通过 Python 获取图片的主题色

Lxns 发表于 2020-02-17 01:17:51
编辑于 2020-02-17 01:22:08

示例代码，谷歌搜索到的相关代码并作改进。

## 引入相关的库

```
from PIL import Image
from mpl_toolkits.mplot3d import Axes3D
from matplotlib import pyplot as plt
from matplotlib import image as img
from scipy.cluster.vq import whiten
from scipy.cluster.vq import kmeans
from urllib import request
from io import BytesIO
import pandas as pd
import numpy
```

## 读取网络图片
```
original_image = request.urlopen("http://hulotte.jp/product/invisible/img/graphic-02.jpg").read()
image = Image.open(BytesIO(original_image))
input = BytesIO(original_image)
```
![image](http://hulotte.jp/product/invisible/img/graphic-02.jpg "image")

如要显示获取的图片，可以使用
```
plt.imshow(image)
plt.show()
```

## 压缩图片
为了加快读取的速度，需要对图片调整大小
```
image = numpy.array(image.resize((50, 50)))
```

## 逐行读取 RGB
```
r = []
g = []
b = []
for line in image:
	for pixel in line:
		temp_r, temp_g, temp_b = pixel
		r.append(temp_r)
		g.append(temp_g)
		b.append(temp_b)
```
可以通过以下代码通过 plt 显示 RGB 三维分布图
```
fig = plt.figure()
ax = Axes3D(fig)
ax.scatter(r, g, b)
plt.show()
```
![Figure_1.png](https://i.loli.net/2020/02/17/fxySW4hbBs7Gjdq.png)

## SciPy 聚类
```
df = pd.DataFrame({'red': r,
	'blue': b,
	'green': g})
df['scaled_red'] = whiten(df['red'])
df['scaled_blue'] = whiten(df['blue'])
df['scaled_green'] = whiten(df['green'])
cluster_centers, distortion = kmeans(df[['scaled_red', 'scaled_green', 'scaled_blue']], 2)
df.sample(n = 10)
```
若要输出标准 RGB 值可以使用
```
print(cluster_centers)
```
这里是本示例输出的结果
```
[[3.0039233  2.68969846 2.44129847]
 [1.25399819 0.88606984 1.07850226]]
```

## 显示主要颜色
```
colors = []
r_std, g_std, b_std = df[['red', 'green', 'blue']].std()
for cluster_center in cluster_centers:
	scaled_r, scaled_g, scaled_b = cluster_center
	colors.append((
		scaled_r * r_std / 255,
		scaled_g * g_std / 255,
		scaled_b * b_std / 255
		))
plt.imshow([colors])
plt.show()
```
![Figure_1.png](https://i.loli.net/2020/02/17/KUIb4m2BtRCJglf.png)

可使用相关函数获取需要的结果，如 HEX：
```
from matplotlib import colors as clr

print(clr.to_hex(colors[0]))
```
```
#d6c29f
```

## 应用
本代码应用于软糖酱 osu!droid 的卡片查询。

![1580705820.png](https://i.loli.net/2020/02/17/V4AGTC17QbrxLd8.png)

Lxns

@Lxns

什么都不会整天摸鱼的垃圾管理员。