agc_mean_luminance.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024 Ideas on Board Oy
 *
 agc_mean_luminance.h - Base class for mean luminance AGC algorithms
 */

#pragma once

#include <map>
#include <memory>
#include <tuple>
#include <vector>

#include <libcamera/base/utils.h>

#include <libcamera/controls.h>

#include "libcamera/internal/yaml_parser.h"

#include "exposure_mode_helper.h"
#include "histogram.h"

namespace libcamera {

namespace ipa {

class AgcMeanLuminance
{
public:
    AgcMeanLuminance();
    virtual ~AgcMeanLuminance();

    struct AgcConstraint {
        enum class Bound {
            Lower = 0,
            Upper = 1
        };
        Bound bound;
        double qLo;
        double qHi;
        double yTarget;
    };

    int parseTuningData(const YamlObject &tuningData);

    void setLimits(utils::Duration minExposureTime, utils::Duration maxExposureTime,
               double minGain, double maxGain);

    std::map<int32_t, std::vector<AgcConstraint>> constraintModes()
    {
        return constraintModes_;
    }

    std::map<int32_t, std::shared_ptr<ExposureModeHelper>> exposureModeHelpers()
    {
        return exposureModeHelpers_;
    }

    ControlInfoMap::Map controls()
    {
        return controls_;
    }

    std::tuple<utils::Duration, double, double>
    calculateNewEv(uint32_t constraintModeIndex, uint32_t exposureModeIndex,
               const Histogram &yHist, utils::Duration effectiveExposureValue);

    void resetFrameCount()
    {
        frameCount_ = 0;
    }

private:
    virtual double estimateLuminance(const double gain) const = 0;

    void parseRelativeLuminanceTarget(const YamlObject &tuningData);
    void parseConstraint(const YamlObject &modeDict, int32_t id);
    int parseConstraintModes(const YamlObject &tuningData);
    int parseExposureModes(const YamlObject &tuningData);
    double estimateInitialGain() const;
    double constraintClampGain(uint32_t constraintModeIndex,
                   const Histogram &hist,
                   double gain);
    utils::Duration filterExposure(utils::Duration exposureValue);

    uint64_t frameCount_;
    utils::Duration filteredExposure_;
    double relativeLuminanceTarget_;

    std::map<int32_t, std::vector<AgcConstraint>> constraintModes_;
    std::map<int32_t, std::shared_ptr<ExposureModeHelper>> exposureModeHelpers_;
    ControlInfoMap::Map controls_;
};

} /* namespace ipa */

} /* namespace libcamera */