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

Applies a PDF /Differences array on top of a base encoding override map.

Spec reference: PDF 1.7 § 9.6.5.1.

Format

/Differences is an array mixing integers and names:

[32 /space 65 /A /B /C 200 /uni0024 ...]
  • An integer N sets the current code position to N.
  • Each subsequent name installs that glyph name at position, then increments by 1.

API 

apply(base_overrides, differences_array) :: %{integer() => glyph_name :: binary()}

The output is a byte→glyph_name map. Codepoint resolution (via AGL or ToUnicode) happens later in the encoding facade (Pdf.Reader.Encoding).

/Differences entries override the base map. Base entries not touched by /Differences are preserved.

Summary

Functions

apply(base, differences)

Applies a /Differences array on top of base, returning the merged byte→glyph_name override map.

Functions

Link to this function

apply(base, differences)

View Source 
@spec apply(%{required(non_neg_integer()) => binary()}, list()) :: %{
  required(non_neg_integer()) => binary()
}

Applies a /Differences array on top of base, returning the merged byte→glyph_name override map.

differences is a list of integers and {:name, binary()} tuples, matching the tagged-tuple convention used by the reader's parser.