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/* Although an Interval where _b[0] > _b[1] is considered empty, for proper functioning of other methods,
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* a proper empty Interval is [+infinity, -infinity]. Then, expandTo(p) will set the interval to [p,p].
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* \brief This class represents a range of numbers that is never empty.
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* The endpoints are included in the range.
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// The default constructor creates an empty interval, that ranges from +infinity to -infinity.
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// Doing an expandTo(p) on this empty interval will correctly set the whole interval to [p,p].
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explicit Interval() { _b[0] = +infinity(); _b[1] = -infinity(); }
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/// The default constructor creates an interval [0,0] DO NOT RELY ON THIS, BEST NOT TO USE THIS CONSTRUCTOR
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explicit Interval() { _b[0] = 0; _b[1] = 0; }
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explicit Interval(Coord u) { _b[0] = _b[1] = u; }
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/* When creating an Interval using the constructor specifying the exact range, the created interval
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* will be [u,v] when u<=v ; and will be [v,u] when v < u !!!
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inline Coord extent() const { return _b[1] - _b[0]; }
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inline Coord middle() const { return (_b[1] + _b[0]) * 0.5; }
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inline bool isEmpty() const { return _b[0] > _b[1]; }
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// inline bool isEmpty() const { return _b[0] > _b[1]; }
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inline bool isSingular() const { return _b[0] == _b[1]; }
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inline bool contains(Coord val) const { return _b[0] <= val && val <= _b[1]; }
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bool contains(const Interval & val) const { return _b[0] <= val._b[0] && val._b[1] <= _b[1]; }
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bool intersects(const Interval & val) const {
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/** When this would create an empty interval, the interval will be the centerpoint of the old range only.
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inline void expandBy(double amnt) {
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Coord halfway = (_b[0]+_b[1])/2;
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_b[0] = _b[1] = halfway;
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inline void unionWith(const Interval & a) {
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return Interval(std::min(a.min(), b.min()),
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std::max(a.max(), b.max()));
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inline boost::optional<Interval> intersect(const Interval & a, const Interval & b) {
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* \brief OptInterval is an Interval that can be empty.
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class OptInterval : public boost::optional<Interval> {
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OptInterval() : boost::optional<Interval>() {};
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OptInterval(Interval const &a) : boost::optional<Interval>(a) {};
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OptInterval(Coord u) : boost::optional<Interval>(Interval(u)) {};
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OptInterval(Coord u, Coord v) : boost::optional<Interval>(Interval(u,v)) {};
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* Check whether this OptInterval is empty or not.
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inline bool isEmpty() { return (*this == false); };
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* If \c this is empty, copy argument \c a. Otherwise, union with it (and do nothing when \c a is empty)
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inline void unionWith(const OptInterval & a) {
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if (*this) { // check that we are not empty
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(*this)->unionWith(*a);
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inline OptInterval intersect(const Interval & a, const Interval & b) {
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Coord u = std::max(a.min(), b.min()),
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v = std::min(a.max(), b.max());
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//technically >= might be incorrect, but singulars suck
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return u >= v ? boost::optional<Interval>()
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: boost::optional<Interval>(Interval(u, v));
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return u >= v ? OptInterval()
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: OptInterval(Interval(u, v));
added
removed
src/2geom/interval.h
