比来项目中应用多次应用了图片合成，为了此后便利特此记下。
在WPF下有两种图片合成的方法，一种还是用本来C#供给的GDI+方法，定名空间是System.Drawing 和 System.Drawing.Imaging，另一种是WPF中新添加的API，定名空间是 System.Windows.Media 和 System.Windows.Media.Imaging 。
我们来做一个简单的例子，分袂用上面的两种方法实现，成果是在一个配景图上面，画一个头像，然后在写一个签名。
首先筹备一张配景图(bg.jpg）和两个头像图片（tiger.png 和 lion.png）最后的生成的图片效果如下图：
把筹备的素材拷贝到项目中，其文件属性【复制到输出目录】选择【始终复制】，【生成操纵】选择【内容】。
这里贴一下两种方法的主要代码，具体代码可以在文章最后点击下载。
要领一
private BitmapSource MakePicture(string bgImagePath, string headerImagePath, string signature) { //获取配景图 BitmapSource bgImage = new BitmapImage(new Uri(bgImagePath, UriKind.Relative)); //获取头像 BitmapSource headerImage = new BitmapImage(new Uri(headerImagePath, UriKind.Relative)); //创建一个RenderTargetBitmap 东西，，将WPF中的Visual东西输出 RenderTargetBitmap composeImage = new RenderTargetBitmap(bgImage.PixelWidth, bgImage.PixelHeight, bgImage.DpiX, bgImage.DpiY, PixelFormats.Default); FormattedText signatureTxt = new FormattedText(signature, System.Globalization.CultureInfo.CurrentCulture, System.Windows.FlowDirection.LeftToRight, new Typeface(System.Windows.SystemFonts.MessageFontFamily, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal), 50, System.Windows.Media.Brushes.White); DrawingVisual drawingVisual = new DrawingVisual(); DrawingContext drawingContext = drawingVisual.RenderOpen(); drawingContext.DrawImage(bgImage, new Rect(0, 0, bgImage.Width, bgImage.Height)); //计算头像的位置 double x = (bgImage.Width / 2 - headerImage.Width) / 2; double y = (bgImage.Height - headerImage.Height) / 2 - 100; drawingContext.DrawImage(headerImage, new Rect(x, y, headerImage.Width, headerImage.Height)); //计算签名的位置 double x2 = (bgImage.Width/2 - signatureTxt.Width) / 2; double y2 = y + headerImage.Height + 20; drawingContext.DrawText(signatureTxt, new System.Windows.Point(x2, y2)); drawingContext.Close(); composeImage.Render(drawingVisual); //界说一个JPG编码器 JpegBitmapEncoder bitmapEncoder = new JpegBitmapEncoder(); //插手第一帧 bitmapEncoder.Frames.Add(BitmapFrame.Create(composeImage)); //生存至文件（不会改削源文件，将改削后的图片生存至措施目录下） string savePath = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"\合成.jpg"; bitmapEncoder.Save(File.OpenWrite(Path.GetFileName(savePath))); return composeImage; }
要领二
private BitmapSource MakePictureGDI(string bgImagePath, string headerImagePath, string signature) { GDI.Image bgImage = GDI.Bitmap.FromFile(bgImagePath); GDI.Image headerImage = GDI.Bitmap.FromFile(headerImagePath); //新建一个画板，画板的巨细和底图一致 System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(bgImage.Width, bgImage.Height); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap); //设置高质量插值法 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量,低速度泛起平滑水平 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; //清空画布并以透明配景色填充 g.Clear(System.Drawing.Color.Transparent); //先在画板上面画底图 g.DrawImage(bgImage, new GDI.Rectangle(0, 0, bitmap.Width, bitmap.Height)); //再在画板上画头像 int x = (bgImage.Width / 2 - headerImage.Width) / 2; int y = (bgImage.Height - headerImage.Height) / 2 - 100; g.DrawImage(headerImage, new GDI.Rectangle(x, y, headerImage.Width, headerImage.Height), new GDI.Rectangle(0, 0, headerImage.Width, headerImage.Height), GDI.GraphicsUnit.Pixel); //在画板上写文字 using (GDI.Font f = new GDI.Font("Arial", 20, GDI.FontStyle.Bold)) { using (GDI.Brush b = new GDI.SolidBrush(GDI.Color.White)) { float fontWidth = g.MeasureString(signature, f).Width; float x2 = (bgImage.Width / 2 - fontWidth) / 2; float y2 = y + headerImage.Height + 20; g.DrawString(signature, f, b, x2, y2); } } try { string savePath = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"\GDI+合成.jpg"; bitmap.Save(savePath, System.Drawing.Imaging.ImageFormat.Jpeg); return ToBitmapSource(bitmap); } catch (System.Exception e) { throw e; } finally { bgImage.Dispose(); headerImage.Dispose(); g.Dispose(); } } #region GDI+ Image 转化成 BitmapSource [System.Runtime.InteropServices.DllImport("gdi32")] static extern int DeleteObject(IntPtr o); public BitmapSource ToBitmapSource(GDI.Bitmap bitmap) { IntPtr ip = bitmap.GetHbitmap(); BitmapSource bitmapSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap( ip, IntPtr.Zero, System.Windows.Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions()); DeleteObject(ip);//释放东西 return bitmapSource; } #endregion