Program Listing for File image_streamer.hpp

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// Copyright (c) 2014, Worcester Polytechnic Institute
// Copyright (c) 2024, The Robot Web Tools Contributors
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#pragma once

#include <chrono>
#include <memory>
#include <string>

#include <opencv2/opencv.hpp>

#include "rclcpp/rclcpp.hpp"
#include "image_transport/image_transport.hpp"
#include "image_transport/transport_hints.hpp"
#include "web_video_server/utils.hpp"
#include "async_web_server_cpp/http_server.hpp"
#include "async_web_server_cpp/http_request.hpp"

namespace web_video_server
{

class ImageStreamer
{
public:
  ImageStreamer(
    const async_web_server_cpp::HttpRequest & request,
    async_web_server_cpp::HttpConnectionPtr connection,
    rclcpp::Node::SharedPtr node);

  virtual void start() = 0;
  virtual ~ImageStreamer();

  bool isInactive()
  {
    return inactive_;
  }

  virtual void restreamFrame(std::chrono::duration<double> max_age) = 0;

  std::string getTopic()
  {
    return topic_;
  }

protected:
  async_web_server_cpp::HttpConnectionPtr connection_;
  async_web_server_cpp::HttpRequest request_;
  rclcpp::Node::SharedPtr node_;
  bool inactive_;
  image_transport::Subscriber image_sub_;
  std::string topic_;
};


class ImageTransportImageStreamer : public ImageStreamer
{
public:
  ImageTransportImageStreamer(
    const async_web_server_cpp::HttpRequest & request,
    async_web_server_cpp::HttpConnectionPtr connection,
    rclcpp::Node::SharedPtr node);
  virtual ~ImageTransportImageStreamer();

  virtual void start();

protected:
  virtual cv::Mat decodeImage(const sensor_msgs::msg::Image::ConstSharedPtr & msg);
  virtual void sendImage(const cv::Mat &, const std::chrono::steady_clock::time_point & time) = 0;
  virtual void restreamFrame(std::chrono::duration<double> max_age);
  virtual void initialize(const cv::Mat &);

  image_transport::Subscriber image_sub_;
  int output_width_;
  int output_height_;
  bool invert_;
  std::string default_transport_;
  std::string qos_profile_name_;

  std::chrono::steady_clock::time_point last_frame_;
  cv::Mat output_size_image;
  std::mutex send_mutex_;

private:
  image_transport::ImageTransport it_;
  bool initialized_;

  void imageCallback(const sensor_msgs::msg::Image::ConstSharedPtr & msg);
};

class ImageStreamerType
{
public:
  virtual std::shared_ptr<ImageStreamer> create_streamer(
    const async_web_server_cpp::HttpRequest & request,
    async_web_server_cpp::HttpConnectionPtr connection,
    rclcpp::Node::SharedPtr node) = 0;

  virtual std::string create_viewer(const async_web_server_cpp::HttpRequest & request) = 0;
};

}  // namespace web_video_server