PPT轉圖片解決方案

使用Aspose組件轉換圖片 

       使用Aspose組件的好處是，不需要用戶的機器上安裝Office，也可以完成我們想要的功能。這個優勢實在是太明顯了，所以，我最終選折了這個方案。而且，Aspose完全支持word、ppt、和pdf，甚至excel也沒問題。

       首先我們要准備好Aspose的dll 引用到我們項目中，這里是下載鏈接：   https://pan.baidu.com/s/11gMa_G05KvQSSrq31Db2Kw

      下面的代碼就摘自示范Demo中。

      上傳文件js,Form表單提交代碼：

 

//保存上傳的課件
function Save() {
    if ($("#txtTitle").val() == "") {
        layer.msg('課件名稱不能為空', function () { });
        return;
    }
    if ($("#upfile").val() == "") {
        layer.msg('上傳文件不能為空', function () { });
        return;
    }
    if ($("#iid").val()==0)
    {
        layer.msg('關聯章節課程不能為空', function () { });
        return;
    }
    $('#form-horizontalid').ajaxSubmit({
        url: "/Resources_Add/Upload",
        type: "POST",
        dataType: "json",
        data: $('#form-horizontalid').serialize(),
        beforeSend: function (xhr, self) {
            var index = layer.load(0, { shade: false }); //0代表加載的風格，支持0-2
            if ($("#WaitingUp").html() != "") { $("#WaitingUp").html("(正在上傳)"); }
            if ($("#WaitingUp_img").html() != "") { $("#WaitingUp_img").html("(正在上傳)"); }
        },
        success: function (data) {
            layer.closeAll();
            if (data == "-1") {
                layer.msg('上傳文件格式錯誤', function () { });
                return;
            } if (data > 0) {
                if (data == "888") {
                    layer.msg('PPT文件異常，請檢查文件！', { icon: 2 });
                    return;
                }
                if (data == "999") {
                    layer.msg('課件名稱已存在', function () { });
                }
                else if (data == "0") {
                    layer.msg('操作失敗', { icon: 2 });
                }
                else {
                    layer.msg('操作成功！', { icon: 1 });
                    if ($("#WaitingUp").html() != "") { $("#WaitingUp").html("(上傳成功)"); }
                    if ($("#WaitingUp_img").html() != "") { $("#WaitingUp_img").html("(上傳成功)"); }
                    setTimeout("window.location.href = '/Admin/Resources'", 1000);

                }
                return;
            }
            else {
                layer.msg('操作失敗', { icon: 2 });
                return;
            }
        },
        error: function (data) {
            layer.closeAll();
            layer.msg('上傳文件異常！', { icon: 2 });
        }
    });
}

 

    #region 1.0上傳文件時調用轉換圖片的方法
        public string Upload()
        {
            double FileSize = 0;
            string imgName = string.Empty;
            string imgUrl = "/img/Map";
            //課程id
            string Curriculumid = Request["Curriculumid"];
            //章id
            string Chapterid = Request["Chapterid"];
            //課程節id
            string SectionId = Request["iid"];
            string url = string.Empty;
            string filePath = string.Empty;
            string CourseName = Request["txtTitle"];
            HttpPostedFileBase hpFile = Request.Files["upfile"];
           
            //1.0判斷文件是否為空
            if (hpFile != null)
            {
                //1.1獲取文件后綴名
                string FileType = System.IO.Path.GetExtension(hpFile.FileName);
                //1.2獲取路徑
                string FileName = Path.GetFileName(hpFile.FileName).Replace(FileType, "").Replace(".", "") + FileType;

                url = ResourceConversionURL(FileName);

                filePath = Server.MapPath(url);
                hpFile.SaveAs(filePath);
                //獲取文件大小
                System.IO.FileInfo fileinfo = new System.IO.FileInfo(Server.MapPath(url));
                FileSize = System.Math.Ceiling(fileinfo.Length/1024.0);
                //這里在執行轉換圖片的時候需要調用Aspose類
                LicenseHelper.ModifyInMemory.ActivateMemoryPatching();
                if (FileType == ".pptx" || FileType == ".ppt")
                {
                    PictureConversion pc = new PictureConversion();
                    imgName = pc.ConvertToImage_PPT(filePath, Server.MapPath(imgUrl), 0, 0, 145, FileType, imgUrl);
                    if (imgName=="888")
                    {
                        return "888";
                    }
                    if (imgName != "" || imgName != null)
                    {
                        int i = 0;
                        i = Add(Curriculumid, Chapterid, SectionId, CourseName, FileType, imgName);
                        if (i > 0)
                        {
                            return "1";
                        }
                        else if (i==-2)
                        {
                            return "999";
                        }
                        else
                        {
                            return "0";
                        }
                    }
                }
                else if (FileType == ".mp4")
                {
                    if (FileSize>0)
                    {
                        int i = 0;
                        i = Add(Curriculumid, Chapterid, SectionId, CourseName, FileType, url);
                        if (i > 0)
                        {
                            return "1";
                        }
                        else if (i == -2)
                        {
                            return "999";
                        }
                        else
                        {
                            return "0";
                        }
                    }
                }
                else
                {
                    return "-1";
                }
            }
            return "";


