affine.hpp 3.2 KB

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  1. //
  2. // Copyright 2005-2007 Adobe Systems Incorporated
  3. //
  4. // Distributed under the Boost Software License, Version 1.0
  5. // See accompanying file LICENSE_1_0.txt or copy at
  6. // http://www.boost.org/LICENSE_1_0.txt
  7. //
  8. #ifndef BOOST_GIL_EXTENSION_NUMERIC_AFFINE_HPP
  9. #define BOOST_GIL_EXTENSION_NUMERIC_AFFINE_HPP
  10. #include <boost/gil/point.hpp>
  11. namespace boost { namespace gil {
  12. ////////////////////////////////////////////////////////////////////////////////////////
  13. ///
  14. /// Simple matrix to do 2D affine transformations. It is actually 3x3 but the last column is [0 0 1]
  15. ///
  16. ////////////////////////////////////////////////////////////////////////////////////////
  17. template <typename T>
  18. class matrix3x2 {
  19. public:
  20. matrix3x2() : a(1), b(0), c(0), d(1), e(0), f(0) {}
  21. matrix3x2(T A, T B, T C, T D, T E, T F) : a(A),b(B),c(C),d(D),e(E),f(F) {}
  22. matrix3x2(const matrix3x2& mat) : a(mat.a), b(mat.b), c(mat.c), d(mat.d), e(mat.e), f(mat.f) {}
  23. matrix3x2& operator=(const matrix3x2& m) { a=m.a; b=m.b; c=m.c; d=m.d; e=m.e; f=m.f; return *this; }
  24. matrix3x2& operator*=(const matrix3x2& m) { (*this) = (*this)*m; return *this; }
  25. static matrix3x2 get_rotate(T rads) { T c=std::cos(rads); T s=std::sin(rads); return matrix3x2(c,s,-s,c,0,0); }
  26. static matrix3x2 get_translate(point<T> const& t)
  27. {
  28. return matrix3x2(1, 0, 0, 1, t.x, t.y);
  29. }
  30. static matrix3x2 get_translate(T x, T y) { return matrix3x2(1 ,0,0,1 ,x, y ); }
  31. static matrix3x2 get_scale(point<T> const& s)
  32. {
  33. return matrix3x2(s.x, 0, 0, s.y, 0, 0);
  34. }
  35. static matrix3x2 get_scale(T x, T y) { return matrix3x2(x, 0,0,y, 0 ,0 ); }
  36. static matrix3x2 get_scale(T s) { return matrix3x2(s ,0,0,s ,0 ,0 ); }
  37. T a,b,c,d,e,f;
  38. };
  39. template <typename T> BOOST_FORCEINLINE
  40. matrix3x2<T> operator*(const matrix3x2<T>& m1, const matrix3x2<T>& m2) {
  41. return matrix3x2<T>(
  42. m1.a * m2.a + m1.b * m2.c,
  43. m1.a * m2.b + m1.b * m2.d,
  44. m1.c * m2.a + m1.d * m2.c,
  45. m1.c * m2.b + m1.d * m2.d,
  46. m1.e * m2.a + m1.f * m2.c + m2.e,
  47. m1.e * m2.b + m1.f * m2.d + m2.f );
  48. }
  49. template <typename T, typename F>
  50. BOOST_FORCEINLINE
  51. point<F> operator*(point<T> const& p, matrix3x2<F> const& m)
  52. {
  53. return { m.a*p.x + m.c*p.y + m.e, m.b*p.x + m.d*p.y + m.f };
  54. }
  55. ////////////////////////////////////////////////////////////////////////////////////////
  56. /// Define affine mapping that transforms the source coordinates by the affine transformation
  57. ////////////////////////////////////////////////////////////////////////////////////////
  58. /*
  59. template <typename MapFn>
  60. concept MappingFunctionConcept {
  61. typename mapping_traits<MapFn>::result_type; where PointNDConcept<result_type>;
  62. template <typename Domain> { where PointNDConcept<Domain> }
  63. result_type transform(MapFn&, const Domain& src);
  64. };
  65. */
  66. template <typename T> struct mapping_traits;
  67. template <typename F>
  68. struct mapping_traits<matrix3x2<F>>
  69. {
  70. using result_type = point<F>;
  71. };
  72. template <typename F, typename F2>
  73. BOOST_FORCEINLINE
  74. point<F> transform(matrix3x2<F> const& mat, point<F2> const& src)
  75. {
  76. return src * mat;
  77. }
  78. }} // namespace boost::gil
  79. #endif