How to zoom a control relative to the current mouse position?

Question

I want to zoom a control based on the current cursor location. The zoom should keep the point behind mouse cursor on the same position.

I have attached two files:

In Form2.cs, I'm zooming and drawing an image on a Form directly. It works fine as intended but it's not my requirement.

In Form1.cs, I'm zooming a panel using the same logic but it's behaving very differently. Can someone help me fix it?

using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;


namespace ImageZoom
{
    public partial class Form1 : Form
    {

        float zoom = 1;
        Size initSize;
        int ctrlX, ctrlY;

        Panel childControl;

        public Form1()
        {
            InitializeComponent();

            string imagefilename = @"..\..\test.tif";
            Image img = Image.FromFile(imagefilename);

            childControl = new Panel
            {
                BackgroundImage = img,
                BackgroundImageLayout = ImageLayout.Stretch,
                BorderStyle = BorderStyle.FixedSingle,
                Location = new Point(100, 100),
                Size = new Size(200, 200)
            };

            Controls.Add(childControl);

            initSize = childControl.Size;

            ctrlX = childControl.Left;
            ctrlY = childControl.Top;
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            float oldzoom = zoom;

            if (e.Delta > 0)
                zoom = Math.Min(zoom + 0.1F, 100F);

            else if (e.Delta < 0)
                zoom = Math.Max(zoom - 0.1F, 0.1F);

            Point currLoc = e.Location;

            int x = currLoc.X;    // Where location of the mouse in the pictureframe
            int y = currLoc.Y;

            int oldimagex = (int)(x / oldzoom);  // Where in the IMAGE is it now
            int oldimagey = (int)(y / oldzoom);

            int newimagex = (int)(x / zoom);     // Where in the IMAGE will it be when the new zoom i made
            int newimagey = (int)(y / zoom);

            ctrlX += newimagex - oldimagex;  // Where to move image to keep focus on one point
            ctrlY += newimagey - oldimagey;

            childControl.Width = (int)(initSize.Width * zoom);
            childControl.Height = (int)(initSize.Height * zoom);

            Point loc = new Point(ctrlX, ctrlY);

            childControl.Location = loc;
        }

    }
}

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace ImageZoom
{
    public partial class Form2 : Form
    {
        Image img;
        int imgx = 0;                         // current offset of image
        int imgy = 0;

        float zoom = 1;
        
        public Form2()
        {

            InitializeComponent();
            string imagefilename = @"..\..\test.tif";
            img = Image.FromFile(imagefilename);

            Paint += new PaintEventHandler(this_Paint);
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            float oldzoom = zoom;

            if (e.Delta > 0)
                zoom = Math.Min(zoom + 0.1F, 100F);

            else if (e.Delta < 0)
                zoom = Math.Max(zoom - 0.1F, 0.1F);

            Point currLoc = e.Location;

            int x = currLoc.X;    // Where location of the mouse in the pictureframe
            int y = currLoc.Y;

            int oldimagex = (int)(x / oldzoom);  // Where in the IMAGE is it now
            int oldimagey = (int)(y / oldzoom);

            int newimagex = (int)(x / zoom);     // Where in the IMAGE will it be when the new zoom i made
            int newimagey = (int)(y / zoom);

            imgx += newimagex - oldimagex;  // Where to move image to keep focus on one point
            imgy += newimagey - oldimagey;

            Invalidate();
        }

        private void this_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            e.Graphics.ScaleTransform(zoom, zoom);
            e.Graphics.DrawImage(img, imgx, imgy);
        }
    }
}

What I want is to zoom that panel according to the mouse location. e.g. Like we zoom a canvas in Paint.NET or Adobe Illustrator etc. The area under the mouse stays there.