it.py

gistfile1.py

#!/usr/bin/env python

import pyglet

window = pyglet.window.Window(resizable=True)
document = pyglet.text.document.FormattedDocument()
layout = pyglet.text.layout.IncrementalTextLayout(document, window.width, window.height, multiline=True)
caret = pyglet.text.caret.Caret(layout)
window.push_handlers(caret)

@window.event
def on_resize(width, height):
    # Wrap text to the width of the window
    layout.width = window.width

    # Keep text vertically centered in the window
    layout.y = window.height // 2

@window.event
def on_draw():
    window.clear()
    layout.draw()

pyglet.gl.glClearColor(1, 1, 0, 1)
pyglet.app.run()