[WPF]自定义鼠标指针

[WPF]自定义鼠标指针

周银辉

看看WPF Cursor类的两个构造函数吧:

public Cursor(Stream cursorStream)
public Cursor(string cursorFile)

恩, 均要求用 ani 或 cur, 无语啊,我要使用一张普通图片呢? 或者甚至是在程序内存中动态生成一张图片而生成鼠标指针呢?

于是乎, 我们可以折腾出如下代码, 它可以从由一张图片来创建鼠标指针:

   /// <summary>
    /// This class allow you create a Cursor form a Bitmap
    /// </summary>
    internal class BitmapCursor : SafeHandle
    {

        public override bool IsInvalid
        {
            get
            {
                return handle == (IntPtr)(-1);
            }
        }

        public static Cursor CreateBmpCursor(Bitmap cursorBitmap)
        {

            var c = new BitmapCursor(cursorBitmap);

            return CursorInteropHelper.Create(c);
        }

        protected BitmapCursor(Bitmap cursorBitmap)
            : base((IntPtr)(-1), true)
        {
            handle = cursorBitmap.GetHicon();
        }

        protected override bool ReleaseHandle()
        {
            bool result = DestroyIcon(handle);

            handle = (IntPtr)(-1);

            return result;
        }

        [DllImport("user32")]
        private static extern bool DestroyIcon(IntPtr hIcon);
    }

下面是一段示例代码:

   private static Cursor CreateMyCursor()
        {
            const int w = 25;
            const int h = 25;
            const int f = 4;

            var bmp = new Bitmap(w, h);

            Graphics g = Graphics.FromImage(bmp);
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;

            var pen = new Pen(Brushes.Black, 2.0F);

            g.DrawEllipse(pen, new Rectangle(f, f, w - 2 * f, w - 2 * f));

            g.Flush();
            g.Dispose();
            pen.Dispose();

            return BitmapCursor.CreateBmpCursor(bmp);
        }

有人会说"啊!Bitmap? WinForm的! 就不可以从WPF的图像来生成么?"
那么免费赠送如下函数:

   public static Bitmap BitmapSourceToBitmap(this BitmapSource source)
        {
            using (var stream = new MemoryStream())
            {
                var e = new BmpBitmapEncoder();
                e.Frames.Add(BitmapFrame.Create(source));
                e.Save(stream);

                var bmp = new Bitmap(stream);

                return bmp;
            }
        }

(责任编辑：admin)