ExtractPageImage Method (GdPicturePDF)

In This Topic

Extracts an image, specified by its number within the currently selected page of the loaded PDF document, into a new GdPictureImage object. The specified image is extracted as a resource to an object of the type GdPictureImage, in other words the image resource becomes independent of the source document. The image is clearly recognizable by the returned unique image identifier and it can be subsequently used outside the source document, for example, you can add this image into another PDF document. It is also possible to take advantages of the GdPictureImaging class and its methods for further manipulation with this image.

Syntax

Visual Basic
C#
Delphi
JScript
Managed Extensions for C++
C++/CLI

'Declaration
 
Public Function ExtractPageImage( _
   ByVal ImageNo As Integer _
) As Integer

public int ExtractPageImage( 
   int ImageNo
)

public function ExtractPageImage( 
    ImageNo: Integer
): Integer;

public function ExtractPageImage( 
   ImageNo : int
) : int;

public: int ExtractPageImage( 
   int ImageNo
)

public:
int ExtractPageImage( 
   int ImageNo
)

Parameters

ImageNo: The image number of the required image within the current page. It must be a value from 1 to GdPicturePDF.GetPageImageCount.

Return Value

A unique image identifier of the newly created image object of the type GdPictureImage. The GdPicturePDF.GetStat method can be subsequently used to determine if this method has been successful.

Just to remind you that you need to release the image after being used, for example, using the static GdPictureDocumentUtilities.DisposeImage method.

Remarks

This method is only allowed for use with non-encrypted documents.

It is recommend to use the GdPicturePDF.GetStat method to identify the specific reason for the method's failure, if any.

Example

How to extract all images from the first page of the source PDF document to the newly created destination PDF document. All images are drawn one image per page.

VB.NET
C#

Dim caption As String = "Example: ExtractPageImage"
Dim gdpicturePDFSrc As New GdPicturePDF()
If gdpicturePDFSrc.LoadFromFile("test.pdf", False) = GdPictureStatus.OK Then
    Dim pageCount As Integer = gdpicturePDFSrc.GetPageCount()
    Dim status As GdPictureStatus = gdpicturePDFSrc.GetStat()
    If (status = GdPictureStatus.OK) AndAlso (pageCount > 0) Then
        'The first page is automatically selected as the current page.
        Dim imageCount As Integer = gdpicturePDFSrc.GetPageImageCount()
        status = gdpicturePDFSrc.GetStat()
        If (status = GdPictureStatus.OK) AndAlso (imageCount > 0) Then
            Dim gdpicturePDFDest As New GdPicturePDF()
            If gdpicturePDFDest.NewPDF() = GdPictureStatus.OK Then
                Dim message As String = ""
                Dim imageID As Integer = 0
                For i As Integer = 1 To imageCount
                    imageID = gdpicturePDFSrc.ExtractPageImage(i)
                    status = gdpicturePDFSrc.GetStat()
                    If status = GdPictureStatus.OK Then
                        Dim res_name As String = gdpicturePDFDest.AddImageFromGdPictureImage(imageID, False, True)
                        status = gdpicturePDFSrc.GetStat()
                        If status = GdPictureStatus.OK Then
                            message = message + "The image nr. " + i.ToString() + " has been successfully drawn." + vbCrLf
                        Else
                            message = message + "The AddImageFromGdPictureImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + vbCrLf
                        End If
                        If GdPictureDocumentUtilities.DisposeImage(imageID) <> GdPictureStatus.OK Then
                            message = message + "The DisposeImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + vbCrLf
                        End If
                    Else
                        message = message + "The ExtractPageImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + vbCrLf
                    End If
                Next
                If gdpicturePDFDest.SaveToFile("test_ExtractPageImage.pdf") = GdPictureStatus.OK Then
                    message = message + "The file has been saved successfully."
                Else
                    message = message + "The file can't be saved. Status: " + gdpicturePDFDest.GetStat().ToString()
                End If
                MessageBox.Show(message, caption)
            Else
                MessageBox.Show("The NewPDF() method has failed with the status: " + gdpicturePDFDest.GetStat().ToString(), caption)
            End If
            gdpicturePDFDest.Dispose()
        Else
            If status = GdPictureStatus.OK Then
                MessageBox.Show("This file doesn't contain any image.", caption)
            Else
                MessageBox.Show("The GetPageImageCount() method has failed with the status: " + status.ToString(), caption)
            End If
        End If
    Else
        If status = GdPictureStatus.OK Then
            MessageBox.Show("The first page doesn't contain any page.", caption)
        Else
            MessageBox.Show("The GetPageCount() method has failed with the status: " + status.ToString(), caption)
        End If
    End If
Else
    MessageBox.Show("The file can't be loaded.", caption)
End If
gdpicturePDFSrc.Dispose()

