Draw the button group without Tailwind

Plan step 36. <x-button-group> renders data-md-button-group (standard or
connected), data-md-size, data-md-shape and, with a selection,
data-md-selection and data-md-selection-required. button-group.css now
also draws the standard group: its gaps per size, the square corner scale
it hands its buttons, and the press expansion that widens a pressed label
button while its neighbours give way. groups.css keeps only the split
button until that is rewritten too.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
This commit is contained in:
Andreas Reinhold / reini
2026-09-14 14:59:18 +02:00
co-authored by Claude Opus 5
parent b8c6d411db
commit 8dd0a7ef9d
5 changed files with 156 additions and 145 deletions
+21 -104
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@@ -1,87 +1,32 @@
/*
* Button groups and split buttons: shapes that depend on a button's place among its siblings.
* Split buttons: shapes that depend on a button's place beside its other half. Button groups and
* `<x-group>` draw theirs from resources/css/components/button-group.css.
*
* Unlayered on purpose. Each <x-button> draws its own corners and padding as utilities, and a
* rule in any @layer loses to a utility whatever its specificity; the group has to win.
* Unlayered on purpose, until the split button leaves Tailwind too.
*
* Standard group (`<x-button-group>`): pressing a label button widens it and narrows its
* neighbours by the same amount, so the row keeps its length — Expressive's press expansion
* (ButtonGroupDefaults.ExpandedRatio is 15%; this uses a fixed step per size). Icon buttons keep
* their width.
*
* Connected group (`<x-button-group connected>`, `<x-group>`): 2px apart, the outer corners
* full, the inner corners small, smaller still while pressed, and a selected segment fully round
* (ConnectedButtonGroupSmallTokens and the M3 Expressive connected button group spec).
*
* Shape (`shape="square"`, M3's "Default shape | Round, square" configuration): `--group-outer`
* is what the two ends of a group round to — half the height for a round group, and for a square
* one the same corner its inner edges take, which is the square table M3 publishes for connected
* groups (4/8/8/16/20dp by size). A square *standard* group has no inner edges, so it hands its
* buttons the square corner scale `<x-button shape="square">` draws (`--group-square`, and
* `--group-square-pressed` under the finger) instead of asking the caller to write it on each
* one. Selection morphs the other way in both: M3 has a toggle inside a group "swap shape
* square/round on selection", so a selected button in a square group turns round, which is why
* the selected rules keep `--group-full` rather than `--group-outer`.
*
* Split button (`<x-split-button>`): the same idea for two halves, on its own corner scale —
* SplitButton*Tokens gives the inner corner 4/4/4/8/12px at rest and *grows* it to 8/12/12/20/20px
* under the finger, the opposite of a connected group, so `--split-inner*` is separate from
* `--group-inner*`. The trailing half turns round and its chevron turns over while its menu is
* open, on M3's standard scheme rather than the expressive springs (the site: "the trailing
* button uses the standard motion scheme, not expressive, when rotating"), and the chevron sits
* a little towards the leading half so the pair reads as one control (`--split-nudge`:
* 1/1/2/3/6px). `--split-icon` is the trailing icon's own size, 22/22/26/38/50px, which the
* icon-button table does not know about.
* Split button (`<x-split-button>`): two halves on their own corner scale — SplitButton*Tokens
* gives the inner corner 4/4/4/8/12px at rest and *grows* it to 8/12/12/20/20px under the finger,
* the opposite of a connected group. The trailing half turns round and its chevron turns over
* while its menu is open, on M3's standard scheme rather than the expressive springs (the site:
* "the trailing button uses the standard motion scheme, not expressive, when rotating"), and the
* chevron sits a little towards the leading half so the pair reads as one control
* (`--split-nudge`: 1/1/2/3/6px). `--split-icon` is the trailing icon's own size,
* 22/22/26/38/50px, which the icon-button table does not know about.
*
* "Full" here is half the size's height (`--group-full`), never `--md-sys-shape-corner-full`'s
* 9999px. One element mixes full outer corners with small inner ones, and when a box's radii
* add up to more than its side, CSS scales every radius by the same factor: a 9999px corner
* beside an 8px one shrank the 8px one to a hundredth of a pixel, so the inner corners drew
* square.
* 9999px: when a box's radii add up to more than its side, CSS scales every radius by the same
* factor, and a 9999px corner beside an 8px one drew the inner corners square.
