WPF + Windows7 Multi-touch (Part 3)

目前在WPF中使用Multi-touch功能,必須透過P/Invoke的方式呼叫Win32 Touch API的功能(可參考這篇文章 : WPF + Windows7 Multi-touch (Part 2) ), 或是可以直接使用微軟提供的Windows 7 Multitouch .NET Interop Sample Library, 它提供 WPF 與 WinForms 3.5 SP1 要開發Multi-Touch 程式所需的功能, 不過利用上述這些方法開發觸控功能時, 還是有稍嫌複雜, 也不是很直覺.

因此在WPF 4.0 已經將一些觸控功能放到UIElement, UIElement3D和ContentElement中,
在 Beta 1中, 將支援高階操作的觸控功能(Manipulation), 如下所示:

• ManipulationStarted
• ManipulationDelta
• ManipulationInertiaStarting
• ManipulationCompleted
• ManipulationBoundaryFeedback

而在Beta 2 中, 除了原本高階操作的觸控功能(Manipulation)外, 還提供的Touch相關的event,如下所示:

• PreviewTouchDown
• TouchDown
• PreviewTouchMove
• TouchMove
• PreviewTouchUp
• TouchUp
• GotTouchCapture
• LostTouchCapture
• TouchEnter
• TouchLeave

下面我們將利用WPF 4.0 Beta2 Touch功能, 撰寫一個顯示目前觸控點的應用程式, 其步驟如下:

軟體和硬體需求

• IDE -安裝Visual Studio 2010 Beta 2
  
• OS 版本 - Windows 7 Ultimate Editions
• 硬體設備 - 準備一台具有多點觸控的螢幕或電腦

程式碼如下:

XAML檔的部份:

<Window x:Class="WPFTouchPoint.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="800" Width="800"
    TouchDown="Window_TouchDown"
    TouchMove="Window_TouchMove"
    TouchUp="Window_TouchUp">
<Canvas Background="Black">
    <Ellipse
        Canvas.Left="0"
        Canvas.Top="0"
        Name="Touch1"
        Stroke="Black"
        Height="60"
        Width="60"
        Fill="LightGreen"
        Visibility="Hidden">
        <Ellipse.BitmapEffect>
            <DropShadowBitmapEffect ShadowDepth="10"
                                    Direction="270"
                                    Color="White"
                                    Opacity="0.5"
                                    Softness="0.25"/>
        </Ellipse.BitmapEffect>
    </Ellipse>

    <Ellipse
        Canvas.Left="0"
        Canvas.Top="0"
        Name="Touch2"
        Stroke="Black"
        Height="60"
        Width="60"
        Fill="LightBlue"
        Visibility="Hidden">
        <Ellipse.BitmapEffect>
            <dropshadowbitmapeffect shadowdepth="10" direction="270" color="White"
            opacity="0.5" softness="0.25">
       </dropshadowbitmapeffect>
     </Ellipse>
  </Canvas>
 </Window>

C#檔的部分:

namespace WPFTouchPoint
{
/// 

/// Interaction logic for MainWindow.xaml
/// 
public partial class MainWindow : Window
{

    private int Touch1ID = 0;    // id for first touch contact
    private int Touch2ID = 0;    // id for second touch contact

    public MainWindow()
    {
        InitializeComponent();
    }


    private void Window_TouchDown(object sender, TouchEventArgs e)
    {
        TouchPoint p = e.GetTouchPoint(this);

        if (Touch1ID == 0)
        {
           // Show the touch point
           Touch1.Visibility = Visibility.Visible;

           Touch1ID = e.TouchDevice.Id;

           // move the ellipse to the given location
           Touch1.SetValue(Canvas.LeftProperty, p.Position.X - Touch1.Width / 2);
           Touch1.SetValue(Canvas.TopProperty, p.Position.Y - Touch1.Height / 2);
        }
        else if (Touch2ID == 0)
        {
           Touch2.Visibility = Visibility.Visible;

           Touch2ID = e.TouchDevice.Id;
           // move the ellipse to the given location
           Touch2.SetValue(Canvas.LeftProperty, p.Position.X - Touch2.Width / 2);
           Touch2.SetValue(Canvas.TopProperty, p.Position.Y - Touch2.Height / 2);
        }

