lsst::geom::Box2D Class Reference

A floating-point coordinate rectangle geometry. More...

#include <Box.h>

Public Types
typedef Point2D	Point
typedef Extent2D	Extent
typedef double	Element

Public Member Functions
	Box2D () noexcept
	Construct an empty box. More...
	Box2D (Point2D const &minimum, Point2D const &maximum, bool invert=true) noexcept
	Construct a box from its minimum and maximum points. More...
	Box2D (Point2D const &corner, Extent2D const &dimensions, bool invert=true) noexcept
	Construct a box from one corner and dimensions. More...
	Box2D (Box2I const &other) noexcept
	Construct a floating-point box from an integer box. More...
	Box2D (Box2D const &) noexcept=default
	Standard copy constructor. More...
	Box2D (Box2D &&) noexcept=default
	~Box2D () noexcept=default
void	swap (Box2D &other) noexcept
Box2D &	operator= (Box2D const &) noexcept=default
	Standard assignment operator. More...
Box2D &	operator= (Box2D &&) noexcept=default
bool	isEmpty () const noexcept
	Return true if the box contains no points. More...
bool	contains (Point2D const &point) const noexcept
	Return true if the box contains the point. More...
bool	contains (Box2D const &other) const noexcept
	Return true if all points contained by other are also contained by this. More...
bool	overlaps (Box2D const &other) const noexcept
	Return true if any points in other are also in this. More...
void	grow (double buffer)
	Increase the size of the box by the given buffer amount in all directions. More...
void	grow (Extent2D const &buffer)
	Increase the size of the box by the given buffer amount in each direction. More...
void	shift (Extent2D const &offset)
	Shift the position of the box by the given offset. More...
void	flipLR (float xExtent)
	Flip a bounding box about the y-axis given a parent box of extent (xExtent). More...
void	flipTB (float yExtent)
	Flip a bounding box about the x-axis given a parent box of extent (yExtent). More...
void	include (Point2D const &point) noexcept
	Expand this to ensure that this->contains(point). More...
void	include (Box2D const &other) noexcept
	Expand this to ensure that this->contains(other). More...
void	clip (Box2D const &other) noexcept
	Shrink this to ensure that other.contains(*this). More...
bool	operator== (Box2D const &other) const noexcept
	Compare two boxes for equality. More...
bool	operator!= (Box2D const &other) const noexcept
	Compare two boxes for equality. More...
std::size_t	hash_value () const noexcept
	Return a hash of this object. More...
std::vector< Point2D >	getCorners () const
	Get the corner points. More...
std::string	toString () const
Min/Max Accessors
Return the minimum (inclusive) and maximum (exclusive) coordinates of the box.
Point2D const	getMin () const noexcept
double	getMinX () const noexcept
double	getMinY () const noexcept
Point2D const	getMax () const noexcept
double	getMaxX () const noexcept
double	getMaxY () const noexcept
Size Accessors
Return the size of the box.
Extent2D const	getDimensions () const noexcept
double	getWidth () const noexcept
double	getHeight () const noexcept
double	getArea () const noexcept
Center Accessors
Return the center coordinate of the box.
Point2D const	getCenter () const noexcept
double	getCenterX () const noexcept
double	getCenterY () const noexcept

Static Public Member Functions
static Box2D	makeCenteredBox (Point2D const &center, Extent const &size) noexcept
	Create a box centered on a particular point. More...

Static Public Attributes
static double const	EPSILON = std::numeric_limits<double>::epsilon() * 2
	Value the maximum coordinate is multiplied by to increase it by the smallest possible amount. More...
static double const	INVALID = std::numeric_limits<double>::quiet_NaN()
	Value used to specify undefined coordinate values. More...

Detailed Description

A floating-point coordinate rectangle geometry.

Box2D is a half-open (minimum is inclusive, maximum is exclusive) box. A box never has negative dimensions; the empty box is defined to zero-size dimensions and its minimum and maximum values set to NaN. Only the empty box may have zero-size dimensions.

Definition at line 305 of file Box.h.

