C# API

The C# API is derived directly from the C++ interfaces via SWIG. In itself, the C#/C++ interface does not introduce new logic to the API. It merely maps the C++ native data types correctly to C#.

Tip

new in 2.0.0: zero-copy memory management from C++ to C#

As the SWIG compiler creates the interface descriptions, currently we do not offer a dedicated C# API documentation. Please refer to our sample applications (publicly available here) and C++ API for details on the actual API.

Also, please do not hesitate to contact us for further assistance.

C# Example

The following minimal example shows how to use the C# ICamera and IFrameObserver to configure the camera hardware device and attach to a camera stream. Setup and bring up should be done in a docker environment, the sample in the repository comes with ready-to-use docker and CMake files.

Setup and run

Log into the camera (see OS section for details) and issue the following commands:

## clone the git sample repository from 3dvl gitlab server
git clone https://git.3dvisionlabs.com/3dvisionlabs/software/ecm/vl-samples.git
## enter c# sample folder
cd vl-samples/dotnet
## build docker image; build c# executable and run in docker context
./run.sh

C# code

Main: the main program handles setup and configuration of the camera instance as well as the "outer logic", e.g. waiting for user-input before stopping the application. "Streaming mode", as outlined in the sample is the recommended way of handling the camera - asynchronously waiting for new camera images in the FrameObserver, and keeping the camera handle and config "idle" in the main tread, e.g. for handling new configurations.

using Vl;

namespace CameraTest
{
    static class Program
    {
        private static void OnFrameIn(Frame frame)
        {
            Console.WriteLine("Frame Received: ");
            Console.WriteLine("  Timestamp: " + frame.timestamp());
            Console.WriteLine("  Width:     " + frame.image().width());
            Console.WriteLine("  Height:    " + frame.image().height());
        }

        public static void Main(string[] args)
        {
            using var cam = camera.createCamera(0);

            // define image settings for the stream
            using var imgSettings = new ImageSettings();

            // create a new frame observer and add a stream
            // frames capture by the camera will be forwarded to the OnFrameIn function
            using var frameObserver = new FrameObserver(OnFrameIn);
            var streamId = cam.addStream(frameObserver, imgSettings);

            cam.setTriggerMode(TriggerMode.Off);

            // start the camera
            // this starts the internal capture loop
            cam.start();

            // keep the application open until key press
            if (cam.triggerMode() == TriggerMode.Software)
            {
                while (true)
                {
                    var cki = Console.ReadKey();
                    if (cki.Key == ConsoleKey.Escape)
                        break;

                    Console.Write("Trigger");
                    cam.trigger();
                }
            }
            else
            {
                Console.ReadKey();
            }

            Console.Write("Stopping");

            // stop the capture loop
            cam.stop();

            // remove the stream
            cam.removeStream(streamId);
        }
    }
}

Tn a second source file, the FrameObserver is demonstrated. Basically, the camera itself will spawn the handler thread for processing the image and perform a callback into FrameObserver.

using Vl;
public class FrameObserver : IFrameObserver
{
    private Action<Frame> frameCallback;

    public FrameObserver(Action<Frame> callback)
    {
        frameCallback = callback;
    }

    public overriupport YAML style delimiters (--- or ...) for MultiMarkdown style meta-data. In fact, MkDocs relies on the the presencde void onFrameReceived(Frame frame)
    {
        frameCallback(frame);
    }
}