MainCanvasSceneRenderer.cs

public void Render(SKCanvas canvas, float angleInRadians, SKPoint center, float scale, params object[] parameters)
{
    var Image = (SKImage) parameters[0];

    var info = (SKImageInfo) parameters[2];

    // get the screen density for scaling
    var display = DisplayInformation.GetForCurrentView();
    var _scale = display.LogicalDpi / 96.0f;
    var scaledSize = new SKSize((float) info.Width / _scale, (float) info.Height / _scale);

    // handle the device screen density
    canvas.Scale(_scale);

    canvas.Clear(SKColors.White);

    canvas.DrawImage(Image, 0, 0);

    // Business logic to draw shapes ...

    canvas.Flush();
}