Mouse scaling in WinForms?

Question

I am trying to use mouse position to calculate the zoom factor to scale the image. Basically, the farther you go from the center of the image, the bigger it gets; and the closer you get to the center, the less it gets. I still have the code, but it works very weirdly, and I have absolutely no ideas. First, I will tell you what I'm trying to do is average 5 distances to get smoother resizing. Here is my code:

private void pictureBoxScale_MouseMove(object sender, MouseEventArgs e)
{
    if (rotateScaleMode && isDraggingToScale)
    {
        // For Scaling              
        int sourceWidth = pictureBox1.Image.Width;
        int sourceHeight = pictureBox1.Image.Height;
        float dCurrCent = 0; // distance between the current mouse pos and the center of the image
        float dPrevCent = 0; // distance between the previous mouse pos and the center of the image

        System.Drawing.Point imgCenter = new System.Drawing.Point();

        imgCenter.X = pictureBox1.Location.X + (sourceWidth / 2);
        imgCenter.Y = pictureBox1.Location.Y + (sourceHeight / 2);

        // Calculating the distance between the current mouse location and the center of the image
        dCurrCent = (float)Math.Sqrt(Math.Pow(e.X - imgCenter.X, 2) + Math.Pow(e.Y - imgCenter.Y, 2));

        // Calculating the distance between the previous mouse location and the center of the image
        dPrevCent = (float)Math.Sqrt(Math.Pow(prevMouseLoc.X - imgCenter.X, 2) + Math.Pow(prevMouseLoc.Y - imgCenter.Y, 2));

        if (smoothScaleCount < 5)
        {
            dCurrCentSmooth[smoothScaleCount] = dCurrCent;
            dPrevCentSmooth[smoothScaleCount] = dPrevCent;
        }


        if (smoothScaleCount == 4)
        {
            float currCentSum = 0;
            float prevCentSum = 0;
            for (int i = 0; i < 4; i++)
            {
                currCentSum += dCurrCentSmooth[i];
            }
            for (int i = 0; i < 4; i++)
            {
                prevCentSum += dPrevCentSmooth[i];
            }

            float scaleAvg = (currCentSum / 5) / (prevCentSum / 5);


            int destWidth = (int)(sourceWidth * scaleAvg);
            int destHeight = (int)(sourceHeight * scaleAvg);

            // If statement is for limiting the size of the image
            if (destWidth > (currentRotatedImage.Width / 2) && destWidth < (currentRotatedImage.Width * 3) && destHeight > (currentRotatedImage.Height / 2) && destWidth < (currentRotatedImage.Width * 3))
            {
                AForge.Imaging.Filters.ResizeBilinear resizeFilter = new AForge.Imaging.Filters.ResizeBilinear(destWidth, destHeight);
                pictureBox1.Image = resizeFilter.Apply((Bitmap)currentRotatedImage);
                pictureBox1.Size = pictureBox1.Image.Size;
                pictureBox1.Refresh();
            }

            smoothScaleCount = -1;
        }
        prevMouseLoc = e.Location;
        currentScaledImage = pictureBox1.Image;
        smoothScaleCount++;

    }
}

EDITOR: Thanks to Ben Voigt and Ray, everything works well. The only thing wrong is how I do it, the image does not support the ratio; but I will fix it later. Here is what I have for those who want to know:

private void pictureBoxScale_MouseMove(object sender, MouseEventArgs e)
    {
        if (rotateScaleMode && isDraggingToScale)
        {
            // For Scaling              
            int sourceWidth = pictureBox1.Image.Width;
            int sourceHeight = pictureBox1.Image.Height;
            int scale = e.X + p0.X; //p0 is the location of the mouse when the button first came down
            int destWidth = (int)(sourceWidth + (scale/10)); //I divide it by 10 to make it slower
            int destHeight = (int)(sourceHeight + (scale/10));

            if (destWidth > 20 && destWidth < 1000 && destHeight > 20 && destWidth < 1000)
            {
                AForge.Imaging.Filters.ResizeBilinear resizeFilter = new AForge.Imaging.Filters.ResizeBilinear(destWidth, destHeight);
                pictureBox1.Image = resizeFilter.Apply((Bitmap)currentRotatedImage);
                pictureBox1.Size = pictureBox1.Image.Size;
                pictureBox1.Refresh();
            }
            currentScaledImage = pictureBox1.Image; // This is only so I can rotate the scaled image in another part of my program

        }
    }

Answer 1

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Answer 2

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