Python 彩色地图it'；它不是由正确的颜色组成的

我需要制作一个从黑到红再到白的256色彩色贴图，并在Python中显示红色通道，但它看起来是唯一一个从黑到红的显示，我不明白为什么。。。此外，只有红色通道不显示。这是我的代码：

import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

# How to create an array filled with zeros
img = np.zeros([256,256])
colormap = np.zeros([256,3])

#image:
for i in range(256):
    img[:,i] = i #on all columns I have the same value
    
#color map:
for i in range(128):
    colormap[i,0] = i/127 
    colormap[i+128,0] = 1 #from line 128 incolo I have 1 on first position because I've already reached red
    colormap[i+128,2] = (i+1)/128
    
#display the thing:
colormap = mpl.colors.ListedColormap(colormap)
plt.figure(), plt.imshow(img, cmap = colormap)

---

您应该在代码中添加这一行：

colormap[i+128,1] = (i+1)/128

不能使用白色，因为绿色值始终等于0

要从红色变为白色，应具有以下RGB值：

[1,0,0]
...
[1,0.5,0.5]
...
[1,1,1]