whaticon

Find matching Iconify icons by visual similarity.

Given an SVG, whaticon renders it and compares against indexed icons using perceptual hashing to find the closest matches.

Installation

npm install whaticon

CLI Usage

# Find matches for an SVG file
npx whaticon icon.svg

# Find similar icons to a known icon
npx whaticon --icon lucide:home

# Limit to specific icon sets
npx whaticon icon.svg --prefix lucide,tabler

# Prefer certain icon sets (sorted first at equal similarity)
npx whaticon icon.svg --prefer lucide

# Adjust threshold and limit
npx whaticon icon.svg --threshold 0.9 --limit 5

# Use different index size
npx whaticon icon.svg --index full    # 200k+ icons
npx whaticon icon.svg --index core    # ~10k icons (faster)

# JSON output
npx whaticon icon.svg --json

Options

Option	Description
-n, --limit <n>	Maximum results (default: 10)
-t, --threshold <n>	Minimum similarity 0-1 (default: 0.8)
-p, --prefix <sets>	Limit to icon sets (comma-separated)
--prefer <sets>	Prefer these icon sets (comma-separated)
-i, --index <variant>	Index: core, popular (default), full
-j, --json	Output as JSON

Index Variants

Variant	Icons	Size	Description
core	~10k	~0.4 MB	lucide, heroicons, tabler
popular	~57k	~1.8 MB	12 popular sets (default)
full	~200k+	~6 MB	All Iconify sets

The popular index is bundled with the package. Other variants are downloaded on first use to ~/.cache/whaticon/.

API Usage

import { findMatches, loadIndex } from 'whaticon'
import { ensureIndex } from 'whaticon/download'

// Ensure index is available (downloads if needed)
const { namesGz, hashesGz } = await ensureIndex('popular')
const index = loadIndex(namesGz, hashesGz)

// Find matches
const svg = '<svg>...</svg>'
const matches = await findMatches(svg, index, {
  limit: 5,
  threshold: 0.85,
  prefixes: ['lucide', 'mdi'],
  prefer: ['lucide']
})

console.log(matches)
// [
//   { name: 'lucide:home', similarity: 0.95 },
//   { name: 'mdi:home', similarity: 0.92 },
//   ...
// ]

Functions

findMatches(svg, index, options?)

Find matching icons from an index.

computeDHash(svg, size?)

Compute difference hash for an SVG. Returns 128-byte Buffer.

loadIndex(namesGz, hashesGz)

Load index from gzipped binary files.

ensureIndex(variant)

Ensure index is downloaded, returns gzipped buffers.

isIndexDownloaded(variant)

Check if index variant is cached locally.

Building Custom Index

import { buildIndex } from 'whaticon'
import { gzipSync, writeFileSync } from 'fs'

const icons = [
  { name: 'my:icon1', svg: '<svg>...</svg>' },
  { name: 'my:icon2', svg: '<svg>...</svg>' },
]

const { names, hashes } = await buildIndex(icons)

writeFileSync('names.txt.gz', gzipSync(names))
writeFileSync('hashes.bin.gz', gzipSync(hashes))

How It Works

1. Render: SVG is rendered to a 33×32 grayscale image using sharp
2. Hash: A difference hash (dHash) is computed — comparing adjacent pixels to produce 1024 bits
3. Match: Hamming distance between hashes determines similarity

Performance

• Index build: ~10,000 icons/sec (sprite sheet batching)
• Search: ~5ms per query (32-bit popcount optimization)
• Index size: ~30 bytes per icon (gzip compressed)

Index Format

Two gzip-compressed files:

• names.txt.gz — icon names, one per line
• hashes.bin.gz — 128 bytes per icon, concatenated

License

MIT