Class: Fontisan::Tables::Os2

Inherits:
Binary::BaseRecord show all
Defined in:
lib/fontisan/tables/os2.rb

Overview

Parser for the ‘OS/2’ (OS/2 and Windows Metrics) table

The OS/2 table contains OS/2 and Windows-specific metrics that are required by Windows and OS/2. This includes font metrics, character ranges, vendor information, and embedding permissions.

The table has evolved through multiple versions (0-5), with newer versions adding additional fields while maintaining backward compatibility.

Reference: OpenType specification, OS/2 table

Instance Method Summary collapse

Methods inherited from Binary::BaseRecord

#raw_data, read, #valid?

Instance Method Details

#has_optical_point_size? ⇒ Boolean

Check if optical point size information is available

Returns:

  • (Boolean) —

    True if version >= 5



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# File 'lib/fontisan/tables/os2.rb', line 150

def has_optical_point_size?
  version >= 5
end

#lower_optical_point_size ⇒ Float?

Get the lower optical point size

Returns:

  • (Float, nil) —

    The lower optical point size in points, or nil if not available



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# File 'lib/fontisan/tables/os2.rb', line 158

def lower_optical_point_size
  return nil unless has_optical_point_size?

  us_lower_optical_point_size / 20.0
end

#s_cap_height ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 95

def s_cap_height
  return nil unless version >= 2

  super
end

#sx_height ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 89

def sx_height
  return nil unless version >= 2

  super
end

#type_flags ⇒ Integer

Get the embedding type flags

Returns:

  • (Integer) —

    The fs_type value (embedding permissions)



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# File 'lib/fontisan/tables/os2.rb', line 143

def type_flags
  fs_type
end

#ul_code_page_range1 ⇒ Object

Override conditional field accessors to return nil when not present BinData’s onlyif fields return default values even when not read, so we need to check the version before accessing them



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# File 'lib/fontisan/tables/os2.rb', line 77

def ul_code_page_range1
  return nil unless version >= 1

  super
end

#ul_code_page_range2 ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 83

def ul_code_page_range2
  return nil unless version >= 1

  super
end

#upper_optical_point_size ⇒ Float?

Get the upper optical point size

Returns:

  • (Float, nil) —

    The upper optical point size in points, or nil if not available



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# File 'lib/fontisan/tables/os2.rb', line 168

def upper_optical_point_size
  return nil unless has_optical_point_size?

  us_upper_optical_point_size / 20.0
end

#us_break_char ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 107

def us_break_char
  return nil unless version >= 2

  super
end

#us_default_char ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 101

def us_default_char
  return nil unless version >= 2

  super
end

#us_lower_optical_point_size ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 119

def us_lower_optical_point_size
  return nil unless version >= 5

  super
end

#us_max_context ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 113

def us_max_context
  return nil unless version >= 2

  super
end

#us_upper_optical_point_size ⇒ Object 



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# File 'lib/fontisan/tables/os2.rb', line 125

def us_upper_optical_point_size
  return nil unless version >= 5

  super
end

#vendor_id ⇒ String

Get the vendor ID as a trimmed string

Returns:

  • (String) —

    The vendor ID with trailing spaces and nulls removed



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# File 'lib/fontisan/tables/os2.rb', line 134

def vendor_id
  return "" unless ach_vend_id

  ach_vend_id.gsub(/[\x00\s]+$/, "")
end