monoFont  = Font clone open("Library/Fonts/Bitstream/VeraMoBd.ttf") setPointSize(12)
sansFont  = Font clone open("Library/Fonts/Bitstream/Vera.ttf") setPointSize(12)
serifFont = Font clone open("Library/Fonts/Bitstream/VeraSe.ttf") setPointSize(12)

//monoFont  = Font clone open("Library/Fonts/Free/FreeMonoBold.ttf") setPointSize(12)
//sansFont  = Font clone open("Library/Fonts/Free/FreeSans.ttf") setPointSize(12)
//serifFont = Font clone open("Library/Fonts/Free/FreeSerif.ttf") setPointSize(12)

Screen = Object clone
Screen parent = OpenGL
Screen string = "Io TrueType 123!@#"
Screen reshape = method(w, h, 
  self width = w
  self height = h
  glViewport(0,0,w,h)
  glLoadIdentity
  gluOrtho2D(0,w,0,h)
  
  monoFont  setPointSize(width/15)
  sansFont  setPointSize(width/15)
  serifFont setPointSize(width/15)
  
  glutPostRedisplay
)

Screen display = method(
  glClearColor(1, 1, 1, 1)
  glClear(GL_COLOR_BUFFER_BIT)

  x = width/(2) -(monoFont widthOfString(string)/2)
  y = height/(2) +(monoFont pointSize*1.5)
  x Ceil
  y Ceil

  //y += monoFont pointSize + 10
  glPushMatrix
  glTranslated(x, y, 0)
  monoFont drawString(string)
  glPopMatrix

  glPushMatrix
  y -= sansFont pointSize *1.5
  glTranslated(x, y, 0)
  sansFont drawString(string)
  glPopMatrix

  y -= serifFont pointSize *1.5
  glPushMatrix
  glTranslated(x, y, 0)
  serifFont drawString(string)
  glPopMatrix

  glFlush
  glutSwapBuffers
)

Screen mouse = method(button, state, x, y,
  if (state == 0,
    if ( y < 50, 
      v = Number random(0,1)
      glColor4d(v, 0, 1 - v, 1)
    )
    self display
  )
)

Screen special = method(c, x, y,

  if (c == GLUT_KEY_UP, 
    monoFont  setPointSize(monoFont  pointSize + 1)
    sansFont  setPointSize(sansFont  pointSize + 1)
    serifFont setPointSize(serifFont pointSize + 1)
  )

  if (c == GLUT_KEY_DOWN, 
    monoFont  setPointSize(monoFont  pointSize - 1)
    sansFont  setPointSize(sansFont  pointSize - 1)
    serifFont setPointSize(serifFont pointSize - 1)
  )

  if (c == GLUT_KEY_RIGHT, 
   glColor4d(1 random, 1 random,1 random, 1)
  )
  self display
)

Screen run = method(
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
  glutInitWindowSize(512, 512)
  glutInit
  glutCreateWindow("Font Test")
  glutEventTarget(Screen)
  glutDisplayFunc
  glutMouseFunc
  glutReshapeFunc
  glutSpecialFunc
  
  glColor4d(0,0,0,1)
  glEnable(GL_BLEND)
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
  glutMainLoop
)

Screen run