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#pragma once
#include <mbgl/style/expression/expression.hpp>
#include <mbgl/style/expression/value.hpp>
#include <mbgl/style/expression/is_constant.hpp>
#include <mbgl/style/expression/interpolate.hpp>
#include <mbgl/style/expression/step.hpp>
#include <mbgl/style/expression/find_zoom_curve.hpp>
#include <mbgl/util/range.hpp>
namespace mbgl {
namespace style {
template <class T>
class CompositeFunction {
public:
// The second parameter should be used only for conversions from legacy functions.
CompositeFunction(std::unique_ptr<expression::Expression> expression_, optional<T> defaultValue_ = {})
: isExpression(defaultValue_),
expression(std::move(expression_)),
defaultValue(std::move(defaultValue_)),
zoomCurve(expression::findZoomCurveChecked(expression.get())) {
assert(!expression::isZoomConstant(*expression));
assert(!expression::isFeatureConstant(*expression));
}
// Return the range obtained by evaluating the function at each of the zoom levels in zoomRange
template <class Feature>
Range<T> evaluate(const Range<float>& zoomRange, const Feature& feature, T finalDefaultValue) {
return Range<T> {
evaluate(zoomRange.min, feature, finalDefaultValue),
evaluate(zoomRange.max, feature, finalDefaultValue)
};
}
template <class Feature>
T evaluate(float zoom, const Feature& feature, T finalDefaultValue) const {
const expression::EvaluationResult result = expression->evaluate(expression::EvaluationContext({zoom}, &feature));
if (result) {
const optional<T> typed = expression::fromExpressionValue<T>(*result);
return typed ? *typed : defaultValue ? *defaultValue : finalDefaultValue;
}
return defaultValue ? *defaultValue : finalDefaultValue;
}
float interpolationFactor(const Range<float>& inputLevels, const float inputValue) const {
return zoomCurve.match(
[&](const expression::Interpolate* z) {
return z->interpolationFactor(Range<double> { inputLevels.min, inputLevels.max }, inputValue);
},
[&](const expression::Step*) { return 0.0f; }
);
}
Range<float> getCoveringStops(const float lower, const float upper) const {
return zoomCurve.match(
[&](auto z) { return z->getCoveringStops(lower, upper); }
);
}
std::vector<optional<T>> possibleOutputs() const {
return expression::fromExpressionValues<T>(expression->possibleOutputs());
}
friend bool operator==(const CompositeFunction& lhs,
const CompositeFunction& rhs) {
return *lhs.expression == *rhs.expression;
}
const expression::Expression& getExpression() const { return *expression; }
bool useIntegerZoom = false;
bool isExpression;
private:
std::shared_ptr<const expression::Expression> expression;
optional<T> defaultValue;
const variant<const expression::Interpolate*, const expression::Step*> zoomCurve;
};
} // namespace style
} // namespace mbgl
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