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#pragma once
#include <mbgl/style/function/exponential_stops.hpp>
#include <mbgl/style/function/interval_stops.hpp>
#include <mbgl/style/function/categorical_stops.hpp>
#include <mbgl/util/interpolate.hpp>
#include <mbgl/util/range.hpp>
#include <mbgl/util/variant.hpp>
#include <string>
#include <tuple>
namespace mbgl {
class GeometryTileFeature;
namespace style {
// A CompositeFunction consists of an outer zoom function whose stop range values are
// "inner" source functions. It provides the GL Native implementation of
// "zoom-and-property" functions from the style spec.
template <class T>
class CompositeFunction {
public:
using InnerStops = std::conditional_t<
util::Interpolatable<T>,
variant<
ExponentialStops<T>,
IntervalStops<T>,
CategoricalStops<T>>,
variant<
IntervalStops<T>,
CategoricalStops<T>>>;
using Stops = std::conditional_t<
util::Interpolatable<T>,
variant<
std::map<float, ExponentialStops<T>>,
std::map<float, IntervalStops<T>>,
std::map<float, CategoricalStops<T>>>,
variant<
std::map<float, IntervalStops<T>>,
std::map<float, CategoricalStops<T>>>>;
CompositeFunction(std::string property_, Stops stops_)
: property(std::move(property_)),
stops(std::move(stops_)) {
}
std::tuple<Range<float>, Range<InnerStops>>
coveringRanges(float zoom) const {
return stops.match(
[&] (const auto& s) {
assert(!s.empty());
auto minIt = s.lower_bound(zoom);
auto maxIt = s.upper_bound(zoom);
if (minIt != s.begin()) {
minIt--;
}
return std::make_tuple(
Range<float> {
minIt == s.end() ? s.rbegin()->first : minIt->first,
maxIt == s.end() ? s.rbegin()->first : maxIt->first
},
Range<InnerStops> {
minIt == s.end() ? s.rbegin()->second : minIt->second,
maxIt == s.end() ? s.rbegin()->second : maxIt->second
}
);
}
);
}
Range<T> evaluate(Range<InnerStops> coveringStops,
const GeometryTileFeature& feature) const {
optional<Value> v = feature.getValue(property);
if (!v) {
return { T(), T() };
}
auto eval = [&] (const auto& s) {
return s.evaluate(*v);
};
return Range<T> {
coveringStops.min.match(eval),
coveringStops.max.match(eval)
};
}
T evaluate(float zoom, const GeometryTileFeature& feature) const {
std::tuple<Range<float>, Range<InnerStops>> ranges = coveringRanges(zoom);
Range<T> resultRange = evaluate(std::get<1>(ranges), feature);
return util::interpolate(
resultRange.min,
resultRange.max,
util::interpolationFactor(1.0f, std::get<0>(ranges), zoom));
}
friend bool operator==(const CompositeFunction& lhs,
const CompositeFunction& rhs) {
return lhs.property == rhs.property && lhs.stops == rhs.stops;
}
std::string property;
Stops stops;
};
} // namespace style
} // namespace mbgl
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