APPENDIX H
1112
Compatibility and Implementation Notes
puts the name of that function into the halftone dictionary; Acrobat uses
that function when printing the PDF document to a PostScript output de-
vice. If the code does not match any of the predefined spot functions, Dis-
tiller samples the specified spot function and generates a function for the
halftone dictionary; when printing to a PostScript device, Acrobat gener-
ates a spot function that interpolates values from that function.
When producing PDF version 1.3 or later, Distiller represents the spot
function by using a Type 4 (PostScript calculator) function whenever pos-
sible (see Section 3.9.4, “Type 4 (PostScript Calculator) Functions”). In
this case, Acrobat uses this function directly when printing the document.
71. When drawing to the screen, Acrobat 6.0 always performs automatic
stroke adjustment, regardless of the value of the
SA
entry in the graphics
state parameter dictionary.
72. PDF 1.3 or earlier viewers ignore all transparency-related graphics state
parameters (blend mode, soft mask, alpha constant, and alpha source). All
graphics objects are painted opaquely.
Note:
This implementation note is also referred to in Sections 7.5.3, “Specifying
and 7.5.4, “Specifying Soft Masks” (Soft-Mask Dictionaries).
73. PDF 1.3 or earlier viewers ignore the
SMask
entry in an image dictionary.
All images are painted opaquely.
Note:
This implementation note is also referred to in Section 7.5.4, “Specifying
74. In PDF 1.2, an additional entry in the outline item dictionary, named
AA
,
was defined but was never implemented. Beginning with PDF 1.3, this
entry is obsolete and should be ignored.