map_range.h

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#pragma once
 
#include <stdint.h>
 
#include "fl/clamp.h"
#include "fl/force_inline.h"
#include "fl/math_macros.h"
 
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wfloat-equal"
 
namespace fl {
 
template <typename T> struct vec2;
 
namespace map_range_detail {
 
// primary template: unchanged
template <typename T, typename U> struct map_range_math;
template <typename T> bool equals(T a, T b) { return a == b; }
 
} // namespace map_range_detail
 
template <typename T, typename U>
FASTLED_FORCE_INLINE U map_range(T value, T in_min, T in_max, U out_min,
                                 U out_max) {
    // Not fully tested with all unsigned types, so watch out if you use this
    // with uint16_t and you value < in_min.
    using namespace map_range_detail;
    if (equals(value, in_min)) {
        return out_min;
    }
    if (equals(value, in_max)) {
        return out_max;
    }
    return map_range_math<T, U>::map(value, in_min, in_max, out_min, out_max);
}
 
template <typename T, typename U>
FASTLED_FORCE_INLINE U map_range_clamped(T value, T in_min, T in_max, U out_min,
                                         U out_max) {
    // Not fully tested with all unsigned types, so watch out if you use this
    // with uint16_t and you value < in_min.
    using namespace map_range_detail;
    value = clamp(value, in_min, in_max);
    return map_range<T, U>(value, in_min, in_max, out_min, out_max);
}

 
namespace map_range_detail {
 
// primary template: unchanged
template <typename T, typename U> struct map_range_math {
    static U map(T value, T in_min, T in_max, U out_min, U out_max) {
        if (in_min == in_max)
            return out_min;
        return out_min +
               (value - in_min) * (out_max - out_min) / (in_max - in_min);
    }
};
 
template <> struct map_range_math<uint8_t, uint8_t> {
    static uint8_t map(uint8_t value, uint8_t in_min, uint8_t in_max,
                       uint8_t out_min, uint8_t out_max) {
        if (value == in_min) {
            return out_min;
        }
        if (value == in_max) {
            return out_max;
        }
        // Promote uint8_t to int16_t for mapping.
        int16_t v16 = value;
        int16_t in_min16 = in_min;
        int16_t in_max16 = in_max;
        int16_t out_min16 = out_min;
        int16_t out_max16 = out_max;
        int16_t out16 = map_range<uint16_t, uint16_t>(v16, in_min16, in_max16,
                                                      out_min16, out_max16);
        if (out16 < 0) {
            out16 = 0;
        } else if (out16 > 255) {
            out16 = 255;
        }
        return static_cast<uint8_t>(out16);
    }
};
 
// partial specialization for U = vec2<V>
template <typename T, typename V> struct map_range_math<T, vec2<V>> {
    static vec2<V> map(T value, T in_min, T in_max, vec2<V> out_min,
                       vec2<V> out_max) {
        if (in_min == in_max) {
            return out_min;
        }
        // normalized [0..1]
        T scale = (value - in_min) / T(in_max - in_min);
        // deltas
        V dx = out_max.x - out_min.x;
        V dy = out_max.y - out_min.y;
        // lerp each component
        V x = out_min.x + V(dx * scale);
        V y = out_min.y + V(dy * scale);
        return {x, y};
    }
};
 
inline bool equals(float a, float b) { return ALMOST_EQUAL_FLOAT(a, b); }
inline bool equals(double d, double d2) { return ALMOST_EQUAL_DOUBLE(d, d2); }
 
} // namespace map_range_detail
 
} // namespace fl
 
#pragma GCC diagnostic pop