应用WPF图像API正确方法讲解

复制using System;  

using System.Collections

.Generic;   using System.Text;   using System.Windows.Controls;   using System.Windows.Media;   using System.Windows;   using System.Globalization;   namespace BrawDraw.Com.Test   {  

class CanvasCustomPaint :

 Canvas   {  

protected override void 

OnRender(DrawingContext dc)   {   base.OnRender(dc);   //画矩形  

dc.DrawRectangle(Brushes

.Red, new Pen(Brushes.Blue, 1),   

new Rect(new Point(20, 20), 

new Size(100, 100)));   //画文字  

dc.DrawText(new FormattedText

("Hello, World!", CultureInfo.

CurrentCulture,   

FlowDirection.LeftToRight, new 

Typeface("Arial"), 40, Brushes.

Orange),   new Point(50,60));   }   }   }  1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.

复制

protected void SavePhoto

(string fileName)   {   DrawingVisual drawingVisual

 = 

new DrawingVisual();   DrawingContext drawingContext

 = 

drawingVisual.RenderOpen();   // 画矩形   Rect rect = new

 Rect(new 

Point(160, 100), new Size(320, 80));  

drawingContext.DrawRectangle

(Brushes.LightBlue, (Pen)null, rect);   // 画文字   drawingContext.DrawText(   new FormattedText("Hello, world",   CultureInfo.GetCultureInfo("en-us"),   FlowDirection.LeftToRight,   new Typeface("Verdana"),   36, Brushes.Black),   new Point(100, 60));   drawingContext.Close();   // 利用RenderTargetBitmap对象，以保存图片   RenderTargetBitmap renderBitmap

 = 

new

 RenderTargetBitmap((int)this.Width,

 (int)this.Height, 96, 96, 

PixelFormats.Pbgra32);   renderBitmap.Render(drawingVisual);  

// 利用JpegBitmapEncoder，

对图像进行编码，以便进行保存   JpegBitmapEncoder encoder

 = 

new JpegBitmapEncoder();  

encoder.Frames.Add(BitmapFrame.

Create(renderBitmap));   // 保存文件   FileStream fileStream

 = 

new

 FileStream(fileName, 

FileMode.Create, FileAccess.ReadWrite);   encoder.Save(fileStream);   // 关闭文件流   fileStream.Close();   }   1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.