*/
[data-button-group] {
--group-inner: var(--md-sys-shape-corner-sm);
--group-inner-pressed: var(--md-sys-shape-corner-xs);
--group-full: 1.25rem;
--group-square: var(--md-sys-shape-corner-md);
--group-square-pressed: var(--md-sys-shape-corner-sm);
--group-outer: var(--group-full);
}
[data-button-group][data-size='xs'] { --group-pad: 1rem; --group-grow: 4px; --group-inner: var(--md-sys-shape-corner-xs); --group-inner-pressed: 2px; --group-full: 1rem; }
[data-button-group][data-size='sm'] { --group-pad: 1rem; --group-grow: 6px; --group-full: 1.25rem; }
[data-button-group][data-size='md'] { --group-pad: 1.5rem; --group-grow: 8px; --group-full: 1.75rem; --group-square: var(--md-sys-shape-corner-lg); --group-square-pressed: var(--md-sys-shape-corner-md); }
[data-button-group][data-size='lg'] { --group-pad: 3rem; --group-grow: 16px; --group-inner: var(--md-sys-shape-corner-lg); --group-inner-pressed: var(--md-sys-shape-corner-md); --group-full: 3rem; --group-square: var(--md-sys-shape-corner-xl); --group-square-pressed: var(--md-sys-shape-corner-lg); }
[data-button-group][data-size='xl'] { --group-pad: 4rem; --group-grow: 20px; --group-inner: var(--md-sys-shape-corner-lg-increased); --group-inner-pressed: var(--md-sys-shape-corner-lg); --group-full: 4.25rem; --group-square: var(--md-sys-shape-corner-xl); --group-square-pressed: var(--md-sys-shape-corner-lg); }
/* A square group's ends take the corner its inner edges take — M3's square table for connected
groups — and a square standard group hands its buttons the button's own square scale. */
[data-button-group][data-shape='square'] { --group-outer: var(--group-inner); }
[data-button-group='standard'][data-shape='square'] > * {
border-radius: var(--group-square);
}
[data-button-group='standard'][data-shape='square'] > :active:not(:disabled, [aria-disabled='true']) {
border-radius: var(--group-square-pressed);
}
[data-button-group='standard'][data-shape='square'] > [aria-pressed='true'] {
border-radius: var(--group-full);
}
[data-button-group='standard'] > :not([data-md-icon-button]):active:not(:disabled, [aria-disabled='true']) {
padding-inline: calc(var(--group-pad) + var(--group-grow));
}
[data-button-group='standard'] > :not([data-md-icon-button]):has(+ :not([data-md-icon-button]):active:not(:disabled, [aria-disabled='true'])) {
padding-inline-end: calc(var(--group-pad) - var(--group-grow));
}
[data-button-group='standard'] > :not([data-md-icon-button]):active:not(:disabled, [aria-disabled='true']) + :not([data-md-icon-button]) {
padding-inline-start: calc(var(--group-pad) - var(--group-grow));
}
[data-button-group][data-size='xs'] { --group-full: 1rem; }
[data-button-group][data-size='md'] { --group-full: 1.75rem; }
[data-button-group][data-size='lg'] { --group-full: 3rem; }
[data-button-group][data-size='xl'] { --group-full: 4.25rem; }
[data-button-group='split'] { --split-inner: var(--md-sys-shape-corner-xs); --split-inner-pressed: var(--md-sys-shape-corner-md); --split-icon: 22px; --split-nudge: 1px; }
[data-button-group='split'][data-size='xs'] { --split-inner-pressed: var(--md-sys-shape-corner-sm); }
@@ -89,58 +34,30 @@
[data-button-group='split'][data-size='lg'] { --split-inner: var(--md-sys-shape-corner-sm); --split-inner-pressed: var(--md-sys-shape-corner-lg-increased); --split-icon: 38px; --split-nudge: 3px; }
[data-button-group='split'][data-size='xl'] { --split-inner: var(--md-sys-shape-corner-md); --split-inner-pressed: var(--md-sys-shape-corner-lg-increased); --split-icon: 50px; --split-nudge: 6px; }
/*
* A connected segment at the two smallest sizes is 32px or 40px tall, and an icon-only one is as
* narrow as it is tall. M3 names both numbers and tells you not to reduce them: "XS and S
* connected button groups have a 48dp target area and a 48dp minimum width". The target is the
* `touch-target` utility on the segment itself; the width is here, where a group can reach the
* `<x-button>`s a caller put inside it.
*/
[data-button-group='connected'][data-size='xs'] > *,
[data-button-group='connected'][data-size='sm'] > * {
min-inline-size: 3rem;
}
/*
* Connected segments and split halves take their inner corner from `--group-corner`, so pressing
* or selecting changes one variable and the rounded outer corners stay put.
*/
[data-button-group='connected'] > *,
/* The halves take their inner corner from `--group-corner`, so pressing changes one variable and
the rounded outer corners stay put. */
[data-split] {
--group-corner: var(--split-inner);
border-start-start-radius: var(--group-corner);
border-end-start-radius: var(--group-corner);
border-start-end-radius: var(--group-corner);
border-end-end-radius: var(--group-corner);
}
[data-button-group='connected'] > * {
--group-corner: var(--group-inner);
}
[data-button-group='connected'] > :active {
--group-corner: var(--group-inner-pressed);
}
[data-split] {
--group-corner: var(--split-inner);
}
[data-split]:active {
--group-corner: var(--split-inner-pressed);
}
[data-button-group='connected'] > :is([aria-pressed='true'], :has(:checked)),
[data-split='trailing'][aria-expanded='true'] {
--group-corner: var(--group-full);
}
[data-button-group='connected'] > :first-child,
[data-split='leading'] {
border-start-start-radius: var(--group-outer);
border-end-start-radius: var(--group-outer);
}
[data-button-group='connected'] > :last-child,
[data-split='trailing'] {
border-start-end-radius: var(--group-outer);
border-end-end-radius: var(--group-outer);