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      CHAPTER 8                                                                   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)
                                                                  nopqrstuvwxyz
                                                                  abcdefghijklm




                  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

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