Member Typedef Documentation

Element

typedef double lsst::geom::Box2D::Element

Definition at line 309 of file Box.h.

Extent

typedef Extent2D lsst::geom::Box2D::Extent

Definition at line 308 of file Box.h.

Point

typedef Point2D lsst::geom::Box2D::Point

Definition at line 307 of file Box.h.

Constructor & Destructor Documentation

Box2D() [1/6]

lsst::geom::Box2D::Box2D ( )

noexcept

Construct an empty box.

Definition at line 244 of file Box.cc.

: _minimum(INVALID), _maximum(INVALID) {}

Box2D() [2/6]

lsst::geom::Box2D::Box2D ( Point2D const &  minimum, Point2D const &  maximum, bool  invert = true  )

noexcept

Construct a box from its minimum and maximum points.

If any(minimum == maximum), the box will always be empty (even if invert==true).

Parameters

[in]	minimum	Minimum (lower left) coordinate (inclusive).
[in]	maximum	Maximum (upper right) coordinate (exclusive).
[in]	invert	If true (default), swap the minimum and maximum coordinates if minimum > maximum instead of creating an empty box.

Definition at line 246 of file Box.cc.

        : _minimum(minimum), _maximum(maximum) {
    for (int n = 0; n < 2; ++n) {
        if (_minimum[n] == _maximum[n]) {
            *this = Box2D();
            return;
        } else if (_minimum[n] > _maximum[n]) {
            if (invert) {
                std::swap(_minimum[n], _maximum[n]);
            } else {
                *this = Box2D();
                return;
            }
        }
    }
}

Box2D() [3/6]

lsst::geom::Box2D::Box2D ( Point2D const &  corner, Extent2D const &  dimensions, bool  invert = true  )

noexcept

Construct a box from one corner and dimensions.

Parameters

[in]	corner	Reference coordinate (inclusive). This is the lower left corner if both dimensions are positive, but a right corner or upper corner if the corresponding dimension is negative and invert is set.
[in]	dimensions	Box dimensions. If either dimension coordinate is 0, the box will be empty.
[in]	invert	If true (default), invert any negative dimensions instead of creating an empty box.

Definition at line 263 of file Box.cc.

        : _minimum(corner), _maximum(corner + dimensions) {
    for (int n = 0; n < 2; ++n) {
        if (_minimum[n] == _maximum[n]) {
            *this = Box2D();
            return;
        } else if (_minimum[n] > _maximum[n]) {
            if (invert) {
                std::swap(_minimum[n], _maximum[n]);
            } else {
                *this = Box2D();
                return;
            }
        }
    }
}

Box2D() [4/6]

lsst::geom::Box2D::Box2D ( Box2I const &  other )

explicitnoexcept

Construct a floating-point box from an integer box.

Integer to floating-point box conversion is based on the concept that a pixel is not an infinitesimal point but rather a square of unit size centered on integer-valued coordinates. While the output floating-point box thus has the same dimensions as the input integer box, its minimum/maximum coordinates are 0.5 smaller/greater.

Definition at line 280 of file Box.cc.

        : _minimum(Point2D(other.getMin()) - Extent2D(0.5)),
          _maximum(Point2D(other.getMax()) + Extent2D(0.5)) {
    if (other.isEmpty()) *this = Box2D();
}

Box2D() [5/6]

lsst::geom::Box2D::Box2D ( Box2D const &  )

defaultnoexcept

Standard copy constructor.

Box2D() [6/6]

lsst::geom::Box2D::Box2D ( Box2D &&  )

defaultnoexcept

~Box2D()

lsst::geom::Box2D::~Box2D ( )

defaultnoexcept

Member Function Documentation

clip()

void lsst::geom::Box2D::clip ( Box2D const &  other )

noexcept

Shrink this to ensure that other.contains(*this).

In particular, if other and this box do not overlap this box will become empty.

Parameters

other

the box that must contain this one

Definition at line 379 of file Box.cc.

