PrawnEx.Font.TrueType (prawn_ex v0.5.0)

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Minimal TrueType (sfnt) parser — just enough metadata to embed a font in a PDF as a simple /TrueType font with WinAnsi encoding.

Reads the table directory and pulls what the PDF FontDescriptor and /Widths array need: units per em, bounding box, ascent/descent, cap height, italic angle, weight, and per-character advance widths for the WinAnsi range (32..255).

CFF-flavoured OpenType (OTTO) is rejected: those need /FontFile3, which is out of scope for now.

Summary

Functions

parse(font)

Parses a TTF binary. Returns {:ok, metrics} or {:error, reason}.

Functions

parse(font)

@spec parse(binary()) :: {:ok, map()} | {:error, atom()}

Parses a TTF binary. Returns {:ok, metrics} or {:error, reason}.

Metrics (all font-design values already scaled to a 1000-unit em, as PDF expects):

  • :ascent, :descent, :cap_height, :italic_angle, :bbox
  • :stem_v — estimated from the OS/2 weight class
  • :widths — advance widths for WinAnsi codes 32..255, in order