UI automation on mouse over draw a rectangle C#

using Microsoft.Win32.SafeHandles;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Forms;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace zee.Views
{
/// <summary>
/// Interaction logic for Inspector.xaml
/// </summary>
public partial class Inspector : System.Windows.Controls.UserControl
{


    #region Win32 API Declarations

    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int Left;
        public int Top;
        public int Right;
        public int Bottom;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int X;
        public int Y;

        #region Helper methods

        public POINT(int x, int y)
        {
            this.X = x;
            this.Y = y;
        }

        public static implicit operator System.Drawing.Point(POINT p)
        {
            return new System.Drawing.Point(p.X, p.Y);
        }

        public static implicit operator POINT(System.Drawing.Point p)
        {
            return new POINT(p.X, p.Y);
        }

        #endregion
    }

    const int DSTINVERT = 0x00550009;

    [DllImport("gdi32.dll")]
    static extern bool PatBlt(IntPtr hdc, int nXLeft, int nYLeft, int nWidth, int nHeight, uint dwRop);

    [DllImport("user32.dll")]
    static extern IntPtr WindowFromPoint(POINT Point);

    [DllImport("user32.dll")]
    static extern int GetWindowText(int hWnd, StringBuilder text, int count);

    [DllImport("user32.dll")]
    static extern IntPtr GetWindowDC(IntPtr hWnd);

    [DllImport("user32.dll")]
    static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

    [DllImport("user32.dll")]
    static extern bool OffsetRect(ref RECT lprc, int dx, int dy);

    [DllImport("user32.dll")]
    static extern int GetClassName(IntPtr hWnd, StringBuilder lpClassName, int nMaxCount);

    [DllImport("user32.dll")]
    static extern uint GetWindowThreadProcessId(IntPtr hWnd, out int lpdwProcessId);

    [DllImport("user32.dll")]
    public static extern bool GetCursorPos(out System.Drawing.Point lpPoint);

    [DllImport("User32.dll")]
    static extern IntPtr GetDC(IntPtr hwnd);

    [DllImport("gdi32.dll")]
    static extern int GetDeviceCaps(IntPtr hdc, int nIndex);

    [DllImport("user32.dll")]
    static extern bool ReleaseDC(IntPtr hWnd, IntPtr hDC);


    #endregion

    bool _dragging;
    IntPtr _hWndCurrent;
    System.Windows.Input.Cursor _curCross;
    System.Drawing.Image _imgAppCross;
    System.Drawing.Image _imgApp;

    public Inspector()
    {
        InitializeComponent();
        Assembly assembly = Assembly.GetExecutingAssembly();
        _imgAppCross = System.Drawing.Image.FromStream(assembly.GetManifestResourceStream("zee.Assets.Images.app_cross.png"));
        _imgApp = System.Drawing.Image.FromStream(assembly.GetManifestResourceStream("zee.Assets.Images.app.png"));
        _curCross = new System.Windows.Input.Cursor(System.IO.Path.Combine(Directory.GetCurrentDirectory(), "Assets\\Images\\cross.cur"));
        dragPictureBox.Image = _imgAppCross;
    }

    private System.Drawing.Point ConvertPixelsToUnits(double x, double y)
    {
        // get the system DPI
        IntPtr dDC = GetDC(IntPtr.Zero); // Get desktop DC
        int dpi = GetDeviceCaps(dDC, 88);
        bool rv = ReleaseDC(IntPtr.Zero, dDC);

        // WPF's physical unit size is calculated by taking the
        // "Device-Independant Unit Size" (always 1/96)
        // and scaling it by the system DPI
        double physicalUnitSize = (1d / 96d) * (double)dpi;
        System.Drawing.Point wpfUnits = new System.Drawing.Point(Convert.ToInt32(physicalUnitSize * (x)),Convert.ToInt32(physicalUnitSize * (y)));

        return wpfUnits;
    }
    public POINT GetCursorPosition()
    {
        System.Drawing.Point lpPoint, wpfPoint= new System.Drawing.Point();

        if(GetCursorPos(out lpPoint))
        {
             wpfPoint = ConvertPixelsToUnits(lpPoint.X, lpPoint.Y);
        }
        //bool success = User32.GetCursorPos(out lpPoint);
        // if (!success)

        return wpfPoint;
    }
    private void DrawRevFrame(IntPtr hWnd)
    {
        if (hWnd == IntPtr.Zero)
            return;

