qv4l2camera_p.h

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#ifndef QV4L2CAMERA_H
#define QV4L2CAMERA_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include <QtMultimedia/private/qplatformcamera_p.h>
 
#include <QtCore/private/qexpected_p.h>
 
#include <linux/videodev2.h>
 
#include <chrono>
#include <optional>
 
QT_BEGIN_NAMESPACE
 
class QSocketNotifier;
 
namespace QtV4L2 {
 
class QV4L2FileDescriptor;
class QV4L2MemoryTransfer;
 
struct V4L2CameraInfo
{
    bool formatInitialized = false;
 
    bool autoWhiteBalanceSupported = false;
    bool colorTemperatureSupported = false;
    bool autoExposureSupported = false;
    bool manualExposureSupported = false;
    bool flashSupported = false;
    bool torchSupported = false;
    qint32 minColorTemp = 5600; // Daylight...
    qint32 maxColorTemp = 5600;
    qint32 minExposure = 0;
    qint32 maxExposure = 0;
    qint32 minExposureAdjustment = 0;
    qint32 maxExposureAdjustment = 0;
    qint32 minFocus = 0;
    qint32 maxFocus = 0;
    qint32 rangedFocus = false;
 
    int minZoom = 0;
    int maxZoom = 0;
};
 
class Q_MULTIMEDIA_EXPORT QV4L2Camera : public QPlatformCamera
{
    Q_OBJECT
 
public:
    explicit QV4L2Camera(QCamera *parent);
    ~QV4L2Camera() override;
 
    bool isActive() const override;
    void setActive(bool active) override;
 
    void setCamera(const QCameraDevice &camera) override;
    bool setCameraFormat(const QCameraFormat &format) override;
    bool resolveCameraFormat(const QCameraFormat &format);
 
    bool isFocusModeSupported(QCamera::FocusMode mode) const override;
    void setFocusMode(QCamera::FocusMode /*mode*/) override;
 
    //    void setCustomFocusPoint(const QPointF &/*point*/) override;
    void setFocusDistance(float) override;
    void zoomTo(float /*newZoomFactor*/, float /*rate*/ = -1.) override;
 
    void setFlashMode(QCamera::FlashMode /*mode*/) override;
    bool isFlashModeSupported(QCamera::FlashMode mode) const override;
    bool isFlashReady() const override;
 
    void setTorchMode(QCamera::TorchMode /*mode*/) override;
    bool isTorchModeSupported(QCamera::TorchMode mode) const override;
 
    void setExposureMode(QCamera::ExposureMode) override;
    bool isExposureModeSupported(QCamera::ExposureMode mode) const override;
    void setExposureCompensation(float) override;
    int isoSensitivity() const override;
    void setManualIsoSensitivity(int) override;
    void setManualExposureTime(float) override;
    float exposureTime() const override;
 
    bool isWhiteBalanceModeSupported(QCamera::WhiteBalanceMode mode) const override;
    void setWhiteBalanceMode(QCamera::WhiteBalanceMode /*mode*/) override;
    void setColorTemperature(int /*temperature*/) override;
 
    QVideoFrameFormat frameFormat() const override;
 
private Q_SLOTS:
    void readFrame();
 
private:
    void setCameraBusy();
    void initV4L2Controls();
    void closeV4L2Fd();
    int setV4L2ColorTemperature(int temperature);
    bool setV4L2Parameter(quint32 id, qint32 value);
    int getV4L2Parameter(quint32 id) const;
 
    q23::expected<void, QString> setV4L2CameraFormat();
    void initV4L2MemoryTransfer();
    void startCapturing();
    void stopCapturing();
 
private:
    bool m_active = false;
    QCameraDevice m_cameraDevice;
 
    std::unique_ptr<QSocketNotifier> m_notifier;
    std::unique_ptr<QV4L2MemoryTransfer> m_memoryTransfer;
    std::shared_ptr<QV4L2FileDescriptor> m_v4l2FileDescriptor;
 
    V4L2CameraInfo m_v4l2Info;
 
    std::optional<std::chrono::microseconds> m_firstFrameTime;
    v4l2_pix_format m_pixFormat{};
    std::chrono::microseconds m_frameDuration{};
    bool m_cameraBusy = false;
};
 
} // namespace QtV4L2
 
QT_END_NAMESPACE
 
#endif // QV4L2CAMERA_H