Font

WOFF

Write WOFF when the font goes to a browser and Brotli is not available in the runtime that produces the files. It is the W3C container that wraps an sfnt font for @font-face, with each table optionally Zlib-compressed and an optional metadata block. Its signature is wOFF, and the package reports it as FontFormat::Woff.

Reading

Loading a WOFF file decompresses its tables with the required Zlib extension and exposes the same face as the original sfnt:

<?php

use Alto\Font\Font;

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

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

Writing

WoffWriter needs no configuration. Each table is compressed with Zlib level 6 and stored compressed only when that makes it smaller:

<?php

use Alto\Font\Font;
use Alto\Font\Writer\WoffWriter;

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

new WoffWriter()->write($font, __DIR__.'/output/inter.woff');

The extended metadata and private data blocks of a source WOFF are not carried over when the font is written again, and DSIG is removed. For the bundled Inter sample, the complete face measures 31,792 bytes as WOFF against 66,912 bytes as TTF. WOFF2 compresses the same face to 23,300 bytes; see Compression.

Subsetting

Subset first, then write the result with WoffWriter; see Subsetting.

Requirements and limits

  • Reading and writing need the Zlib extension, which the package requires.
  • Outlines must be TrueType glyf.
  • Metadata and private blocks are read but not preserved on output.