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                                                      229
       SECTION 4.4                                              Path Construction and Painting



       Two more operators, v and y, each specify one of the two control points implic-
       itly (see Figure 4.9). In both of these cases, one control point and the final point
       of the curve are supplied as operands; the other control point is implied:

       • For the v operator, the first control point coincides with initial point of the
         curve.
       • For the y operator, the second control point coincides with final point of the
         curve.



                            (x2 , y2 )



                                                                  (x1 , y1 )




                                         (x3 , y3 )                                              (x3 , y3 )




 Current point                                              Current point
                  x2 y2 x3 y3 v                                                x1 y1 x3 y3 y



                    FIGURE 4.9 Cubic Bézier curves generated by the v and y operators


4.4.2 Path-Painting Operators

       The path-painting operators end a path object, causing it to be painted on the
       current page in the manner that the operator specifies. The principal path-
       painting operators are S (for stroking) and f (for filling). Variants of these opera-
       tors combine stroking and filling in a single operation or apply different rules for
       determining the area to be filled. Table 4.10 lists all the path-painting operators.

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