points.h

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#pragma once
 
#include "../config.h"
 
namespace alfi::points {
    template <typename Number = DefaultNumber, template <typename, typename...> class Container = DefaultContainer>
    void lin_map(Container<Number>& points, const Number& a, const Number& b, const Number& c, const Number& d) {
        const auto mid1 = (a + b) / 2;
        const auto mid2 = (c + d) / 2;
        const auto scale = (d - c) / (b - a);
        for (auto& point : points) {
            point = mid2 + scale * (point - mid1);
        }
    }
 
    template <typename Number = DefaultNumber, template <typename, typename...> class Container = DefaultContainer>
    Container<Number> lin_mapped(const Container<Number>& points, const Number& a, const Number& b, const Number& c, const Number& d) {
        auto mapped_points = points;
        lin_map<Number,Container>(mapped_points, a, b, c, d);
        return mapped_points;
    }
 
    template <typename Number = DefaultNumber, template <typename, typename...> class Container = DefaultContainer>
    void stretch(Container<Number>& points, const Number& a, const Number& b) {
        if (points.empty()) {
            return;
        }
        if (points.size() == 1 || points.front() == points.back()) {
            std::fill(points.begin(), points.end(), (a + b) / 2);
            return;
        }
        lin_map<Number,Container>(points, points.front(), points.back(), a, b);
        points.front() = a;
        points.back() = b;
    }
 
    template <typename Number = DefaultNumber, template <typename, typename...> class Container = DefaultContainer>
    Container<Number> stretched(const Container<Number>& points, const Number& a, const Number& b) {
        auto stretched_points = points;
        stretch<Number,Container>(stretched_points, a, b);
        return stretched_points;
    }
}