Jungfraujoch/image_analysis/bragg_integration/RingBackground.h

// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <cstdint>
#include <vector>

// A frame's background as a function of q, from a peak-excluded background per resolution ring of the
// whole detector (the adaptive spot finder's GetRingBackground): ring i holds the q of q_centre[i]
// (AzimuthalIntegrationSettings::GetQBinCentres_recipA), entries past the first q_centre.size() are
// further azimuthal bins and are averaged in, and a ring with no
// value (NAN) is bridged by its neighbours. Between rings the value is interpolated linearly; beyond
// the first and the last ring the end value is held, which has no curvature.
struct RingBackground {
    std::vector<double> q, b;

    RingBackground(const std::vector<float> &ring_bkg, const std::vector<double> &q_centre);
    [[nodiscard]] bool empty() const { return q.size() < 2; }
    [[nodiscard]] double At(double q_recipA) const;
};