Python中的 Matplotlib.axes.Axes.draw_artist()

Matplotlib是Python中的一个库，它是 NumPy 库的数值数学扩展。 Axes 类包含大部分图形元素：Axis、Tick、Line2D、Text、Polygon 等，并设置坐标系。 Axes 的实例通过回调属性支持回调。

matplotlib.axes.Axes.draw_artist()函数

matplotlib 库的 axes 模块中的Axes.draw_artist()函数用于有效更新 Axes 数据。

Syntax: Axes.draw_artist(self, a)

Parameters: This method accepts the following parameters.

• a: This parameter is the artist to be draw.

Returns: This method does not return any value.

注意：此方法只能在缓存渲染器的初始绘制之后使用。

下面的示例说明了 matplotlib.axes 中的 matplotlib.axes.Axes.draw_artist()函数：

示例 1：

# Implementation of matplotlib function 
from random import randint, choice
import time
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
  
  
back_color = "black"
colors = ['red', 'green', 'blue', 'purple']
width, height = 4, 4
  
fig, ax = plt.subplots()
ax.set(xlim =[0, width], ylim =[0, height])
  
fig.canvas.draw()
  
def update():
    x = randint(0, width - 1)
    y = randint(0, height - 1)
  
    arti = mpatches.Rectangle(
        (x, y), 1, 1,
        facecolor = choice(colors),
        edgecolor = back_color
    )
    ax.add_artist(arti)
  
    start = time.time()
    ax.draw_artist(arti)
    fig.canvas.blit(ax.bbox)
    print("Draw at time :", time.time() - start)
  
timer = fig.canvas.new_timer(interval = 1)
timer.add_callback(update)
timer.start()
  
ax.set_title('matplotlib.axes.Axes.draw_artist()\
 function Example') 
  
plt.show() 

输出：

Draw at time : 0.37501978874206543
Draw at time : 0.015624046325683594
Draw at time : 0.03127431869506836
Draw at time : 0.015625953674316406
Draw at time : 0.015601396560668945
Draw at time : 0.015614986419677734
........
so on...

示例 2：

# Implementation of matplotlib function 
import matplotlib.pyplot as plt
import numpy as np
import time
  
  
fig, ax = plt.subplots()
line, = ax.plot(np.random.randn(100))
  
tstart = time.time()
num_plots = 0
fig.canvas.draw()
  
while time.time()-tstart < 5:
    line.set_ydata(np.random.randn(100))
    ax.draw_artist(ax.patch)
    ax.draw_artist(line)
    num_plots += 1
      
ax.set_title('matplotlib.axes.Axes.draw_artist() \
function Example') 
  
plt.show() 

输出：