Brother International HL-1660 Users Manual - English - Page 247

APPENDICES The block data is composed as follows: Position Data Description 0 - 1 Block length n - 2 2 - 3 Horizontal position dots from the left of the page 4 - 5 Vertical position dots from the leading edge of the page 6 Height dots number of image vertical dots 7 - 8 Width words number of image horizontal 16 bit words 9 - (n - 1) Compression data compression image data Ex.) Data is at horizontal position = 256, vertical position = 64, height = 32 dots, width = 100 x 16 bit words (1600 dots), and compression data is 800 bytes; ESC*b809W 03h 27h 01h 00h 00h 40h 20h 00h 64h [Data800Byte] | a b c de f 0 (256, 64) 64 32 1600 128 Band 1 Band 2 a: Block length(807) b: Horizontal position(256) c: Vertical position(64) d: Height dots(32) e: Width words(100) f: Compression image data Data compression compresses the original image data word by word (16 bits). The compressed data consists of both horizontal compression which uses 16 bit, 8 bit and 4 bit repeating patterns within 1 word or 2 words of data, and vertical compression which indicates to repeat the same data as in the previous line with 1 word of data. O Non-compressed data When the most significant bit in the first 2 bytes is 0, the printer goes into non-compression mode. The following 11 bits then indicate the number of words of data, and the least significant 4 bits are not used. After that, the image data follows word by word. 15 14 0 data word count (11 bits) data 1 (16 bits) : data n (16 bits) 4 3 0 not used Appendix-53