visual.py 文件源码

def rgba(colors, dtype=None):
    '''
    Convert an RGB color to an RGBA color.

    Arguments
    ----------
    colors: (n,[3|4]) set of RGB or RGBA colors

    Returns
    ----------
    colors: (n,4) set of RGBA colors
    '''
    if not is_sequence(colors): 
        return
    if dtype is None:
        dtype = COLOR_DTYPE
    colors = np.asanyarray(colors, dtype=dtype)
    if is_shape(colors, (-1,3)):
        opaque = (2**(np.dtype(dtype).itemsize * 8)) - 1
        colors = np.column_stack((colors,
                                  opaque * np.ones(len(colors)))).astype(dtype)
    return colors