exposure_mode_helper.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024, Paul Elder <paul.elder@ideasonboard.com>
 *
 * Helper class that performs computations relating to exposure
 */
 
#pragma once
 
#include <span>
#include <utility>
#include <vector>
 
#include <libcamera/base/utils.h>
 
#include "camera_sensor_helper.h"
 
namespace libcamera {
 
namespace ipa {
 
class ExposureModeHelper
{
public:
    ExposureModeHelper(std::span<std::pair<utils::Duration, double>> stages);
    ~ExposureModeHelper() = default;
 
    void configure(utils::Duration lineLength, const CameraSensorHelper *sensorHelper);
    void setLimits(utils::Duration minExposureTime, utils::Duration maxExposureTime,
               double minGain, double maxGain);
 
    struct Result {
        utils::Duration exposureTime;
        double analogueGain;
        double quantizationGain;
        double digitalGain;
    };
 
    [[nodiscard]] Result splitExposure(utils::Duration exposure) const;
 
    utils::Duration minExposureTime() const { return minExposureTime_; }
    utils::Duration maxExposureTime() const { return maxExposureTime_; }
    double minGain() const { return minGain_; }
    double maxGain() const { return maxGain_; }
 
private:
    utils::Duration clampExposureTime(utils::Duration exposureTime,
                      double *quantizationGain = nullptr) const;
    double clampGain(double gain, double *quantizationGain = nullptr) const;
 
    std::vector<utils::Duration> exposureTimes_;
    std::vector<double> gains_;
 
    utils::Duration lineDuration_;
    utils::Duration minExposureTime_;
    utils::Duration maxExposureTime_;
    double minGain_;
    double maxGain_;
    const CameraSensorHelper *sensorHelper_;
};
 
} /* namespace ipa */
 
} /* namespace libcamera */