Row deficit distribution (layout/row.rs). `Row` knew how to hand out leftover width but had no notion of a shortfall: `leftover` was floored at zero and every child was laid out at its preferred width, so a cluster wider than its rect simply overflowed — and symmetrically, because the no-spacer branch centres the block, which is why both end labels of a segmented control were clipped at once rather than only the trailing one. The shortfall now comes off the widest children first, by water filling: `width_cap` sorts the flexible widths and returns the largest per-child cap `c` for which `sum( min( w, c ) ) <= available`, so a long title absorbs the whole deficit while an icon button beside it keeps its size, and equal siblings — a segmented control — share it evenly. A uniform scale-down, which was the first attempt, was wrong precisely there: it thinned a header's back arrow along with the title it sat next to. Spacers and flex children stay out of the flexible set, so a pinned gap keeps the width it was given — an explicit spacer is a decision, not slack — and `Row::no_shrink()` opts a row out entirely, for strips deliberately wider than their viewport such as a carousel rail meant to be scrolled. `align_right` and the centring branch now measure the laid width rather than the preferred one, so a shrunken row is positioned against what it actually occupies.
Button label elision (widget/button/mod.rs, widget/mod.rs, widget/list_item/mod.rs). Shrinking a row is only half the fix: a leaf handed less width than it asked for still painted its full string, so the deficit came out clipped instead of truncated. `draw_text_button` now elides the label against the rect the layout granted, less the horizontal padding, for all three variants. The truncation rule moves out of `ListItem`, where it was a private helper, into a single crate-internal `widget::elide` the two share. `Text` keeps its own inline copy for now: it measures through an optional font override that this signature does not carry, and folding the two together is a separate change.
icon_size as a Length (widget/button/mod.rs). `Button::icon_size` was the one geometry setter that ignored the widget-scaling mode — it took a bare `f32`, pinned it, and used `0.0` as the "unset" sentinel. It now takes `impl Into<Length>` behind an `Option` and resolves through `Canvas::resolve_geom`, the way `height`, `width` and `font_size` already do. A bare number still means `Length::px`, so every existing call keeps its exact size; what it adds is `Length::widget( n )`, which follows the active mode the way stock icons do. Without it a back arrow pinned at 21 px sat next to a `list_item` chevron that fluid sizing had grown well past 21, and read as visibly smaller on the same row.
Pedro M. de Echanove Pasquin
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