                                            {
    if (isEmpty()) return;
    if (other.isEmpty()) {
        *this = Box2D();
        return;
    }
    Point2D const& otherMin = other.getMin();
    Point2D const& otherMax = other.getMax();
    for (int n = 0; n < 2; ++n) {
        if (otherMin[n] > _minimum[n]) {
            _minimum[n] = otherMin[n];
        }
        if (otherMax[n] < _maximum[n]) {
            _maximum[n] = otherMax[n];
        }
    }
    if (any(_maximum.le(_minimum))) {
        *this = Box2D();
        return;
    }
}

contains() [1/2]

bool lsst::geom::Box2D::contains ( Point2D const &  point ) const

noexcept

Return true if the box contains the point.

Definition at line 292 of file Box.cc.

                                                        {
    return all(point.ge(this->getMin())) && all(point.lt(this->getMax()));
}

contains() [2/2]

bool lsst::geom::Box2D::contains ( Box2D const &  other ) const

noexcept

Return true if all points contained by other are also contained by this.

An empty box is contained by every other box, including other empty boxes.

Definition at line 296 of file Box.cc.

                                                      {
    return other.isEmpty() ||
           (all(other.getMin().ge(this->getMin())) && all(other.getMax().le(this->getMax())));
}

flipLR()

void lsst::geom::Box2D::flipLR

(

float

xExtent

)

Flip a bounding box about the y-axis given a parent box of extent (xExtent).

Definition at line 319 of file Box.cc.

                                {
    if (isEmpty()) return;  // should we throw an exception here instead of a no-op?
    // Swap min and max values for x dimension
    _minimum[0] += _maximum[0];
    _maximum[0] = _minimum[0] - _maximum[0];
    _minimum[0] -= _maximum[0];
    // Apply flip assuming coordinate system of parent.
    _minimum[0] = xextent - _minimum[0];
    _maximum[0] = xextent - _maximum[0];
    // _dimensions should remain unchanged
}

flipTB()

void lsst::geom::Box2D::flipTB

(

float

yExtent

)

Flip a bounding box about the x-axis given a parent box of extent (yExtent).

Definition at line 331 of file Box.cc.

                                {
    if (isEmpty()) return;  // should we throw an exception here instead of a no-op?
    // Swap min and max values for y dimension
    _minimum[1] += _maximum[1];
    _maximum[1] = _minimum[1] - _maximum[1];
    _minimum[1] -= _maximum[1];
    // Apply flip assuming coordinate system of parent.
    _minimum[1] = yextent - _minimum[1];
    _maximum[1] = yextent - _maximum[1];
    // _dimensions should remain unchanged
}

getArea()

double lsst::geom::Box2D::getArea ( ) const

inlinenoexcept

Definition at line 411 of file Box.h.

                                    {
        Extent2D dim(getDimensions());
        return dim.getX() * dim.getY();
    }

getCenter()

Point2D const lsst::geom::Box2D::getCenter ( ) const

inlinenoexcept

Definition at line 423 of file Box.h.

                                             {
        return Point2D((_minimum.asEigen() + _maximum.asEigen()) * 0.5);
    }

getCenterX()

double lsst::geom::Box2D::getCenterX ( ) const

inlinenoexcept

Definition at line 426 of file Box.h.

{ return (_minimum.getX() + _maximum.getX()) * 0.5; }

getCenterY()

double lsst::geom::Box2D::getCenterY ( ) const

inlinenoexcept

Definition at line 427 of file Box.h.

{ return (_minimum.getY() + _maximum.getY()) * 0.5; }

getCorners()

std::vector< Point2D > lsst::geom::Box2D::getCorners

(

)

const

Get the corner points.

The order is counterclockise, starting from the lower left corner, i.e.: (minX, minY), (maxX, maxY), (maxX, maxX), (minX, maxY)

Definition at line 421 of file Box.cc.

                                           {
    std::vector<Point2D> retVec;
    retVec.push_back(getMin());
    retVec.push_back(Point2D(getMaxX(), getMinY()));
    retVec.push_back(getMax());
    retVec.push_back(Point2D(getMinX(), getMaxY()));
    return retVec;
}

getDimensions()

Extent2D const lsst::geom::Box2D::getDimensions ( ) const

inlinenoexcept

Definition at line 408 of file Box.h.

