedIdx >= 0 && ps.SelectedIdx < len(ps.Tabs) {
		selected := &ps.Tabs[ps.SelectedIdx]
		flPaintTabIndicator(canvas, selected.Bounds, ps.Position, colors.Indicator)
	}

	// Focus ring.
	if ps.Focused {
		innerBounds := ps.Bounds.Expand(-flTabFocusRingInset)
		canvas.StrokeRoundRect(innerBounds, colors.FocusRing, flTabFocusRadius, flTabFocusRingStroke)
	}
}

type TabViewPainter struct {
	Theme *Theme	// nil uses default Fluent Blue fallback
}