Make an order in using scale and unscale, remove some warnings.

src/libslic3r/MTUtils.hpp

@@ -7,6 +7,9 @@
 #include <utility>    // for std::forward
 #include <algorithm>
 
+#include "libslic3r.h"
+#include "Point.hpp"
+
 namespace Slic3r {
 
 /// Handy little spin mutex for the cached meshes.
@@ -248,6 +251,94 @@ template<class X, class Y> inline X ceil_i(X x, Y y)
     return (x % y) ? x / y + 1 : x / y;
 }
 
+// A shorter C++14 style form of the enable_if metafunction
+template<bool B, class T>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
+// /////////////////////////////////////////////////////////////////////////////
+// Type safe conversions to and from scaled and unscaled coordinates
+// /////////////////////////////////////////////////////////////////////////////
+
+// A meta-predicate which is true for integers wider than or equal to coord_t
+template<class I> struct is_scaled_coord
+{
+    static const SLIC3R_CONSTEXPR bool value =
+        std::is_integral<I>::value &&
+        std::numeric_limits<I>::digits >=
+            std::numeric_limits<coord_t>::digits;
+};
+
+// Meta predicates for floating, 'scaled coord' and generic arithmetic types
+template<class T>
+using FloatingOnly = enable_if_t<std::is_floating_point<T>::value, T>;
+
+template<class T>
+using ScaledCoordOnly = enable_if_t<is_scaled_coord<T>::value, T>;
+
+template<class T>
+using ArithmeticOnly = enable_if_t<std::is_arithmetic<T>::value, T>;
+
+// A shorter form for a generic Eigen vector which is widely used in PrusaSlicer 
+template<class T, int N>
+using EigenVec = Eigen::Matrix<T, N, 1, Eigen::DontAlign>;
+
+// 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 types (or Vec) to either
+//                           floating point only
+
+// Conversion definition from unscaled to floating point scaled
+template<class Tout,
+         class Tin,
+         class = FloatingOnly<Tin>,
+         class = FloatingOnly<Tout>>
+inline SLIC3R_CONSTEXPR Tout scaled(const Tin &v) SLIC3R_NOEXCEPT
+{
+    return static_cast<Tout>(v / static_cast<Tout>(SCALING_FACTOR));
+}
+
+// Conversion definition from unscaled to integer 'scaled coord'.
+// TODO: is the rounding necessary ? Here it is to show that it can be different
+// 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 SLIC3R_CONSTEXPR ScaledCoordOnly<Tout> scaled(const Tin &v) SLIC3R_NOEXCEPT
+{
+    //return static_cast<Tout>(std::round(v / SCALING_FACTOR));
+    return static_cast<Tout>(v / static_cast<Tout>(SCALING_FACTOR));
+}
+
+// Conversion for Eigen vectors (N dimensional points)
+template<class Tout = coord_t, class Tin, int N, class = FloatingOnly<Tin>>
+inline EigenVec<ArithmeticOnly<Tout>, N> scaled(const EigenVec<Tin, N> &v)
+{
+    return v.template cast<Tout>() / SCALING_FACTOR;
+}
+
+// Conversion from arithmetic scaled type to floating point unscaled
+template<class Tout = double,
+         class Tin,
+         class = ArithmeticOnly<Tin>,
+         class = FloatingOnly<Tout>>
+inline SLIC3R_CONSTEXPR Tout unscaled(const Tin &v) SLIC3R_NOEXCEPT
+{
+    return static_cast<Tout>(v * static_cast<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>>
+inline SLIC3R_CONSTEXPR EigenVec<Tout, N> unscaled(
+    const EigenVec<Tin, N> &v) SLIC3R_NOEXCEPT
+{
+    return v.template cast<Tout>() * SCALING_FACTOR;
+}
+
 } // namespace Slic3r
 
 #endif // MTUTILS_HPP