# File lib/pdf/writer.rb, line 1098
1098:   def font_height(size = nil)
1099:     size = @font_size if size.nil? or size <= 0
1100: 
1101:     select_font("Helvetica") if @fonts.empty?
1102:     hh = @fonts[@current_font].fontbbox[3].to_f - @fonts[@current_font].fontbbox[1].to_f
1103:     (size * hh / 1000.0)
1104:   end