pixelaccess.py 文件源码

def _getitem(self, start, end):
        if self.itemsize == 1:
            # byte-wise access
            return self.source[start:end]
        # move the pointer to the correct location
        src = ctypes.byref(self.source.contents, start)
        casttype = ctypes.c_ubyte
        if self.itemsize == 2:
            casttype = ctypes.c_ushort
        elif self.itemsize == 3:
            # TODO
            raise NotImplementedError("unsupported bpp")
        elif self.itemsize == 4:
            casttype = ctypes.c_uint
        return ctypes.cast(src, ctypes.POINTER(casttype)).contents.value