Prawn::Font

Provides font information and helper functions.

Attributes

name[R]

The current font name

family[R]

The current font family

options[R]

The options hash used to initialize the font

Public Class Methods

load(document,name,options={}) click to toggle source

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()

     # File lib/prawn/font.rb, line 241
241:     def self.load(document,name,options={})
242:       case name
243:       when /\.ttf$/   then TTF.new(document, name, options)
244:       when /\.dfont$/ then DFont.new(document, name, options)
245:       when /\.afm$/   then AFM.new(document, name, options)
246:       else                  AFM.new(document, name, options)
247:       end
248:     end

Public Instance Methods

add_to_current_page(subset) click to toggle source

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.

     # File lib/prawn/font.rb, line 320
320:     def add_to_current_page(subset)
321:       @references[subset] ||= register(subset)
322:       @document.state.page.fonts.merge!(identifier_for(subset) => @references[subset])
323:     end

ascender() click to toggle source

The size of the font ascender in PDF points

     # File lib/prawn/font.rb, line 264
264:     def ascender
265:       @ascender / 1000.0 * size
266:     end

descender() click to toggle source

The size of the font descender in PDF points

     # File lib/prawn/font.rb, line 270
270:     def descender
271:       -@descender / 1000.0 * size
272:     end

height() click to toggle source

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

     # File lib/prawn/font.rb, line 312
312:     def height
313:       height_at(size)
314:     end

height_at(size) click to toggle source

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

     # File lib/prawn/font.rb, line 305
305:     def height_at(size)
306:       @normalized_height ||= (@ascender - @descender + @line_gap) / 1000.0
307:       @normalized_height * size
308:     end

identifier_for(subset) click to toggle source

     # File lib/prawn/font.rb, line 280
280:     def identifier_for(subset)
281:       "#{@identifier}.#{subset}".to_sym
282:     end

inspect() click to toggle source

     # File lib/prawn/font.rb, line 284
284:     def inspect
285:       "#{self.class.name}< #{name}: #{size} >"
286:     end

line_gap() click to toggle source

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

     # File lib/prawn/font.rb, line 276
276:     def line_gap
277:       @line_gap / 1000.0 * size
278:     end

normalize_encoding(string) click to toggle source

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!.

     # File lib/prawn/font.rb, line 292
292:     def normalize_encoding(string)
293:       raise NotImplementedError, "subclasses of Prawn::Font must implement #normalize_encoding"
294:     end

normalize_encoding!(str) click to toggle source

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

     # File lib/prawn/font.rb, line 299
299:     def normalize_encoding!(str)
300:       str.replace(normalize_encoding(str))
301:     end

Private Instance Methods

generate_unique_id() click to toggle source

generate a font identifier that hasn’t been used on the curretn page yet

     # File lib/prawn/font.rb, line 337
337:     def generate_unique_id
338:       offset, id = 0, nil
339: 
340:       while id.nil? || page_contains_font_id?(id)
341:         offset += 1
342:         id = :"F#{@document.font_registry.size + offset}"
343:       end
344: 
345:       id
346:     end

page_contains_font_id?(id) click to toggle source

Returns true if the provided font identifier already exists in the document. This is used when adding new fonts to a document to ensure we don’t step on fonts imported from a template.

  page_contains_font_id?("F1")
  => true

     # File lib/prawn/font.rb, line 355
355:     def page_contains_font_id?(id)
356:       id = id.to_s
357:       @document.state.page.fonts.keys.any? { |exist_id|
358:         exist_id.to_s[0,id.size] == id
359:       }
360:     end

size() click to toggle source

     # File lib/prawn/font.rb, line 362
362:     def size
363:       @document.font_size
364:     end

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