Video player function implemented in Python

# -*- coding:utf-8 -*-
#! python3
# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
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# * Redistributions of source code must retain the above copyright
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'''Audio and video player with simple GUI controls.
'''
__docformat__ = 'restructuredtext'
__version__ = '$Id: $'
import sys
from pyglet.gl import *
import pyglet
from pyglet.window import key
def draw_rect(x, y, width, height):
  glBegin(GL_LINE_LOOP)
  glVertex2f(x, y)
  glVertex2f(x + width, y)
  glVertex2f(x + width, y + height)
  glVertex2f(x, y + height)
  glEnd()
class Control(pyglet.event.EventDispatcher):
  x = y = 0
  width = height = 10
  def __init__(self, parent):
    super(Control, self).__init__()
    self.parent = parent
  def hit_test(self, x, y):#点中控件
    return (self.x < x < self.x + self.width and 
        self.y < y < self.y + self.height)
  def capture_events(self):
    self.parent.push_handlers(self)
  def release_events(self):
    self.parent.remove_handlers(self)
class Button(Control):
  charged = False
  def draw(self):
    if self.charged:
      glColor3f(0, 1, 0)
    draw_rect(self.x, self.y, self.width, self.height)
    glColor3f(1, 1, 1)
    self.draw_label()
  def on_mouse_press(self, x, y, button, modifiers):
    self.capture_events()
    self.charged = True
  def on_mouse_drag(self, x, y, dx, dy, buttons, modifiers):
    self.charged = self.hit_test(x, y)
  def on_mouse_release(self, x, y, button, modifiers):
    self.release_events()
    if self.hit_test(x, y):
      self.dispatch_event(&#39;on_press&#39;)
    self.charged = False
Button.register_event_type(&#39;on_press&#39;)#注册事件
class TextButton(Button):
  def __init__(self, *args, **kwargs):
    super(TextButton, self).__init__(*args, **kwargs)
    self._text = pyglet.text.Label(&#39;&#39;, anchor_x=&#39;center&#39;, anchor_y=&#39;center&#39;)
  def draw_label(self):
    self._text.x = self.x + self.width / 2
    self._text.y = self.y + self.height / 2
    self._text.draw()
  def set_text(self, text):
    self._text.text = text
  text = property(lambda self: self._text.text,
          set_text)
class Slider(Control):
  THUMB_WIDTH = 6
  THUMB_HEIGHT = 10
  GROOVE_HEIGHT = 2
  def draw(self):
    center_y = self.y + self.height / 2
    draw_rect(self.x, center_y - self.GROOVE_HEIGHT / 2, 
         self.width, self.GROOVE_HEIGHT)
    pos = self.x + self.value * self.width / (self.max - self.min)
    draw_rect(pos - self.THUMB_WIDTH / 2, center_y - self.THUMB_HEIGHT / 2, 
         self.THUMB_WIDTH, self.THUMB_HEIGHT)
  def coordinate_to_value(self, x):#改变进度
    return float(x - self.x) / self.width * (self.max - self.min) + self.min
  def on_mouse_press(self, x, y, button, modifiers):
    value = self.coordinate_to_value(x)
    self.capture_events()
    self.dispatch_event(&#39;on_begin_scroll&#39;)
    self.dispatch_event(&#39;on_change&#39;, value)
  def on_mouse_drag(self, x, y, dx, dy, buttons, modifiers):
    value = min(max(self.coordinate_to_value(x), self.min), self.max)
    self.dispatch_event(&#39;on_change&#39;, value)
  def on_mouse_release(self, x, y, button, modifiers):
    self.release_events()
    self.dispatch_event(&#39;on_end_scroll&#39;)
Slider.register_event_type(&#39;on_begin_scroll&#39;)
Slider.register_event_type(&#39;on_end_scroll&#39;)
Slider.register_event_type(&#39;on_change&#39;)
class PlayerWindow(pyglet.window.Window):
  GUI_WIDTH = 400
  GUI_HEIGHT = 40
  GUI_PADDING = 4#按钮间隔
  GUI_BUTTON_HEIGHT = 16
  def __init__(self, player):
    super(PlayerWindow, self).__init__(caption=&#39;Media Player&#39;,
                      visible=False, 
                      resizable=True)
    self.player = player
    self.player.push_handlers(self)
    self.player.eos_action = self.player.EOS_PAUSE
    self.slider = Slider(self)
    self.slider.x = self.GUI_PADDING#类变量
    self.slider.y = self.GUI_PADDING * 2 + self.GUI_BUTTON_HEIGHT
    self.slider.on_begin_scroll = lambda: player.pause()
    self.slider.on_end_scroll = lambda: player.play()
    self.slider.on_change = lambda value: player.seek(value)
    self.play_pause_button = TextButton(self)
    self.play_pause_button.x = self.GUI_PADDING
    self.play_pause_button.y = self.GUI_PADDING
    self.play_pause_button.height = self.GUI_BUTTON_HEIGHT
    self.play_pause_button.width = 45
    self.play_pause_button.on_press = self.on_play_pause
    win = self#自有妙用
    self.window_button = TextButton(self)
    self.window_button.x = self.play_pause_button.x + \
