Resizing Image Canvas - Fit original Image to an square

CanvasResizer.cs

private Bitmap ExpandCanvas(System.Drawing.Image inputImage)
{
	var img = inputImage;

	// Calculate the square side
	var max = Math.Max(img.Width, img.Height);

	int side;
	var isVertical = false;

	// Check if the image is vertical or horizontal
	// and then calculate the side white space
	if (img.Height > img.Width)
	{
		isVertical = true;
		side = (img.Height - img.Width) / 2;
	}
	else
	{
		side = (img.Width - img.Height) / 2;
	}
	
	Size szDimensions = new Size(max, max);

	// Create blank canvas
	Bitmap resizedImg = new Bitmap(szDimensions.Width, szDimensions.Height);
	resizedImg.SetResolution(img.HorizontalResolution, img.VerticalResolution);

	// Fill canvas with White color
	Graphics gfx = Graphics.FromImage(resizedImg);
	gfx.FillRectangle(Brushes.White, 0, 0, max, max);


	//Check if the image is vertical
	if (isVertical)
	{
		// Paste source image on white canvas and shift image from right to the center
		gfx.DrawImageUnscaled(img, side, 0);
	}
	else
	{
		// Paste source image on white canvas and shift image from top to the center
		gfx.DrawImageUnscaled(img, 0, side);
	}

	// Dispose gfx
	gfx.Dispose();
	
	return resizedImg;
}