Skia Sharp - problem on Android

Hi everybody,
i am developing a radial menu with skia sharp on xamarin forms

here is the function that draws the control

    SKCanvasView ElementBuilder()
    {
        var element = new SKCanvasView();
        element.PaintSurface += (sender, e) =>
        {
            diameter = (float)(Width / 1.5);
            var canvas = e.Surface.Canvas;
            canvas.Clear(SKColors.Transparent);
            canvas.Translate((float)(Width), (float)(Height));
            var angles = new float[5] { 234, 306, 18, 90, 162 };
            using (var path = new SKPath())
            {
                foreach (var item in angles)
                {
                    path.ArcTo(new SKRect(-diameter, -diameter, diameter, diameter), item, 72, true);
                }
                canvas.DrawPath(path, elementPaint);
            }
            using (var path = new SKPath())
            {
                foreach (var item in angles)
                {
                    path.LineTo(DegreesToXY(item, (-diameter - (strokeWidth / 2))));
                    path.MoveTo(0, 0);
                    path.LineTo(DegreesToXY(item + 72, (-diameter - (strokeWidth / 2))));
                    path.MoveTo(0, 0);
                }
                canvas.DrawPath(path, backgroundPaint);
            }

        };
        return element;
    }

Works perfectly on every iOS device I have tested and on my personal device which i used during development (Sony xperia z3 compact)
On every other Android device, with any version of the os the sizing of the view is different

I upload here 3 screenshot (IPhone 7 simulator, Xperia z3 compact, Nexus 5)

Every Android device renders the same (the third image), except the sony
How to give the correct size to the view?

Thank in advance