Chart legend

Chart legend data Primitive

The shared tail of every multi-series chart: swatch + series-name chips and a sample/series summary line.

Layer: L1 surface · Recipe: unset — see docs/agent/pick-a-surface.md. Curriculum: AGENTS.md; pick matrix: docs/agent/pick-a-surface.md; blast radius: CONSUMER_MAP.md.

  • Revenue
  • Costs

12 buckets · 2 series · peak £48,900

Copy this

html
<div class="hm-measure-lg">
  <ul class="chart-legend">
    <li class="chart-legend-item"><span class="chart-legend-swatch" style="background:var(--colour-brand)"></span><span class="chart-legend-name">Revenue</span></li>
    <li class="chart-legend-item"><span class="chart-legend-swatch" style="background:var(--colour-success)"></span><span class="chart-legend-name">Costs</span></li>
  </ul>
  <p class="chart-summary">12 buckets · 2 series · peak £48,900</p>
</div>

Server exchange

This Hyperpart has no server exchange — it is presentation or client chrome only. htmx does not issue a request on this part's behalf. If you put an affordance (hx-*) on a control that uses this markup, that action's exchange belongs to the action, not this part. See Swap contract for host-owned envelopes.

Swap contract

Agent-visible HTMX topology (ADR-0054 / decision 0012). exchange envelope = what the response may re-emit relative to the persistent slot (body_only | outer | none | host_owned | document). dual-lock validates part markup only — not this envelope. Stem: stems/morph-safe-hypermedia.md; decision: docs/decisions/0012-swap-identity-contract.md.

No host HTMX exchange on this part — presentation or client chrome only. exchange envelope: n/a.

If a host wraps this markup in hx-*, that host owns the swap contract (sole identity + envelope). Prefer innerMorph / outerMorph for stable slots; replacement for flash; body-only responses under inner swaps.

Envelope response examples

This part has no owned exchange (envelope n/a). If a host adds hx-*, that host’s envelope applies — typically body_only:

html
<!-- Host wraps this presentation part with hx-* (host owns envelope) -->
<!-- Prefer: hx-swap="innerMorph" hx-target="#panel-body" -->
<!-- Server returns body_only interior for #panel-body -->
<div class="dz-stack">content…</div>

Do not re-own the slot:

html
<!-- WRONG: server returns the presentation root with a new id every poll -->
<div id="chart-legend-root" data-dz-region>…</div>

How to use it

No extended guidance authored yet — start from Copy this and the dependency chips (Primitive = markup only; controller = load listed JS; Endpoint = implement Server exchange).

Seams

  • copy the partial under Copy this; keep root class and data-* modifiers so the CSS/JS bundle matches
  • no Server exchange on this part — pure presentation or client chrome
  • satisfy the DOM contract tables (CI stop-ship)

DOM contract

What the emitted HTML must satisfy — the table is the required surface; Python under contracts/ is the package-internal dual-lock CI runs (tests/test_contracts.py), not an app route. Standalone HTMX4: implement the API so responses match this markup. Dazzle: the agent emits SSR that already satisfies it. Do not invent attrs outside these tables. For request/response wiring see Server exchange.

contracts/chart_legend.py

Required in the DOM: root .chart-legend (part chart_legend). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

NodeAttrConstraint
.chart-legend——

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

python
"""HYPERPART: chart_legend — shared multi-series chart legend (swatch + name).

Dual-lock unit is the legend list root. Items, swatch colours, series names,
and the optional summary line are host-owned. Class ``.dz-chart-legend`` is
the stable substrate root (gallery CSS; no FragmentRenderer emit yet).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="chart_legend",
    root=".dz-chart-legend",
    nodes=(Node(".dz-chart-legend", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

Notes

Every SVG chart (line / area / radar / box-plot) ends with this pair instead of restyling it per chart: a <ul> of swatch + mono series-name items, and a mono summary line of bucket/series counts and the peak. The swatch background is the series colour the chart body uses for its strokes — inline, per series, server-assigned. Dual-lock root .chart-legend (HMC-142).

Source files

Canonical registration in the registry. No dedicated controller — CSS for this part lives in the layered bundle.

site/registry.py · contracts/chart_legend.py