HP L 5 manual Logical Operations and Transparency Interactions

Logical Operations and Transparency

Interactions

As described above, transparency modes operate in addition to logical operations. The Logical Operations (ROP3) in Table 5-4 are true only if source and pattern transparency (for white pixels) are explicitly set to opaque (?*v1N and ?*v1O). If source and/or pattern transparency modes are transparent (defaulted), the additional operations shown below must be performed to achieve the final result.

	The four basic interactions are:
	• Case 1: Source and Pattern are opaque.
	Texture = Color & Pattern.
	RETURN ROP3 ( Dest, Src, Texture ).
	• Case 2: Source is opaque, Pattern is transparent.
	Texture = Color & Pattern.
	Temporary_ROP3 = ROP3 ( Dest, Src, Texture ).
	Image_A = Temporary_ROP3, & Not Src.
	Image_B = Temporary_ROP3 & Pattern.
	Image_C = Not Pattern & Src & Dest.
	RETURN Image_A Image_B Image_C
	• Case 3: Source is transparent, Pattern is opaque.
	Texture = Color & Pattern.
	Temporary_ROP3 = ROP3 ( Dest, Src, Texture ).
	Image_A = Temporary_ROP3 & Src.
	Image_B = Dest & Not Src.
	RETURN Image_A Image_B
	• Case 4: Source and Pattern are transparent
	Texture = Color & Pattern.
	Temporary_ROP3 = ROP3 ( Dest, Src, Texture ).
	Image_A = Temporary_ROP3 & Src & Pattern.
	Image_B = Dest & Not Src.
	Image_C = Dest & Not Pattern.
	RETURN Image_A Image_B Image_C.
Note	The Transparency Mode is applied based on the color of each pixel.
	However, the Logical Operation is applied on a bit-by-bit basis without
	regard to color. In order to obtain a result consistent with the Logical
	Operation, the transparency modes should be set to Source Opaque
	and Pattern Opaque. In order to obtain a result consistent with the
	desired transparency mode, the Logical Operation should be set to
	252 and the foreground color set to black.

5-12 The PCL Print Model EN