lsst::geom::polynomials::Scaling2d Class Reference

A 2-d separable affine transform that can be used to map one interval to another. More...

#include <Scaling2d.h>

Public Member Functions
	Scaling2d (Scaling1d const &x, Scaling1d const &y) noexcept
	Construct from the given 1-d scalings. More...
	Scaling2d (Scaling2d const &) noexcept=default
	Default copy constructor. More...
	Scaling2d (Scaling2d &&) noexcept=default
	Default move constructor. More...
Scaling2d &	operator= (Scaling2d const &) noexcept=default
	Default copy assignment. More...
Scaling2d &	operator= (Scaling2d &&) noexcept=default
	Default move assignment. More...
Scaling1d const &	getX () const noexcept
	Return the 1-d scaling in the X direction. More...
Scaling1d const &	getY () const noexcept
	Return the 1-d scaling in the Y direction. More...
geom::Point2D	applyForward (geom::Point2D const &p) const noexcept
	Apply the transform in the forward direction. More...
geom::Point2D	applyInverse (geom::Point2D const &p) const noexcept
	Apply the inverse of the forward transform. More...
Scaling2d	inverted () const noexcept
	Invert the transform. More...
Scaling2d	then (Scaling2d const &second) const noexcept
	Compose two transforms. More...

Detailed Description

A 2-d separable affine transform that can be used to map one interval to another.

The transform is represented in each dimension as an additive shift followed by a multiplicative scaling. Unlike a full affine transform, Scaling2d cannot include rotations.

Note

This class (and to a lesser extent its 1-d counterpart, Scaling1d) has a lot in common with geom::AffineTransform, and ideally they should share code and be highly interoperable. Doing that well would require a larger-scale rethink of geom, however, and at present we don't actually have a use case for that interoperability, so it's something we should keep in mind for the future, not a high priority for the present.

See also

makeUnitRangeScaling2d

Definition at line 48 of file Scaling2d.h.

Constructor & Destructor Documentation

Scaling2d() [1/3]

lsst::geom::polynomials::Scaling2d::Scaling2d ( Scaling1d const &  x, Scaling1d const &  y  )

inlinenoexcept

Construct from the given 1-d scalings.

Definition at line 52 of file Scaling2d.h.

: _x(x), _y(y) {}

Scaling2d() [2/3]

lsst::geom::polynomials::Scaling2d::Scaling2d ( Scaling2d const &  )

defaultnoexcept

Default copy constructor.

Scaling2d() [3/3]

lsst::geom::polynomials::Scaling2d::Scaling2d ( Scaling2d &&  )

defaultnoexcept

Default move constructor.

Member Function Documentation

applyForward()

geom::Point2D lsst::geom::polynomials::Scaling2d::applyForward ( geom::Point2D const &  p ) const

inlinenoexcept

Apply the transform in the forward direction.

Definition at line 73 of file Scaling2d.h.

                                                                   {
        return geom::Point2D(getX().applyForward(p.getX()), getY().applyForward(p.getY()));
    }

applyInverse()

geom::Point2D lsst::geom::polynomials::Scaling2d::applyInverse ( geom::Point2D const &  p ) const

inlinenoexcept

Apply the inverse of the forward transform.

Definition at line 78 of file Scaling2d.h.

                                                                   {
        return geom::Point2D(getX().applyInverse(p.getX()), getY().applyInverse(p.getY()));
    }

getX()

Scaling1d const& lsst::geom::polynomials::Scaling2d::getX ( ) const

inlinenoexcept

Return the 1-d scaling in the X direction.

Definition at line 67 of file Scaling2d.h.

{ return _x; }

getY()

Scaling1d const& lsst::geom::polynomials::Scaling2d::getY ( ) const

inlinenoexcept

Return the 1-d scaling in the Y direction.

Definition at line 70 of file Scaling2d.h.

{ return _y; }

inverted()

Scaling2d lsst::geom::polynomials::Scaling2d::inverted ( ) const

inlinenoexcept

Invert the transform.

If r = t.inverted(), then r.applyForward(p) is equivalent to t.applyInverse(p) and r.applyInverse(q) is equivalent to t.applyForward(q).

Definition at line 89 of file Scaling2d.h.

                                        {
        return Scaling2d(getX().inverted(), getY().inverted());
    }

operator=() [1/2]

Scaling2d& lsst::geom::polynomials::Scaling2d::operator= ( Scaling2d const &  )

defaultnoexcept

Default copy assignment.

operator=() [2/2]

Scaling2d& lsst::geom::polynomials::Scaling2d::operator= ( Scaling2d &&  )

defaultnoexcept

Default move assignment.

then()

Scaling2d lsst::geom::polynomials::Scaling2d::then ( Scaling2d const &  second ) const

inlinenoexcept

Compose two transforms.

If r = a.then(b), then r.applyForward(p) is equivalent to b.applyForward(a.applyForward(p)) and r.applyInverse(q) is equivalent to a.applyInverse(b.applyInverse(q)).

Definition at line 100 of file Scaling2d.h.

                                                            {
        return Scaling2d(getX().then(second.getX()), getY().then(second.getY()));
    }

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

• /j/snowflake/release/lsstsw/stack/Linux64/geom/19.0.0-1-ge3aa853/include/lsst/geom/polynomials/Scaling2d.h