    }

    private void Window_TouchMove(object sender, TouchEventArgs e)
    {
        TouchPoint p = e.GetTouchPoint(this);
        // determine which contact this belongs to
        if (Touch1ID == e.TouchDevice.Id)
        {
           Touch1.SetValue(Canvas.LeftProperty, p.Position.X - Touch1.Width / 2);
           Touch1.SetValue(Canvas.TopProperty, p.Position.Y - Touch1.Height / 2);
        }
        else if (Touch2ID == e.TouchDevice.Id)
        {
           Touch2.SetValue(Canvas.LeftProperty, p.Position.X - Touch2.Width / 2);
           Touch2.SetValue(Canvas.TopProperty, p.Position.Y - Touch2.Height / 2);
        }
    }

    private void Window_TouchUp(object sender, TouchEventArgs e)
    {
        if (e.TouchDevice.Id == Touch1ID)
        {
            Touch1.Visibility = Visibility.Hidden;

            Touch1ID = 0;
        }
        else if (e.TouchDevice.Id == Touch2ID)
        {
            Touch2.Visibility = Visibility.Hidden;

            Touch2ID = 0;
        }

    }
}
}

顯示結果如下所示:


[圖 1] Multi-touch points in WPF4.0 Beta 2


不過目前這些觸控功能在Beta版還是有很多bug, 可參考這些文章測試出來的結果:
Multi-touch in WPF4.0 Beta2

WPF 4, Beta 2 expands multi-touch API but is buggy


參考文章:
Windows 7: Experimenting with Multi-Touch on Windows 7 ( Part 5 )

Windows using Multi-touch using WPF

Multi-touch in WPF4.0 and VS2010

Introduction to WPF 4 Multitouch

Walkthrough: Creating Your First Touch Application

What's New in WPF Version 4

WPF + Windows7 Multi-touch (Part 2)

在 WPF + Windows7 Multi-touch (Part 1) 這篇文章中, 我們可以透過 P/ Invoke 的方式來取得Windows 7 的手勢訊息, 並對物體作手勢操作.

不過當你用這個方法來取得觸控點的資訊時, 你會發現收不到WM_TOUCH 的訊息, 這個是因為WPF團隊還沒把這部分加進去(這篇 WPF Windows 7 Multi-touch.文章中, WPF團隊有回答此問題)

因此, 如果要在WPF程式中取得觸控點的資訊的話, 就必須採用下面步驟:

• 新增一個"MicrosoftTabletPenServiceProperty"屬性到視窗上
  

             IntPtr hWnd = new WindowInteropHelper(this).Handle;
           HwndSource src = HwndSource.FromHwnd(hWnd);
           Win7TouchMethod.SetProp(src.Handle,
                     "MicrosoftTabletPenServiceProperty",
                      new IntPtr(0x01000000));            

• 新增StylusDown/StylusUp/StylusMove的事件, 來處理觸控的相關事件.

        this.StylusDown += new StylusDownEventHandler(Window1_StylusDown);
        this.StylusMove += new StylusEventHandler(Window1_StylusMove);
        this.StylusUp += new StylusEventHandler(Window1_StylusUp);
        

下面的範例中, 我們會寫一個WPF的觸控應用程式, 當有觸控發生時, 畫面上會出現圓點(用來表示觸控點的位置)

source code如下:

<Window x:Class="WPFTouch.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="Window1" Height="600" Width="800">
  <Canvas>
      <Ellipse
          Canvas.Left="0"
          Canvas.Top="0"
          Name="Touch1"
          Stroke="Black"
          Height="30"
          Width="30"
          Fill="Blue"
          Visibility="Hidden"/>
   
      <Ellipse
          Canvas.Left="0"
          Canvas.Top="0"
          Name="Touch2"
          Stroke="Black"
          Height="30"
          Width="30"
          Fill="Green"
          Visibility="Hidden"/>
  </Canvas>

</Window>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Interop;
using Win7TouchInterop;

namespace WPFTouch
{
  public partial class Window1 : Window
  {
  
      private int Touch1ID = 0;    // id for first touch contact
      private int Touch2ID = 0;    // id for second touch contact

      public Window1()
      {
          InitializeComponent();

          Loaded += new RoutedEventHandler(Window1_Loaded);

          // Add StylusDown/StylusMove/StylusUp events to handle the touch related events
          this.StylusDown += new StylusDownEventHandler(Window1_StylusDown);
          this.StylusMove += new StylusEventHandler(Window1_StylusMove);
          this.StylusUp += new StylusEventHandler(Window1_StylusUp);
      }

      void Window1_Loaded(object sender, RoutedEventArgs e)
      {
          IntPtr hWnd = new WindowInteropHelper(this).Handle;
          HwndSource src = HwndSource.FromHwnd(hWnd);

          Win7TouchMethod.SetProp(src.Handle,
                                   "MicrosoftTabletPenServiceProperty",
                                   new IntPtr(0x01000000));
  
