character_drawer.rb

class CharacterDrawer
  CHARACTERS = {
    'A' => [[ [0,0], [2,5], [4,0] ], [ [1,2], [3,2] ]],
    'B' => [[ [0,0], [0,5], [2,5], [3,4], [2,3], [3,2], [3,1], [2,0], [0,0] ], [ [0,3], [2,3] ]],
    'C' => [[ [4,1], [3,0], [1,0], [0,1], [0,4], [1,5], [3,5], [4,4] ]],
    'D' => [[ [0,0], [0,5], [2,5], [3,4], [3,1], [2,0], [0,0] ]],
    'E' => [[ [3,0], [0,0], [0,5], [3,5] ], [ [0,3], [2,3] ]],
    'F' => [[ [0,0], [0,5], [3,5] ], [ [0,3], [2,3] ]],
    'G' => [[ [2,2], [4,2], [4,1], [3,0], [1,0], [0,1], [0,4], [1,5], [3,5], [4,4] ]],
    'H' => [[ [0,0], [0,5] ], [ [3,0], [3,5] ], [ [0,3], [3,3] ]],
    'I' => [[ [1,0], [1,5] ], [ [0,0], [2,0] ], [ [0,5], [2,5] ]],
    'J' => [[ [0,1], [1,0], [2,0], [3,1], [3,5] ]],
    'K' => [[ [0,0], [0,5] ], [ [3,5], [0,3], [3,0] ]],
    'L' => [[ [0,5], [0,0], [3,0] ]],
    'M' => [[ [0,0], [0,5], [2,2], [4,5], [4,0] ]],
    'N' => [[ [0,0], [0,5], [3,0], [3,5] ]],
    'O' => [[ [0,1], [0,4], [1,5], [3,5], [4,4], [4,1], [3,0], [1,0], [0,1] ]],
    'P' => [[ [0,0], [0,5], [2,5], [3,4], [3,3], [2,2], [0,2] ]],
    'Q' => [[ [0,1], [0,4], [1,5], [3,5], [4,4], [4,1], [3,0], [1,0], [0,1] ], [ [2,2], [5,-1] ]],
    'R' => [[ [0,0], [0,5], [2,5], [3,4], [3,3], [2,2], [0,2] ], [ [2,2], [3,0] ]],
    'S' => [[ [0,1], [1,0], [2,0], [3,1], [3,2], [0,3], [0,4], [1,5], [2,5], [3,4] ]],
    'T' => [[ [0,5], [4,5] ], [ [2,0], [2,5] ]],
    'U' => [[ [0,5], [0,1], [1,0], [3,0], [4,1], [4,5] ]],
    'V' => [[ [0,5], [2,0], [4,5] ]],
    'W' => [[ [0,5], [1,0], [2,2], [3,0], [4,5] ]],
    'X' => [[ [0,0], [4,5] ], [ [0,5], [4,0] ]],
    'Y' => [[ [0,5], [2,3], [4,5] ], [ [2,3], [2,0] ]],
    'Z' => [[ [0,5], [4,5], [0,0], [4,0] ]],
    'a' => [[ [3,3], [3,0] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
    'b' => [[ [0,5], [0,0] ], [ [0,1], [1,0], [2,0], [3,1], [3,2], [2,3], [1,3], [0,2] ]],
    'c' => [[ [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1] ]],
    'd' => [[ [3,5], [3,0] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
    'e' => [[ [0,1], [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1] ]],
    'f' => [[ [1,0], [1,4], [2,5] ], [ [0,3], [2,3] ]],
    'g' => [[ [3,3], [3,-1], [2,-2], [1,-2], [0,-1] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
    'h' => [[ [0,5], [0,0] ], [ [0,3], [1,3], [2,2], [2,0] ]],
    'i' => [[ [0,0], [0,3] ], [ [0,5] ]],
    'j' => [[ [0,-1], [1,-2], [2,-1], [2,3] ], [ [2,5] ]],
    'k' => [[ [0,0], [0,5] ], [ [2,3], [0,2], [2,0] ]],
    'l' => [[ [0,0], [0,5] ]],
    'm' => [[ [0,0], [0,3], [1,3], [2,2], [2,3], [3,3], [4,2], [4,0] ], [ [2,2], [2,0] ]],
    'n' => [[ [0,0], [0,3], [1,3], [2,2], [2,0] ]],
    'o' => [[ [3,2], [2,3], [1,3], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2] ]],
    'p' => [[ [0,-2], [0,3] ], [ [0,2], [1,3], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
    'q' => [[ [3,-2], [3,3] ], [ [3,1], [2,0], [1,0], [0,1], [0,2], [1,3], [2,3], [3,2] ]],
    'r' => [[ [0,0], [0,3] ], [ [0,2], [1,3], [2,2] ]],
    's' => [[ [0,1], [0,0], [2,0], [2,1], [0,2], [0,3], [2,3], [2,2] ]],
    't' => [[ [1,5], [1,1], [2,0] ], [ [0,3], [2,3] ]],
    'u' => [[ [0,3], [0,1], [1,0], [2,1] ], [ [2,3], [2,0] ]],
    'v' => [[ [0,3], [1,0], [2,3] ]],
    'w' => [[ [0,3], [1,0], [2,3], [3,0], [4,3] ]],
    'x' => [[ [0,3], [2,0] ], [ [0,0], [2,3] ]],
    'y' => [[ [0,3], [1,0] ], [ [2,3], [1,0], [0,-2] ]],
    'z' => [[ [0,3], [2,3], [0,0], [2,0] ]],
    '0' => [[ [0,1], [0,4], [1,5], [2,5], [3,4], [3,1], [2,0], [1,0], [0,1] ], [ [2,4], [1,1] ]],
    '1' => [[ [0,4], [1,5], [1,0] ], [ [0,0], [2,0] ]],
    '2' => [[ [0,4], [1,5], [2,5], [3,4], [0,0], [3,0] ]],
    '3' => [[ [0,4], [1,5], [2,5], [3,4], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
    '4' => [[ [0,5], [0,3], [3,3] ], [ [3,5], [3,0] ]],
    '5' => [[ [3,5], [0,5], [0,3], [2,3], [3,2], [3,1], [2,0], [1,0], [0,1] ]],
    '6' => [[ [2,5], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2], [2,3], [1,3], [0,2] ]],
    '7' => [[ [0,5], [3,5], [1,0] ]],
    '8' => [[ [0,4], [1,5], [2,5], [3,4], [3,3], [0,2], [0,1], [1,0], [2,0], [3,1], [3,2], [0,3], [0,4] ]],
    '9' => [[ [1,0], [3,3], [3,4], [2,5], [1,5], [0,4], [0,3], [1,2], [2,2], [3,3] ]],
    ' ' => [],
    '.' => [[ [0,0] ]],
    '?' => [[ [0,4], [1,5], [2,4], [2,3], [1,2] ], [ [1,0] ]]
  }

