How the Font File Viewer Works
AnyTool parses fonts with opentype.js to read the name table, metrics, cmap, GSUB/GPOS feature lists, and variable-font fvar axes, rendering live text via the browser FontFace API. WOFF2 files are Brotli-compressed, so they are first decompressed with a self-hosted wawoff2 WASM module and then parsed, with parsing run in a Web Worker so large CJK fonts stay responsive. The interface presents a searchable glyph grid with Unicode-block filtering, a metadata panel, OpenType feature toggles, variable-axis sliders, an editable specimen, and a multi-size waterfall.
- Supports TTF, OTF, WOFF, and WOFF2
- Glyph grid with codepoints, names, search, and block filtering
- OpenType feature toggles and variable-axis sliders
- Live specimen and waterfall via the FontFace API
- Virtualized glyph rendering for large CJK/emoji fonts
