HP L 5 manual Pixel Combinations Desired Destination Values

•Opcode — Specifies the logical operations performed on a source, destination, and pattern prior to drawing the final image. These raster opcodes (ROPs) are listed on the following pages in reverse polish notation (RPN) using the following abbreviations:

D — Destination S — Source

T — Texture a — and

n — not o — or

x — exclusive or

For example, when mode = 0, the opcode default is 252, which is the logical function TSo (Texture OR Source).

The operation code (opcode) specifies the logical operations that are performed on a source, destination, and patterned image prior to drawing the final image. The opcodes are created by listing all possible combinations of a single pattern, source and destination pixel, and constructing the desired final pixel values. The following table shows three common opcodes constructed by reading the output values bottom up.

Pixel Combinations				Desired Destination Values
Patter Pixel		Source Pixel	Destination	Source	Transparency	Source
			Pixel	Overwrite	(TR command)	Destination
0		0	0	0	0	0
0		0	1	0	1	1
0		1	0	1	1	1
0		1	1	1	1	0
1		0	0	0	0	0
1		0	1	0	1	1
1		1	0	1	1	1
1		1	1	1	1	0
	Resulting Opcode			204 (0xCC)	238 (0xEE)	102 (0x66)

EN Color Vector Graphics (HP-GL/2) 7-7