  def initialize(string)
    @string = string
  end

  def draw(x, y)
    glPushMatrix
      glLoadIdentity
      glTranslate(x, y, 0)
      glColor(1.0, 1.0, 1.0)
      @string.scan(/./).each do |char|
        draw_character(char)
        glTranslate(character_width(char), 0, 0)
      end
    glPopMatrix
  end

  def width
    @string.scan(/./).inject(0) do |sum, c|
      sum + character_width(c)
    end
  end

  protected

  def draw_character(char)
    polys = CHARACTERS[char] || CHARACTERS['?']
    polys.each do |poly|
      glBegin(poly.size == 1 ? GL_POINTS : GL_LINE_STRIP)
      poly.each do |x, y|
        glVertex(x, y)
      end
      glEnd
    end
  end

  def character_width(char)
    return 4 if char == " "
    polys = CHARACTERS[char] || CHARACTERS['?']
    xs = polys.map { |poly| poly.map { |x,y| x } }.flatten
    xs.max - xs.min + 1
  end
end

font_test.rb

require 'rubygems'
require 'glapp'
require 'character_drawer'

class FontTest
  include GLApp

  def update(s)
  end

  def draw
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity
    glOrtho(0, 200, 0, 200, -100, 100)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity
    glEnable(GL_LINE_SMOOTH)
    glEnable(GL_POINT_SMOOTH)
    glDepthMask(GL_FALSE)
    glLineWidth(2.0)
    glPointSize(3.0)
    CharacterDrawer.new("ABCDEFGHI").draw(10, 70)
    CharacterDrawer.new("JKLMNOPQR").draw(10, 60)
    CharacterDrawer.new("STUVWXYZ").draw(10, 50)
    CharacterDrawer.new("0123456789").draw(10, 40)
    CharacterDrawer.new("abcdefghi").draw(10, 30)
    CharacterDrawer.new("jklmnopqr").draw(10, 20)
    CharacterDrawer.new("stuvwxyz").draw(10, 10)
    CharacterDrawer.new("The Quick Brown Fox Jumps Over The Lazy Dog").draw(10, 80)
  end

  def keyboard_down(key, special)
    exit if key == 27
  end
end

FontTest.new.show(500, 500)