+ gRegion operator&(const gRegion &r2) const;
+ gRegion operator-(const gRegion &r2) const;
+ gRegion operator|(const gRegion &r2) const;
+ gRegion &operator&=(const gRegion &r2);
+ gRegion &operator-=(const gRegion &r2);
+ gRegion &operator|=(const gRegion &r2);
+