string caption = "Example: ExtractPageImage";
GdPicturePDF gdpicturePDFSrc = new GdPicturePDF();
if (gdpicturePDFSrc.LoadFromFile("test.pdf", false) == GdPictureStatus.OK)
{
    int pageCount = gdpicturePDFSrc.GetPageCount();
    GdPictureStatus status = gdpicturePDFSrc.GetStat();
    if ((status == GdPictureStatus.OK) && (pageCount > 0))
    {
        //The first page is automatically selected as the current page.
        int imageCount = gdpicturePDFSrc.GetPageImageCount();
        status = gdpicturePDFSrc.GetStat();
        if ((status == GdPictureStatus.OK) && (imageCount > 0))
        {
            GdPicturePDF gdpicturePDFDest = new GdPicturePDF();
            if (gdpicturePDFDest.NewPDF() == GdPictureStatus.OK)
            {
                string message = "";
                int imageID = 0;
                for (int i = 1; i <= imageCount; i++)
                {
                    imageID = gdpicturePDFSrc.ExtractPageImage(i);
                    status = gdpicturePDFSrc.GetStat();
                    if (status == GdPictureStatus.OK)
                    {
                        string res_name = gdpicturePDFDest.AddImageFromGdPictureImage(imageID, false, true);
                        status = gdpicturePDFSrc.GetStat();
                        if (status == GdPictureStatus.OK)
                            message = message + "The image nr. " + i.ToString() + " has been successfully drawn.\n";
                        else
                            message = message + "The AddImageFromGdPictureImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + "\n";
                        if (GdPictureDocumentUtilities.DisposeImage(imageID) != GdPictureStatus.OK)
                            message = message + "The DisposeImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + "\n";
                    }
                    else
                        message = message + "The ExtractPageImage() method has failed for the image nr. " + i.ToString() + " with the status: " + status.ToString() + "\n";
                }
                if (gdpicturePDFDest.SaveToFile("test_ExtractPageImage.pdf") == GdPictureStatus.OK)
                    message = message + "The file has been saved successfully.";
                else
                    message = message + "The file can't be saved. Status: " + gdpicturePDFDest.GetStat().ToString();
                MessageBox.Show(message, caption);
            }
            else
                MessageBox.Show("The NewPDF() method has failed with the status: " + gdpicturePDFDest.GetStat().ToString(), caption);
            gdpicturePDFDest.Dispose();
        }
        else
        {
            if (status == GdPictureStatus.OK)
                MessageBox.Show("The first page doesn't contain any image.", caption);
            else
                MessageBox.Show("The GetPageImageCount() method has failed with the status: " + status.ToString(), caption);
        }
    }
    else
    {
        if (status == GdPictureStatus.OK)
            MessageBox.Show("This file doesn't contain any page.", caption);
        else
            MessageBox.Show("The GetPageCount() method has failed with the status: " + status.ToString(), caption);
    }
}
else
    MessageBox.Show("The file can't be loaded.", caption);
gdpicturePDFSrc.Dispose();

Reference

GdPicturePDF Class
GdPicturePDF Members
GetPageImageCount Method
GetPageImageResName Method
ExtractPageImage Method
GetPageCount Method
SelectPage Method
LoadFromFile Method
SaveToFile(String) Method