c# pdf 转 图片

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media.Imaging;
using Acrobat;
using Microsoft.VisualBasic;
using Point = System.Drawing.Point;

namespace WpfApp1
{
    /// <summary>
    ///     MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public delegate void CompleteDelegate(string completeMsg);

        /// <summary>
        ///     转换异常委托
        /// </summary>
        /// <param name="errMessage"></param>
        public delegate void ConvertExceptionDelegate(Exception errMessage);

        /// <summary>
        ///     进度提示委托
        /// </summary>
        /// <param name="progressValue"></param>
        /// <param name="progressMessage"></param>
        public delegate void ProcessChangedDelegate(int progressValue, string progressMessage);

        public MainWindow()
        {
            InitializeComponent();

            const string filename = @"E:\文档\人月神话.pdf";
            var tr = new Thread(() =>
            {
                //间接法，清晰度低，但是能有进度
                //  Pdf2Png(filename, (a, b) => { Dispatcher.Invoke(() => { Title = b; }); }, a => { Dispatcher.Invoke(() => { MessageBox.Show(a.Message); }); }, (a) => { Dispatcher.Invoke(() => { MessageBox.Show(a); }); });

                //直接法，但是没有进度
                cvt(filename, "", (a, b) => { Dispatcher.Invoke(() => { Title = b; }); },
                    a => { Dispatcher.Invoke(() => { MessageBox.Show(a.Message); }); },
                    a => { Dispatcher.Invoke(() => { MessageBox.Show(a); }); });
            });
            tr.IsBackground = true;
            tr.SetApartmentState(ApartmentState.STA);
            tr.Start();
        }

        private static void cvt(string szPdfPathConst, string imageOutputPath, ProcessChangedDelegate processChange,
            ConvertExceptionDelegate convertException, CompleteDelegate completeAction)
        {
            CAcroApp mApp = new AcroApp();
            mApp.Hide();

            var g_AVDoc = new AcroAVDoc();
            //open the PDF
            if (g_AVDoc.Open(szPdfPathConst, ""))
            {
                var currentIndex = 0;
                var formDataExists = true;


                object newDoc = null;

                var dt = DateTime.Now;
                if (g_AVDoc.IsValid())
                {
                    var pdDoc = (CAcroPDDoc) g_AVDoc.GetPDDoc();
                    var iNum = pdDoc.GetNumPages();
                    object jsObj = pdDoc.GetJSObject();
                    if (formDataExists)
                    {
                        var T = jsObj.GetType();

                        object[] extractPagesParam = {currentIndex, iNum - 1};
                        newDoc = T.InvokeMember(
                            "extractPages",
                            BindingFlags.InvokeMethod |
                            BindingFlags.Public |
                            BindingFlags.Instance,
                            null, jsObj, extractPagesParam);

                        var newFileName = AppDomain.CurrentDomain.BaseDirectory + "data\\" + currentIndex + ".png";
                        Directory.CreateDirectory(AppDomain.CurrentDomain.BaseDirectory + "data");


                        object[] saveAsParam = {newFileName, "com.adobe.acrobat.png"};
                        T.InvokeMember(
                            "saveAs",
                            BindingFlags.InvokeMethod |
                            BindingFlags.Public |
                            BindingFlags.Instance,
                            null, newDoc, saveAsParam);
                        formDataExists = currentIndex != iNum - 1;


                        object[] closeDocParam = {true};
                        T.InvokeMember(
                            "closeDoc",
                            BindingFlags.InvokeMethod |
                            BindingFlags.Public |
                            BindingFlags.Instance,
                            null, newDoc, closeDocParam);

                        currentIndex++;
                    }
                }

                completeAction?.Invoke((DateTime.Now - dt).TotalSeconds.ToString());
            }

            mApp.CloseAllDocs();
            mApp.Exit();
        }

        private static void Pdf2Png(string pdfInputPath, ProcessChangedDelegate processChange,
            ConvertExceptionDelegate convertException, CompleteDelegate completeAction)
        {
            Thread tr = null;
            tr = new Thread(() =>
            {
                try
                {
                    CAcroPDDoc pdfDoc = null;
                    CAcroPDPage pdfPage = null;
                    CAcroRect pdfRect = null;
                    CAcroPoint pdfPoint = null;
                    if (processChange != null) processChange(0, "加载pdf文件中...");
                    pdfDoc = (CAcroPDDoc) Interaction.CreateObject("AcroExch.PDDoc", "");
                    if (!pdfDoc.Open(pdfInputPath))
                    {
                        if (convertException != null)
                            convertException(new Exception("未找到文件或文件不是pdf格式：" + pdfInputPath));
                        if (processChange != null) processChange(0, "未找到文件或文件不是pdf格式：" + pdfInputPath);
                        return;
                    }

                    for (var i = 1; i <= pdfDoc.GetNumPages(); i++)
                    {
                        pdfPage = (CAcroPDPage) pdfDoc.AcquirePage(i - 1);
                        pdfPoint = (CAcroPoint) pdfPage.GetSize();
                        pdfRect = (CAcroRect) Interaction.CreateObject("AcroExch.Rect", "");

                        var imgWidth = pdfPoint.x;
                        var imgHeight = (int) pdfPoint.y;

                        pdfRect.Left = 0;
                        pdfRect.right = imgWidth;
                        pdfRect.Top = 0;
                        pdfRect.bottom = (short) imgHeight;

                        if (processChange != null)
                            processChange(i * 100 / pdfDoc.GetNumPages(),
                                "转换进度" + i * 100 / pdfDoc.GetNumPages() + "%");
                        pdfPage.CopyToClipboard(pdfRect, 0, 0, 100);

                        var clipboardData = Clipboard.GetDataObject();

                        if (clipboardData.GetDataPresent(DataFormats.Bitmap))
                        {
                            var pdfBitmap = GetBitmap((InteropBitmap) clipboardData.GetData(DataFormats.Bitmap));
                            var newFileName = AppDomain.CurrentDomain.BaseDirectory + "data\\" + i + ".png";
                            if (!File.Exists(newFileName) && pdfBitmap != null)
                            {
                                pdfBitmap.Save(newFileName, ImageFormat.Png);
                                pdfBitmap.Dispose();
                            }
                        }
                    }

                    if (processChange != null) processChange(100, "转换完成");
                    Marshal.ReleaseComObject(pdfPage);
                    Marshal.ReleaseComObject(pdfRect);
                    Marshal.ReleaseComObject(pdfDoc);
                    Marshal.ReleaseComObject(pdfPoint);
                    if (completeAction != null) completeAction("完成：" + pdfInputPath + DateTime.Now);
                }
                catch (Exception ex)
                {
                    if (convertException != null) convertException(ex);
                    if (processChange != null) processChange(0, "转换发生异常。源文件" + pdfInputPath + "(" + ex.Message + ")");
                }
            });
            tr.SetApartmentState(ApartmentState.STA);
            tr.Start();
        }

        private static Bitmap GetBitmap(BitmapSource source)
        {
            var bmp = new Bitmap(
                source.PixelWidth,
                source.PixelHeight,
                PixelFormat.Format32bppRgb);
            var data = bmp.LockBits(
                new Rectangle(Point.Empty, bmp.Size),
                ImageLockMode.WriteOnly,
                PixelFormat.Format32bppRgb);
            source.CopyPixels(
                Int32Rect.Empty,
                data.Scan0,
                data.Height * data.Stride,
                data.Stride);
            bmp.UnlockBits(data);
            return bmp;
        }
    }
}