Change Cursor HotSpot in WinForms / .NET

Question

I'm creating a cursor at runtime from a image resource. The HotSpot of the new Cursor is always set to 16x16 (32x32 image). Is it possible to change the HotSpot at runtime or will I need to create .cur files?

Answer 1

You sure can. Here are my utility functions, edit as you see fit :)

    public struct IconInfo
    {
        public bool fIcon;
        public int xHotspot;
        public int yHotspot;
        public IntPtr hbmMask;
        public IntPtr hbmColor;
    }
    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool GetIconInfo(IntPtr hIcon, ref IconInfo pIconInfo);
    [DllImport("user32.dll")]
    public static extern IntPtr CreateIconIndirect(ref IconInfo icon);

    /// <summary>
    /// Create a cursor from a bitmap without resizing and with the specified
    /// hot spot
    /// </summary>
    public static Cursor CreateCursorNoResize(Bitmap bmp, int xHotSpot, int yHotSpot)
    {
        IntPtr ptr = bmp.GetHicon();
        IconInfo tmp = new IconInfo();
        GetIconInfo(ptr, ref tmp);
        tmp.xHotspot = xHotSpot;
        tmp.yHotspot = yHotSpot;
        tmp.fIcon = false;
        ptr = CreateIconIndirect(ref tmp);
        return new Cursor(ptr);
    }


    /// <summary>
    /// Create a 32x32 cursor from a bitmap, with the hot spot in the middle
    /// </summary>
    public static Cursor CreateCursor(Bitmap bmp)
    {
        int xHotSpot = 16;
        int yHotSpot = 16;

        IntPtr ptr = ((Bitmap)ResizeImage(bmp, 32, 32)).GetHicon();
        IconInfo tmp = new IconInfo();
        GetIconInfo(ptr, ref tmp);
        tmp.xHotspot = xHotSpot;
        tmp.yHotspot = yHotSpot;
        tmp.fIcon = false;
        ptr = CreateIconIndirect(ref tmp);
        return new Cursor(ptr);
    }

Answer 2

Take a look at this post on MSDN. There seem to be a couple possible solutions (using P/Invoke) which you should be able to copy-paste and use.

Answer 3

Can you explain how the ResizeImage() method above is defined? I am getting an undefined error