!
        \~english
        Initialize the buffer object instance, use PIL Image as for buffer
        @param bufferColorMode: "RGB" or "1"
        @param bufferSize: (width, height)
        \~chinese
        初始化缓冲区对象实例，使用PIL Image作为缓冲区
        @param bufferColorMode: 色彩模式, 取值： "RGB" 或 "1"
        @param bufferSize: 缓存大小 (width, height)，例如： (128, 64)

def _initBuffer(self, bufferColorMode, bufferSize):
        """!
        \~english
        Initialize the buffer object instance, use PIL Image as for buffer
        @param bufferColorMode: "RGB" or "1"
        @param bufferSize: (width, height)
        \~chinese
        初始化缓冲区对象实例，使用PIL Image作为缓冲区
        @param bufferColorMode: 色彩模式, 取值： "RGB" 或 "1"
        @param bufferSize: 缓存大小 (width, height)，例如： (128, 64)
        """
        # super(SSScreenBase)._initBuffer(bufferColorMode, bufferSize)
        self._buffer_color_mode = bufferColorMode

        #create screen image buffer and canvas
        if bufferSize==None:
            self._buffer = Image.new( bufferColorMode , self._display_size )
        else:
            self._buffer = Image.new( bufferColorMode , bufferSize )        
        self.Canvas = ImageDraw.Draw( self._buffer )

        #creare screen view
        self.View = SSRect( 0, 0, self._display_size[0], self._display_size[1] )