HP PCL 5 - Page 63

ENWW Printer-Specific Differences 2-15
Logical Operations and Transparency
Interactions
As described above, transparency modes operate in addition to
logical operations. The logical operations in Table 2-5, Logical
Operations (ROP3), on the following pages, 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 on the
following page must be performed to achieve the final result.
The four basic interactions are:
• Case 1: Source and Pattern are opaque.
Return ROP3 (Dest, Src, Texture).
• Case 2: Source is opaque, Pattern is transparent.
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.
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
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.