# 1. Matplotlib

Matplotlib的方便之处在于使用Jupyter notebook时能实时画图并显示，这样一来，远程即可看到服务器上的图。Jupyter notebook上使用matplotlib的魔法——需要加上%matplotlib inline

%matplotlib inline

import matplotlib.pyplot as plt
plt.imshow(img)

## 1.1. 柱状图 bar

plt.bar(range(len(mean_hist)), mean_hist, width=1.0, linewidth=1)
plt.xlim([0,256])
#设置横坐标的文字说明
#设置纵坐标的文字说明
plt.ylabel('Frequency')
#设置标题
plt.title('Title')
plt.show()

## 1.2. 散点图 plot

plot(X(pos, 1), X(pos, 2), 'k+', 'LineWidth', 2, 'MarkerSize')

k-black

b     blue          .     point              -     solid
g     green         o     circle             :     dotted
r     red           x     x-mark             -.    dashdot
c     cyan          +     plus               --    dashed
m     magenta       *     star             (none)  no line
y     yellow        s     square
k     black         d     diamond
w     white         v     triangle (down)
^     triangle (up)
<     triangle (left)
>     triangle (right)
p     pentagram
h     hexagram

pos = find(y==1);
neg = find(y==0);

plot(X(pos, 1), X(pos, 2), 'k+', 'LineWidth', 2, 'MarkerSize', 7);

plot(X(neg, 1), X(neg, 2), 'ko', 'MarkerFaceColor', 'y', 'MarkerSize', 7);

## 1.3. 在图上画框 Rectangle + 画子图

import matplotlib.pyplot as plt
import matplotlib.patches as patches

image = cv2.imread(png_dir + image_name + '.png')
fig1 = plt.figure()
ax1 = fig1.add_subplot(111, aspect='equal')
ax1.imshow(image)
x1,y1,w,h = box
patches.Rectangle(
(x1, y1),   # (x,y)
w,          # width
h,          # height
linewidth=1,edgecolor='r',facecolor='none'
)
)
plt.text(x1, y1,str(score)[:5], color='w')
plt.imshow(image)

plt.axis('off')

## 1.4. 保存图片

plt.savefig('example.jpg')