        }
        #endregion

ModifyInMemory類代碼：

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Text;
using System.Xml;


namespace LicenseHelper
{
    public static class ModifyInMemory
    {
        private static string AsposeList = "Aspose.3D.dll, Aspose.BarCode.dll, Aspose.BarCode.Compact.dll, Aspose.BarCode.WPF.dll, Aspose.Cells.GridDesktop.dll, Aspose.Cells.GridWeb.dll, Aspose.CAD.dll, Aspose.Cells.dll, Aspose.Diagram.dll, Aspose.Email.dll, Aspose.Imaging.dll, Aspose.Note.dll, Aspose.OCR.dll, Aspose.Pdf.dll, Aspose.Slides.dll, Aspose.Tasks.dll, Aspose.Words.dll";

        public static void ActivateMemoryPatching()
        {
            Assembly[] arr = AppDomain.CurrentDomain.GetAssemblies();
            foreach (Assembly assembly in arr)
            {
                if (AsposeList.IndexOf(assembly.FullName.Split(',')[0] + ".dll") != -1)
                    ActivateForAssembly(assembly);
            }
            AppDomain.CurrentDomain.AssemblyLoad += new AssemblyLoadEventHandler(ActivateOnLoad);
        }

        private static void ActivateOnLoad(object sender, AssemblyLoadEventArgs e)
        {
            if (AsposeList.IndexOf(e.LoadedAssembly.FullName.Split(',')[0] + ".dll") != -1)
                ActivateForAssembly(e.LoadedAssembly);
        }

        private static void ActivateForAssembly(Assembly assembly)
        {
            MethodInfo miLicensed1 = typeof(ModifyInMemory).GetMethod("InvokeMe1", BindingFlags.NonPublic | BindingFlags.Static);
            MethodInfo miLicensed2 = typeof(ModifyInMemory).GetMethod("InvokeMe2", BindingFlags.NonPublic | BindingFlags.Static);
            MethodInfo miEvaluation = null;

            Dictionary<string, MethodInfo> miDict = new Dictionary<string, MethodInfo>()
            {
                {"System.DateTime"      , miLicensed1},
                {"System.Xml.XmlElement", miLicensed2}
            };

            Type[] arrType = null;
            bool isFound = false;
            int nCount = 0;

            try
            {
                arrType = assembly.GetTypes();
            }
            catch (ReflectionTypeLoadException err)
            {
                arrType = err.Types;
            }


            foreach (Type type in arrType)
            {
                if (isFound) break;

                if (type == null) continue;

                MethodInfo[] arrMInfo = type.GetMethods(BindingFlags.NonPublic | BindingFlags.Static);

                foreach (MethodInfo info in arrMInfo)
                {
                    if (isFound) break;

                    try
                    {
                        string strMethod = info.ToString();
                        if ((strMethod.IndexOf("(System.Xml.XmlElement, System.String)") > 0) && (miDict.ContainsKey(info.ReturnType.ToString())))
                        {
                            miEvaluation = info;
                            MemoryPatching(miEvaluation, miDict[miEvaluation.ReturnType.ToString()]);
                            nCount++;

                            if (((assembly.FullName.IndexOf("Aspose.Pdf") == -1) && (nCount == 2)) ||
                                ((assembly.FullName.IndexOf("Aspose.Pdf") != -1) && (nCount == 6)))
                            {
                                isFound = true;
                                break;
                            }
                        }
                    }
                    catch
                    {
                        throw new InvalidOperationException("MemoryPatching for \"" + assembly.FullName + "\" failed !");
                    }
                }
            }

