Font

WOFF2

WOFF2 is the container to write for browsers: the smallest, and accepted by every current one. It packages an sfnt font whose tables are transformed and Brotli-compressed, referenced from CSS through @font-face. Its signature is wOF2, and the package reports it as FontFormat::Woff2.

Reading

Loading a WOFF2 file decompresses it with the PHP Brotli extension when it is loaded, otherwise with the brotli executable found on PATH. If neither is available, loading fails with UnsupportedFontException rather than returning incomplete data; a stream that fails to decompress raises InvalidFontException.

<?php

use Alto\Font\Font;

$font = Font::fromFile(__DIR__.'/fonts/Inter-Regular.woff2');

echo $font->metadata()->format->value; // woff2

Transformed glyf, loca, and hmtx tables are supported for single-font files. WOFF2 collections are rejected explicitly. The reconstructed font keeps the same functionality as the original sfnt, not necessarily the same bytes.

Writing

Woff2Writer requires a Brotli compressor, even when the extension is installed, so that the application decides between the PHP extension, a child process, or its own implementation. Compression shows both adapters, the quality profiles, and the memory behavior.

Output updates the required head.flags, may reconstruct glyf, loca, and hmtx canonically, and removes DSIG. Extended metadata and private data blocks of a source WOFF2 are not carried over when the font is written again. For the bundled Inter sample, the complete face measures 23,300 bytes at maximum quality, against 66,912 bytes as TTF.

Subsetting

Subset first, then write the result with Woff2Writer; the container does not change what a subset keeps. See Subsetting.

Requirements and limits

  • Reading needs ext-brotli, or the brotli executable on the runtime's PATH.
  • Writing needs an explicit BrotliCompressorInterface passed to Woff2Writer.
  • Collections are not supported; use the TTC or OTC source instead.
  • Outlines must be TrueType glyf, as for every other container.

When Brotli is installed but WOFF2 still fails, the PHP process that runs your script is usually not the one you tested in a terminal; see Adapters.