Background is white instead of being transparent

[hriguich]

What did you do?

Overlay add png images on a gif file frames

What did you expect to happen?

Get a gif with the pngs added on each layer and a transparent background

What actually happened?

I'm getting the gif as I want it but with a white background

What are your OS, Python and Pillow versions?

• OS: MacOs 11.6.5
• Python: python3.7
• Pillow: 9.1

All the png files have a transparent background and also the gif has a transparent background !

Here is an image from the end result gif (the file is too big i couldn't upload it here):

from PIL import Image, ImageSequence

background   = Image.open('images/1.png')#.convert('RGBA')
animated_gif = Image.open("images/2.gif")
layer1 = Image.open('images/3.png')
layer2 = Image.open('images/4.png')
all_frames = []


for gif_frame in ImageSequence.Iterator(animated_gif):


    new_frame = background.copy()
    layerr1 = layer1.copy()
    layerr2 = layer2.copy()

    gif_frame = gif_frame.convert('RGBA')
    
    new_frame.paste(layerr2, mask=layerr2)
    new_frame.paste(gif_frame, mask=gif_frame) 
    new_frame.paste(layerr1, mask=layerr1)
    all_frames.append(new_frame)


all_frames[0].save("image2.gif",transparency = 255, background = 255, save_all=True, append_images=all_frames[1:], duration=50, loop=0)

Please help me with this, this is the first time I'm using pillow !

[radarhere]

Hi. It would be ideal to get a copy of your original files, so that we could exactly replicate your problem.

Otherwise, your problem looks similar to #6115. On April 1, Pillow 9.1.0 is due to be released with the fix for that issue. I suspect that if you wait until then, upgrade your copy of Pillow, and run your code without transparency = 255, your problem will be fixed.

[hriguich]

Hi,
Thank you so much for your reply. I did wait for the new update release to test again but it still doesn't work.
It shows a transparent background in some frames and the others have a background.
I've uploaded the script and the images I used to google drive here: https://drive.google.com/file/d/12zh9ouo5Pk3Tsh6tZ6QWo28QsXqRsoxw/view?usp=sharing

And here is the gif I get when i run the script: https://drive.google.com/file/d/1010FRU3sy3IBMv3E3h1nUHRqzssyy_QN/view?usp=sharing

The files are big, I couldn't upload them here.
You'd do me a big favor if you can help with this issue.
Thank you so much

[radarhere]

Ok, the problem is that Pillow calculates a different transparency for each frame of your GIF, but then doesn't use those different transparencies when saving. I've created PR #6176 to resolve this.

However, I imagine you would like a fix sooner than the next release of Pillow. So I've put together the following code that saves your image as intended.

from PIL import Image, ImageSequence, GifImagePlugin

# Patch Pillow to set the transparency of all frames to 255 when saving a GIF
original_normalize_mode = GifImagePlugin._normalize_mode
def _normalize_mode(im):
	im = original_normalize_mode(im)
	if "transparency" in im.info:
		dest_map = list(range(256))
		dest_map[im.info["transparency"]] = 255
		dest_map[255] = im.info["transparency"]
		im.info["transparency"] = 255
		im = im.remap_palette(dest_map)
	return im
GifImagePlugin._normalize_mode = _normalize_mode

background   = Image.open('images/1.png').convert('RGBA')
animated_gif = Image.open("images/2.gif")
layer1 = Image.open('images/3.png').convert('RGBA')
layer2 = Image.open('images/4.png').convert('RGBA')
all_frames = []
durations = []

for gif_frame in ImageSequence.Iterator(animated_gif):

    # duplicate background image because we will change it (we will paste 
    new_frame = Image.new('RGBA',gif_frame.size,(0,0,0,0))
    back = background.copy()
    layerr1 = layer1.copy()
    layerr2 = layer2.copy()
    # convert to `RGBA` to use `Alpha` in `paste` as transparency mask
    gif_frame = gif_frame.convert('RGBA')
    new_frame.paste(back, mask=back)
    new_frame.paste(layerr2, mask=layerr2)
    new_frame.paste(gif_frame, mask=gif_frame) 
    new_frame.paste(layerr1, mask=layerr1)
    all_frames.append(new_frame)
    durations.append(gif_frame.info['duration'])

# save first frame and append other frames with duration 100ms 
all_frames[0].save("image2.gif",transparency=255,interlace=True, disposal=0, save_all=True, append_images=all_frames[1:], loop=0, duration=durations)