            String[] aParts = assembly.FullName.Split(',');
            string fName = aParts[0];
            if (fName.IndexOf("Aspose.BarCode.") != -1)
                fName = "Aspose.BarCode";
            else if (fName.IndexOf("Aspose.3D") != -1)
                fName = "Aspose.ThreeD";

            try
            {
                Type type2 = assembly.GetType(fName + ".License");
                MethodInfo mi = type2.GetMethod("SetLicense", new Type[] { typeof(Stream) });
                string LData = "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";
                Stream stream = new MemoryStream(Convert.FromBase64String(LData));
                stream.Seek(0, SeekOrigin.Begin);
                mi.Invoke(Activator.CreateInstance(type2, null), new Stream[] { stream });
            }
            catch
            {
                //throw new InvalidOperationException("SetLicense for \"" + assembly.FullName + "\" failed !");
            }

        }


        private static DateTime InvokeMe1(XmlElement element, string name)
        {
            return DateTime.MaxValue;
        }


        private static XmlElement InvokeMe2(XmlElement element, string name)
        {
            if (element.LocalName == "License")
            {
                string License64 = "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";
                element.InnerXml = new UTF8Encoding().GetString(Convert.FromBase64String(License64));
            }

            if (element.LocalName == "BlackList")
            {
                string BlackList64 = "PERhdGE+PC9EYXRhPjxTaWduYXR1cmU+cUJwMEx1cEVoM1ZnOWJjeS8vbUVXUk9KRWZmczRlY25iTHQxYlNhanU2NjY5RHlad09FakJ1eEdBdVBxS1hyd0x5bmZ5VWplYUNGQ0QxSkh2RVUxVUl5eXJOTnBSMXc2NXJIOUFyUCtFbE1lVCtIQkZ4NFMzckFVMnd6dkxPZnhGeU9DQ0dGQ2UraTdiSHlGQk44WHp6R1UwdGRPMGR1RTFoRTQ5M1RNY3pRPTwvU2lnbmF0dXJlPg==";
                element.InnerXml = new UTF8Encoding().GetString(Convert.FromBase64String(BlackList64));
            }

            XmlNodeList elementsByTagName = element.GetElementsByTagName(name);
            if (elementsByTagName.Count <= 0)
            {
                return null;
            }

            return (XmlElement)elementsByTagName[0];
        }


        private static unsafe void MemoryPatching(MethodBase miEvaluation, MethodBase miLicensed)
        {
            IntPtr IntPtrEval = GetMemoryAddress(miEvaluation);
            IntPtr IntPtrLicensed = GetMemoryAddress(miLicensed);

            if (IntPtr.Size == 8)
                *((long*)IntPtrEval.ToPointer()) = *((long*)IntPtrLicensed.ToPointer());
            else
                *((int*)IntPtrEval.ToPointer()) = *((int*)IntPtrLicensed.ToPointer());

        }


        private static unsafe IntPtr GetMemoryAddress(MethodBase mb)
        {
            RuntimeHelpers.PrepareMethod(mb.MethodHandle);

            if ((Environment.Version.Major >= 4) || ((Environment.Version.Major == 2) && (Environment.Version.MinorRevision >= 3053)))
            {
                return new IntPtr(((int*)mb.MethodHandle.Value.ToPointer() + 2));
            }

            UInt64* location = (UInt64*)(mb.MethodHandle.Value.ToPointer());
            int index = (int)(((*location) >> 32) & 0xFF);
            if (IntPtr.Size == 8)
            {
                ulong* classStart = (ulong*)mb.DeclaringType.TypeHandle.Value.ToPointer();
                ulong* address = classStart + index + 10;
                return new IntPtr(address);
            }
            else
            {
                uint* classStart = (uint*)mb.DeclaringType.TypeHandle.Value.ToPointer();
                uint* address = classStart + index + 10;
                return new IntPtr(address);
            }
        }
    }
}
//End

PictureConversion代碼：

using Aspose.Cells;
using BSI_InsuranceProject_DBUtility.Error;
using ESBasic;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BSI_InsuranceProject_DBUtility
{

    /***************************************************************
        FileName:文件轉圖片工具類（支持格式：pdf、ppt、word）
        Author:邵
        Create Date:2018-5月15號
        ******************************************************************/
    public class PictureConversion
    {
        /// <summary>
        /// 將Word文檔轉換為圖片的方法      
        /// </summary>
        /// <param name="wordInputPath">Word文件路徑</param>
        /// <param name="imageOutputDirPath">圖片輸出路徑，如果為空，默認值為Word所在路徑</param>      
        /// <param name="startPageNum">從PDF文檔的第幾頁開始轉換，如果為0，默認值為1</param>
        /// <param name="endPageNum">從PDF文檔的第幾頁開始停止轉換，如果為0，默認值為Word總頁數</param>
        /// <param name="imageFormat">設置所需圖片格式，如果為null，默認格式為PNG</param>
        /// <param name="resolution">設置圖片的像素，數字越大越清晰，如果為0，默認值為128，建議最大值不要超過1024</param>
        public string ConvertToImage_Words(string wordInputPath, string imageOutputDirPath, int startPageNum, int endPageNum, ImageFormat imageFormat, int resolution, string imgUrl)
        {
            try
            {
                Aspose.Words.Document doc = new Aspose.Words.Document(wordInputPath);

