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CHAPTER 6                                                                    Rendering



lines of uniform thickness. The thickness is as near as possible to the requested
line width—no more than half a pixel different.



                               Line width                     Line width


                                  Path                           Path




                1
              pixel

                              Resulting line                Resulting line



                      FIGURE 6.7 Rasterization without stroke adjustment


Note: If stroke adjustment is enabled and the requested line width, transformed into
device space, is less than half a pixel, the stroke is rendered as a single-pixel line.
This is the thinnest line that can be rendered at device resolution. It is equivalent to
the effect produced by setting the line width to 0 (see Section 6.5.3, “Scan Conver-
sion Rules”).

Because automatic stroke adjustment can have a substantial effect on the appear-
ance of lines, a PDF document must be able to control whether the adjustment is
to be performed. This can be specified with the stroke adjustment parameter in
the graphics state, set by means of the SA entry in a graphics state parameter dic-
tionary (see Section 4.3.4, “Graphics State Parameter Dictionaries”); see imple-
mentation note 71 in Appendix H.

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