def _render()

in gym/gym/envs/classic_control/acrobot.py [0:0]

• 29 lines of code
• 6 McCabe index (conditional complexity)

    def _render(self, mode='human', close=False):
        if close:
            if self.viewer is not None:
                self.viewer.close()
                self.viewer = None
            return
        from gym.envs.classic_control import rendering

        s = self.state

        if self.viewer is None:
            self.viewer = rendering.Viewer(500,500)
            self.viewer.set_bounds(-2.2,2.2,-2.2,2.2)

        if s is None: return None

        p1 = [-self.LINK_LENGTH_1 *
              np.cos(s[0]), self.LINK_LENGTH_1 * np.sin(s[0])]

        p2 = [p1[0] - self.LINK_LENGTH_2 * np.cos(s[0] + s[1]),
              p1[1] + self.LINK_LENGTH_2 * np.sin(s[0] + s[1])]

        xys = np.array([[0,0], p1, p2])[:,::-1]
        thetas = [s[0]-np.pi/2, s[0]+s[1]-np.pi/2]

        self.viewer.draw_line((-2.2, 1), (2.2, 1))
        for ((x,y),th) in zip(xys, thetas):
            l,r,t,b = 0, 1, .1, -.1
            jtransform = rendering.Transform(rotation=th, translation=(x,y))
            link = self.viewer.draw_polygon([(l,b), (l,t), (r,t), (r,b)])
            link.add_attr(jtransform)
            link.set_color(0,.8, .8)
            circ = self.viewer.draw_circle(.1)
            circ.set_color(.8, .8, 0)
            circ.add_attr(jtransform)

        return self.viewer.render(return_rgb_array = mode=='rgb_array')