                if (doc == null)
                {
                    throw new Exception("Word文件無效或者Word文件被加密！");
                }

                if (imageOutputDirPath.Trim().Length == 0)
                {
                    imageOutputDirPath = Path.GetDirectoryName(wordInputPath);
                }

                if (!Directory.Exists(imageOutputDirPath))
                {
                    Directory.CreateDirectory(imageOutputDirPath);
                }

                if (startPageNum <= 0)
                {
                    startPageNum = 1;
                }

                if (endPageNum > doc.PageCount || endPageNum <= 0)
                {
                    endPageNum = doc.PageCount;
                }

                if (startPageNum > endPageNum)
                {
                    int tempPageNum = startPageNum; startPageNum = endPageNum; endPageNum = startPageNum;
                }

                if (imageFormat == null)
                {
                    imageFormat = ImageFormat.Png;
                }

                if (resolution <= 0)
                {
                    resolution = 128;
                }

                string imageName = Path.GetFileNameWithoutExtension(wordInputPath);
                Aspose.Words.Saving.ImageSaveOptions imageSaveOptions = new Aspose.Words.Saving.ImageSaveOptions(Aspose.Words.SaveFormat.Png);
                imageSaveOptions.Resolution = resolution;
                string imgName = string.Empty;
                for (int i = startPageNum; i <= endPageNum; i++)
                {
                    MemoryStream stream = new MemoryStream();
                    imageSaveOptions.PageIndex = i - 1;
                    string imgPath = Path.Combine(imageOutputDirPath, imageName) + "_" + i.ToString("000") + "." + imageFormat.ToString();
                    imgName += imgUrl + "/" + imageName + "_" + i.ToString("000") + "." + imageFormat.ToString() + "|";
                    doc.Save(stream, imageSaveOptions);
                    System.Drawing.Image img = System.Drawing.Image.FromStream(stream);
                    System.Drawing.Bitmap bm = ESBasic.Helpers.ImageHelper.Zoom(img, 0.6f);
                    bm.Save(imgPath, imageFormat);
                    img.Dispose();
                    stream.Dispose();
                    bm.Dispose();
                    System.Threading.Thread.Sleep(200);
                }
                if (!string.IsNullOrEmpty(imgName))
                {
                    imgName = imgName.Substring(0, imgName.Length - 1);
                }
                return imgName;
            }

            catch (Exception ex)
            {
                ErrorHandler.WriteError(ex);
                throw;
            }
        }


        /// <summary>
        /// 將PPT、Excel、Txt文檔轉換為圖片的方法      
        /// </summary>
        /// <param name="originFilePath">ppt文件路徑</param>
        /// <param name="imageOutputDirPath">圖片輸出路徑，如果為空，默認值為pdf所在路徑</param>       
        /// <param name="startPageNum">從PDF文檔的第幾頁開始轉換，如果為0，默認值為1</param>
        /// <param name="endPageNum">從PDF文檔的第幾頁開始停止轉換，如果為0，默認值為pdf總頁數</param>       
        /// <param name="resolution">設置圖片的像素，數字越大越清晰，如果為0，默認值為128，建議最大值不要超過1024</param>
        public string ConvertToImage_PPT(string originFilePath, string imageOutputDirPath, int startPageNum, int endPageNum, int resolution, string Format, string imgUrl)
        {
            try
            {
                //先將文件轉換為pdf臨時文件
                string tmpPdfPath = originFilePath.Replace(Format, "pdf");
                if (Format == ".xls" || Format == ".xlsx" || Format == ".txt")
                {
                    Workbook wb = new Workbook(originFilePath);
                    wb.Save(tmpPdfPath, SaveFormat.Pdf);
                }
                else
                {
                    Aspose.Slides.Presentation doc = new Aspose.Slides.Presentation(originFilePath);
                    if (doc == null)
                    {
                        throw new Exception("ppt文件無效或者ppt文件被加密！");
                    }

                    if (imageOutputDirPath.Trim().Length == 0)
                    {
                        imageOutputDirPath = Path.GetDirectoryName(originFilePath);
                    }