{ return isEmpty() ? Extent2D(0.0) : _maximum - _minimum; }

getHeight()

double lsst::geom::Box2D::getHeight ( ) const

inlinenoexcept

Definition at line 410 of file Box.h.

{ return isEmpty() ? 0 : _maximum.getY() - _minimum.getY(); }

getMax()

Point2D const lsst::geom::Box2D::getMax ( ) const

inlinenoexcept

Definition at line 397 of file Box.h.

{ return _maximum; }

getMaxX()

double lsst::geom::Box2D::getMaxX ( ) const

inlinenoexcept

Definition at line 398 of file Box.h.

{ return _maximum.getX(); }

getMaxY()

double lsst::geom::Box2D::getMaxY ( ) const

inlinenoexcept

Definition at line 399 of file Box.h.

{ return _maximum.getY(); }

getMin()

Point2D const lsst::geom::Box2D::getMin ( ) const

inlinenoexcept

Definition at line 393 of file Box.h.

{ return _minimum; }

getMinX()

double lsst::geom::Box2D::getMinX ( ) const

inlinenoexcept

Definition at line 394 of file Box.h.

{ return _minimum.getX(); }

getMinY()

double lsst::geom::Box2D::getMinY ( ) const

inlinenoexcept

Definition at line 395 of file Box.h.

{ return _minimum.getY(); }

getWidth()

double lsst::geom::Box2D::getWidth ( ) const

inlinenoexcept

Definition at line 409 of file Box.h.

{ return isEmpty() ? 0 : _maximum.getX() - _minimum.getX(); }

grow() [1/2]

void lsst::geom::Box2D::grow ( double  buffer )

inline

Increase the size of the box by the given buffer amount in all directions.

If a negative buffer is passed and the final size of the box is less than or equal to zero, the box will be made empty.

Definition at line 456 of file Box.h.

{ grow(Extent2D(buffer)); }

grow() [2/2]

void lsst::geom::Box2D::grow

(

Extent2D const &

buffer

)

Increase the size of the box by the given buffer amount in each direction.

If a negative buffer is passed and the final size of the box is less than or equal to zero, the box will be made empty.

Definition at line 306 of file Box.cc.

                                       {
    if (isEmpty()) return;  // should we throw an exception here instead of a no-op?
    _minimum -= buffer;
    _maximum += buffer;
    if (any(_minimum.ge(_maximum))) *this = Box2D();
}

hash_value()

std::size_t lsst::geom::Box2D::hash_value ( ) const

noexcept

Return a hash of this object.

Definition at line 411 of file Box.cc.

                                           {
    if (isEmpty()) {
        // All empty boxes are equal and must have equal hashes
        return 179;
    } else {
        // Completely arbitrary seed
        return utils::hashCombine(17, _minimum, _maximum);
    }
}

include() [1/2]

void lsst::geom::Box2D::include ( Point2D const &  point )

noexcept

Expand this to ensure that this->contains(point).

If the point sets a new maximum value for the box, the maximum coordinate will be adjusted to ensure the point is actually contained by the box instead of sitting on its exclusive upper edge.

Definition at line 343 of file Box.cc.

                                                 {
    if (isEmpty()) {
        _minimum = point;
        _maximum = point;
        _tweakMax(0);
        _tweakMax(1);
        return;
    }
    for (int n = 0; n < 2; ++n) {
        if (point[n] < _minimum[n]) {
            _minimum[n] = point[n];
        } else if (point[n] >= _maximum[n]) {
            _maximum[n] = point[n];
            _tweakMax(n);
        }
    }
}

include() [2/2]

void lsst::geom::Box2D::include ( Box2D const &  other )

noexcept

Expand this to ensure that this->contains(other).

Definition at line 361 of file Box.cc.

