converts a gif into a sprite sheet. handles transparency.

gif2sprite.py

import os
from PIL import Image


def split(gif):

    im = Image.open(gif)
    for frame in range(im.n_frames):
        im.seek(frame)

        # convert transparent background to black
        bg_colour = (0, 0, 0)
        temp = im.convert("RGBA")
        if temp.mode in ('RGBA', 'LA'):
            background = Image.new(temp.mode[:-1], im.size, bg_colour)
            background.paste(temp, temp.split()[-1])  # omit transparency

        print(f'Saving frame {frame}')
        background.convert('RGB').save(f'./{gif.split(".")[0]}{frame}.jpg')


def combine(gif):
    # remove old file
    try:
        os.remove(f'./{gif.split(".")[0]}.bmp')
    except OSError:
        pass
    # retrieve all relevant bitmaps
    files = os.listdir('.')
    files = [f for f in files if gif.split(".")[0] in f and '.jpg' in f]

    # set up initial image with first frame
    first = Image.open(files[0]).convert('RGBA')
    sheet = Image.new('RGB', (first.width, first.height))
    sheet.paste(first, (0, 0))
    sheet.save(f'./{gif.split(".")[0]}.bmp', 'BMP')

    # continue for all subsequent frames
    for file in files[1:]:
        im = Image.open(file).convert('RGBA')
        sheet = Image.open(f'./{gif.split(".")[0]}.bmp').convert('RGBA')
        combined = Image.new('RGB', (sheet.width, sheet.height + im.height))
        combined.paste(sheet, (0, 0))
        combined.paste(im, (0, sheet.height))
        combined.save(f'./{gif.split(".")[0]}.bmp', 'BMP')

    for file in files:
        try:
            os.remove(f'./{file}')
        except OSError:
            pass


if __name__ == '__main__':
    filename = 'ball.gif'
    split(filename)
    combine(filename)

hor2ver.py

from PIL import Image


# converts .png horizontal sprite sheet to .bpm vertical sprite sheet
def convert(png):
    # open horizontal sprite sheet and count number of frames
    hor = Image.open(png)
    frames = hor.width // 64

    # create new vertical sprite sheet, crop and copy frame by frame
    ver = Image.new('RGB', (64, hor.height * frames))
    for frame in range(frames):
        ver.paste(hor.crop((frame*64, 0, (frame+1)*64, 32)), (0, frame*32))
    # save new sprite sheet
    ver.save(f'./{png.split(".")[0]}.bmp')


if __name__ == '__main__':
    filename = 'myball.png'
    convert(filename)