Class: Prawn::Font

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/font.rb,
lib/prawn/font/afm.rb,
lib/prawn/font/ttc.rb,
lib/prawn/font/ttf.rb,
lib/prawn/font/dfont.rb

Overview

Provides font information and helper functions.

Experimental API collapse

Experimental API collapse

Constructor Details

#initialize(document, name, options = {}) ⇒ Font

:nodoc:



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# File 'lib/prawn/font.rb', line 316

def initialize(document, name, options = {}) #:nodoc:
  @document = document
  @name = name
  @options = options

  @family = options[:family]

  @identifier = generate_unique_id

  @references = {}
end

Instance Attribute Details

#family ⇒ Object (readonly)

The current font family



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# File 'lib/prawn/font.rb', line 287

def family
  @family
end

#name ⇒ Object (readonly)

The current font name



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# File 'lib/prawn/font.rb', line 284

def name
  @name
end

#options ⇒ Object (readonly)

The options hash used to initialize the font



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# File 'lib/prawn/font.rb', line 290

def options
  @options
end

Class Method Details

.font_format(src, options) ⇒ Object 



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# File 'lib/prawn/font.rb', line 305

def self.font_format(src, options)
  return options.fetch(:format, 'ttf') if src.respond_to? :read

  case src.to_s
  when /\.ttf$/i   then return 'ttf'
  when /\.dfont$/i then return 'dfont'
  when /\.ttc$/i   then return 'ttc'
  else return 'afm'
  end
end

.load(document, src, options = {}) ⇒ Object

Shortcut interface for constructing a font object. Filenames of the form *.ttf will call Font::TTF.new, *.dfont Font::DFont.new, *.ttc goes to Font::TTC.new, and anything else will be passed through to Font::AFM.new()



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# File 'lib/prawn/font.rb', line 296

def self.load(document, src, options = {})
  case font_format(src, options)
  when 'ttf'   then TTF.new(document, src, options)
  when 'dfont' then DFont.new(document, src, options)
  when 'ttc'   then TTC.new(document, src, options)
  else AFM.new(document, src, options)
  end
end

Instance Method Details

#add_to_current_page(subset) ⇒ Object

Registers the given subset of the current font with the current PDF page. This is safe to call multiple times for a given font and subset, as it will only add the font the first time it is called.



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# File 'lib/prawn/font.rb', line 379

def add_to_current_page(subset)
  @references[subset] ||= register(subset)
  @document.state.page.fonts.merge!(
    identifier_for(subset) => @references[subset]
  )
end

#ascender ⇒ Object

The size of the font ascender in PDF points



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# File 'lib/prawn/font.rb', line 330

def ascender
  @ascender / 1000.0 * size
end

#descender ⇒ Object

The size of the font descender in PDF points



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# File 'lib/prawn/font.rb', line 336

def descender
  -@descender / 1000.0 * size
end

#eql?(other) ⇒ Boolean

Compliments the #hash implementation above

Returns:

  • (Boolean) 


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# File 'lib/prawn/font.rb', line 405

def eql?(other) #:nodoc:
  self.class == other.class && name == other.name &&
    family == other.family && size == other.send(:size)
end

#hash ⇒ Object

Return a hash (as in Object#hash) for the font based on the output of #inspect. This is required since font objects are used as keys in hashes that cache certain values (See Prawn::Table::Text#styled_with_of_single_character)



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# File 'lib/prawn/font.rb', line 399

def hash #:nodoc:
  [self.class, name, family, size].hash
end

#height ⇒ Object

Gets height of current font in PDF points at current font size



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# File 'lib/prawn/font.rb', line 371

def height
  height_at(size)
end

#height_at(size) ⇒ Object

Gets height of current font in PDF points at the given font size



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# File 'lib/prawn/font.rb', line 364

def height_at(size)
  @normalized_height ||= (@ascender - @descender + @line_gap) / 1000.0
  @normalized_height * size
end

#identifier_for(subset) ⇒ Object

:nodoc:



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# File 'lib/prawn/font.rb', line 386

def identifier_for(subset) #:nodoc:
  "#{@identifier}.#{subset}"
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/prawn/font.rb', line 390

def inspect #:nodoc:
  "#{self.class.name}< #{name}: #{size} >"
end

#line_gap ⇒ Object

The size of the recommended gap between lines of text in PDF points



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# File 'lib/prawn/font.rb', line 342

def line_gap
  @line_gap / 1000.0 * size
end

#normalize_encoding(_string) ⇒ Object

Normalizes the encoding of the string to an encoding supported by the font. The string is expected to be UTF-8 going in. It will be re-encoded and the new string will be returned. For an in-place (destructive) version, see normalize_encoding!.

Raises:

  • (NotImplementedError) 


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# File 'lib/prawn/font.rb', line 350

def normalize_encoding(_string)
  raise NotImplementedError,
    'subclasses of Prawn::Font must implement #normalize_encoding'
end

#normalize_encoding!(str) ⇒ Object

Destructive version of normalize_encoding; normalizes the encoding of a string in place.



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# File 'lib/prawn/font.rb', line 358

def normalize_encoding!(str)
  str.replace(normalize_encoding(str))
end