js-rich-body-highlighter

A premium, framework-agnostic muscle map. Instead of flat polygon fills (the look every other body-highlighter library ships), it highlights muscles with mix-blend-mode over a detailed body illustration. The color settles into the grooves between muscle bundles, so each muscle looks lit from within and three-dimensional rather than painted flat. That richer look is the whole point.

• Framework-agnostic core in plain TypeScript, zero runtime dependencies.
• Wrappers for React, Vue, Svelte, and a <muscle-map> Web Component (which also covers Angular and anything else). Each framework runtime is an optional peer dependency, so you never pull in one you don't use.
• Full body set: male + female, front + back, light + dark, with 14 muscle groups masked on each view.
• Data-driven: highlight by muscle group (or individual mask id), each with its own intensity (0–100) and optional color.
• Adaptive size for free: image and masks share one SVG viewBox, so sizing the <svg> scales everything together — just give it a width.

Install

npm install js-rich-body-highlighter

Usage

Core (any framework / vanilla)

import { MuscleMap } from 'js-rich-body-highlighter';

const map = new MuscleMap(document.querySelector('#app')!, {
  gender: 'female',
  view: 'front',
  width: 360,
  highlights: [
    { group: 'chest', intensity: 70 },
    { group: 'abs', intensity: 45, color: '#22c55e' },
  ],
  onMuscleClick: (muscle) => console.log(muscle.group), // 'chest', 'abs', …
});

map.update({ highlights: [{ group: 'quads', intensity: 60 }] });
map.destroy();

React

import { MuscleMap } from 'js-rich-body-highlighter/react';

<MuscleMap
  gender="female"
  view="back"
  width={360}
  highlights={[{ group: 'lats', intensity: 70 }]}
  onMuscleClick={(muscle) => console.log(muscle.group)}
/>;

Vue 3

<script setup lang="ts">
import { MuscleMap } from 'js-rich-body-highlighter/vue';
</script>

<template>
  <MuscleMap gender="female" view="back" :width="360"
    :highlights="[{ group: 'lats', intensity: 70 }]"
    @muscle-click="(m) => console.log(m.group)" />
</template>

Svelte (action — no Svelte runtime dependency)

<script lang="ts">
  import { muscleMap } from 'js-rich-body-highlighter/svelte';
  const options = { gender: 'female', highlights: [{ group: 'chest', intensity: 70 }] };
</script>

<div use:muscleMap={options}></div>

Web Component — <muscle-map> (and Angular)

The universal wrapper. Works in plain HTML and in any framework. Simple values are attributes; complex values (highlights, registry, bodySrc) are properties; hover/click are DOM CustomEvents.

import 'js-rich-body-highlighter/web-component';

const el = document.querySelector('muscle-map')!;
el.highlights = [{ group: 'chest', intensity: 70 }];
el.addEventListener('muscleclick', (e) => console.log(e.detail.muscle.group));

<muscle-map gender="female" view="front" width="360"></muscle-map>

In Angular, import the element once and add CUSTOM_ELEMENTS_SCHEMA to your component/module, then use <muscle-map> in the template and set [highlights] / listen to (muscleclick) as usual. (A custom element is Angular's officially supported way to use non-Angular UI and works in AOT/production builds.)

Highlighting

A highlight targets a group (recommended — most callers think in groups) or a single mask id, with an intensity of 0–100 and an optional per-entry color:

highlights: [
  { group: 'chest', intensity: 70 },              // both pecs, red (the default)
  { group: 'biceps', intensity: 50, color: '#22c55e' }, // green
  { id: 'rectus_abdominis_female', intensity: 30 }, // one specific mask
];

Targeting by group resolves to every mask of that group in the current gender + view, so one entry lights up both bodies and both genders. Hovering a muscle highlights it too (hoverHighlight, hoverIntensity, optional hoverColor for a distinct tint).

Muscle groups

chest, shoulders, biceps, triceps, forearms, abs, obliques, upper_back, lats, lower_back, glutes, quads, hamstrings, calves.

Exported as MUSCLE_GROUPS (in head-to-toe order) for building legends, pickers, or presets.

Options

| Option | Type | Default | Notes | | ----------------------------------------------- | --------------------------------------------- | ------------- | ----- | | gender | 'male' \| 'female' | 'male' | picks body + mask set | | view | 'front' \| 'back' | 'front' | | | theme | 'light' \| 'dark' | 'light' | swaps body image only | | width | number \| string | '100%' | px number or CSS string | | height | number \| string | 'auto' | derived from body aspect ratio | | highlights | { id?, group?, intensity, color? }[] | [] | intensity 0–100 | | color | string | '#ff0000' | global highlight color | | blendMode | string | 'multiply' | any CSS mix-blend-mode | | hoverHighlight | boolean | true | highlight on hover | | hoverIntensity | number | 35 | 0–100 | | hoverColor | string | muscle color | distinct tint for the hovered muscle | | bodySrc | string \| { front?, back? } | bundled image | bring your own image(s) | | registry | MuscleDefinition[] | built-in | custom muscle set | | onMuscleEnter / onMuscleLeave / onMuscleClick | (muscle, event) => void | — | muscle is { id, group, name } |

How it works

• The body is a raster image at (0,0) inside an <svg>. Each muscle is a <path> traced over it, filled with the highlight color and blended with mix-blend-mode: multiply. Intensity is the path's opacity (0–100 → 0–1).
• The <svg> is isolation: isolate, so the blend only affects the body image, not the page behind it.
• Image and masks share one viewBox (0 0 361.16 541.87, the 1365×2048 body at 96 DPI), so sizing the <svg> scales everything together.

Bundle & images

The 8 bodies are WebP, ~0.66 MB total (≈100 KB each). They are referenced with new URL('./bodies/<file>', import.meta.url), which modern bundlers (Vite / webpack 5 / Rollup) emit as separate asset files — not inlined into your JS bundle. At runtime only the single visible body is fetched (~100 KB), not the whole set. The JS engine itself is ~30 KB gzipped.

To keep images out of your build entirely (e.g. serve from a CDN), pass bodySrc (a single URL, or { front, back }); it wins over the bundled default.

License

MIT