GetPageImage Method

Summary

Gets a raster image of a page in the PDF file associated with this PDFDocument.

Syntax

C++

Java

public RasterImage GetPageImage( 
   RasterCodecs codecs, 
   int pageNumber 
)

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

public RasterImage getPageImage(RasterCodecs codecs, int 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, 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). Use the special value of -1 to represent the last page in the document.

Return Value

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

Remarks

This method does not perform anything beyond 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 resulting 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 (where each unit is 1/72 of an inch) and the resolution value is 300, then the resulting 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 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 and GetPageSvg(RasterCodecs,Int32,CodecsLoadSvgOptions) to get an SVG representation of the page.

Example

This example will convert a multipage PDF to a multipage TIF file

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Controls; 
using Leadtools.Pdf; 
using Leadtools.Svg; 
using Leadtools.WinForms; 
 
public void PDFDocumentGetPageImageExample() 
{ 
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, @"Leadtools.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"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Controls 
Imports Leadtools.Pdf 
Imports Leadtools.Svg 
Imports Leadtools.WinForms 
 
Public Sub PDFDocumentGetPageImageExample() 
   Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Leadtools.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 PDFDocument = New PDFDocument(pdfFileName) 
      ' Set the resolution to 200 dots/inch 
      document.Resolution = 200 
 
      Using codecs As RasterCodecs = New RasterCodecs() 
         ' For each page... 
         Dim i As Integer = 1 
         Do While i <= 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 
            i += 1 
         Loop 
      End Using 
   End Using 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class

Requirements

Target Platforms

Reference

PDFDocument Class

PDFDocument Members

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Help Version 20.0.2020.4.3

Leadtools.Pdf Assembly

Introduction

Getting Started

Namespaces

Leadtools.Pdf Namespace

Assemblies