      }


      void Window1_StylusDown(object sender, StylusDownEventArgs e)
      {
          Point p = e.GetPosition(this);   // get the location for this contact


          if (Touch1ID == 0)
          {
              // Show the touch point
              Touch1.Visibility = Visibility.Visible;

              Touch1ID = e.StylusDevice.Id;
           
              // move the ellipse to the given location
              Touch1.SetValue(Canvas.LeftProperty, p.X - Touch1.Width / 2);
              Touch1.SetValue(Canvas.TopProperty, p.Y - Touch1.Height / 2);
          }
          else if (Touch2ID == 0)
          {
              Touch2.Visibility = Visibility.Visible;

              Touch2ID = e.StylusDevice.Id;
              // move the ellipse to the given location
              Touch2.SetValue(Canvas.LeftProperty, p.X - Touch2.Width / 2);
              Touch2.SetValue(Canvas.TopProperty, p.Y - Touch2.Height / 2);
          }
      }

      void Window1_StylusMove(object sender, StylusEventArgs e)
      {
          Point p = e.GetPosition(this);
          // determine which contact this belongs to
          if (Touch1ID == e.StylusDevice.Id)
          {
              Touch1.SetValue(Canvas.LeftProperty, p.X - Touch1.Width / 2);
              Touch1.SetValue(Canvas.TopProperty, p.Y - Touch1.Height / 2);
          }
          else if (Touch2ID == e.StylusDevice.Id)
          {
              Touch2.SetValue(Canvas.LeftProperty, p.X - Touch2.Width / 2);
              Touch2.SetValue(Canvas.TopProperty, p.Y - Touch2.Height / 2);
          }
      }

      void Window1_StylusUp(object sender, StylusEventArgs e)
      {
          if (e.StylusDevice.Id == Touch1ID)
          {
              Touch1.Visibility = Visibility.Hidden;

              Touch1ID = 0;
          }
          else if (e.StylusDevice.Id == Touch2ID)
          {
              Touch2.Visibility = Visibility.Hidden;

              Touch2ID = 0;
          }
      }
  }
}

執行畫面如下:


[圖 1] WPF Touch Application

參考文章:
Windows 7 Multi-touch using WPF

如何讓WPF控制項產生陰影效果

在WPF中可以利用BitmapEffect(點陣圖效果), 使控制項呈現一些影像特效;如: Blur(模糊效果), Shadow(陰影效果), Bevel(斜面), Emboss(凹凸)和色彩光暈等....

在這篇文章中, 我們先來介紹會使控制像看起來比較有立體感的陰影效果.

由於BitmapEffect 是 Visual 物件上的屬性, 因此, 我們可將BitmapEffect套用至任何視覺物件(例如 Button,Image, DrawingVisual 或 UIElement)上. 例如我們可以利用DropShadowBitmapEffect 物件建立 WPF 物件的各種下拉式陰影效果.

它提供下列屬性來讓你自訂陰影效果:

• Color - 設定陰影的顏色
• Opacity - 設定陰影的透明度, 設定範圍為0 至1, 預設值是1
• ShadowDepth - 控制陰影的寬,有效值的範圍為 0 至 300。預設值為 5
• Direction - 控制陰影的方向。請將這個屬性的方向值設定為介於 0 與 360 之間的度數. 0表示陰影會顯示在物件的正右方, 隨著Direction的增加, 陰影會逆時針方向移動
• Softness - 控制陰影的柔和度或模糊,值 0.0 表示沒有模糊，而值 1.0 則表示全部模糊

下面的範例中, 我們將圖1透過DropShadowBitmapEffect 的效果, 產生出如圖片2的陰影效果:

XAML檔如下所示:

<Image Source="tulips.jpg"
       HorizontalAlignment="Center"
       VerticalAlignment="Center"
       Margin="80, 50, 80, 50"
       Name="image1"
       Stretch="Fill" >
    <Image.BitmapEffect>
          <DropShadowBitmapEffect ShadowDepth="20"
                                  Direction="300"
                                  Color="Black"
                                  Opacity="0.5"
                                  Softness="0.25" />                                   
    </Image.BitmapEffect>
</Image>

[圖1]沒有陰影效果



[圖2]加上陰影效果



需要注意的地方:

WPF 點陣圖效果是在軟體模式中呈現. 而且是由UI執行緒執行, 而不是呈現的執行緒, 因此使用點陣圖效果會對效能有很大的影響(效能和元素的數量成正比), 所以最好在少量而且是靜態的內容才使用這些效果. 尤其在大型視覺物件上使用點陣圖效果, 或者以點陣圖效果的屬性建立動畫時, 效能會降低最多.

參考文章 :
MSDN - 點陣圖效果概觀
MSDN - 建立含陰影的文字