Creating Cursor in form of ELLIPSE in C#

Here is the method, that describe how easily create custom cursors in forms of geometric figures:

using System;
using System.Runtime.InteropServices;
namespace CustomCursor
{    
    static class createCursor    
    {        
        [DllImport("user32.dll")]
        private static extern IntPtr CreateCursor(
            IntPtr hInst, 
            int xHotSpot, 
            int yHotSpot, 
            int nWidth, 
            int nHeight, 
            byte[] pvANDPlane, 
            byte[] pvXORPlane
            );
        static byte[] PointCodes = new byte[] {
            127, //10000000   
            191, //01000000                                               
            223, //00100000                                               
            239, //00010000                                               
            247, //00001000                                               
            251, //00000100                                               
            253, //00000010                                               
            254, //00000001                                               
            255};//00000000                                                     
        //1 -black; 0 -white;         
        static public IntPtr Ellipse(IntPtr handle, int radiusX, int radiusY, double angle)
        {            
            angle = Math.PI * angle / 180;                                                    
            int MaxRadius = Math.Max(radiusX, radiusY);                         
            int sideLength = GetSide(MaxRadius*2+4);                          
            int hotspotX = sideLength/2, hotspotY = sideLength/2;             
            int length = sideLength * sideLength / 8;                         
            byte[] andMaskCursor = new byte[length];                            
            MakeTransparent(ref andMaskCursor);            
            _Ellipse(ref andMaskCursor, hotspotX, hotspotY, radiusX, radiusY, angle);            
            byte[] xorMaskCursor = new byte[length];            
            return CreateCursor(                
                handle,             // app. instance                 
                hotspotX,             // hot spot horiz pos                
                hotspotY,             // hot spot vert pos                 
                sideLength,         // cursor width                 
                sideLength,         // cursor height                 
                andMaskCursor,      // AND mask                 
                xorMaskCursor       // XOR mask                 
                );        
        }        
        static void MakeTransparent(ref byte[] andMaskCursor)        
        {            
            for (int i = 0; i < andMaskCursor.Length; i++)            
            {                
                andMaskCursor[i] = PointCodes[8]; //make transparent cursor            
            }        
        }        
        static int GetSide(int sideLength)        
        {            
            if (sideLength % 16 != 15)            
            {                
                return sideLength + 16 - sideLength % 16;            
            }           
            else return sideLength;        
        }        
        static int rot_x(int x, int y, double theta)        
        {            
            return (int)Math.Round(x * Math.Cos(theta) - y * Math.Sin(theta));        
        }        
        static int rot_y(int x, int y, double theta)        
        {            
            return (int)Math.Round(x * Math.Sin(theta) + y * Math.Cos(theta));        
        }        
        static void _Ellipse(ref byte[] andMaskCursor, int x, int y, int a, int b, double alfa)       
        {            
            int firstx = x + rot_x(a, 0, alfa);            
            int firsty = y + rot_y(a, 0, alfa);            
            double angle = 0;            
            int itercount = Math.Max(a, b) * 2 + 40;             
            double delta = 2 * Math.PI / itercount;            
            int x1 = firstx, y1 = firsty; //moveto            
            for (int i = 1; i < itercount; i++)           
            {                angle += delta;                
                int rx = (int)Math.Round(a * Math.Cos(angle));               
                int ry = (int)Math.Round(b * Math.Sin(angle));               
                _Line(ref andMaskCursor, x1, y1, x + rot_x(rx, ry, alfa),            
                y + rot_y(rx, ry, alfa));              
                x1 = x + rot_x(rx, ry, alfa);              
                y1 = y + rot_y(rx, ry, alfa);            
            }            
            _Line(ref andMaskCursor, x1, y1, firstx, firsty);        
        }        
        static void _Line(ref byte[] andMaskCursor, float x1, float y1, float x2, float y2)        
        {            
            float itercount = Math.Max(Math.Abs(x1 - x2), Math.Abs(y1 - y2));            
            float dx = (x1 - x2) / itercount;            
            float dy = (y1 - y2) / itercount;           
            int sideLength = (int)(Math.Sqrt(andMaskCursor.Length * 8));      
            for (int i = 0; i < itercount; i++)            
            {                
                int xy = (int)Math.Truncate(Math.Round(y1) * sideLength / 8 + Math.Round(x1) / 8);    
                andMaskCursor[xy] &= PointCodes[(int)(Math.Round(x1) % 8)];                
                x1 -= dx;               
                y1 -= dy;            
            }        
        }    
    }
}