How do I replace the alpha channel of any image (png, jpg, rgb, rbga) with specified background color? It must also work with images that do not have an alpha channel.
3 Answers
I'd suggest using Image.alpha_composite.
This code can avoid a tuple index out of range error if png has no alpha channel.
from PIL import Image
png = Image.open(img_path).convert('RGBA')
background = Image.new('RGBA', png.size, (255,255,255))
alpha_composite = Image.alpha_composite(background, png)
alpha_composite.save('foo.jpg', 'JPEG', quality=80)
I also recommend you inspect both results with a image.show().
Credits for this answer goes to shuuji3 and others who helped build a vast answers repertoire in this other question.
I updated Vincius M's code with the user, tutuDajuju, suggestion to make [height, width, 3] matrix (not [height, width, 4]):
from PIL import Image
import numpy as np
png = Image.open(img_path).convert('RGBA')
background = Image.new('RGBA', png.size, (255,255,255))
alpha_composite = Image.alpha_composite(background, png)
# if you check the matrix dimension, channel, it would be still 4.
h, w, channel = np.asarray(alpha_composite)
alpha_composite_3 = alpha_composite.convert('RGB')
# if you check the matrix dimension, channel, it would be 3.
h, w, channel = np.asarray(alpha_composite_3)
Related