                    if (!Directory.Exists(imageOutputDirPath))
                    {
                        Directory.CreateDirectory(imageOutputDirPath);
                    }

                    if (startPageNum <= 0)
                    {
                        startPageNum = 1;
                    }

                    if (endPageNum > doc.Slides.Count || endPageNum <= 0)
                    {
                        endPageNum = doc.Slides.Count;
                    }

                    if (startPageNum > endPageNum)
                    {
                        int tempPageNum = startPageNum; startPageNum = endPageNum; endPageNum = startPageNum;
                    }

                    if (resolution <= 0)
                    {
                        resolution = 128;
                    }
                    if (doc != null)
                    {
                        doc.Save(tmpPdfPath, Aspose.Slides.Export.SaveFormat.Pdf);
                    }
                }

                //再將pdf轉換為圖片
                string imgName = ConvertToImage_PDF(tmpPdfPath, imageOutputDirPath, startPageNum, endPageNum, resolution, imgUrl);
                //刪除pdf臨時文件
                File.Delete(tmpPdfPath);
                return imgName;
            }
            catch (Exception ex)
            {
                ErrorHandler.WriteError(ex);
                return "888";
                throw;
            }
        }


        /// <summary>
        /// 將pdf文檔轉換為圖片的方法      
        /// </summary>
        /// <param name="originFilePath">pdf文件路徑</param>
        /// <param name="imageOutputDirPath">圖片輸出路徑，如果為空，默認值為pdf所在路徑</param>       
        /// <param name="startPageNum">從PDF文檔的第幾頁開始轉換，如果為0，默認值為1</param>
        /// <param name="endPageNum">從PDF文檔的第幾頁開始停止轉換，如果為0，默認值為pdf總頁數</param>       
        /// <param name="resolution">設置圖片的像素，數字越大越清晰，如果為0，默認值為128，建議最大值不要超過1024</param>
        public string ConvertToImage_PDF(string originFilePath, string imageOutputDirPath, int startPageNum, int endPageNum, int resolution, string imgUrl)
        {
            try
            {
                Aspose.Pdf.Document doc = new Aspose.Pdf.Document(originFilePath);

                if (doc == null)
                {
                    throw new Exception("pdf文件無效或者pdf文件被加密！");
                }

                if (imageOutputDirPath.Trim().Length == 0)
                {
                    imageOutputDirPath = Path.GetDirectoryName(originFilePath);
                }

                if (!Directory.Exists(imageOutputDirPath))
                {
                    Directory.CreateDirectory(imageOutputDirPath);
                }

                if (startPageNum <= 0)
                {
                    startPageNum = 1;
                }

                if (endPageNum > doc.Pages.Count || endPageNum <= 0)
                {
                    endPageNum = doc.Pages.Count;
                }

                if (startPageNum > endPageNum)
                {
                    int tempPageNum = startPageNum; startPageNum = endPageNum; endPageNum = startPageNum;
                }

                if (resolution <= 0)
                {
                    resolution = 128;
                }

                string imageNamePrefix = Path.GetFileNameWithoutExtension(originFilePath);
                string imgName = string.Empty;
                for (int i = startPageNum; i <= endPageNum; i++)
                {
                    MemoryStream stream = new MemoryStream();
                    string imgPath = Path.Combine(imageOutputDirPath, imageNamePrefix) + "_" + i.ToString("000") + ".jpg";
                    imgName += imgUrl + "/" + imageNamePrefix + "_" + i.ToString("000") + ".jpg|";
                    Aspose.Pdf.Devices.Resolution reso = new Aspose.Pdf.Devices.Resolution(resolution);
                    Aspose.Pdf.Devices.JpegDevice jpegDevice = new Aspose.Pdf.Devices.JpegDevice(reso, 100);
                    jpegDevice.Process(doc.Pages[i], stream);

                    Image img = Image.FromStream(stream);
                    Bitmap bm = ESBasic.Helpers.ImageHelper.Zoom(img, 0.6f);
                    bm.Save(imgPath, ImageFormat.Jpeg);
                    img.Dispose();
                    stream.Dispose();
                    bm.Dispose();
                    System.Threading.Thread.Sleep(200);
                }
                if (!string.IsNullOrEmpty(imgName))
                {
                    imgName = imgName.Substring(0, imgName.Length - 1);
                }

                return imgName;
            }
            catch (Exception ex)
            {
                ErrorHandler.WriteError(ex);
                throw;
            }
        }
    }
}

到這里就可以完美轉換圖片了.....