Font

Compression

Compress a font when it is served over the network. WOFF and WOFF2 wrap the same tables in a compressed container; the browser unpacks them, so nothing changes in the glyphs, hinting, or layout. Compression happens while writing, through the writer you choose, and it combines with subsetting: subset first to remove glyphs, then write a compressed container.

  • Writing WOFF2 produces the smallest container, with the PHP Brotli extension or the brotli executable.
  • Adapters plugs in your own Brotli implementation and covers streaming, memory, and runtime checks.
  • Sizes lists measured sizes for TTF, WOFF, and WOFF2, with and without subsetting.

Choose WOFF or WOFF2

Write WOFF2 when you can: every current browser accepts it, and on the bundled Inter Latin sample it is 27% smaller than WOFF. Writing it needs Brotli, which PHP does not ship; Writing WOFF2 shows the two ways to provide it. Write WOFF when Brotli is not available in the runtime that produces the files: it needs only the Zlib extension, which the package already requires.

For the complete sample face, the TTF measures 66,912 bytes, the WOFF 31,792, and the WOFF2 23,272 at maximum quality.

Write a WOFF file

<?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');

Each table is compressed with Zlib at level 6, and stored as it is when compression would not make it smaller. There is nothing to configure.

Write a WOFF2 file

<?php

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

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

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

Woff2Writer takes the compressor explicitly, even when Brotli is installed, so that the dependency is visible in your code. Replace BrotliExtensionCompressor with BrotliProcessCompressor to use the brotli executable; see Writing WOFF2.