2001/10/02
CHAPTER 2 "PCL" - 81
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# = 5 indicates that adaptive compression is to be used.
This compression compresses multiple rows (a block) into one transfer graphics command.
Most other compression methods compress only one row to one transfer graphics command.
One transfer graphic command (ESC *b##W) can contain only up to 32,767 bytes.
As mode 5 compression compresses multiple rows, the amount of transferred data may become large.
If compressed data exceeds this limit, reduce the number of rows in the block.
We can use mode 0 to mode 3 compression to compress each row. We can even compress empty (white) rows
and duplicate rows with these compression methods.
Command byte
Mode 5 compressed data consists of multiple elements. Each element contains 3 header bytes at the
beginning.
The first byte of the header bytes is a command byte.
First byte
Second, third byte
0
Unencoded
1
Run-length Encoding
Number of bytes of data
2
TIFF
3
Delta Row compression
4
Empty Row
Number of empty row or repetition
5
Duplicate Row
Command byte
0 -
This element is an uncompressed row. The next two bytes contain the byte count of the uncompressed
data. Uncompressed data follows the header.
1 -
This element identifies a compressed row. Compression method is mode 1. The next two bytes (upper
byte first) contain the byte count of the compressed data. Compressed data follows the header.
2 -
This element identifies a compressed row. Compression method is mode 2. The next two bytes (upper
byte first) contain the byte count of the compressed data. Compressed data follows the header
3 -
This element identifies a compressed row. Compression method is mode 3. The next two bytes (upper
byte first) contain the byte count of the compressed data. Compressed data follows the header
4 -
This element identifies multiple empty rows. The next two bytes (upper byte first) contain the empty
row count.
5 -
This element identifies duplicate rows. The next two bytes (upper byte first) contain the duplicate row
count.
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# = 9 Mode 9 compression
Like mode 3 compression, this mode 9 compression data contains only the difference of the current row from
the preceding row.
Replacement data often consists of a repetition of a particular byte in mode 3 compression.
Mode 9 compression is effective in such cases.
Simple mode 9 compression data consists of a command byte and the replacement data.
A Command byte consists of 3 parts. These are the control bit, the offset count and the replacement count.
The Control bit is the most significant bit (bit 7) of a control byte.
7
6
5
4
3
2
1
0
Offset count
Replacement count-1
Control bit
0
Command byte for mode 9 compression (non repeated replacement data)
Содержание HL-1250
Страница 15: ...2001 10 02 CHAPTER 1 INTRODUCTION 1 CHAPTER 1 INTRODUCTION ...
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Страница 21: ...2001 10 02 CHAPTER 2 PCL 1 CHAPTER 2 PCL PRINTER CONTROL LANGUAGE ...
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Страница 131: ...2001 10 02 CHAPTER 3 PCL5C 1 CHAPTER 3 PCL5C ...
Страница 149: ...2001 10 02 CHAPTER 4 HP GL 2 1 CHAPTER 4 HP GL 2 GRAPHICS LANGUAGE ...
Страница 185: ...2001 10 02 CHAPTER 4 HP GL 2 37 150 LPRINT TR0 PA3900 4900 PM0 PA5100 4900 4500 6100 PM1 160 LPRINT PM2 FP ...
Страница 199: ...2001 10 02 CHAPTER 4 HP GL 2 51 ...
Страница 204: ...2001 10 02 CHAPTER 4 HP GL 2 56 ...
Страница 205: ...2001 10 02 CHAPTER 5 PJL 1 CHAPTER 5 PJL PRINTER JOB LANGUAGE ...
Страница 232: ...2001 10 02 CHAPTER 5 PJL 28 AUTOLF Sets AUTO LF ON or OFF AUTOMASK Sets AUTO MASK ON or OFF SELREADOUT ON or OFF ...
Страница 248: ...2001 10 02 CHAPTER 5 PJL 44 ...
Страница 263: ...2001 10 02 CHAPTER 5 PJL 59 ...
Страница 264: ...2001 10 02 CHAPTER 6 EPSON 1 CHAPTER 6 EPSON FX 850 ...
Страница 286: ...2001 10 02 CHAPTER 6 EPSON 23 LPRINT CHR 27 CHR 37 CHR 1 CHR 0 Select downloaded characters ...
Страница 290: ...2001 10 02 CHAPTER 6 EPSON 27 Sample 12 ...
Страница 292: ...2001 10 02 CHAPTER 6 EPSON 29 Sample 14 ...
Страница 294: ...2001 10 02 CHAPTER 7 IBM PROPRINTER 1 CHAPTER 7 IBM PROPRINTER XL ...
Страница 315: ...2001 10 02 CHAPTER 7 IBM PROPRINTER 22 ...
Страница 316: ...2001 10 02 CHAPTER 8 BAR CODE CONTROL 1 CHAPTER 8 BAR CODE CONTROL ...
Страница 326: ...2001 10 02 CHAPTER 9 HP GL 1 CHAPTER 9 HP GL GRAPHICS LANGUAGE ...
Страница 353: ...10 5 2001 APPENDIX A COMPARISON LIST 1 APPENDIX A COMPARISON LIST ...
Страница 391: ...10 5 2001 APPENDIX A COMPARISON LIST 39 AUTOSKIP ON OFF ON OFF ON OFF ON OFF ...
Страница 413: ...2001 10 02 APPENDIX C HBP MODE COMMANDS 1 APPENDIX C HBP MODE COMMANDS For HL 820 1020 1040 Only ...
Страница 426: ...2001 10 02 APPENDIX C HBP MODE COMMANDS 14 ...