draw_signature() does not keep customization settings about django-jsignature HOT 2 OPEN

def change_color(img, orig_color, new_color):
    """
    Parameters:
        img= PIL image
        colors must be in (R,G,B) format
    """
    for y in range(img.size[1]):
        for x in range(img.size[0]):
            pixel = img.getpixel((x, y))
            if pixel[0:-1] == orig_color:
                alpha = pixel[-1]
                new_value = new_color + (alpha, )
                img.putpixel((x,y), new_value)
    return img