2.0交互之InkPresenter(涂鸦板)

介绍
Silverlight 2.0 人机交互：InkPresenter(涂鸦板)
    InkPresenter - 涂鸦板，也就是在面板上呈现墨迹。InkPresenter 可以包含子控件
    Cursor - 鼠标移动到 InkPresenter 上面时，鼠标指针的样式
    Background - 涂鸦板背景
    Opacity - 面板上墨迹的不透明度
    Clip - InkPresenter 的剪辑区域
    Stroke.DrawingAttributes - Stroke（笔划）的外观属性
    UIElement.CaptureMouse() - 为 UIElement 对象启用鼠标捕捉
    UIElement.CaptureMouse() - 为 UIElement 对象释放鼠标捕捉


在线DEMO
http://www.cnblogs.com/webabcd/archive/2008/10/09/1307486.html


示例
InkPresenter.xaml

< UserControl  x:Class ="Silverlight20.Interactive.InkPresenter"
    xmlns ="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x ="http://schemas.microsoft.com/winfx/2006/xaml"  xmlns:d ="http://schemas.microsoft.com/expression/blend/2008"  xmlns:mc ="http://schemas.openxmlformats.org/markup-compatibility/2006"  mc:Ignorable ="d" >
     < Canvas >

         <!-- InkPresenter 的外围的带边框的背景图 -->
         < Rectangle  Width ="420"  Height ="350"  Stroke ="Black"  StrokeThickness ="1" >
             < Rectangle.Fill >
                 < ImageBrush  ImageSource ="/Silverlight20;component/Images/Background.jpg"  Stretch ="Fill"   />
             </ Rectangle.Fill >
         </ Rectangle >
        
         <!-- 用于描绘 InkPresenter 的工作区 -->
         < Rectangle  Canvas.Top ="10"  Canvas.Left ="10"  Width ="400"  Height ="300"  RadiusX ="25"  RadiusY ="25"  Fill ="Black"  Opacity ="0.2"   />

         <!--
        InkPresenter - 涂鸦板，也就是在面板上呈现墨迹
            Cursor - 鼠标移动到 InkPresenter 上面时，鼠标指针的样式
                Arrow - 箭头
                Hand - 手形 
                Wait - 沙漏
                IBeam - “I”字形 
                Stylus - 点
                Eraser - 橡皮
                None - 无
            Background - 涂鸦板背景。建议设置其为“Transparent”，需要的话可以使用其他控件来描绘背景
            Opacity - 面板上墨迹的不透明度
            Clip - InkPresenter 的剪辑区域。本例给 InkPresenter 做了一个圆角效果，其Clip值由 Blend 生成
         -->
         < InkPresenter  x:Name ="inkPresenter"  Cursor ="Stylus"  Canvas.Top ="10"  Canvas.Left ="10"  Width ="400"  Height ="300"  Background ="Transparent"
         
            MouseLeftButtonDown ="inkPresenter_MouseLeftButtonDown"  
            MouseLeftButtonUp ="inkPresenter_MouseLeftButtonUp"  
            MouseMove ="inkPresenter_MouseMove"  
            Clip ="M0.5,25.5 C0.5,11.692882 11.692882,0.5 25.5,0.5 L374.5,0.5 C388.30713,0.5 399.5,11.692882 399.5,25.5 L399.5,274.5 C399.5,288.30713 388.30713,299.5 374.5,299.5 L25.5,299.5 C11.692882,299.5 0.5,288.30713 0.5,274.5 z" >

             <!--
            InkPresenter 可以包含子控件。本例为在 InkPresenter 的底部循环播放视频
             -->
             < MediaElement  x:Name ="mediaElement"  Source ="/Silverlight20;component/Video/Demo.wmv"  Width ="400"  Height ="100"  Canvas.Top ="200"  Stretch ="UniformToFill"  MediaEnded ="mediaElement_MediaEnded"   />

         </ InkPresenter >
    
         <!-- 红色取色点，点此后可画红色的线 -->
         < Ellipse  x:Name ="ellipseRed"  Canvas.Top ="320"  Canvas.Left ="20"  Cursor ="Hand"  Fill ="Red"  Width ="20"  Height ="20"  MouseLeftButtonDown ="ellipseRed_MouseLeftButtonDown"   />

         <!-- 黑色取色点，点此后可画黑色的线 -->
         < Ellipse  x:Name ="ellipseBlack"  Canvas.Top ="320"  Canvas.Left ="50"  Cursor ="Hand"  Fill ="Black"  Width ="20"  Height ="20"  MouseLeftButtonDown ="ellipseBlack_MouseLeftButtonDown"   />

         <!-- 橡皮擦，点此后可擦除之前画的线 -->
         < Button  x:Name ="btnEraser"  Canvas.Top ="320"  Canvas.Left ="80"  Content ="橡皮擦"  Click ="btnEraser_Click"   />

         <!-- 用于清除 InkPresenter 上的墨迹的按钮 -->
         < Button  x:Name ="btnClear"  Canvas.Top ="320"  Canvas.Left ="130"  Content ="清除"  Click ="btnClear_Click"   />

         <!-- 用于显示当前 Stroke（笔划） 所在的 矩形范围 的位置信息 -->
         < TextBox  x:Name ="txtMsg"  Canvas.Top ="320"  Canvas.Left ="180"  Width ="220"   />
           
     </ Canvas >
</ UserControl >

InkPresenter.xaml.cs

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;
        }
    }
}