Class: Ucode::Glyphs::EmbeddedFonts::CodepointMapper::Strategy

Inherits:
Object
  • Object
show all
Defined in:
lib/ucode/glyphs/embedded_fonts/codepoint_mapper/strategy.rb

Overview

Abstract base for the codepoint→GID resolution strategies.

Each subclass owns ONE mutool subcommand and ONE collaborator. Subclasses declare their role via #positional?:

* `positional? == false` — the strategy reads the font's own
intrinsic mapping (ToUnicode CMap). Authoritative for
cross-reference typography, but can be misleading when
the embedded font's CMap encodes composing characters
rather than the chart specimens (Enclosed Ideographic
Supplement, where CJKSymbols' CIDs map to the inner CJK
ideographs, not the squared characters themselves).
* `positional? == true` — the strategy attributes glyphs to
codepoints via chart-grid geometry (mutool trace, content
stream correlation). Authoritative for in-block specimens.

The orchestrator (Ucode::Glyphs::EmbeddedFonts::CodepointMapper) partitions strategies by this predicate, gates positional strategies behind a block-scope check, and merges with positional precedence when both produce a result. Adding a new strategy = one subclass + one positional? override + one entry in the chain. No edit to CodepointMapper (Open/Closed Principle).

Instance Method Summary collapse

Instance Method Details

#map(_descriptor) ⇒ Hash{Integer=>Integer}

Returns codepoint => gid; empty when the strategy cannot produce a mapping.

Parameters:

Returns:

  • (Hash{Integer=>Integer}) —

    codepoint => gid; empty when the strategy cannot produce a mapping

Raises:

  • (NotImplementedError) 


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# File 'lib/ucode/glyphs/embedded_fonts/codepoint_mapper/strategy.rb', line 38

def map(_descriptor)
  raise NotImplementedError
end

#positional? ⇒ Boolean

Declares whether this strategy attributes glyphs by chart geometry (true) or by the font's intrinsic mapping (false). The default is false; positional strategies override.

Returns:

  • (Boolean) 


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# File 'lib/ucode/glyphs/embedded_fonts/codepoint_mapper/strategy.rb', line 47

def positional?
  false
end

#supports?(_descriptor) ⇒ Boolean

Parameters:

Returns:

  • (Boolean)

Raises:

  • (NotImplementedError) 


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# File 'lib/ucode/glyphs/embedded_fonts/codepoint_mapper/strategy.rb', line 31

def supports?(_descriptor)
  raise NotImplementedError
end