Font

TrueType

A .ttf file is the case the package handles completely: read, write, subset. Its glyph shapes are quadratic glyf outlines, and its signature is 0x00010000, or true for fonts produced by Apple tools; both load and are reported as FontFormat::TrueType, whatever the file extension. Every other container is read into the same table structure and written back from it.

Reading

<?php

use Alto\Font\Font;

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

printf("%s, %d glyphs\n", $font->metadata()->format->value, $font->face()->glyphCount);

Compound glyphs, which reference other glyphs, are supported. TrueType instructions and their tables (cvt , fpgm, prep, gasp) are read and preserved; see Hinting. A TrueType file whose fvar table declares axes is a variable font; see Variable fonts.

Writing

SfntWriter writes any loaded face as a standalone TrueType file. An unchanged standalone source is written byte for byte; a collection face, a decoded WOFF or WOFF2, or a subset gets a rebuilt table directory and checksums. See Writing.

Subsetting

Subsetting rewrites glyf, loca, cmap, the metrics tables, and the supported layout and variation tables. Which tables survive, and under which policy, is listed in Tables.

Requirements and limits

  • Reading and writing need PHP 8.4 with the Iconv and Zlib extensions, nothing else.
  • Outlines must be glyf; a file with the OTTO signature is OpenType with CFF outlines.
  • Bitmap and color glyph data in EBDT, CBDT, sbix, COLR, and SVG is not rendered.