A special Clear code is defined which resets all compression /
decompression parameters and tables to a start-up state.
The value of this code is 2 ^ code size.
For example if the code size indicated was 4 (image was 4 bits/pixel)
the Clear code value would be 16 (10000 binary).
The Clear code can appear at any point in the image data stream and
therefore requires the LZW algorithm to process succeeding codes as
if a new data stream was starting.
Encoders should output a Clear code as the first code of each image
data stream.
Declaration Syntax