Class: Arrolio::Font::TextEncoder

Inherits:
Object
  • Object
show all
Defined in:
lib/arrolio/font/text_encoder.rb

Overview

Converts a Unicode string into a 2-byte-big-endian glyph-ID sequence for an Identity-H-encoded CIDFont.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(embedder) ⇒ TextEncoder

Returns a new instance of TextEncoder.



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# File 'lib/arrolio/font/text_encoder.rb', line 10

def initialize(embedder)
  @embedder = embedder
end

Instance Attribute Details

#embedder ⇒ Object (readonly)

Returns the value of attribute embedder.



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# File 'lib/arrolio/font/text_encoder.rb', line 8

def embedder
  @embedder
end

Instance Method Details

#encode(text) ⇒ Object

Returns a binary-encoded String of 2-byte GIDs for the codepoints in text. The renderer passes this to canvas.text instead of the Unicode string.



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# File 'lib/arrolio/font/text_encoder.rb', line 17

def encode(text)
  bytes = String.new.force_encoding(Encoding::BINARY)
  text.each_codepoint do |cp|
    gid = @embedder.subset_gid_for_codepoint(cp)
    bytes << (gid >> 8).chr(Encoding::BINARY)
    bytes << (gid & 0xff).chr(Encoding::BINARY)
  end
  bytes
end