Font

Font formats

Font::fromFile() detects the container from its signature. The reported format therefore remains correct when a file has no extension or a misleading extension.

Format Support Requirement or boundary
TrueType with glyf outlines Supported Includes compound glyphs
OpenType with glyf outlines Supported CFF and CFF2 outlines are rejected
WOFF 1 Supported Requires the Zlib extension
WOFF2 Supported Reading requires ext-brotli or the brotli executable; writing requires an explicit compressor
TTC and OTC collections Supported Select a face with faceIndex
WOFF2 collections Not supported Rejected explicitly
Variable glyf fonts Supported Includes fvar, avar, gvar, and HVAR; compact subsets can remap VVAR with vhea and vmtx
Color glyphs Not supported COLR, CPAL, SVG, sbix, CBDT, and CBLC are not rendered

Container and outline support does not guarantee that every table can be rewritten for compact subsetting. See OpenType subsetting support for layout offset limits and the boundaries of variable-font compaction. Static variable-font export and axis-range reduction are not supported.

Font collections

Select a zero-based face when loading a TrueType or OpenType collection:

<?php

use Alto\Font\Font;

$font = Font::fromFile(__DIR__.'/fonts/Collection.ttc', faceIndex: 1);

echo $font->face()->faceIndex;
echo $font->face()->faceCount;

An index outside the collection raises InvalidFontException.

WOFF2 decompression

WOFF2 uses Brotli compression. ALTO Font first uses the PHP Brotli extension when it is available, then falls back to the brotli command-line program. If neither is available, loading a WOFF2 file fails rather than silently returning incomplete data.

WOFF2 support includes transformed glyf, loca, and hmtx tables for single-font files.

Failure types

Catch the shared interface when the recovery action is the same for every font-loading problem:

<?php

use Alto\Font\Exception\FontExceptionInterface;
use Alto\Font\Font;

try {
    $font = Font::fromFile($path);
} catch (FontExceptionInterface $error) {
    // Reject the file or try another candidate.
}

Use UnsupportedFontException when you need to distinguish a valid but unsupported feature from an InvalidFontException caused by malformed data or an invalid selection.