Class: Prawn::Font

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/font.rb,
lib/prawn/font/ttf.rb,
lib/prawn/font/afm.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 292

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

  @family     = options[:family]

  @identifier = generate_unique_id

  @references = {}
end

Instance Attribute Details

#familyObject (readonly)

The current font family



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# File 'lib/prawn/font.rb', line 274

def family
  @family
end

#nameObject (readonly)

The current font name



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# File 'lib/prawn/font.rb', line 271

def name
  @name
end

#optionsObject (readonly)

The options hash used to initialize the font



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# File 'lib/prawn/font.rb', line 277

def options
  @options
end

Class Method Details

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

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



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# File 'lib/prawn/font.rb', line 283

def self.load(document,name,options={})
  case name.to_s
  when /\.ttf$/i   then TTF.new(document, name, options)
  when /\.dfont$/i then DFont.new(document, name, options)
  when /\.afm$/i   then AFM.new(document, name, options)
  else                  AFM.new(document, name, 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 354

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

#ascenderObject

The size of the font ascender in PDF points



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# File 'lib/prawn/font.rb', line 306

def ascender
  @ascender / 1000.0 * size
end

#descenderObject

The size of the font descender in PDF points



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# File 'lib/prawn/font.rb', line 312

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 378

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

#hashObject

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 372

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

#heightObject

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



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# File 'lib/prawn/font.rb', line 346

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 339

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 359

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

#inspectObject

:nodoc:



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# File 'lib/prawn/font.rb', line 363

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

#line_gapObject

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



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# File 'lib/prawn/font.rb', line 318

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 326

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 333

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