Python matplotlib生成图片背景透明的示例代码

使用matplotlib生成图片，想要背景透明，而且图例部分也显示透明效果，找到了大概的设置方法，特此记录。

# coding=utf-8
# matplotlib背景透明示例图
# python 3.5
 
import numpy as np
import matplotlib.pyplot as plt
from pylab import mpl
import scipy.stats as stats
 
# 设置中文字体
mpl.rcparams['font.sans-serif'] = ['simhei']
 
 
def autolabel(rects):
  # attach some text labels
  for rect in rects:
    height = rect.get_height()
    # 设置标注文字及位置
    ax.text(rect.get_x() + rect.get_width() / 2, 0.03 + height, '%.4f' % height, ha='center', va='bottom')
 
# 数据
testdata = [[0.87, 0.40, 0.56],
      [0.97, 0.50, 0.33],
      [0.88, 0.30, 0.44],
      [0.25, 0.23, 0.17],
      [0.73, 0.33, 0.45]]
 
n = 3
width = 0.5
ind = np.arange(width, width*6*n, width*6)
 
fig, ax = plt.subplots()
rectstest1 = ax.bar(ind, (testdata[0][0], testdata[0][1], testdata[0][2]), width, color=(0, 0, 1, 1), edgecolor=(0, 0, 1, 1))
 
rectstest2 = ax.bar(ind + width, (testdata[1][0], testdata[1][1], testdata[1][2]), width, color=(1, 0, 0, 1), edgecolor=(1, 0, 0, 1))
 
rectstest3 = ax.bar(ind + 2*width, (testdata[2][0], testdata[2][1], testdata[2][2]), width, color=(0, 1, 0, 1), edgecolor=(0, 1, 0, 1))
 
rectstest4 = ax.bar(ind + 3*width, (testdata[3][0], testdata[3][1], testdata[3][2]), width, color=(1, 0.6471, 0, 1), edgecolor=(1, 0.6471, 0, 1))
 
rectstest5 = ax.bar(ind + 4*width, (testdata[4][0], testdata[4][1], testdata[4][2]), width, color=(0.5804, 0, 0.8275, 1), edgecolor=(0.5804, 0, 0.8275, 1))
 
ax.set_xlim(0, 9.5)
ax.set_ylim(0, 1.4)
ax.set_ylabel('数值')
ax.yaxis.grid(true)
ax.set_xticks(ind + width * 2.5)
ax.set_xticklabels(('p', 'r', 'f'))
 
# 设置图例
legend = ax.legend((rectstest1, rectstest2, rectstest3, rectstest4, rectstest5), ('test1', 'test2', 'test3', 'test4', 'test5'))
frame = legend.get_frame()
frame.set_alpha(1)
frame.set_facecolor('none') # 设置图例legend背景透明
 
# 给每个数据矩形标注数值
autolabel(rectstest1)
autolabel(rectstest2)
autolabel(rectstest3)
autolabel(rectstest4)
autolabel(rectstest5)
 
plt.savefig('c:/users/xx/desktop/test.png', format='png', bbox_inches='tight', transparent=true, dpi=600) # bbox_inches='tight' 图片边界空白紧致, 背景透明
效

效果可能在网页上看不出来，但还是把图片贴上来吧。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。