Favicon

Rasterizers

ALTO Favicon selects rasterizer adapters according to the source extension and tries each available adapter until one succeeds.

SVG pipeline

SvgRasterizer tries these adapters in order:

  1. rsvg-convert.
  2. Inkscape.
  3. ImageMagick CLI through magick or convert.
  4. The Imagick PHP extension.

The original SVG is copied to icon.svg, while the selected adapter produces the PNG sizes used by the remaining output files.

PNG pipeline

PngRasterizer tries the Imagick PHP extension first and GD second. PNG input also produces 16 by 16 and 32 by 32 PNG fallbacks because there is no vector icon to publish.

Failure behavior

An adapter failure is logged and the next adapter is tried. Generation raises RasterizerUnavailableException only when no compatible adapter completes the requested conversion.

Applications can inject their own RasterizerInterface implementations into FaviconGenerator:

<?php
$generator = new FaviconGenerator(rasterizers: [$customRasterizer]);

The custom rasterizer must declare whether it supports the input file and write the requested square PNG to the supplied destination.