稳扎稳打Silverlight(38) - 3.0滤镜之BlurEffect, DropShadowEffect, 自定义滤镜

/* 
 * WriteableBitmap - 位图 API（Bitmap API） 
 * WriteableBitmap.Pixels - 一个整型数组，用于描述某像素的颜色（ARGB） 
 * WriteableBitmap.Render() - 将指定的 UIElement 以位图的方式呈现出来 
 * WriteableBitmap.Invalidate() - 绘图 
 * WriteableBitmap.PixelWidth - 宽度。单位：像素 
 * WriteableBitmap.PixelHeight - 高度。单位：像素 
 */ 
 
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.Navigation; 
 
using System.Windows.Media.Imaging; 
 
namespace Silverlight30.Graphic 
{ 
         public partial  class WriteableBitmapDemo : Page 
        { 
                 public WriteableBitmapDemo() 
                { 
                        InitializeComponent(); 
 
                         this.Loaded +=  new RoutedEventHandler(WriteableBitmapDemo_Loaded); 
                         this.Loaded +=  new RoutedEventHandler(WriteableBitmapDemo_Loaded2); 
                } 
 
                 /// <summary> 
                 /// 以自定义像素点颜色的方式生成位图 
                 /// </summary> 
                 void WriteableBitmapDemo_Loaded( object sender, RoutedEventArgs e) 
                { 
                         // 初始化一个宽 40 高 20 的 WriteableBitmap 对象 
                        WriteableBitmap bitmap =  new WriteableBitmap(40, 30); 
                         
                         for ( int i = 0; i < 40 * 30; i++) 
                        { 
                                 unchecked 
                                { 
                                         // 每个像素的颜色的描述规范为 ARGB 
                                        bitmap.Pixels[i] = ( int)0xFFFF0000; 
                                } 
                        } 
 
                        bitmap.Invalidate(); 
 
                        img.Source = bitmap; 
                } 
 
                 /// <summary> 
                 /// 将指定的 UIElement 以位图的方式做呈现 
                 /// </summary> 
                 void WriteableBitmapDemo_Loaded2( object sender, RoutedEventArgs e) 
                { 
                        WriteableBitmap bitmap =  new WriteableBitmap(320, 240); 
 
                        var txt =  new TextBlock(); 
                        txt.Text =  "webabcd"; 
 
                         // 将指定的 TextBlock 以位图的方式呈现出来 
                        bitmap.Render(txt,  new ScaleTransform() { ScaleX = 320 / txt.ActualWidth, ScaleY = 240 / txt.ActualHeight }); 
                        bitmap.Invalidate(); 
 
                        img2.Source = bitmap; 
                } 
 
                 /// <summary> 
                 /// 获取指定图片的某像素点的颜色 
                 /// </summary> 
                 private  void img3_MouseMove( object sender, MouseEventArgs e) 
                { 
                        WriteableBitmap bitmap =  new WriteableBitmap(img3,  null); 
 
                         int color = bitmap.Pixels[( int)e.GetPosition(img3).Y * ( int)img3.ActualWidth + ( int)e.GetPosition(img3).X]; 
 
                         // 将整型转换为字节数组 
                         byte[] bytes = BitConverter.GetBytes(color); 
 
                         // 将字节数组转换为颜色（bytes[3] - A, bytes[2] - R, bytes[1] - G, bytes[0] - B） 
                        lbl.Text = Color.FromArgb(bytes[3], bytes[2], bytes[1], bytes[0]).ToString(); 
                } 
 
                 /// <summary> 
                 /// 用 WriteableBitmap 实现对视频文件的截屏功能 
                 /// </summary> 
                 private  void Button_Click( object sender, RoutedEventArgs e) 
                { 
                         // 将指定的 UIElement 转换为 WriteableBitmap 对象 
                        WriteableBitmap bitmap =  new WriteableBitmap(mediaElement,  null); 
 
                        img4.Source = bitmap; 
                } 
 
                 private  void mediaElement_MediaEnded( object sender, RoutedEventArgs e) 
                { 
                        mediaElement.Stop(); 
                        mediaElement.Play(); 
                } 
        } 
}