| 摘要 |
PURPOSE:To quickly pick a polygonal area by obtaining minimum and maximum values of X coordinates and Y coordinates of the apex coordinate string of a polygon and comparing coordinates of a rectangular area including the polygonal area with those of a designated pick area to remove polygonal areas, which do not cross the pick area, from the pick object. CONSTITUTION:A polygonal area 20 defined by plural apexes 20a, 20b... is included in a rectangular area 22 defined by minimum and maximum values of X coordinates and Y coordinates of the coordinate string of plural apexes. Coordinates of the rectangular area 22 and those of a designated pick area 21 are compared with each other to easily discriminate whether they cross each other or not. If they do not cross, the polygonal area 20 is removed from the pick object; but if they cross each other, the polygon is divided into horizontal segments in each one unit of the coordinate system where the polygon is defined and it is discriminated whether divided segments cross the designated pick area 21 or not.
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