如何绘制在圆圈内移动的动画点？

Question

我正在尝试编写一个函数来生成在圆圈内移动的点。我已经有一个用 matpltolib 动画绘制动画点的函数（感谢 Tony Babarino），但是我在编写迫使点留在圆圈中的部分时遇到了麻烦

这就是产生运动的部分的工作原理

import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation

# Initializing number of dots
N = 25


# Creating dot class
class dot(object):
    def __init__(self):
        self.x = 10 * np.random.random_sample()
        self.y = 10 * np.random.random_sample()
        self.velx = self.generate_new_vel()
        self.vely = self.generate_new_vel()

    def generate_new_vel(self):
        return (np.random.random_sample() - 0.5) / 5

    def move(self) :
            if np.random.random_sample() < 0.95:
                self.x = self.x + self.velx
                self.y = self.y + self.vely
            else:
                self.velx = self.generate_new_vel()
                self.vely = self.generate_new_vel()
                self.x = self.x + self.velx
                self.y = self.y + self.vely

# Initializing dots
dots = [dot() for i in range(N)]

# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, 10), ylim=(0, 10))
d, = ax.plot([dot.x for dot in dots],
             [dot.y for dot in dots], 'ro', markersize=3)
circle = plt.Circle((5, 5), 1, color='b', fill=False)
ax.add_artist(circle)


# animation function.  This is called sequentially
def animate(i):
    for dot in dots:
        dot.move()
    d.set_data([dot.x for dot in dots],
               [dot.y for dot in dots])
    return d,

# call the animator. 
anim = animation.FuncAnimation(fig, animate, frames=200, interval=20)

plt.show()

我想通过添加一个强制圆点饱和的部分来改进功能移动 我希望圆的边界像栅栏一样，点不能越过

我知道如何检测点何时越线，但我不知道在那之后该怎么做。

非常感谢您的帮助

Answer 1

我更改了代码，这样您就不会遇到振动和逃脱圈子的问题。进入圆圈的每个点都不会逃逸（这些点在开始时可以在圆圈之外），也不会在圆圈的边缘振动。 将 numpy 导入为 np 从 matplotlib 导入 pyplot 作为 plt 从 matplotlib 导入动画

# Initializing number of dots
N = 25
XC = 5
YC = 5
R = 1
R_SQR = R **2

# Creating dot class
class dot(object):
    def __init__(self, ind):
        self.x = 10 * np.random.random_sample()
        self.y = 10 * np.random.random_sample()
        self.velx = self.generate_new_vel()
        self.vely = self.generate_new_vel()
        self.in_circle = not self.calc_out_of_circle()

    def generate_new_vel(self):
        return (np.random.random_sample() - 0.5) / 5

    def move(self) :
        if np.random.random_sample() < 0.95:
            self.check_out_of_circle()
            self.x += self.velx
            self.y += self.vely
        else:
            self.velx = self.generate_new_vel()
            self.vely = self.generate_new_vel()
            self.check_out_of_circle()
            self.x += self.velx
            self.y += self.vely
        self.check_inside_circle()

    def calc_out_of_circle_with_params(self, x, y):
        return (x - XC) ** 2 + (y - YC) ** 2 >= R_SQR ** 2

    def calc_out_of_circle(self):
        return self.calc_out_of_circle_with_params(self.x, self.y)

    def check_out_of_circle(self):
        if self.in_circle and self.calc_out_of_circle_with_params(self.x + self.velx, self.y + self.vely):
            self.velx = -self.velx
            self.vely = -self.vely

    def check_inside_circle(self):
        if not self.calc_out_of_circle():
            self.in_circle = True


# Initializing dots
dots = [dot(i) for i in range(N)]

# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, 10), ylim=(0, 10))
d, = ax.plot([dot.x for dot in dots],
             [dot.y for dot in dots], 'ro', markersize=3)
circle = plt.Circle((XC, YC), R, color='b', fill=False)
ax.add_artist(circle)


# animation function.  This is called sequentially
def animate(i):
    for dot in dots:
        dot.move()
    d.set_data([dot.x for dot in dots],
               [dot.y for dot in dots])
    return d,

# call the animator.
anim = animation.FuncAnimation(fig, animate, frames=200, interval=20)
# plt.axis('equal')
plt.show()