在教学和演示中，我们通常需要对重点进行批注，下载安装第三方工具批注显得很麻烦。本篇使用WPF开发了一个批注工具，工具小巧，功能丰富，非常使用日常免费使用，或者进行再次开发。

自制批注工具具有以下功能特点：

• 支持图画，擦除，撤销，恢复，改变画板颜色功能
• 提供颜色选择和线条大小设置功能
• 方便演示教学

示例代码如下：

        Stack<StrokeCollection> undoStack = new Stack<StrokeCollection>();//撤销
        Stack<StrokeCollection> recoverStack = new Stack<StrokeCollection>();//恢复撤销
 
        public MainWindow()
        {
            InitializeComponent();
            try
            {
                EraserCanvas.MouseDown += EraserCanvas_MouseDown;
                EraserCanvas.MouseMove += EraserCanvas_MouseMove;
                EraserCanvas.MouseUp += EraserCanvas_MouseUp;

                
                Global.Instance.CurrentCanvas.PreviewMouseDown += WriteBorad_PreviewMouseDown;
                InkCanvasRootPanel.Children.Clear();
                InkCanvasRootPanel.Children.Add(Global.Instance.CurrentCanvas);
            }
            catch (Exception)
            {

            }

        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            //设置色板和清空橡皮位置
            Window window = Window.GetWindow(rdoPen);
            Point point = rdoPen.TransformToAncestor(window).Transform(new Point(0, 0));
            translateColor.X = translateColor.X - 100;
            translateEraser.X = translateEraser.X-30;


            if (rdoPenWidthMin.Content.ToString() == Global.Instance.ColorHelper.selectedPenWidth.Trim())
                rdoPenWidthMin.IsChecked = true;
            else if (rdoPenWidthMedium.Content.ToString() == Global.Instance.ColorHelper.selectedPenWidth.Trim())
                rdoPenWidthMedium.IsChecked = true;
            else if (rdoPenWidthMax.Content.ToString() == Global.Instance.ColorHelper.selectedPenWidth.Trim())
                rdoPenWidthMax.IsChecked = true;

            //初始化色板
            foreach (string color in Global.Instance.ColorHelper.colorList)
            {
                RadioButton btntemp = new RadioButton();
                btntemp.SetResourceReference(StyleProperty, "ColorSelectStyle");
                btntemp.Width = 30;
                btntemp.Height = 30;
                btntemp.Margin = new Thickness(2, 2, 2, 0);
                btntemp.Background = new SolidColorBrush((System.Windows.Media.Color)ColorConverter.ConvertFromString(color));

                if (btntemp.Background.ToString() == Global.Instance.ColorHelper.selectedColor)
                {
                    btntemp.IsChecked = true;
                    Global.Instance.CurrentCanvas.DefaultDrawingAttributes.Color =(System.Windows.Media.Color)ColorConverter.ConvertFromString((string)Global.Instance.ColorHelper.selectedColor);
                }                    
                uniformColor.Children.Add(btntemp);
            }

        }


        #region InkCanvas操作
        bool transformColorFlag = false;
        bool transformEraserClearFlag = false;
        private void RadioButton_Click(object sender, RoutedEventArgs e)
        {
            //橡皮模式下选择其他工具关闭橡皮擦功能
            EraserCanvas.Visibility = Visibility.Collapsed;
            _eraserisDown = false;

            //如果色板打开下选择其他工具,隐藏色板工具
            if (!(bool)rdoPen.IsChecked)
            {
                transformColorFlag = false;
                translateColor.Y = 300;
            }

            if (!(bool)rdoEraser.IsChecked)
            {
                transformEraserClearFlag = false;
                translateEraser.Y = 100;
            }

            if ((sender as RadioButton).Content.ToString() == "画笔")
            {
                //Topmost = false;
                this.Background = (Brush)new BrushConverter().ConvertFromString("#01000000");
                if (transformColorFlag)
                {
                    translateColor.Y = -10;
                }
                else
                {
                    translateColor.Y = 300;
                }
                transformColorFlag = !transformColorFlag;
                Global.Instance.CurrentCanvas.EditingMode = InkCanvasEditingMode.Ink;
            }
            else if ((sender as RadioButton).Content.ToString() == "橡皮")
            {
                this.Background = (Brush)new BrushConverter().ConvertFromString("#01000000");
                if (transformEraserClearFlag)
                {
                    translateEraser.Y = -10;
                }
                else
                {
                    translateEraser.Y = 100;
                }
                transformEraserClearFlag = !transformEraserClearFlag;

                Global.Instance.CurrentCanvas.EditingMode = InkCanvasEditingMode.None;
                EraserCanvas.Visibility = Visibility.Visible;
                TranslateTransform.X = -1000;
                TranslateTransform.Y = -1000;

            }
            else if ((sender as RadioButton).Content.ToString() == "选择")
            {
                //Topmost = true;
                this.Background = System.Windows.Media.Brushes.Transparent;
                Global.Instance.CurrentCanvas.EditingMode = InkCanvasEditingMode.None;
                // Global.Instance.CurrentCanvas.EditingMode = InkCanvasEditingMode.Select;
            }
            else if ((sender as RadioButton).Content.ToString() == "撤销")
            {
                if (undoStack.Count > 0)
                {
                    recoverStack.Push(Global.Instance.CurrentCanvas.Strokes.Clone());
                     Global.Instance.CurrentCanvas.Strokes = undoStack.Pop();
                }
            }
            else if ((sender as RadioButton).Content.ToString() == "恢复")
            {
                if (recoverStack.Count > 0)
                {
                    undoStack.Push( Global.Instance.CurrentCanvas.Strokes.Clone());
                     Global.Instance.CurrentCanvas.Strokes = recoverStack.Pop();
                }
            }
        }
        #endregion

实例链接：https://download.csdn.net/download/lvxingzhe3/89505204