HP 5961-0509 manual Adaptive Compression Operation Hints

	Adaptive Compression Operation Hints
Note	Some HP LaserJet printers perform internal compression techniques
	to support full-page graphics. Refer to Chapter 1 of the PCL 5
	Comparison Guide for specifics.
	z The compression methods cannot be mixed within one raster row.
	A raster row must be compressed using only one method.
	z The cursor position is updated with each row of the raster block.
	The cursor position is also incremented when a block count of
	less than 3 is sent.
	z A Raster Y-Offset command moves the entire block of raster data
	and initializes the seed row to zeros. The seed row is set to zero
	even if the y-offset is zero.
	z Block size takes precedence over row length. If the row length of
	any line exceeds the block size, the row length is truncated to the
	block size.
	z For duplicate and empty rows a row length value of zero does not
	update the cursor, however, the seed row is initialized to zero.
	z If an unsupported command byte for a raster row is encountered,
	the remaining bytes for the block are skipped, the seed row is
	cleared, and the cursor is not incremented.
	z For method 1, run length encoded, if the row length is odd, the
	cursor is incremented and the row data is skipped (thrown away),
	and the seed row is left unchanged.
	z For method 1, a row length value of zero increments the cursor
	and zero fills the seed row.
	z For method 2, TIFF, if row length terminates the data before the
	control byte value is satisfied (literal byte count greater than row
	length), the data following the control byte (if any) is printed as
	text. The cursor is incremented.
	z For method 2 - If row length is equal to one, the one byte is
	consumed from the I/O and the cursor is incremented. The data
	is ignored and the seed row is zeroed.
	z For method 3 - delta row compression, within an adaptive
	compression block, the seed row is updated by every raster
	compression method or type of row. For example, a row
	compressed with method 2, TIFF, updates the seed row, while
	the effect of an empty row initializes the seed row to zeros.
	Maintaining the seed row allows method 3 to be mixed with
	other methods to achieve optimal compression performance.

EN Set Compression Method Command 15-27