Pdfium.Net.Free 一个免费的Pdfium的 .net包装器--PDF操作

标签：doc Pdfium Free pathPdf using var PDF new

项目地址：

Pdfium.Net：https://github.com/1000374/Pdfium.Net

PdfiumViewer：https://github.com/1000374/PdfiumViewer

Pdfium.Net支持对PDF操作：

转成图片
拆分
合并
插入
替换
删除
旋转
导出缩略图
多页合并成一页

1.转成图片

1.基于GDI+下：

  /// <summary>
  /// Renders a page of the PDF document to the provided graphics instance. <see cref="Platforms.Windows"/>
  /// </summary>
  /// <param name="graphics">Graphics instance to render the page on.</param>
  /// <param name="dpiX">Horizontal DPI.</param>
  /// <param name="dpiY">Vertical DPI.</param>
  /// <param name="bounds">Bounds to render the page in.</param>
  /// <param name="rotation"><see cref="FpdfRotation"/></param>
  /// <param name="flags">Flags used to influence the rendering.</param>
  public void Render(Graphics graphics, float dpiX, float dpiY, Rectangle bounds, FpdfRotation rotation, RenderFlags flags)

示例代码：

 var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 {
     var page0 = doc.Pages[0];
     Image image = new Bitmap((int)page0.Width, (int)page0.Height);
     var g = Graphics.FromImage(image);
     page0.Render(g, g.DpiX, g.DpiY, new Rectangle(
         AdjustDpi(g.DpiX, 0),
         AdjustDpi(g.DpiY, 0),
         AdjustDpi(g.DpiX, image.Width),
         AdjustDpi(g.DpiY, image.Height)),FpdfRotation.Rotate0,RenderFlags.None);
     image.Save("./Pdfium.NetTests/Render.png");
 }

2.不基于GDI+

  /// <summary>
  /// Renders a page of the PDF document to an image.
  /// </summary>
  /// <param name="width">Width of the rendered image.</param>
  /// <param name="height">Height of the rendered image.</param>
  /// <param name="dpiX">Horizontal DPI.</param>
  /// <param name="dpiY">Vertical DPI.</param>
  /// <param name="rotate">Rotation.</param>
  /// <param name="flags">Flags used to influence the rendering.</param>
  /// <returns>The rendered image.</returns>
  public Image Render(int width, int height, float dpiX, float dpiY, FpdfRotation rotate, RenderFlags flags)

示例代码：

  var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
  using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
      for (int i = 0; i < doc.PageCount; i++)
      {
          using (var image = doc.Pages[i].Render((int)doc.Pages[i].Width * 4 / 3, (int)doc.Pages[i].Height * 4 / 3, 96, 96, FpdfRotation.Rotate0, RenderFlags.Annotations | RenderFlags.CorrectFromDpi))
          {

          }
      }

3.不基于GDI+ 获取指定区域

区域坐标可通过框选获取，详情查看此

Pdfium.Net.Free 一个免费的Pdfium的 .net包装器--PDF预览器框选

        /// <summary>
        /// Renders the page.
        /// </summary>
        /// <param name="width">
        /// The full width of the rendered image in px.
        /// If 0, width will be calculated from height using the correct apsect ratio.
        /// Height and width can not be both set to zero. 
        /// </param>
        /// <param name="height">
        /// The full wiheightth of the rendered image in px.
        /// If 0, height will be calculated from height using the correct apsect ratio.
        /// Height and width can not be both set to zero.
        /// </param>
        /// <param name="clipX">X value of the start point of the clipping area</param>
        /// <param name="clipY">Y value of the start point of the clipping area</param>
        /// <param name="clipWidth">Width of the clip area</param>
        /// <param name="clipHeight">Height of the clip area</param>
        /// <param name="dpiX">DPI to render page. If set, width and height will accept percentage.</param>
        /// <param name="dpiY">DPI to render page. If set, width and height will accept percentage.</param>
        /// <param name="rotate">Specify rotation.</param>
        /// <param name="flags">Specify flags.</param>
        /// <returns>Image from the page.</returns>
        public Image Render(int width, int height, int clipX, int clipY, int clipWidth, int clipHeight, float dpiX, float dpiY, FpdfRotation rotate, RenderFlags flags)

