Module: Prawn::Document::Text::Wrapping

Included in:
Prawn::Document::Text
Defined in:
lib/prawn/document/text/wrapping.rb

Overview

:nodoc:

Instance Method Summary collapse

Instance Method Details

#height_of(string, line_width, size = font_size) ⇒ Object

Gets height of text in PDF points at current font size. Text :line_width must be specified in PDF points.

If using an AFM, string must be encoded as WinAnsi (Use normalize_encoding to convert)


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# File 'lib/prawn/document/text/wrapping.rb', line 20

def height_of(string, line_width, size=font_size)
  string = naive_wrap(string, line_width, size)
  string.lines.to_a.length * font.height_at(size)
end

#naive_unwrap(string) ⇒ Object


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# File 'lib/prawn/document/text/wrapping.rb', line 56

def naive_unwrap(string)
  string.gsub(/(\S)\n/, '\1 ')
end

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

TODO: Replace with TeX optimal algorithm


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# File 'lib/prawn/document/text/wrapping.rb', line 26

def naive_wrap(string, line_width, font_size, options = {})
  scan_pattern = options[:mode] == :character ? /./ : /\S+|\s+/                                    
  
  output = ""                
  string.lines.each do |line| 
    accumulated_width = 0        
    segments = line.scan(scan_pattern)
                                  
    segments.each do |segment|    
      segment_width = width_of(segment, :size => font_size, :kerning => options[:kerning]) 

      if (accumulated_width + segment_width).round > line_width.round
        output = "#{output.sub(/[ \t]*\n?(\n*)\z/, "\n\\1")}"
        
        if segment =~ /\s/           
          accumulated_width = 0
        else
          output << segment
          accumulated_width = segment_width
        end
      else                           
        output << segment
        accumulated_width += segment_width
      end
    end    
  end

  output
end