WPF实现图片合成或加水印的方法【2种方法】

private BitmapSource MakePicture(string bgImagePath, string headerImagePath, string signature){  //获取背景图  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 对象，将WPF中的Visual对象输出  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);  //定义一个JPG编码器  JpegBitmapEncoder bitmapEncoder = new JpegBitmapEncoder();  //加入第一帧  bitmapEncoder.Frames.Add(BitmapFrame.Create(composeImage));  //保存至文件（不会修改源文件，将修改后的图片保存至程序目录下）  string savePath = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"/合成.jpg";  bitmapEncoder.Save(File.OpenWrite(Path.GetFileName(savePath)));  return composeImage;}

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，画板的大小和底图一致  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,低速度呈现平滑程度  g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;  //清空画布并以透明背景色填充  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);//释放对象  return bitmapSource;}#endregion