获取 PDF 的原始大小

Question

I want to get the same image quality as if I would use the export pdf to png from Adobe Acrobat.

But somehow this does not work for me. The dimensions that I get if I export the pdf to a png with help of the Adobe Acrobat tool are: Width:11264 pix Height:15940 pix

As you may see I provide you the method that I use to read the pdf an create per page a image. The possibilities that I have are to use the .Render Method which needs a int page(index) float dpiX, float dpiY, bool forPrinting

But some how it has no effect on the image saved ?

using (var document = PdfiumViewer.PdfDocument.Load(file)) 
{
    //This int is used to get the page count for each document 
    int pagecount = document.PageCount;

    //With the int pagecount we can create as may screenshots as there are pages in the document
    for (int index = 0; index < pagecount; index++)
    {
        //render the image created
        var image = document.Render(index,8448,11955, true);

        //savde the created screenshot temporerlay as a png + number (count)
        image.Save(@"C:\Users\chnikos\Desktop\Test\output" + index.ToString("000") + ".png",ImageFormat.Png);
        application.Selection.InlineShapes.AddPicture(@"C:\Users\chnikos\Desktop\Test\output" + index.ToString("000") + ".png");
    }
}

Answer 1

try
{
    using (var document = PdfiumViewer.PdfDocument.Load(@"C:\Users\ohernandez\Pictures\img\descarga.pdf"))
    {
        for (int index = 0; index < document.PageCount; index++)
        {
            var image = document.Render(index, 300, 300, PdfRenderFlags.CorrectFromDpi);
            image.Save(@"C:\Users\ohernandez\Pictures\img\output.Jpeg" + index.ToString("000") + ".Jpeg", ImageFormat.Jpeg);
        }

    //    var image = document.Render(0, 300, 300, true);
     //   image.Save(@"C:\Users\ohernandez\Pictures\img\output.png", ImageFormat.Png);
    }
}
catch (Exception ex)
{
    // handle exception here;
}

Answer 2

This might be a better example: Library files

using System.Drawing.Imaging;

string Desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);

//This one is with Spire.Pdf
void PDF_To_Image(string pdf)
{
   var doc = new Spire.Pdf.PdfDocument();
   doc.LoadFromFile(pdf);

   //This int is used to get the page count for each document 
   int pagecount = doc.Pages.Count;

   //With the int pagecount we can create as many screenshots as there are pages in the document
   for (int index = 0; index < pagecount; index++)
   {
      //render the image created
      var dpiX = 75;
      var dpiY = 75;
      var image = doc.SaveAsImage(index, Spire.Pdf.Graphics.PdfImageType.Bitmap, dpiX, dpiY);

      //save the created screenshot temporerlay as a png + number (count)
      image.Save(Desktop + @"\Test\output\" + index.ToString("000") + ".png", ImageFormat.Png);
   }
}

//This one is with Aspose.Pdf & xps2img.
//Aspose.Pdf converts the Pdf document to Xps format..
//xps2img creates images from the xps file..
void PDF_To_Image2(string pdf)
{
   var doc = new Aspose.Pdf.Document(pdf);
   var saveOptions = new Aspose.Pdf.XpsSaveOptions();
   doc.Save("Preview.xps", saveOptions);

   xps2img.Parameters pp = new xps2img.Parameters();
   pp.Dpi = 300;
   pp.ImageType = xps2img.ImageType.Png;
   pp.RequiredSize = new System.Drawing.Size((int)doc.PageInfo.Width, (int)doc.PageInfo.Height);
   pp.ImageOptions = xps2img.ImageOptions.Default;
   var img3 = xps2img.Xps2Image.ToBitmap("Preview.xps", pp).ToList();


   //This int is used to get the page count for each document 
   int pagecount = img3.Count;

   //With the int pagecount we can create as many screenshots as there are pages in the document
   for (int index = 0; index < pagecount; index++)
   {
      img3[index].Save(Desktop + @"\Test\Output\" + index.ToString("000") + ".png", ImageFormat.Png);
   }
}

Answer 3

Use PDFSharp & Migradocs

// Create a new PDF document
PdfDocument document = new PdfDocument();

// Create a font
XFont font = new XFont("Times", 25, XFontStyle.Bold);

PageSize[] pageSizes = (PageSize[])Enum.GetValues(typeof(PageSize));
foreach (PageSize pageSize in pageSizes)
{
  if (pageSize == PageSize.Undefined)
    continue;

  // One page in Portrait...
  PdfPage page = document.AddPage();
  page.Size = pageSize;
  XGraphics gfx = XGraphics.FromPdfPage(page);
  gfx.DrawString(pageSize.ToString(), font, XBrushes.DarkRed,
    new XRect(0, 0, page.Width, page.Height),
    XStringFormat.Center);

  // ... and one in Landscape orientation.
  page = document.AddPage();
  page.Size = pageSize;
  page.Orientation = PageOrientation.Landscape;
  gfx = XGraphics.FromPdfPage(page);
  gfx.DrawString(pageSize.ToString() + " (landscape)", font,
    XBrushes.DarkRed, new XRect(0, 0, page.Width, page.Height),
    XStringFormat.Center);
}

// Save the document...
string filename = "PageSizes.pdf";
document.Save(filename);
// ...and start a viewer.
Process.Start(filename);