如何使用PIL使所有白色像素透明?

您需要进行以下更改:

• (255, 255, 255, 0) 而不是列表 [255, 255, 255, 0]
• 使用 img.putdata(newData)

这是工作代码:

from PIL import Image

img = Image.open('img.png')
img = img.convert("RGBA")
datas = img.getdata()

newData = []
for item in datas:
    if item[0] == 255 and item[1] == 255 and item[2] == 255:
        newData.append((255, 255, 255, 0))
    else:
        newData.append(item)

img.putdata(newData)
img.save("img2.png", "PNG")

您还可以使用像素访问模式就地修改图像:

from PIL import Image

img = Image.open('img.png')
img = img.convert("RGBA")

pixdata = img.load()

width, height = img.size
for y in range(height):
    for x in range(width):
        if pixdata[x, y] == (255, 255, 255, 255):
            pixdata[x, y] = (255, 255, 255, 0)

img.save("img2.png", "PNG")

如果你经常使用,你也可以把上面的内容包装成一个脚本。

import numpy as np

def white_to_transparency(img):
    x = np.asarray(img.convert('RGBA')).copy()

    x[:, :, 3] = (255 * (x[:, :, :3] != 255).any(axis=2)).astype(np.uint8)

    return Image.fromarray(x)

def white_to_transparency_gradient(img):
    x = np.asarray(img.convert('RGBA')).copy()

    x[:, :, 3] = (255 - x[:, :, :3].mean(axis=2)).astype(np.uint8)

    return Image.fromarray(x)

备注: .copy()