View Source Pdf.Reader.Encoding (ExPDF v1.0.1)

Encoding cascade facade for resolving PDF character codes to Unicode codepoints.

Spec reference: PDF 1.7 § 9.6.5 (Type1 encoding), § 9.10.3 (ToUnicode CMap).

Cascade priority (highest first)

  1. ToUnicode CMap — if a %Pdf.Reader.CMap{} is provided and the code is mapped, return that codepoint immediately.
  2. /Differences + AGL — if a /Differences map is provided and has a glyph name for this byte, resolve the glyph name through the Adobe Glyph List.
  3. Base encoding — one of :win_ansi, :mac_roman, or :standard (Standard Encoding).
  4. Unresolved fallback — emit {:unresolved, marker} where marker is the glyph name (from /Differences) or "byte:0xNN" if no glyph name is available.

resolve_byte/3 

resolve_byte(byte, cmap_or_nil, opts) :: {:ok, codepoint :: integer()} | {:unresolved, binary()}

Options:

  • :differences — %{integer() => glyph_name :: binary()} or nil

  • :base_encoding — :win_ansi | :mac_roman | :standard | nil

The caller substitutes U+FFFD for each {:unresolved, _} result and accumulates unresolved entries for the TextRun.unresolved field (option B shape).

Summary

Functions

resolve_byte(byte, cmap, opts \\ [])

Resolves a single byte to a Unicode codepoint using the encoding cascade.

Functions

Link to this function

resolve_byte(byte, cmap, opts \\ [])

View Source 
@spec resolve_byte(0..255, Pdf.Reader.CMap.t() | nil, keyword()) ::
  {:ok, non_neg_integer()} | {:unresolved, binary()}

Resolves a single byte to a Unicode codepoint using the encoding cascade.

Returns {:ok, codepoint} on success or {:unresolved, marker} when no mapping can be found. The marker is either a glyph name (if /Differences provided one) or "byte:0xNN" for a raw byte with no name.