gen_rst.py 文件源码

def scale_image(in_fname, out_fname, max_width, max_height):
    """Scales an image with the same aspect ratio centered in an
       image with a given max_width and max_height
       if in_fname == out_fname the image can only be scaled down
    """
    # local import to avoid testing dependency on PIL:
    try:
        from PIL import Image
    except ImportError:
        import Image
    img = Image.open(in_fname)
    width_in, height_in = img.size
    scale_w = max_width / float(width_in)
    scale_h = max_height / float(height_in)

    if height_in * scale_w <= max_height:
        scale = scale_w
    else:
        scale = scale_h

    if scale >= 1.0 and in_fname == out_fname:
        return

    width_sc = int(round(scale * width_in))
    height_sc = int(round(scale * height_in))

    # resize the image using resize; if using .thumbnail and the image is
    # already smaller than max_width, max_height, then this won't scale up
    # at all (maybe could be an option someday...)
    img = img.resize((width_sc, height_sc), Image.BICUBIC)
    # img.thumbnail((width_sc, height_sc), Image.BICUBIC)
    # width_sc, height_sc = img.size  # necessary if using thumbnail

    # insert centered
    thumb = Image.new('RGB', (max_width, max_height), (255, 255, 255))
    pos_insert = ((max_width - width_sc) // 2, (max_height - height_sc) // 2)
    thumb.paste(img, pos_insert)

    thumb.save(out_fname)
    # Use optipng to perform lossless compression on the resized image if
    # software is installed
    if os.environ.get('SKLEARN_DOC_OPTIPNG', False):
        try:
            subprocess.call(["optipng", "-quiet", "-o", "9", out_fname])
        except Exception:
            logger.warning(
                'Install optipng to reduce the size of the generated images')