GetPageImage Method

Visual Basic
C#
Objective-C
Java
C++

public RasterImage GetPageImage( 
   RasterCodecs codecs,
   int pageNumber
)

'Declaration
 
Public Function GetPageImage( _
   ByVal codecs As RasterCodecs, _
   ByVal pageNumber As Integer _
) As RasterImage

'Usage
 
Dim instance As PDFDocument
Dim codecs As RasterCodecs
Dim pageNumber As Integer
Dim value As RasterImage
 
value = instance.GetPageImage(codecs, pageNumber)

public:
RasterImage^ GetPageImage( 
   RasterCodecs^ codecs,
   int pageNumber
)

Parameters

codecs: An optional Leadtools.Codecs.RasterCodecs to use when reading the page. If you pass a null reference (Nothing in Visual Basic), then this method will internal create a new Leadtools.Codecs.RasterCodecs object and dispose before it returns.
pageNumber: The 1-based page number to read. Must be greater than or equal to 1 and less than or equal to the total number of pages in the document (Pages.Count). You can use the special value of -1 to donate "last page in the document".

Return Value

A Leadtools.RasterImage that represents the rendering of the requested page.

This method does not perform anything beyound simply using the Leadtools.Codecs.RasterCodecs object passed (or the temporary one created) to load the PDF page:


            rasterCodecsObject.Load(document.FileName, 0, CodecsLoadByteOrder.Bgr, pageNumber, pageNumber)

For more information, refer to RasterCodecs.Load.

The size of the result Leadtools.RasterImage depends on the size of the page (PDFDocumentPage.Width and PDFDocumentPage.Height) and the current resolution value of the document PDFDocument.Resolution). For example, if the PDF size is 612 by 792 PDF units (or 1/72 of an inch) and resolution value is 300, then the result image size is: 300 * 612/72 by 300 * 792/72 = 2550 by 3300 pixels. You can increase or decrease the value of the resolution to load the image at larger or smaller pixel size. Refer to PDF Coordinate System for more information.

Once the page is rendered as a Leadtools.RasterImage object, you can use this object to perform any other image functionality with LEADTOOLS, such as setting it into a viewer control, image processing, saving to other formats, etc.

Since a Leadtools.Codecs.RasterCodecs object is required by this method, you can either pass one through the codecs parameter and the method will use this object to load the page. This is helpful if you need to change the default Leadtools.Codecs.RasterCodecs load options or subscribe to any of the events that will occur during loading. If none of that is required, you can simply pass null (Nothing in Visual Basic) for the codecs parameter and this method will internally create, use and dispose a temporary Leadtools.Codecs.RasterCodecs object.

To get a thumbnail of any page in a PDF document, use GetThumbnail.

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Pdf
Imports Leadtools.WinForms

Public Sub PDFDocumentGetPageImageExample()
   Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LEAD.pdf")
   Dim tifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LEAD_pdf.tif")

   If File.Exists(tifFileName) Then
      ' So we won't append to it twice
      File.Delete(tifFileName)
   End If

   ' Open the document
   Using document As New PDFDocument(pdfFileName)

      ' Set the resolution to 200 dots/inch
      document.Resolution = 200

      Using codecs As New RasterCodecs()
         ' For each page...
         For i As Integer = 1 To document.Pages.Count
            ' Get the page as a raster image
            Using image As RasterImage = document.GetPageImage(codecs, i)
               ' Save it to the destination file
               codecs.Save(image, tifFileName, RasterImageFormat.TifJpeg, 24, 1, 1, -1, CodecsSavePageMode.Append)
            End Using
         Next
      End Using
   End Using
End Sub

Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Pdf;
using Leadtools.WinForms;

public void PDFDocumentGetPageImageExample()
{
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, @"LEAD.pdf");
   string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, @"LEAD_pdf.tif");

   if(File.Exists(tifFileName))
   {
      // So we won't append to it twice
      File.Delete(tifFileName);
   }

   // Open the document
   using(PDFDocument document = new PDFDocument(pdfFileName))
   {
      // Set the resolution to 200 dots/inch
      document.Resolution = 200;

      using(RasterCodecs codecs = new RasterCodecs())
      {
         // For each page...
         for(int i = 1; i <= document.Pages.Count; i++)
         {
            // Get the page as a raster image
            using(RasterImage image = document.GetPageImage(codecs, i))
            {
               // Save it to the destination file
               codecs.Save(image, tifFileName, RasterImageFormat.TifJpeg, 24, 1, 1, -1, CodecsSavePageMode.Append);
            }
         }
      }
   }
}

static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

Target Platforms

Reference

PDFDocument Class
PDFDocument Members