python - 如何在枕头中使用 alpha_composite？

Question

我尝试用 Pillow 在照片上放一个透明的标志:

# First, I convert my photo and watermark to RGBA:
image = Image.open(photo_image_path).convert('RGBA')
watermark = Image.open(watermark_image_path).convert('RGBA')

# then I сreate an empty layer with the same size as image
# and put watermark in x/y position
layer = Image.new('RGBA', image.size, (0, 0, 0, 0))
layer.paste(watermark, (x, y))

# then add transparency 
layer.putalpha(128)

# and merge image with logo
result = Image.alpha_composite(image, layer)

最初我的水印有一个全透明的背景。但是我在所有图像尺寸上都有黑色半透明背景的结果。我做错了什么？

Answer 1

我已经解决了这个问题:

image = Image.open(photo_image_path).convert('RGBA')
watermark = Image.open(watermark_image_path).convert('RGBA')
layer = Image.new('RGBA', image.size, (0, 0, 0, 0))
layer.paste(watermark, (x, y))

# Create a copy of the layer
layer2 = layer.copy()

# Put alpha on the copy
layer2.putalpha(128)

# merge layers with mask
layer.paste(layer2, layer)


result = Image.alpha_composite(image, layer)