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),

                                                   ,

                                                   System.Windows.Media.Brushes.White);

            DrawingVisual drawingVisual = new DrawingVisual();

            DrawingContext drawingContext = drawingVisual.RenderOpen();

            drawingContext.DrawImage(bgImage, new Rect(, , bgImage.Width, bgImage.Height));

            //计算头像的位置

            double x = (bgImage.Width /  - headerImage.Width) / ;

            double y = (bgImage.Height - headerImage.Height) /  - ;

            drawingContext.DrawImage(headerImage, new Rect(x, y, headerImage.Width, headerImage.Height));

            //计算签名的位置

            double x2 = (bgImage.Width/ - signatureTxt.Width) / ;

            double y2 = y + headerImage.Height + ;

            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(, , bitmap.Width, bitmap.Height));

            //再在画板上画头像

            int x = (bgImage.Width /  - headerImage.Width) / ;

            int y = (bgImage.Height - headerImage.Height) /  - ;

            g.DrawImage(headerImage, new GDI.Rectangle(x, y, headerImage.Width, headerImage.Height),

                                     new GDI.Rectangle(, , headerImage.Width, headerImage.Height),

                                     GDI.GraphicsUnit.Pixel);

            //在画板上写文字

            using (GDI.Font f = new GDI.Font("Arial", , GDI.FontStyle.Bold))

            {

                using (GDI.Brush b = new GDI.SolidBrush(GDI.Color.White))

                {

                    float fontWidth = g.MeasureString(signature, f).Width;

                    float x2 = (bgImage.Width /  - fontWidth) / ;

                    float y2 = y + headerImage.Height + ;

                    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