Module: Ucode::Glyphs::EmbeddedFonts

Defined in:

lib/ucode/glyphs/embedded_fonts.rb,
lib/ucode/glyphs/embedded_fonts/svg.rb,
lib/ucode/glyphs/embedded_fonts/source.rb,
lib/ucode/glyphs/embedded_fonts/writer.rb,
lib/ucode/glyphs/embedded_fonts/catalog.rb,
lib/ucode/glyphs/embedded_fonts/renderer.rb,
lib/ucode/glyphs/embedded_fonts/tounicode.rb,
lib/ucode/glyphs/embedded_fonts/font_entry.rb,
lib/ucode/glyphs/embedded_fonts/content_stream_correlator.rb

Overview

Code Charts PDF font-stream extraction — pillar 1 of the v0.2 glyph strategy.

The Unicode Code Charts PDFs (per-block or the ‘CodeCharts.pdf` monolith) embed one subsetted CID-keyed font per “script group” shown in the charts. Each font is a Type0 font whose descendant CIDFont uses `/CIDToGIDMap /Identity` — so the 2-byte character code used in the page’s text-show operators IS the GID into the embedded font program. The codepoint mapping lives in the Type0 font’s ‘/ToUnicode` CMap stream.

The pipeline is therefore:

1. {Catalog} walks the PDF's fonts (via `mutool info`) and builds
   a global `{codepoint => [font_entry, gid]}` index by parsing
   every Type0 font's ToUnicode CMap.
2. {Renderer} looks up a codepoint, lazily extracts the font's
   stream to a cache file, loads it via `fontisan`, and asks for
   the outline at the resolved GID.
3. {Svg} wraps the fontisan outline as a standalone SVG document
   (y-flipped, viewBox-padded) — same shape as the LastResort
   SVGs so downstream consumers don't care which pillar produced
   the glyph.

The v0.1 cell extractor operated on rendered PDF pages and was defeated by the chart cell border being composited into the same glyph as the outline. Going straight to the embedded font program sidesteps that bug entirely: the font’s outlines are clean vector geometry with no page chrome.

System dependency: ‘mutool` (mupdf-tools) is on the PATH. Used for `mutool info` (font enumeration) and `mutool show -b -o` (raw stream extraction).

Defined Under Namespace

Modules: ToUnicode Classes: Catalog, ContentStreamCorrelator, FontEntry, Renderer, Source, Svg, Writer