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#pragma once
#include <mbgl/style/expression/expression.hpp>
#include <mbgl/style/expression/find_zoom_curve.hpp>
#include <mbgl/style/expression/interpolate.hpp>
#include <mbgl/style/expression/is_constant.hpp>
#include <mbgl/style/expression/step.hpp>
#include <mbgl/util/range.hpp>
namespace mbgl {
namespace style {
class PropertyExpressionBase {
public:
explicit PropertyExpressionBase(std::unique_ptr<expression::Expression>);
bool isZoomConstant() const noexcept;
bool isFeatureConstant() const noexcept;
bool canEvaluateWith(const expression::EvaluationContext&) const noexcept;
float interpolationFactor(const Range<float>&, const float) const noexcept;
Range<float> getCoveringStops(const float, const float) const noexcept;
const expression::Expression& getExpression() const noexcept;
bool useIntegerZoom = false;
protected:
std::shared_ptr<const expression::Expression> expression;
variant<std::nullptr_t, const expression::Interpolate*, const expression::Step*> zoomCurve;
bool isZoomConstant_;
bool isFeatureConstant_;
};
template <class T>
class PropertyExpression final : public PropertyExpressionBase {
public:
// Second parameter to be used only for conversions from legacy functions.
PropertyExpression(std::unique_ptr<expression::Expression> expression_,
optional<T> defaultValue_ = nullopt)
: PropertyExpressionBase(std::move(expression_)), defaultValue(std::move(defaultValue_)) {
}
T evaluate(const expression::EvaluationContext& context, T finalDefaultValue = T()) const {
assert(canEvaluateWith(context));
const expression::EvaluationResult result = expression->evaluate(context);
if (result) {
const optional<T> typed = expression::fromExpressionValue<T>(*result);
return typed ? *typed : defaultValue ? *defaultValue : finalDefaultValue;
}
return defaultValue ? *defaultValue : finalDefaultValue;
}
T evaluate(float zoom) const {
return evaluate(expression::EvaluationContext(zoom));
}
T evaluate(optional<double> accumulated,
mapbox::feature::feature<double>& f,
T finalDefaultValue = T()) const {
const expression::EvaluationResult result = expression->evaluate(accumulated, f);
if (result) {
const optional<T> typed = expression::fromExpressionValue<T>(*result);
return typed ? *typed : defaultValue ? *defaultValue : finalDefaultValue;
}
return defaultValue ? *defaultValue : finalDefaultValue;
}
T evaluate(const GeometryTileFeature& feature, T finalDefaultValue) const {
return evaluate(expression::EvaluationContext(&feature), finalDefaultValue);
}
T evaluate(float zoom, const GeometryTileFeature& feature, T finalDefaultValue) const {
return evaluate(expression::EvaluationContext(zoom, &feature), finalDefaultValue);
}
std::vector<optional<T>> possibleOutputs() const {
return expression::fromExpressionValues<T>(expression->possibleOutputs());
}
friend bool operator==(const PropertyExpression& lhs, const PropertyExpression& rhs) {
return *lhs.expression == *rhs.expression;
}
private:
optional<T> defaultValue;
};
} // namespace style
} // namespace mbgl
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