Font

Reading files

Load a font from a path or from bytes, then read the face it contains. Loading leaves the source unchanged.

Load a file

Pass the path of a TrueType, OpenType, WOFF, or WOFF2 file:

<?php

use Alto\Font\Font;

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

ALTO Font detects the container from its signature instead of trusting the file extension. A TTC or OTC collection contains several faces; pass a zero-based faceIndex to select one:

<?php

use Alto\Font\Font;

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

Standalone files accept only index zero. Read Formats for the supported containers and outlines, and Find to select a file by family, weight, and style instead of a path.

Load from memory

When the font bytes come from a database, an upload, or another document, load them without writing a temporary file:

<?php

use Alto\Font\Font;

$font = Font::fromBytes($bytes);

Font::fromBytes(string $data, int $faceIndex = 0) uses the same parser and the same signature detection as fromFile(). face()->path is <memory>. WOFF2 bytes keep their Brotli requirement and may use the configured process-backed decompressor.

Read the loaded face

A Font represents one loaded face. These methods expose its data:

  • Font::fromFile(string|Stringable $file, int $faceIndex = 0): Font reads a local file immediately, detects its container from the bytes, and selects a zero-based face in a TTC or OTC collection.
  • Font::fromBytes(string $data, int $faceIndex = 0): Font loads a supported container from memory.
  • face(): FontFace returns structural data for the loaded face: original path, container, dimensions, glyph count, and table tags.
  • metadata(): FontMetadata returns names, version, license fields, and the detected format. See Metadata.
  • descriptor(): FontDescriptor returns the family, weight, style, and stretch used by font discovery. It does not implement the full CSS font-matching algorithm.
  • metrics(): FontMetrics returns declared default-instance bounds and global metrics. See Metrics.

FontFace is readonly. Its public properties are:

  • path and format hold the source label and the detected FontFormat.
  • faceIndex and faceCount hold the selected zero-based face and the number of faces in the source.
  • unitsPerEm, ascender, and descender are design-unit dimensions. Divide a measurement by unitsPerEm and multiply by the target size to scale it.
  • glyphCount counts glyph slots, including empty slots retained by preserve-mode subsetting.
  • tables lists the available table tags, not raw table bytes.
  • names holds decoded name fields keyed by name ID; name(int $nameId): ?string returns one value or null.

Some table validation occurs when the requested data is accessed, so a successful load does not guarantee that every later operation succeeds.

When loading fails

Missing, unreadable, empty, or malformed files and invalid face selections raise InvalidFontException, and so does a WOFF2 stream that fails to decompress. Valid but unsupported structures raise UnsupportedFontException: CFF outlines, WOFF2 collections, or a WOFF2 file when neither ext-brotli nor the brotli executable is available. An .otf extension does not tell you which outlines the file holds, and renaming a file changes nothing: the signature decides, see Formats. Errors describes each exception.

Next

Continue with Glyphs to map characters and measure them, Variable fonts to select a weight, or Subset to keep only the characters you need.