1. Documentation
2. Defining new Figures

    [ExecuteInEditMode]
    [RequireComponent(typeof(VectorizerMesh))]
    public class VectorizerEllipse : VectorizerFigure
    {
        [Range(3f, 320f)] public int Tessellation = 32;

        [Range(0.001f, 256f)] public float SemiMajorAxis = 8;
        [Range(0.001f, 256f)] public float SemiMinorAxis = 8;

        public override void Rebuild()
        {
            // This function is called every time the parameters change.
            // Therefore, we need to clear the instructions having old values.
            Designer.ClearInstructions();

            // We add a new Fill Ellipse instruction based on the current values.
            // To avoid an overlap between the interior part and the outline,
            // we reduce the length of the semi-major and semi-minor axis
            // by half the stroke thickness' width.
            Designer.AddInstruction(new FillEllipse(Tessellation, SemiMajorAxis-StrokeThickness/2,
                SemiMinorAxis - StrokeThickness / 2));

            // If this figure has a stroke part (HasStroke), then we 
            // need to add the corresponding instructions.
            if (HasStroke)
            {
                Designer.AddInstruction(new DrawEllipse(Tessellation, SemiMajorAxis, SemiMinorAxis,
                    strokeThickness:StrokeThickness));
                
                // This instruction makes sure that the vertices belonging to the
                // interior area have the same exact values as those on the outline,
                // to account for floating-point errors.
                Designer.AddInstruction(new WeldPolygonVerticesInstruction());
            }
        }

        protected override bool Validate()
        {
            // return true when the figure is valid according to the current
            // value of the parameters.
            return SemiMajorAxis >= 0.01f && SemiMinorAxis >= 0.01f;
        }

        // To make your figure appear in the menu, implement a similar function
        [MenuItem("GameObject/Vectorizer/Add Ellipse")]
        public static void CreatePolygon()
        {
            Create<VectorizerEllipse>();
        }
    }
}