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VNC

VNC (Virtual Network Computing) lets you view and interact with the SITCore's display remotely from a PC, phone, or tablet — no physical screen needed on the device. The device runs a VncServer that exposes its graphics framebuffer over TCP, and the client connects with a standard VNC viewer.

Useful for headless deployments, remote diagnostics, kiosks behind glass, and devices that don't have a local display at all (you still draw with the graphics engine — the pixels just go over the network instead of to a panel).

NuGet package: GHIElectronics.TinyCLR.Vnc.

Supported clients​

The implementation has been tested with the following VNC viewers:

  • TightVNC Viewer 2.8.27
  • TightVNC Java Viewer 2.8.3
  • UltraVNC 1.2.4.0
  • bVNC: Secure VNC Viewer (mobile)
tip

RealVNC is not supported. Use one of the above instead.

In your VNC viewer, set the preferred encoding to Raw.

Example​

The device needs an active network connection (WiFi, Ethernet, etc.) before the VNC server starts. The example below starts a 320×240 VNC server on port 5900, animates a moving ellipse with a frame counter, and prints any mouse interaction received from the client.

using GHIElectronics.TinyCLR.Vnc;
using System.Diagnostics;
using System.Drawing;
using System.Threading;

// Network connection (WiFi, Ethernet, etc.) must be up before this runs.

var vncServer = new VncServer("VNC Viewer", port: 5900, width: 320, height: 240);
vncServer.PointerChangedEvent += (x, y, pressed) =>
    Debug.WriteLine("Pointer: x=" + x + ", y=" + y + ", pressed=" + pressed);

vncServer.Start();
Debug.WriteLine("VNC started");

// Draw into a 320×240 bitmap; flush events push to the VNC client.
var vncDisplay = Graphics.FromImage(new Bitmap(320, 240));
var font = Resources.GetFont(Resources.FontResources.Arial);

Graphics.OnFlushEvent += (sender, data, x, y, width, height, originalWidth) =>
    vncServer.Send(data, x, y, width, height);

var cnt = 0;
while (true) {
    vncDisplay.Clear();
    vncDisplay.DrawString(cnt + " SITCore VNC!", font, new SolidBrush(Color.Yellow), 15, 20);
    vncDisplay.DrawEllipse(new Pen(Color.Red), cnt, 160, 40, 40);
    vncDisplay.Flush();

    cnt += 5;
    if (cnt > 320) cnt = 0;

    Thread.Sleep(10);
}

The pattern is the same as virtual displays — draw into a RAM bitmap, register an OnFlushEvent handler, push the bytes to the destination (here: the VNC client).

Connecting from a client​

The only thing you need to enter in the VNC viewer is the device's IP address (and port 5900 if you changed it):

Entering the SITCore IP address in TightVNC Viewer

Set the preferred encoding to Raw:

Setting preferred encoding to Raw in TightVNC

Once connected, the TinyCLR graphics surface shows up in the VNC window:

Live TinyCLR graphics displayed in the VNC client

Mouse coordinates and click state from the VNC client are routed back to the device through the PointerChangedEvent:

Debug output showing pointer events from the VNC client