                                               {
    if (other.isEmpty()) return;
    if (this->isEmpty()) {
        *this = other;
        return;
    }
    Point2D const& otherMin = other.getMin();
    Point2D const& otherMax = other.getMax();
    for (int n = 0; n < 2; ++n) {
        if (otherMin[n] < _minimum[n]) {
            _minimum[n] = otherMin[n];
        }
        if (otherMax[n] > _maximum[n]) {
            _maximum[n] = otherMax[n];
        }
    }
}

isEmpty()

bool lsst::geom::Box2D::isEmpty ( ) const

inlinenoexcept

Return true if the box contains no points.

Definition at line 431 of file Box.h.

{ return _minimum.getX() != _minimum.getX(); }

makeCenteredBox()

Box2D lsst::geom::Box2D::makeCenteredBox ( Point2D const &  center, Box2D::Extent const &  size  )

staticnoexcept

Create a box centered on a particular point.

Parameters

center	The desired center of the box.
size	The desired width and height (in that order) of the box.

Returns

if size is positive, a box with size size; otherwise, an empty box. If the returned box is not empty, it shall be centered on center. Behavior is undefined if either center or size is non-finite.

Definition at line 286 of file Box.cc.

                                                                                    {
    lsst::geom::Point2D corner(center);
    corner.shift(-0.5 * size);
    return lsst::geom::Box2D(corner, size, false);
}

operator!=()

bool lsst::geom::Box2D::operator!= ( Box2D const &  other ) const

noexcept

Compare two boxes for equality.

All empty boxes are equal.

Definition at line 406 of file Box.cc.

                                                        {
    return !(other.isEmpty() && other.isEmpty()) &&
           (other._minimum != this->_minimum || other._maximum != this->_maximum);
}

operator=() [1/2]

Box2D& lsst::geom::Box2D::operator= ( Box2D const &  )

defaultnoexcept

Standard assignment operator.

operator=() [2/2]

Box2D& lsst::geom::Box2D::operator= ( Box2D &&  )

defaultnoexcept

operator==()

bool lsst::geom::Box2D::operator== ( Box2D const &  other ) const

noexcept

Compare two boxes for equality.

All empty boxes are equal.

Definition at line 401 of file Box.cc.

                                                        {
    return (other.isEmpty() && this->isEmpty()) ||
           (other._minimum == this->_minimum && other._maximum == this->_maximum);
}

overlaps()

bool lsst::geom::Box2D::overlaps ( Box2D const &  other ) const

noexcept

Return true if any points in other are also in this.

Any overlap operation involving an empty box returns false.

Definition at line 301 of file Box.cc.

                                                      {
    return !(other.isEmpty() || this->isEmpty() || any(other.getMax().le(this->getMin())) ||
             any(other.getMin().ge(this->getMax())));
}

shift()

void lsst::geom::Box2D::shift

(

Extent2D const &

offset

)

Shift the position of the box by the given offset.

Definition at line 313 of file Box.cc.

                                        {
    if (isEmpty()) return;  // should we throw an exception here instead of a no-op?
    _minimum += offset;
    _maximum += offset;
}

swap()

void lsst::geom::Box2D::swap ( Box2D &  other )

inlinenoexcept

Definition at line 378 of file Box.h.

                                     {
        _minimum.swap(other._minimum);
        _maximum.swap(other._maximum);
    }

toString()

std::string lsst::geom::Box2D::toString ( ) const

inline

Definition at line 520 of file Box.h.

                               {
        return (boost::format("Box2D(%s,%s)") % _minimum.toString() % _maximum.toString()).str();
    }

Member Data Documentation

EPSILON

double const lsst::geom::Box2D::EPSILON = std::numeric_limits<double>::epsilon() * 2

static

Value the maximum coordinate is multiplied by to increase it by the smallest possible amount.

Definition at line 315 of file Box.h.

INVALID

double const lsst::geom::Box2D::INVALID = std::numeric_limits<double>::quiet_NaN()

static

Value used to specify undefined coordinate values.

Definition at line 318 of file Box.h.

---

The documentation for this class was generated from the following files:

• /j/snowflake/release/lsstsw/stack/Linux64/geom/18.1.0/include/lsst/geom/Box.h
• /j/snowflake/release/lsstsw/stack/Linux64/geom/18.1.0/src/Box.cc