processors.py 文件源码

def autocrop(im, autocrop=False, **kwargs):
    """
    Remove any unnecessary whitespace from the edges of the source image.

    This processor should be listed before :func:`scale_and_crop` so the
    whitespace is removed from the source image before it is resized.

    autocrop
        Activates the autocrop method for this image.

    """
    if autocrop:
        # If transparent, flatten.
        if utils.is_transparent(im) and False:
            no_alpha = Image.new('L', im.size, (255))
            no_alpha.paste(im, mask=im.split()[-1])
        else:
            no_alpha = im.convert('L')
        # Convert to black and white image.
        bw = no_alpha.convert('L')
        # bw = bw.filter(ImageFilter.MedianFilter)
        # White background.
        bg = Image.new('L', im.size, 255)
        bbox = ImageChops.difference(bw, bg).getbbox()
        if bbox:
            im = im.crop(bbox)
    return im