Font

Compress WOFF2 output

WOFF2 writing requires an explicit Brotli compressor. This keeps extension and process choices outside the writer API.

Reading is different: the loader automatically tries the Brotli extension and then the brotli executable.

Use the Brotli extension

<?php

use Alto\Font\Compression\BrotliCompressionProfile;
use Alto\Font\Compression\BrotliExtensionCompressor;
use Alto\Font\Writer\Woff2Writer;

$brotli = new BrotliExtensionCompressor(
    BrotliCompressionProfile::Maximum,
);

new Woff2Writer($brotli)->write(
    $font,
    __DIR__.'/output/font.woff2',
);

The extension must expose brotli_compress() and BROTLI_FONT. Maximum uses quality 11 and is the default. Fast uses quality 5 for faster iterative builds.

Use the Brotli executable

<?php

use Alto\Font\Compression\BrotliCompressionProfile;
use Alto\Font\Compression\BrotliProcessCompressor;
use Alto\Font\Writer\Woff2Writer;

$brotli = new BrotliProcessCompressor(
    profile: BrotliCompressionProfile::Fast,
);

new Woff2Writer($brotli)->write(
    $font,
    __DIR__.'/output/font.woff2',
);

The binary defaults to brotli from PATH; the profile defaults to Maximum. Pass binary: '/opt/homebrew/bin/brotli' when a macOS installation is not available through PATH.

The process adapter requires proc_open(), a writable temporary directory, and enough temporary disk space for the transformed and compressed streams.

Choose dump() or write()

dump() returns the complete WOFF2 file as one string. write() with BrotliProcessCompressor streams data at the compression boundary through temporary resources. The parsed font document and WOFF2 table transforms still exist in memory, so this is not a constant-memory promise for the complete operation.

The extension adapter implements string compression only. Its write() path therefore materializes the same compressed data used by dump().

Implement a custom compressor

Implement BrotliCompressorInterface::compress() to return one raw Brotli stream for the supplied WOFF2 table data. Do not add a WOFF2 header, length prefix, or padding.

An implementation may also implement BrotliStreamCompressorInterface. compressStream() reads from the input's current position through EOF, writes at the output's current position, leaves both resources open, and does not rewind them.

Missing extension support, unavailable temporary resources, an unavailable executable, non-zero process exits, and extension compression calls that report failure raise CompressionException.