在 Python 中仅重绘特定的轴对象

Question

我正在尝试用 Python 专门使用 matplotlib 编写一个小型视频游戏。这个想法是让一个小坐标轴对象上有一个角色，该坐标轴对象在更大的地图上移动。我设法更新了轴的位置，但该方法似乎重绘了完整的图形而不是小轴对象（通过在源代码中调用 plt.draw() ），因此角色后面的重地图也是如此，使得处理速度极慢。

有没有办法在 matplotlib 中重绘特定的轴对象？

我在终端的 IPython shell 中工作。

这是一个模拟我的问题的测试代码，我得到的东西比理想情况慢 10 倍：

import matplotlib.pylab as plt 
import time
import numpy as np 

dtframe = 0.02 #time between plot updating in seconds
frames = 30

plt.subplots(5,5) #to simulate an heavy background matplotlib figure 
ax = plt.axes([0.1,0.5,0.03,0.03])
plt.show(block=False)

begin = time.time()
for j in np.linspace(0.1,0.9,frames):
    plt.pause(dtframe)
    ax.set_position([j,0.5,0.03,0.03])
    #ax.set_position([j,0.5,0.03,0.03], redraw_only_axes=True) ???

print('Current time [s] :',time.time() - begin)
print('Expected time [s] :',dtframe*frames)

#Current time [s] : 5.70146918296814
#Expected time [s] : 0.6 

Answer 1

您正在寻找的技术称为 blitting。

这里有一个关于 matplotlib 的教程：https://matplotlib.org/stable/tutorials/advanced/blitting.html

Answer 2

根据@ianhi 提供的教程，这里是blitting的解决方案：

import matplotlib.pylab as plt 
import time
import numpy as np 

dtframe = 0.02 #time between plot updating in seconds
frames = 30

fig,axes = plt.subplots(5,5) #to simulate an heavy background matplotlib figure 
ax = plt.axes([0.1,0.5,0.03,0.03],animated=True)
plt.show(block=False)
plt.pause(0.1)

bg = fig.canvas.copy_from_bbox(fig.bbox)
fig.canvas.blit(fig.bbox)

begin = time.time()
for j in np.linspace(0.1,0.9,frames):
    fig.canvas.restore_region(bg)
    ax.set_position([j,0.5,0.03,0.03])
    plt.pause(dtframe)
    fig.draw_artist(ax)
    fig.canvas.blit(fig.bbox)
    fig.canvas.flush_events()

print('Current time [s] :',time.time() - begin)
print('Expected time [s] :',dtframe*frames)

#Current time [s] : 1.2531671524047852
#Expected time [s] : 0.6