When compressing, in accordance with {HEAD ~ a compression method} which is designated by extra character registration information, {TAIL ~ the relevant compression method} is selected and the bit map data is compressed 
When compressing , in accordance with { HEAD ~ a compression method } which is designated by extra character registration information , { TAIL ~ the relevant compression method } is selected and the bit map data is compressed
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH