SECTION 4.10
379
Optional Content
A PDF viewer should display the optional content groups as follows:
Frog Anatomy
Skin
Bones
Tree Anatomy
Bark
Wood
Example 4.38
Given the following PDF objects:
/OC /L1 BDC
/OC /L1a BDC
0 0 100 100 re f
EMC
/OC /L1b BDC
% Sublayer B of layer 1
0 100 100 100 re f
EMC
EMC
...
<< /L1 1 0 R
% Resource names
/L1a 2 0 R
/L1b 3 0 R
>>
...
%Optional content groups
1 0 obj <</Type /OCG /Name (Layer 1)>> endobj
2 0 obj <</Type /OCG /Name (Sublayer A)>> endobj
3 0 obj <</Type /OCG /Name (Sublayer B)>> endobj
...
4 0 obj
% Configuration dictionary
<< /Order [1 0 R [2 0 R 3 0 R]] >>
A PDF viewer should display the OCGs as follows:
Layer 1
Sublayer A
Sublayer B
% Page contents
% Layer 1
% Sublayer A of layer 1
The
AS
entry is an
auto state
array consisting of one or more
usage application
dictionaries
that specify how viewer applications should automatically set the
state of optional content groups based on external factors, as discussed in the fol-
lowing section.