稳扎稳打Silverlight(14) - 2.0交互之InkPresenter(涂鸦板)

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Net; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Documents; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Media.Animation; 
using System.Windows.Shapes; 
using System.Windows.Ink; 
using System.Xml.Linq; 
using System.ServiceModel; 
using System.ServiceModel.Channels; 
 
namespace Silverlight20.Interactive 
{ 
         public partial  class InkPresenter : UserControl 
        { 
                 // 在涂鸦板上描绘的笔划 
                 private System.Windows.Ink.Stroke _newStroke; 
 
                 // 在涂鸦板上描绘的笔划的颜色 
                 private System.Windows.Media.Color _currentColor = Colors.Red; 
 
                 // 是否是擦除操作 
                 private  bool _isEraser =  false; 
 
                 // 当前是否正在 InkPresenter 上捕获鼠标 
                 private  bool _isCapture =  false; 
 
                 public InkPresenter() 
                { 
                        InitializeComponent(); 
                } 
 
                 void inkPresenter_MouseLeftButtonDown( object sender, MouseEventArgs e) 
                { 
                         // UIElement.CaptureMouse() - 为 UIElement 对象启用鼠标捕捉 
 
                         // 为 InkPresenter 启用鼠标捕捉 
                        inkPresenter.CaptureMouse(); 
                        _isCapture =  true; 
 
                         if (_isEraser) 
                        { 
                                 // 擦除鼠标当前位置所属的 Stroke（笔划） 
                                RemoveStroke(e); 
                        } 
                         else 
                        { 
                                 // System.Windows.Input.MouseEventArgs.StylusDevice.Inverted - 是否正在使用手写笔（tablet pen）的辅助笔尖 
 
                                 // System.Windows.Ink.Stroke.DrawingAttributes - Stroke（笔划）的外观属性 
                                 // System.Windows.Ink.Stroke.DrawingAttributes.Width - 笔划的宽 
                                 // System.Windows.Ink.Stroke.DrawingAttributes.Height - 笔划的高 
                                 // System.Windows.Ink.Stroke.DrawingAttributes.Color - 笔划的颜色 
                                 // System.Windows.Ink.Stroke.DrawingAttributes.OutlineColor - 笔划的外框的颜色 
 
                                _newStroke =  new System.Windows.Ink.Stroke(); 
                                _newStroke.DrawingAttributes.Width = 3d; 
                                _newStroke.DrawingAttributes.Height = 3d; 
                                _newStroke.DrawingAttributes.Color = _currentColor; 
                                _newStroke.DrawingAttributes.OutlineColor = Colors.Yellow; 
 
                                 // 为 Stroke（笔划） 在当前鼠标所在位置处增加 StylusPoint（点） 
                                _newStroke.StylusPoints.Add(e.StylusDevice.GetStylusPoints(inkPresenter)); 
                                 // 将设置好的 Stroke（笔划） 添加到 InkPresenter 的 Strokes（笔划集） 中 
                                inkPresenter.Strokes.Add(_newStroke); 
 
                                 // Stroke.GetBounds() - 获取当前 Stroke（笔划） 所在的 矩形范围 的位置信息 
                                 // Strokes.GetBounds() - 获取当前 Strokes（笔划集） 所在的 矩形范围 的位置信息 
 
                                 // 显示该 Stroke（笔划） 所在的 矩形范围 的位置信息 
                                Rect rect = _newStroke.GetBounds(); 
                                txtMsg.Text =  string.Format( "上:{0}; 下:{1}; 左:{2}; 右:{3}", 
                                     rect.Top, rect.Bottom, rect.Left, rect.Right); 
                        } 
                } 
 
                 void inkPresenter_MouseMove( object sender, MouseEventArgs e) 
                { 
                         if (_isCapture) 
                        { 
                                 if (_isEraser) 
                                { 
                                         // 擦除鼠标当前位置所属的 Stroke 
                                        RemoveStroke(e); 
                                } 
                                 else  if (_newStroke !=  null) 
                                { 
                                         // 为已经添加到 InkPresenter 的 Strokes 中的 Stroke 增加 StylusPoint 
                                        _newStroke.StylusPoints.Add(e.StylusDevice.GetStylusPoints(inkPresenter)); 
 
                                         // 显示该 Stroke 所在的 矩形范围 的位置信息 
                                        Rect rect = _newStroke.GetBounds(); 
                                        txtMsg.Text =  string.Format( "上:{0}; 下:{1}; 左:{2}; 右:{3}", 
                                                     rect.Top, rect.Bottom, rect.Left, rect.Right); 
                                } 
                        } 
                } 
 
                 void inkPresenter_MouseLeftButtonUp( object sender, MouseEventArgs e) 
                { 
                         // UIElement.CaptureMouse() - 为 UIElement 对象释放鼠标捕捉 
 
                         // 为 InkPresenter 释放鼠标捕捉 
                        inkPresenter.ReleaseMouseCapture(); 
                        _newStroke =  null; 
                        _isCapture =  false; 
                } 
 
                 void RemoveStroke(MouseEventArgs e) 
                { 
                         // Stroke.HitTest(StylusPointCollection) -    Stroke 是否与指定的 StylusPoint 集合相连 
                         // Strokes.HitTest(StylusPointCollection) - 与指定的 StylusPoint 集合相连的 Stroke 集合 
 
                         // 获取当前鼠标所在位置处的 StylusPoint 集合 
                        StylusPointCollection erasePoints =  new StylusPointCollection(); 
                        erasePoints.Add(e.StylusDevice.GetStylusPoints(inkPresenter)); 
 
                         // 与当前鼠标所在位置处的 StylusPoint 集合相连的 Stroke 集合 
                        StrokeCollection hitStrokes = inkPresenter.Strokes.HitTest(erasePoints); 
 
                         for ( int i = 0; i < hitStrokes.Count; i++) 
                        { 
                                 // 在 InkPresenter 上清除指定的 Stroke 
                                inkPresenter.Strokes.Remove(hitStrokes[i]); 
                        } 
                } 
 
                 private  void mediaElement_MediaEnded( object sender, RoutedEventArgs e) 
                { 
                         // 视频播放完后，再重新播放 
                        mediaElement.Position = TimeSpan.FromMilliseconds(0); 
                        mediaElement.Play(); 
                } 
 
                 private  void ellipseRed_MouseLeftButtonDown( object sender, MouseButtonEventArgs e) 
                { 
                         // 单击了 红色取色点 
                        _currentColor = Colors.Red; 
                        inkPresenter.Cursor = Cursors.Stylus; 
                        _isEraser =  false; 
                } 
 
                 private  void ellipseBlack_MouseLeftButtonDown( object sender, MouseButtonEventArgs e) 
                { 
                         // 单击了 黑色取色点 
                        _currentColor = Colors.Black; 
                        inkPresenter.Cursor = Cursors.Stylus; 
                        _isEraser =  false; 
                } 
 
                 private  void btnClear_Click( object sender, RoutedEventArgs e) 
                { 
                         // 单击了 清除 按钮 
                        inkPresenter.Strokes.Clear(); 
                } 
 
                 private  void btnEraser_Click( object sender, RoutedEventArgs e) 
                { 
                         // 单击了 橡皮擦 按钮 
                        inkPresenter.Cursor = Cursors.Eraser; 
                        _isEraser =  true; 
                } 
        } 
}