feat: add plasma-face-unlock

src/core/camera.h

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// Where frames come from.
+//
+// Normally a V4L2 device. For testing without a camera (a virtual machine, a
+// build server) a video file or a folder of pictures stands in for one and is
+// played back at the pace a camera would deliver it, so that anything timed in
+// the liveness checks behaves the way it would with the real thing.
+
+#pragma once
+
+#include <QList>
+#include <QString>
+
+#include <opencv2/core.hpp>
+#include <opencv2/videoio.hpp>
+
+#include <chrono>
+#include <memory>
+
+struct CameraInfo {
+    QString path;
+    QString name;
+    // Infrared cameras (the kind Windows Hello uses) only offer grey formats.
+    bool infrared = false;
+};
+
+class Camera
+{
+public:
+    Camera();
+    ~Camera();
+
+    // spec is a /dev/video path, "auto", "file:<video>" or "images:<dir>".
+    bool open(const QString &spec, QString *error);
+    void close();
+    bool isOpen() const;
+
+    // Blocks until the next frame. The timestamp is in milliseconds on a
+    // monotonic clock and only means something relative to other frames.
+    bool read(cv::Mat &bgr, double *timestampMs);
+
+    bool isInfrared() const
+    {
+        return m_infrared;
+    }
+    QString description() const
+    {
+        return m_description;
+    }
+
+    // Every V4L2 device that can capture video. Metadata nodes, which every
+    // UVC camera also exposes, are left out.
+    static QList<CameraInfo> list();
+    // What "auto" means on this machine: the first colour camera, else the
+    // first camera at all.
+    static QString autoPath();
+
+private:
+    bool openImages(const QString &dir, QString *error);
+    bool readImages(cv::Mat &bgr);
+    void pace(double frameMs);
+
+    cv::VideoCapture m_capture;
+    bool m_open = false;
+    bool m_infrared = false;
+    bool m_paced = false;
+    QString m_description;
+
+    QList<cv::Mat> m_images;
+    qsizetype m_imageIndex = 0;
+    int m_imageRepeat = 0;
+
+    std::chrono::steady_clock::time_point m_start;
+    std::chrono::steady_clock::time_point m_next;
+};