noteshrink.py 文件源码

def apply_palette(img, palette, options):

    '''Apply the pallete to the given image. The first step is to set all
background pixels to the background color; then, nearest-neighbor
matching is used to map each foreground color to the closest one in
the palette.

    '''

    if not options.quiet:
        print('  applying palette...')

    bg_color = palette[0]

    fg_mask = get_fg_mask(bg_color, img, options)

    orig_shape = img.shape

    pixels = img.reshape((-1, 3))
    fg_mask = fg_mask.flatten()

    num_pixels = pixels.shape[0]

    labels = np.zeros(num_pixels, dtype=np.uint8)

    labels[fg_mask], _ = vq(pixels[fg_mask], palette)

    return labels.reshape(orig_shape[:-1])

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