background.py

# background.py
# Copyrighted (C) 2009 by Conrad "Lynx" Wong

import glob
import os
import pyglet
from pyglet import gl

class Background:
    """Selects one of several backgrounds to display behind the test dialog."""

    def __init__(self, loc=os.getcwd(), batch=None, group=None):
        """
        Load a set of backgrounds from a given directory.

        @param loc  Location, defaults to current working directory.
        @param batch Batch to which to add our background
        @param group Group to which to add our background
        """
        filenames = glob.glob(os.path.join(loc, '*.jpg'))
        images = [pyglet.image.load(x) for x in filenames]
        self.textures = [x.get_texture() for x in images]
        self.texture = None
        self.vertex_list = None
        if batch is None:
            self.batch = pyglet.graphics.Batch()
            self.own_batch = True
        else:
            self.own_batch = False
            self.batch = batch
        self.parent_group = group
        self.group = None
        self.width = self.height = 0
        self.needs_resizing = False

    def draw(self):
        if self.own_batch:
            self.batch.draw()
        else:
            self.batch.draw_subset([self.vertex_list])

    def on_key_press(self, symbol, modifiers):
        next_texture = None
        if symbol == pyglet.window.key.RIGHT:
            next_texture = self.textures.pop(0)
            if self.texture is not None:
                self.textures.append(self.texture)
        elif symbol == pyglet.window.key.LEFT:
            next_texture = self.textures.pop(-1)
            if self.texture is not None:
                self.textures.insert(0, self.texture)
        if next_texture is not None:
            self.texture = next_texture
            self.needs_resizing = True
            return pyglet.event.EVENT_HANDLED

    def on_resize(self, width, height):
        if width != self.width or height != self.height:
            self.width, self.height = width, height
            self.needs_resizing = True

    def on_update(self, dt):
        # We only update the background size on on_update because
        # otherwise we might receive several resize events between frames.
        if not self.needs_resizing:
            return
        self.needs_resizing = False

        if self.texture is None:
            self.texture = self.textures.pop(0) # pick first texture

        if self.vertex_list is not None:
            self.vertex_list.delete() # clear existing vertex_list

        # Now size the texture quad to retain its proportions but completely
        # overlap the screen
        our_width = self.texture.width * self.height / self.texture.height
        if our_width >= self.width:
            our_height = self.height
        else:
            our_height = self.texture.height * self.width / self.texture.width
            our_width = self.width
        x1 = int(self.width/2 - our_width/2)
        y1 = int(self.height/2 - our_height/2)
        x2 = int(x1 + our_width)
        y2 = int(y1 + our_height)
        self.group = pyglet.graphics.TextureGroup(
            self.texture, self.parent_group)
        self.vertex_list = self.batch.add(4, gl.GL_QUADS, self.group,
            ('v2i', (x1, y1, x2, y1, x2, y2, x1, y2)),
            ('c3B', (255, 255, 255) * 4),
            ('t3f', self.texture.tex_coords))