transform-pan-zoom.py

# -----------------------------------------------------------------------------
# Copyright (c) 2009-2016 Nicolas P. Rougier. All rights reserved.
# Distributed under the (new) BSD License.
# -----------------------------------------------------------------------------
import numpy as np
from PIL import Image
from glumpy import app, gl, glm, gloo, data
from glumpy.transforms import PanZoom, Position

vertex = """
    attribute vec2 position;
    attribute vec2 texcoord;
    varying vec2 v_texcoord;
    void main()
    {
        gl_Position = <transform>;
        v_texcoord = texcoord;
    }
"""

fragment = """
    uniform sampler2D texture;
    varying vec2 v_texcoord;
    void main()
    {
        gl_FragColor = texture2D(texture, v_texcoord);
    }
"""

window = app.Window(width=800, height=800)

@window.event
def on_draw(dt):
    window.clear()
    program.draw(gl.GL_TRIANGLE_STRIP)

@window.event
def on_key_press(key, modifiers):
    if key == app.window.key.SPACE:
        transform.reset()

program = gloo.Program(vertex, fragment, count=4)
program['position'] = [(-1,-1), (-1,1), (1,-1), (1,1)]
program['texcoord'] = [( 0, 1), ( 0, 0), ( 1, 1), ( 1, 0)]
program['texture'] = data.get("lena.png")

transform = PanZoom(Position("position"), aspect=1)
program['transform'] = transform
window.attach(transform)

app.run()