1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10 #ifndef EIGEN_SCALING_H
11 #define EIGEN_SCALING_H
12
13 namespace Eigen {
14
15 /** \geometry_module \ingroup Geometry_Module
16 *
17 * \class Scaling
18 *
19 * \brief Represents a generic uniform scaling transformation
20 *
21 * \param _Scalar the scalar type, i.e., the type of the coefficients.
22 *
23 * This class represent a uniform scaling transformation. It is the return
24 * type of Scaling(Scalar), and most of the time this is the only way it
25 * is used. In particular, this class is not aimed to be used to store a scaling transformation,
26 * but rather to make easier the constructions and updates of Transform objects.
27 *
28 * To represent an axis aligned scaling, use the DiagonalMatrix class.
29 *
30 * \sa Scaling(), class DiagonalMatrix, MatrixBase::asDiagonal(), class Translation, class Transform
31 */
32 template<typename _Scalar>
33 class UniformScaling
34 {
35 public:
36 /** the scalar type of the coefficients */
37 typedef _Scalar Scalar;
38
39 protected:
40
41 Scalar m_factor;
42
43 public:
44
45 /** Default constructor without initialization. */
UniformScaling()46 UniformScaling() {}
47 /** Constructs and initialize a uniform scaling transformation */
UniformScaling(const Scalar & s)48 explicit inline UniformScaling(const Scalar& s) : m_factor(s) {}
49
factor()50 inline const Scalar& factor() const { return m_factor; }
factor()51 inline Scalar& factor() { return m_factor; }
52
53 /** Concatenates two uniform scaling */
54 inline UniformScaling operator* (const UniformScaling& other) const
55 { return UniformScaling(m_factor * other.factor()); }
56
57 /** Concatenates a uniform scaling and a translation */
58 template<int Dim>
59 inline Transform<Scalar,Dim,Affine> operator* (const Translation<Scalar,Dim>& t) const;
60
61 /** Concatenates a uniform scaling and an affine transformation */
62 template<int Dim, int Mode, int Options>
63 inline Transform<Scalar,Dim,(int(Mode)==int(Isometry)?Affine:Mode)> operator* (const Transform<Scalar,Dim, Mode, Options>& t) const
64 {
65 Transform<Scalar,Dim,(int(Mode)==int(Isometry)?Affine:Mode)> res = t;
66 res.prescale(factor());
67 return res;
68 }
69
70 /** Concatenates a uniform scaling and a linear transformation matrix */
71 // TODO returns an expression
72 template<typename Derived>
73 inline typename internal::plain_matrix_type<Derived>::type operator* (const MatrixBase<Derived>& other) const
74 { return other * m_factor; }
75
76 template<typename Derived,int Dim>
77 inline Matrix<Scalar,Dim,Dim> operator*(const RotationBase<Derived,Dim>& r) const
78 { return r.toRotationMatrix() * m_factor; }
79
80 /** \returns the inverse scaling */
inverse()81 inline UniformScaling inverse() const
82 { return UniformScaling(Scalar(1)/m_factor); }
83
84 /** \returns \c *this with scalar type casted to \a NewScalarType
85 *
86 * Note that if \a NewScalarType is equal to the current scalar type of \c *this
87 * then this function smartly returns a const reference to \c *this.
88 */
89 template<typename NewScalarType>
cast()90 inline UniformScaling<NewScalarType> cast() const
91 { return UniformScaling<NewScalarType>(NewScalarType(m_factor)); }
92
93 /** Copy constructor with scalar type conversion */
94 template<typename OtherScalarType>
UniformScaling(const UniformScaling<OtherScalarType> & other)95 inline explicit UniformScaling(const UniformScaling<OtherScalarType>& other)
96 { m_factor = Scalar(other.factor()); }
97
98 /** \returns \c true if \c *this is approximately equal to \a other, within the precision
99 * determined by \a prec.
100 *
101 * \sa MatrixBase::isApprox() */
102 bool isApprox(const UniformScaling& other, typename NumTraits<Scalar>::Real prec = NumTraits<Scalar>::dummy_precision()) const
103 { return internal::isApprox(m_factor, other.factor(), prec); }
104
105 };
106
107 /** Concatenates a linear transformation matrix and a uniform scaling */
108 // NOTE this operator is defiend in MatrixBase and not as a friend function
109 // of UniformScaling to fix an internal crash of Intel's ICC
110 template<typename Derived> typename MatrixBase<Derived>::ScalarMultipleReturnType
111 MatrixBase<Derived>::operator*(const UniformScaling<Scalar>& s) const
112 { return derived() * s.factor(); }
113
114 /** Constructs a uniform scaling from scale factor \a s */
Scaling(float s)115 static inline UniformScaling<float> Scaling(float s) { return UniformScaling<float>(s); }
116 /** Constructs a uniform scaling from scale factor \a s */
Scaling(double s)117 static inline UniformScaling<double> Scaling(double s) { return UniformScaling<double>(s); }
118 /** Constructs a uniform scaling from scale factor \a s */
119 template<typename RealScalar>
Scaling(const std::complex<RealScalar> & s)120 static inline UniformScaling<std::complex<RealScalar> > Scaling(const std::complex<RealScalar>& s)
121 { return UniformScaling<std::complex<RealScalar> >(s); }
122
123 /** Constructs a 2D axis aligned scaling */
124 template<typename Scalar>
Scaling(Scalar sx,Scalar sy)125 static inline DiagonalMatrix<Scalar,2> Scaling(Scalar sx, Scalar sy)
126 { return DiagonalMatrix<Scalar,2>(sx, sy); }
127 /** Constructs a 3D axis aligned scaling */
128 template<typename Scalar>
Scaling(Scalar sx,Scalar sy,Scalar sz)129 static inline DiagonalMatrix<Scalar,3> Scaling(Scalar sx, Scalar sy, Scalar sz)
130 { return DiagonalMatrix<Scalar,3>(sx, sy, sz); }
131
132 /** Constructs an axis aligned scaling expression from vector expression \a coeffs
133 * This is an alias for coeffs.asDiagonal()
134 */
135 template<typename Derived>
Scaling(const MatrixBase<Derived> & coeffs)136 static inline const DiagonalWrapper<const Derived> Scaling(const MatrixBase<Derived>& coeffs)
137 { return coeffs.asDiagonal(); }
138
139 /** \addtogroup Geometry_Module */
140 //@{
141 /** \deprecated */
142 typedef DiagonalMatrix<float, 2> AlignedScaling2f;
143 /** \deprecated */
144 typedef DiagonalMatrix<double,2> AlignedScaling2d;
145 /** \deprecated */
146 typedef DiagonalMatrix<float, 3> AlignedScaling3f;
147 /** \deprecated */
148 typedef DiagonalMatrix<double,3> AlignedScaling3d;
149 //@}
150
151 template<typename Scalar>
152 template<int Dim>
153 inline Transform<Scalar,Dim,Affine>
154 UniformScaling<Scalar>::operator* (const Translation<Scalar,Dim>& t) const
155 {
156 Transform<Scalar,Dim,Affine> res;
157 res.matrix().setZero();
158 res.linear().diagonal().fill(factor());
159 res.translation() = factor() * t.vector();
160 res(Dim,Dim) = Scalar(1);
161 return res;
162 }
163
164 } // end namespace Eigen
165
166 #endif // EIGEN_SCALING_H
167