将pdf文件转换成图片文件

Posted 2021-01-02 skywalker037

将pdf文件转换成图片文件

       概要

             现在手头的项目有一个需求是要从微信卡包里面拉取发票下来，把它的PDF文档保存下来，并且转换成图片保存在本地，我以前也使用过像Components.PDFRender4NET.dll这些PDF插件，可是这些都测试了一下，或多或少有一些地方不是很满意，转换出来的发票图片有点模糊。最后同事推荐我使用Acrobat，结果真是让我惊喜。作为Adobe官方出品产品，其转换效率要比其他的DLL要快多了，而且应该更可靠一些。所以迫不及待的想和大家分享一下我的使用经验。

       使用该插件基本要求:

                工程中添加COM引用：Adobe Acrobat 9.0 Type Library（必须装了Adobe Acrobat9.0才会有）。

 

       思路：

 

          1、需要用到的COM对象：

               1）CAcroPDDoc：Acrobat文档对象。

               2）CAcroPDPage：页对象。

               3）CAcroRect：用来描述页中一个矩形区域的对象。

               4）CAcroPoint：实际上代表的是Size。

         2、转换过程：

              1）打开文档。

              2）取出每一页。

              3）获取每一页的大小，生成一个表示该页的矩形区域。

              4）将当前页的指定区域编码成图片，并且复制到剪贴板中。

             5）将剪贴板中的图片取出，保存为图片文件。

 

        转换函数代码：

 

  1 public static class PdfToImag
  2     {
  3         private class Info
  4         {
  5             public CAcroPDPage Page;
  6 
  7             public CAcroRect Rect;
  8 
  9             public double Resolution;
 10 
 11             public Bitmap Bitmap = null;
 12         }
 13 
 14         [CompilerGenerated]
 15         private static class Wo__0
 16         {
 17             public static CallSite<Func<CallSite, object, CAcroPDPage>> Wp__0;
 18 
 19             public static CallSite<Func<CallSite, object, CAcroPoint>> Wp__1;
 20         }
 21         /// <summary>
 22         /// 
 23         /// </summary>
 24         /// <param name="filePath" pdf路径含扩展名></param>
 25         /// <param name="imagPath" 图片存放路径含扩展名></param>
 26         /// <param name="resolution"></param>
 27         /// <returns></returns>
 28         public static bool ConvertPDF2Image(string filePath,string imagPath, double resolution = 6.0)
 29         {
 30             CAcroPDDoc cAcroPDDoc = null;
 31             CAcroPDPage cAcroPDPage = null;
 32             CAcroRect cAcroRect = null;
 33             CAcroPoint cAcroPoint = null;
 34             Image result;
 35             try
 36             {
 37                 cAcroPDDoc = (AcroPDDoc)Activator.CreateInstance(Marshal.GetTypeFromCLSID(new Guid("FF76CB60-2E68-101B-B02E-04021C009402")));
 38                 bool flag = !cAcroPDDoc.Open(filePath);
 39                 if (flag)
 40                 {
 41                     throw new FileNotFoundException();
 42                 }
 43                 bool flag2 = resolution <= 0.0;
 44                 if (flag2)
 45                 {
 46                     resolution = 1.0;
 47                 }
 48                 if (PdfToImag.Wo__0.Wp__0 == null)
 49                 {
 50                     PdfToImag.Wo__0.Wp__0 = CallSite<Func<CallSite, object, CAcroPDPage>>.Create(Binder.Convert(CSharpBinderFlags.ConvertExplicit, typeof(CAcroPDPage), typeof(PdfToImag)));
 51                 }
 52                 cAcroPDPage = PdfToImag.Wo__0.Wp__0.Target(PdfToImag.Wo__0.Wp__0, cAcroPDDoc.AcquirePage(0));
 53                 if (PdfToImag.Wo__0.Wp__1 == null)
 54                 {
 55                     PdfToImag.Wo__0.Wp__1 = CallSite<Func<CallSite, object, CAcroPoint>>.Create(Binder.Convert(CSharpBinderFlags.ConvertExplicit, typeof(CAcroPoint), typeof(PdfToImag)));
 56                 }
 57                 cAcroPoint = PdfToImag.Wo__0.Wp__1.Target(PdfToImag.Wo__0.Wp__1, cAcroPDPage.GetSize());
 58                 cAcroRect = (AcroRect)Activator.CreateInstance(Marshal.GetTypeFromCLSID(new Guid("6D12C400-4E34-101B-9CA8-9240CE2738AE")));
 59                 int num = (int)((double)cAcroPoint.x * resolution);
 60                 int num2 = (int)((double)cAcroPoint.y * resolution);
 61                 cAcroRect.Left = 0;
 62                 cAcroRect.right = (short)num;
 63                 cAcroRect.Top = 0;
 64                 cAcroRect.bottom = (short)num2;
 65                 result = PdfToImag.GetclipboardData(cAcroPDPage, cAcroRect, resolution);
 66                 result.Save(imagPath, System.Drawing.Imaging.ImageFormat.Jpeg);
 67             }
 68             catch (Exception ex)
 69             {
 70                 return false;
 71             }
 72             finally
 73             {
 74                 bool flag3 = cAcroPDDoc != null;
 75                 if (flag3)
 76                 {
 77                     if (cAcroPDDoc != null)
 78                     {
 79                         cAcroPDDoc.Close();
 80                     }
 81                 }
 82                 bool flag4 = cAcroPDPage != null;
 83                 if (flag4)
 84                 {
 85                     Marshal.ReleaseComObject(cAcroPDPage);
 86                 }
 87                 bool flag5 = cAcroRect != null;
 88                 if (flag5)
 89                 {
 90                     Marshal.ReleaseComObject(cAcroRect);
 91                 }
 92                 bool flag6 = cAcroPDDoc != null;
 93                 if (flag6)
 94                 {
 95                     Marshal.ReleaseComObject(cAcroPDDoc);
 96                 }
 97                 bool flag7 = cAcroPoint != null;
 98                 if (flag7)
 99                 {
100                     Marshal.ReleaseComObject(cAcroPoint);
101                 }
102             }
103             return true;
104         }
105 
106         private static Image GetclipboardData(CAcroPDPage page, CAcroRect pdfRect, double resolution)
107         {
108             PdfToImag.Info info = new PdfToImag.Info
109             {
110                 Page = page,
111                 Rect = pdfRect,
112                 Resolution = resolution
113             };
114             Thread thread = new Thread(new ParameterizedThreadStart(PdfToImag.CopyToClipboard));
115             thread.TrySetApartmentState(ApartmentState.STA);
116             thread.Start(info);
117             thread.Join();
118             return info.Bitmap;
119         }
120 
121         [STAThread]
122         private static void CopyToClipboard(object arge)
123         {
124             PdfToImag.Info info = arge as PdfToImag.Info;
125             CAcroPDPage page = info.Page;
126             CAcroRect rect = info.Rect;
127             double resolution = info.Resolution;
128             page.CopyToClipboard(rect, 0, 0, (short)(100.0 * resolution));
129             IDataObject dataObject = Clipboard.GetDataObject();
130             bool dataPresent = dataObject.GetDataPresent(DataFormats.Bitmap);
131             if (dataPresent)
132             {
133                 Bitmap bitmap = (Bitmap)dataObject.GetData(DataFormats.Bitmap);
134                 info.Bitmap = bitmap;
135             }
136         }
137     }