Class: Prawn::Font::Metrics::Adobe

Inherits:
Prawn::Font::Metrics show all
Defined in:
lib/prawn/font/metrics.rb

Overview

:nodoc:

Constant Summary collapse

ISOLatin1Encoding = 
%w[
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef .notdef
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef .notdef
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef .notdef
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef .notdef space
 exclam quotedbl numbersign dollar percent ampersand quoteright
 parenleft parenright asterisk plus comma minus period slash zero one
 two three four five six seven eight nine colon semicolon less equal
 greater question at A B C D E F G H I J K L M N O P Q R S
 T U V W X Y Z bracketleft backslash bracketright asciicircum
 underscore quoteleft a b c d e f g h i j k l m n o p q r s
 t u v w x y z braceleft bar braceright asciitilde .notdef .notdef
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef .notdef
 .notdef .notdef .notdef .notdef .notdef .notdef .notdef dotlessi grave
 acute circumflex tilde macron breve dotaccent dieresis .notdef ring
 cedilla .notdef hungarumlaut ogonek caron space exclamdown cent
 sterling currency yen brokenbar section dieresis copyright ordfeminine
 guillemotleft logicalnot hyphen registered macron degree plusminus
 twosuperior threesuperior acute mu paragraph periodcentered cedilla
 onesuperior ordmasculine guillemotright onequarter onehalf threequarters
 questiondown Agrave Aacute Acircumflex Atilde Adieresis Aring AE
 Ccedilla Egrave Eacute Ecircumflex Edieresis Igrave Iacute Icircumflex
 Idieresis Eth Ntilde Ograve Oacute Ocircumflex Otilde Odieresis
 multiply Oslash Ugrave Uacute Ucircumflex Udieresis Yacute Thorn
 germandbls agrave aacute acircumflex atilde adieresis aring ae
 ccedilla egrave eacute ecircumflex edieresis igrave iacute icircumflex
 idieresis eth ntilde ograve oacute ocircumflex otilde odieresis divide
 oslash ugrave uacute ucircumflex udieresis yacute thorn ydieresis
]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Prawn::Font::Metrics

[], data, #font_height, #string_height

Methods included from Wrapping

#naive_wrap

Constructor Details

#initialize(font_name) ⇒ Adobe

Returns a new instance of Adobe.



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# File 'lib/prawn/font/metrics.rb', line 78

def initialize(font_name)            
  @attributes     = {}   
  @glyph_widths   = {}
  @bounding_boxes = {}
  @kern_pairs     = {}
  
  file = font_name.sub(/\.afm$/,'') + '.afm'
  unless file[0..0] == "/"
     file = find_font(file)
  end    
                   
  parse_afm(file)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

Hackish, but does the trick for now.



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# File 'lib/prawn/font/metrics.rb', line 167

def method_missing(method, *args, &block)
  name = method.to_s.delete("_")
  @attributes.include?(name) ? @attributes[name] : super
end

Instance Attribute Details

#attributes ⇒ Object (readonly)

Returns the value of attribute attributes.



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# File 'lib/prawn/font/metrics.rb', line 76

def attributes
  @attributes
end

Instance Method Details

#ascender ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 154

def ascender
  @attributes["ascender"].to_i
end

#bbox ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 92

def bbox
  fontbbox.split(/\s+/).map { |e| Integer(e) }
end

#convert_text(text, options = {}) ⇒ Object

perform any changes to the string that need to happen before it is rendered to the canvas

String must be encoded as iso-8859-1



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# File 'lib/prawn/font/metrics.rb', line 197

def convert_text(text, options={})
  options[:kerning] ? kern(text) : text
end

#descender ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 158

def descender
  @attributes["descender"].to_i 
end

#has_kerning_data? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/prawn/font/metrics.rb', line 184

def has_kerning_data?
  true
end

#kern(string) ⇒ Object

converts a string into an array with spacing offsets bewteen characters that need to be kerned

String must be encoded as iso-8859-1



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# File 'lib/prawn/font/metrics.rb', line 120

def kern(string) 
  kerned = string.unpack("C*").inject([]) do |a,r|
    if a.last.is_a? Array
      if k = latin_kern_pairs_table[[a.last.last, r]]
        a << k << [r]
      else
        a.last << r
      end
    else
      a << [r]
    end
    a
  end            
  
  kerned.map { |r| 
    i = r.is_a?(Array) ? r.pack("C*") : r 
    i.force_encoding("ISO-8859-1") if i.respond_to?(:force_encoding)
    i.is_a?(Numeric) ? -i : i
  }                        
end

#latin_glyphs_table ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 148

def latin_glyphs_table
  @glyphs_table ||= (0..255).map do |i|
    @glyph_widths[ISOLatin1Encoding[i]].to_i
  end 
end

#latin_kern_pairs_table ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 141

def latin_kern_pairs_table   
  @kern_pairs_table ||= @kern_pairs.inject({}) do |h,p|
    h[p[0].map { |n| ISOLatin1Encoding.index(n) }] = p[1]
    h
  end
end

#line_gap ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 162

def line_gap    
  Float(bbox[3] - bbox[1]) - (ascender - descender)
end

#metrics_path ⇒ Object 



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# File 'lib/prawn/font/metrics.rb', line 172

def metrics_path
  if m = ENV['METRICS']
    @metrics_path ||= m.split(':')
  else 
    @metrics_path ||= [
      ".", "/usr/lib/afm",
      "/usr/local/lib/afm",
      "/usr/openwin/lib/fonts/afm/", 
       Prawn::BASEDIR+'/data/fonts/'] 
  end
end

#string_width(string, font_size, options = {}) ⇒ Object

calculates the width of the supplied string. String must be encoded as iso-8859-1



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# File 'lib/prawn/font/metrics.rb', line 98

def string_width(string, font_size, options = {}) 
  scale = font_size / 1000.0
  
  if options[:kerning]
    kern(string).inject(0) do |s,r|   
      if r.is_a? String
        s + string_width(r, font_size, :kerning => false)
      else 
        s - (r * scale)
      end
    end
  else
    string.unpack("C*").inject(0) do |s,r|
      s + latin_glyphs_table[r]
    end * scale
  end
end

#type0? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/prawn/font/metrics.rb', line 188

def type0?
  false
end