Brother International QL-810W Raster Command Reference - Page 36

Raster Command Reference M Select compression mode ASCII: M {n} Hexadecimal: 4D {n} Parameters Definitions of {n} 0 No-compression mode (Enabled) 1 Reserved (Disabled) 2 TIFF (Enabled) Description  Selects the compression mode. Data compression is available only for data in raster graphic transfer. * The QL-800 does not support the compression mode. [TIFF(Pack Bits)]  1-byte units  If the same data is repeated, the number of data units and that 1 byte of data are specified. If different data is in a series, the number of data items and all of the different data are specified.  If the same data is repeated, the number of data units is specified as the actual number minus 1, expressed as a negative number. If different data is in a series, the number of data units is specified as the number of bytes minus 1, expressed as a positive number.  If the above process results in more than 90 bytes of compressed data, the data is treated as being all different. As a result, the data will be 91 bytes, including the 1 byte that specifies the data length. Example 1 raster of raster graphics transfer: Without compression: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 22 22 23 BA BF A2 22 2B...... With compression: ED 00 FF 22 05 23 BA BF A2 22 2B ... a b c a. Since "00h" is repeated for 20 bytes, 20d -> 19d -> 13h changed into a negative number is EDh. Therefore: ED 00 b. Since "22h" is repeated for 2 bytes, 2d -> 1d -> 1h changed into a negative number is FFh. Therefore: FF 22 c. The following 6 bytes remain unchanged. 6d -> 5d -> 5h Therefore: 05 23 BA BF A2 22 2B Continue for the remaining number of bytes for the uncompressed data. Even if 00h continues until the end, it cannot be omitted. - 32 - 4. Printing Command Details