        IntPtr hdc = GetWindowDC(hWnd);
        RECT rect;
        GetWindowRect(hWnd, out rect);
        OffsetRect(ref rect, -rect.Left, -rect.Top);

        const int frameWidth = 3;

        PatBlt(hdc, rect.Left, rect.Top, rect.Right - rect.Left, frameWidth, DSTINVERT);
        PatBlt(hdc, rect.Left, rect.Bottom - frameWidth, frameWidth,-(rect.Bottom - rect.Top - 2 * frameWidth), DSTINVERT);
        PatBlt(hdc, rect.Right - frameWidth, rect.Top + frameWidth, frameWidth,rect.Bottom - rect.Top - 2 * frameWidth, DSTINVERT);
        PatBlt(hdc, rect.Right, rect.Bottom - frameWidth, -(rect.Right - rect.Left),frameWidth, DSTINVERT);
    }

    private string GetWindowText(IntPtr hWnd)
    {
        StringBuilder text = new StringBuilder(256);
        if (GetWindowText(hWnd.ToInt32(), text, text.Capacity) > 0)
        {
            return text.ToString();
        }

        return String.Empty;
    }

    private string GetClassName(IntPtr hWnd)
    {
        StringBuilder className = new StringBuilder(100);
        if (GetClassName(hWnd, className, className.Capacity) > 0)
        {
            return className.ToString();
        }

        return String.Empty;
    }

    private string GetApplication(IntPtr hWnd)
    {
        int procId;
        GetWindowThreadProcessId(hWnd, out procId);
        Process proc = Process.GetProcessById(procId);
        return proc.MainModule.ModuleName;
    }

    private void dragPictureBox_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            _dragging = true;
            Assembly assembly = Assembly.GetExecutingAssembly();
            System.Windows.Input.Mouse.OverrideCursor = _curCross;
            dragPictureBox.Image = _imgApp;
        }
    }

    private void dragPictureBox_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
    {
        if (_dragging)
        {
            _dragging = false;
            System.Windows.Input.Mouse.OverrideCursor = System.Windows.Input.Cursors.Arrow;
            if (_hWndCurrent != IntPtr.Zero)
            {
                DrawRevFrame(_hWndCurrent);
                _hWndCurrent = IntPtr.Zero;
                // The image in the dragPictureBox will be restored when the context menu is closed
            }
            else
            {
                dragPictureBox.Image = _imgAppCross;
            }
            dragPictureBox.Image = _imgAppCross;
        }
    }

    private void dragPictureBox_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
    {
        if (_dragging)
        {
            IntPtr hWnd = WindowFromPoint(GetCursorPosition());
            if (hWnd == dragPictureBox.Handle)
            {
                // Drawing a border around the dragPictureBox (where we start
                // dragging) doesn't look nice, so we ignore this window
                hWnd = IntPtr.Zero;
            }

            if (hWnd != _hWndCurrent)
            {
                if (_hWndCurrent != null)
                {
                    DrawRevFrame(_hWndCurrent);
                }
                DrawRevFrame(hWnd);
                _hWndCurrent = hWnd;
            }

            if (hWnd != IntPtr.Zero)
            {
                txtWindowHandle.Text = hWnd.ToString();
                txtWindowText.Text = GetWindowText(hWnd);
                txtClassName.Text = GetClassName(hWnd);
                txtApplication.Text = GetApplication(hWnd);
            }
            else
            {
                txtWindowHandle.Text = String.Empty;
                txtWindowText.Text = String.Empty;
                txtClassName.Text = String.Empty;
                txtApplication.Text = String.Empty;
            }
        }
    }
 }