Chart background via visualization

[david-brink-talogy]

I'm trying to set up a gradient for the chart background, but I'm having difficulty calculating the position when using legends and titles.

When using the code below, the gradient renders, but the border is cut off because using X = 0, Y = 0 is relative to the entire canvas and not simply the chart area.

Is there a proper way to calculate the top/left of the chart area including titles, legends, margins, etc? Is there a better or more standard way of adding backgrounds that are not simply solid colors to the chart?

            var chart2 = new SKPieChart { Width = 640, Height = 480 };
            chart2.Title = new LabelVisual
            {
                Text = "gradient",
                Paint = new SolidColorPaint(SKColors.Black)
            };
            chart2.Series = new List<ISeries>
            {
                new PieSeries<double>
                {
                    Values = new List<double> { 10f },
                    MaxRadialColumnWidth = 150,
                    Fill = new SolidColorPaint(SKColors.Yellow),
                    Name = "yellow"
                },
                new PieSeries<double>
                {
                    Values = new List<double> { 20f },
                    MaxRadialColumnWidth = 150,
                    Fill = new SolidColorPaint(SKColors.Red),
                    Name = "red"
                },
                new PieSeries<double>
                {
                    Values = new List<double> { 30f },
                    MaxRadialColumnWidth = 150,
                    Fill = new SolidColorPaint(SKColors.Green),

                    Name = "green"
                }
            };

            chart2.LegendPosition = LegendPosition.Top;
            chart2.VisualElements = new[]
            {
                new GeometryVisual<RectangleGeometry>
                {
                    X = 0,
                    Y = 0,
                    LocationUnit = MeasureUnit.Pixels,
                    Width = chart2.Width,
                    Height = chart2.Height,
                    SizeUnit = MeasureUnit.Pixels,
                    Fill =  new LinearGradientPaint(SKColors.LightBlue, SKColors.Transparent, new SKPoint(0, .5f), new SKPoint(1, .5f)),
                    Stroke = new SolidColorPaint
                    {
                        Color = SKColors.Black,
                        StrokeThickness = 3f,
                    },
                }
            };

            using (var stream = new MemoryStream())
            {
                chart2.SaveImage(stream, SkiaSharp.SKEncodedImageFormat.Png);
                return stream.ToArray();
            }