Resizable high resolution hello world in pyglet - https://bitbucket.org/pyglet/pyglet/issues/249

text_rendering.py

'''Resizable hello world example which works on mac and windows

There are a few bugs / differences between pyglet on these platforms.
This example tries to work around those issues.

Based on:
https://bitbucket.org/pyglet/pyglet/issues/78/
https://bitbucket.org/pyglet/pyglet/issues/248/
...and a lot of trial and error.
'''

import pyglet

def font_size_from_height(height):
    return height // 6

class HelloWorldWindow(pyglet.window.Window):
    def __init__(self):
        width, height = 800, 600
        super(HelloWorldWindow, self).__init__(
            width, height, caption='Text rendering example', resizable=True)
        self.ratio = width / height
        self.set_minimum_size(width // 2, height // 2)

        self.label = pyglet.text.Label(
            'Hello, world',
            font_name='Times New Roman',
            font_size=font_size_from_height(height),
            anchor_x='center',
            anchor_y='center')

        self.on_resize(width, height)

    def on_draw(self):
        self.clear()

        # Use viewport size to set the coordinate system:
        pyglet.gl.glMatrixMode(pyglet.gl.GL_PROJECTION)
        pyglet.gl.glLoadIdentity()
        width, height = self.get_viewport_size()
        pyglet.gl.glOrtho(0, width, 0, height, -1, 1)
        pyglet.gl.glMatrixMode(pyglet.gl.GL_MODELVIEW)
        # The glOrtho call is necessary for high resolution mac font rendering

        # Start normal drawing:
        self.label.draw()

    def on_resize(self, w, h):
        w = int(self.ratio * h)  # Locked aspect ratio
        self.width = w
        self.height = h

        # Don't use window dimensions for coordinate system, use viewport:
        width, height = self.get_viewport_size() # May be scaled (on mac)

        # Resize viewport (only necessary on windows):
        pyglet.gl.glViewport(0, 0, max(1, width), max(1, height))

        # Resize font in label:
        self.label.font_size = font_size_from_height(height)

        # Center label:
        self.label.x, self.label.y = width // 2, height // 2


def main():
    window = HelloWorldWindow()
    pyglet.app.run()


if __name__ == "__main__":
    main() # main function ensures no variables are in global scope