57 lines
1.3 KiB
C++
57 lines
1.3 KiB
C++
#pragma once
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#include <mbgl/util/feature.hpp>
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#include <mbgl/util/interpolate.hpp>
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#include <map>
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namespace mbgl {
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namespace style {
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template <class T>
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class ExponentialStops {
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public:
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using Stops = std::map<float, T>;
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Stops stops;
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float base = 1.0f;
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ExponentialStops() = default;
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ExponentialStops(Stops stops_, float base_ = 1.0f)
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: stops(std::move(stops_)),
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base(base_) {
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}
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optional<T> evaluate(float z) const {
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if (stops.empty()) {
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return {};
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}
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auto it = stops.upper_bound(z);
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if (it == stops.end()) {
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return stops.rbegin()->second;
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} else if (it == stops.begin()) {
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return stops.begin()->second;
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} else {
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return util::interpolate(std::prev(it)->second, it->second,
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util::interpolationFactor(base, { std::prev(it)->first, it->first }, z));
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}
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}
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optional<T> evaluate(const Value& value) const {
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optional<float> z = numericValue<float>(value);
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if (!z) {
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return {};
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}
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return evaluate(*z);
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}
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friend bool operator==(const ExponentialStops& lhs,
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const ExponentialStops& rhs) {
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return lhs.stops == rhs.stops && lhs.base == rhs.base;
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}
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};
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} // namespace style
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} // namespace mbgl
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