pong.kv

#:kivy 1.0.9
# The name of the kv file, e.g. pong.kv, must match the name of the app, e.g. PongApp (the part before the App ending)

<PongBall>:
    size: 50, 50
    canvas:
        Ellipse:
            pos: self.pos
            size: self.size
            source: 'res/ball.jpg'

<PongPlayer>:
    size: 25, 200
    canvas:
        Rectangle:
            pos:self.pos
            size:self.size

<PongGame>: # this is the name of the application class
    ball: pong_ball # see PongBall ID
    player1: player_left
    player2: player_right
    canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
            source: 'res/gras.jpg'
    canvas:
        Rectangle: # this rectangle defines the horizontal line that seperates left and right player
            pos: self.center_x - 5, 0 # five pixels left of the center is the x starting point
            size: 10, self.height # the x-size is 10 pixels, the y-size is the widget-height
    # The root keyword can be used inside the child block to refer back to the parent/root widget the rule applies to
    # (PongGame in this case)
    Label:
        font_size: 70
        center_x: root.width / 4
        top: root.top - 50
        text: str(root.player1.score)

    Label:
        font_size: 70
        center_x: root.width * 3 / 4
        top: root.top - 50
        text: str(root.player2.score)

    PongBall:
        id: pong_ball
        center: self.parent.center

    PongPlayer:
        id: player_left
        x: root.x
        center_y: root.center_y

    PongPlayer:
        id: player_right
        x: root.width - self.width
        center_y: root.center_y