Integrate scaling and unscaling into Point.hpp

src/libslic3r/Point.hpp

@@ -288,6 +288,72 @@ private:
 
 std::ostream& operator<<(std::ostream &stm, const Vec2d &pointf);
 
+
+// /////////////////////////////////////////////////////////////////////////////
+// Type safe conversions to and from scaled and unscaled coordinates
+// /////////////////////////////////////////////////////////////////////////////
+
+// Semantics are the following:
+// Upscaling (scaled()): only from floating point types (or Vec) to either
+//                       floating point or integer 'scaled coord' coordinates.
+// Downscaling (unscaled()): from arithmetic (or Vec) to floating point only
+
+// Conversion definition from unscaled to floating point scaled
+template<class Tout,
+         class Tin,
+         class = FloatingOnly<Tin>>
+inline constexpr FloatingOnly<Tout> scaled(const Tin &v) noexcept
+{
+    return Tout(v / Tin(SCALING_FACTOR));
+}
+
+// Conversion definition from unscaled to integer 'scaled coord'.
+// TODO: is the rounding necessary? Here it is commented  out to show that
+// it can be different for integers but it does not have to be. Using
+// std::round means loosing noexcept and constexpr modifiers
+template<class Tout = coord_t, class Tin, class = FloatingOnly<Tin>>
+inline constexpr ScaledCoordOnly<Tout> scaled(const Tin &v) noexcept
+{
+    //return static_cast<Tout>(std::round(v / SCALING_FACTOR));
+    return Tout(v / Tin(SCALING_FACTOR));
+}
+
+// Conversion for Eigen vectors (N dimensional points)
+template<class Tout = coord_t,
+         class Tin,
+         int N,
+         class = FloatingOnly<Tin>,
+         int...EigenArgs>
+inline Eigen::Matrix<ArithmeticOnly<Tout>, N, EigenArgs...>
+scaled(const Eigen::Matrix<Tin, N, EigenArgs...> &v)
+{
+    return (v / SCALING_FACTOR).template cast<Tout>();
+}
+
+// Conversion from arithmetic scaled type to floating point unscaled
+template<class Tout = double,
+         class Tin,
+         class = ArithmeticOnly<Tin>,
+         class = FloatingOnly<Tout>>
+inline constexpr Tout unscaled(const Tin &v) noexcept
+{
+    return Tout(v * Tout(SCALING_FACTOR));
+}
+
+// Unscaling for Eigen vectors. Input base type can be arithmetic, output base
+// type can only be floating point.
+template<class Tout = double,
+         class Tin,
+         int N,
+         class = ArithmeticOnly<Tin>,
+         class = FloatingOnly<Tout>,
+         int...EigenArgs>
+inline constexpr Eigen::Matrix<Tout, N, EigenArgs...>
+unscaled(const Eigen::Matrix<Tin, N, EigenArgs...> &v) noexcept
+{
+    return v.template cast<Tout>() * SCALING_FACTOR;
+}
+
 } // namespace Slic3r
 
 // start Boost