CHAPTER 8
610
Interactive Features
In either case, the annotation’s position is determined by the coordinates of the
upper-left corner of its annotation rectangle, as defined by the
Rect
entry in the
annotation dictionary and interpreted in the default user space of the page. When
the default user space is scaled or rotated, the positions of the other three corners
of the annotation rectangle are different in the altered user space than they were
in the original user space. The viewer application performs this alteration auto-
matically. However, it does not actually change the annotation’s
Rect
entry, which
continues to describe the annotation’s relationship with the unscaled, unrotated
user space.
For example, Figure 8.3 shows how an annotation whose NoRotate flag is set re-
mains upright when the page it is on is rotated 90 degrees clockwise. The upper-
left corner of the annotation remains at the same point in default user space; the
annotation pivots around that point.
(0, 0)
abcdefghijklm
nopqrstuvwxyz
abcdefghijklm
nopqrstuvwxyz
(0, 0)
Before page rotation
After page rotation
FIGURE 8.3
Coordinate adjustment with the NoRotate flag
8.4.3 Border Styles
An annotation may optionally be surrounded by a border when displayed or
printed. If present, the border is drawn completely inside the annotation rec-
tangle. In PDF 1.1, the characteristics of the border are specified by the
Border
entry in the annotation dictionary (see Table 8.15 on page 606). Beginning with