                self.play_pause_button.width + self.GUI_PADDING
    self.window_button.y = self.GUI_PADDING
    self.window_button.height = self.GUI_BUTTON_HEIGHT
    self.window_button.width = 90
    self.window_button.text = &#39;Windowed&#39;
    self.window_button.on_press = lambda: win.set_fullscreen(False)#注意不能写self
    self.controls = [
      self.slider, 
      self.play_pause_button,
      self.window_button,
    ]
    x = self.window_button.x + self.window_button.width + self.GUI_PADDING
    i = 0
    for screen in self.display.get_screens():
      screen_button = TextButton(self)
      screen_button.x = x
      screen_button.y = self.GUI_PADDING
      screen_button.height = self.GUI_BUTTON_HEIGHT
      screen_button.width = 80
      screen_button.text = &#39;Screen %d&#39; % (i + 1)
      screen_button.on_press = \
        (lambda s: lambda: win.set_fullscreen(True, screen=s))(screen)
      self.controls.append(screen_button)
      i += 1
      x += screen_button.width + self.GUI_PADDING
  def on_eos(self):
    self.gui_update_state()
  def gui_update_source(self):
    if self.player.source:
      source = self.player.source
      self.slider.min = 0.
      self.slider.max = source.duration
    self.gui_update_state()
  def gui_update_state(self):
    if self.player.playing:
      self.play_pause_button.text = &#39;Pause&#39;
    else:
      self.play_pause_button.text = &#39;Play&#39;
  def get_video_size(self):
    if not self.player.source or not self.player.source.video_format:
      return 0, 0
    video_format = self.player.source.video_format
    width = video_format.width
    height = video_format.height
    if video_format.sample_aspect > 1:
      width *= video_format.sample_aspect
    elif video_format.sample_aspect < 1:
      height /= video_format.sample_aspect
    return width, height
  def set_default_video_size(self):
    &#39;&#39;&#39;Make the window size just big enough to show the current
    video and the GUI.&#39;&#39;&#39;
    width = self.GUI_WIDTH
    height = self.GUI_HEIGHT
    video_width, video_height = self.get_video_size()
    width = max(width, video_width)
    height += video_height
    self.set_size(int(width), int(height))
  def on_resize(self, width, height):
    &#39;&#39;&#39;Position and size video image.&#39;&#39;&#39;
    super(PlayerWindow, self).on_resize(width, height)
    self.slider.width = width - self.GUI_PADDING * 2
    height -= self.GUI_HEIGHT
    if height <= 0:
      return
    video_width, video_height = self.get_video_size()
    if video_width == 0 or video_height == 0:
      return
    display_aspect = width / float(height)
    video_aspect = video_width / float(video_height)
    if video_aspect > display_aspect:
      self.video_width = width
      self.video_height = width / video_aspect
    else:
      self.video_height = height
      self.video_width = height * video_aspect
    self.video_x = (width - self.video_width) / 2
    self.video_y = (height - self.video_height) / 2 + self.GUI_HEIGHT
  def on_mouse_press(self, x, y, button, modifiers):
    for control in self.controls:
      if control.hit_test(x, y):
        control.on_mouse_press(x, y, button, modifiers)
  def on_key_press(self, symbol, modifiers):
    if symbol == key.SPACE:
      self.on_play_pause()
    elif symbol == key.ESCAPE:
      self.dispatch_event(&#39;on_close&#39;)
  def on_close(self):
    self.player.pause()
    self.close()
  def on_play_pause(self):
    if self.player.playing:
      self.player.pause()
    else:
      if self.player.time >= self.player.source.duration:#如果放完了
        self.player.seek(0)
      self.player.play()
    self.gui_update_state()
  def on_draw(self):
    self.clear()
    # Video
    if self.player.source and self.player.source.video_format:
      self.player.get_texture().blit(self.video_x,
                      self.video_y,
                      width=self.video_width,
                      height=self.video_height)
    # GUI
    self.slider.value = self.player.time
    for control in self.controls:
      control.draw()
if __name__ == &#39;__main__&#39;:
  if len(sys.argv) < 2:
    print(&#39;Usage: media_player.py <filename> [<filename> ...]&#39;)
    sys.exit(1)
  for filename in sys.argv[1:]:
    player = pyglet.media.Player()
    window = PlayerWindow(player)
    source = pyglet.media.load(filename)
    player.queue(source)
    window.gui_update_source()
    window.set_default_video_size()
    window.set_size(400,400)
    window.set_visible(True)
    window.gui_update_state()
    player.play()
  pyglet.app.run()