示例代码：

 var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
     for (int i = 0; i < doc.PageCount; i++)
     {
         using (var image = doc.Pages[i].Render(
             (int)doc.Pages[i].Width,
             (int)doc.Pages[i].Height,
             16, // x of the top/left of clipping rectangle
            283, // y of the top/left point of clipping rectangle
            555, // width of clipping reactangle
            316, // height of clipping reactangle
            0,//DPIx
            0,//DPIy
            FpdfRotation.Rotate0, // no rotation
            RenderFlags.None // no render flags
                                ))
         {
             Assert.AreEqual(555, image.Width);
         }
     }

2.拆分

可使用封装好的函数直接获取每一页后保存

     var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
     using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
     {
         for (int i = 0; i < doc.PageCount; i++)
         {
             var doci = doc.GetPDFPage(i);
         }
     }

也可直接使用doc对象保存

  var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
  using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
  {
      for (int i = 0; i < doc.PageCount; i++)
      {
          var newDocument = PdfDocument.CreateNew();
          if (newDocument.Pages.Add(doc, i))
          {
              newDocument.Save($"./Pdfium.NetTests/AddTest{i}.pdf");
          }
      }
  }

3.合并

  var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
  using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
  using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
  {
      doc.MergePDF(doc1);
  }

4.插入

 var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
 var pathPdf1 = "./Pdfium.NetTests/resources/zero_length_stream.pdf";

 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf1))))
 {
     doc.ImportPage(doc1, 1);
 }

5.替换　　

 var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
 var pathPdf1 = "./Pdfium.NetTests/resources/zero_length_stream.pdf";

 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf1))))
 {
     doc.DeletePage(1);
     doc.ImportPage(doc1, 1);
 }

6.删除

 var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 {
      doc.DeletePage(0); 
 }

也可通过以下删除

  var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
  using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
  {
      doc.Pages.RemoveAt(0);
  }

7.旋转

pdf可进行360度旋转具体看枚举值FpdfRotation

 /// <summary>
 /// Specifies the rotation of pages shown in the PDF renderer.
 /// </summary>
 public enum FpdfRotation
 {
     /// <summary>
     /// Rotates the output 0 degrees.
     /// </summary>
     Rotate0,
     /// <summary>
     /// Rotates the output 90 degrees.
     /// </summary>
     Rotate90,
     /// <summary>
     /// Rotates the output 180 degrees.
     /// </summary>
     Rotate180,
     /// <summary>
     /// Rotates the output 270 degrees.
     /// </summary>
     Rotate270
 }

示例：

 var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 {
     doc.RotatePage(0,FpdfRotation.Rotate90);
 }

8.导出缩略图

  var pathPdf = "./Pdfium.NetTests/resources/simple_thumbnail.pdf";
  using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
      for (int i = 0; i < doc.PageCount; i++)
      {
          var image = doc.Pages[i].RenderThumbnail();
      }

9.多页合并成一页

函数声明：

num_pages_on_x_axis ：横向几页合并成一页默认2

num_pages_on_y_axis ：纵向几页合并成一页默认1

   /// <summary>
   /// Create a new document from |src_doc|.  The pages of |src_doc| will be combined to provide |num_pages_on_x_axis x num_pages_on_y_axis| pages per |output_doc| page.
   /// number of pages per page = num_pages_on_x_axis * num_pages_on_y_axis
   /// </summary>
   /// <param name="output_width">The output page width in PDF "user space" units.</param>
   /// <param name="output_height">The output page height in PDF "user space" units.</param>
   /// <param name="num_pages_on_x_axis">The number of pages on X Axis.</param>
   /// <param name="num_pages_on_y_axis">The number of pages on Y Axis.</param>
   /// <returns>A handle to the created document, or NULL on failure.</returns>
   public PdfDocument ImportNPagesToOne(float output_width, float output_height, uint num_pages_on_x_axis = 2, uint num_pages_on_y_axis = 1)

 var pathPdf = "./Pdfium.NetTests/resources/rectangles_multi_pages.pdf";
 using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
 {
     using (var doc1 = doc.ImportNPagesToOne(612 * 2, 792))
{}
 }

标签：doc,Pdfium,Free,pathPdf,using,var,PDF,new
From： https://www.cnblogs.com/xiaohemiao/p/18002765

Pdfium.Net.Free 一个免费的Pdfium的 .net包装器--PDF操作

1.转成图片

1.基于GDI+下：

2.不基于GDI+

3.不基于GDI+ 获取指定区域

Pdfium.Net.Free 一个免费的Pdfium的 .net包装器--PDF预览器框选

2.拆分

3.合并

4.插入

5.替换

6.删除

7.旋转

8.导出缩略图

9.多页合并成一页

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