watermark.py 文件源码

def set_opacity(im, opacity):
    """?????"""

    assert opacity >=0 and opacity < 1
    if im.mode != "RGBA":
        im = im.convert('RGBA')
    else:
        im = im.copy()
    alpha = im.split()[3]
    alpha = ImageEnhance.Brightness(alpha).enhance(opacity)
    im.putalpha(alpha)
    return im