IsPageImage(Int32,Boolean) Method

In This Topic

Returns if the currently selected page of the loaded PDF is entirely image-based. If yes, the method returns a unique image identifier referring to the newly created image object of the type GdPictureImage, that corresponds to the embedded image. You can take advantages of the GdPictureImaging class and its methods for further manipulation with the resulting image.

Image-based pages are considered to contain nothing but one fully visible image covering the whole page area. This image must not be in any way rotated and must not contain any other particular drawing operation such as a clipping path.

Syntax

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

'Declaration

 

Public Overloads Function IsPageImage( _

   ByRef ImageID As Integer, _

   ByVal AutoRotate As Boolean _

) As Boolean

public bool IsPageImage( 

   ref int ImageID,

   bool AutoRotate

)

public function IsPageImage( 

   var  ImageID: Integer;

    AutoRotate: Boolean

): Boolean;

public function IsPageImage( 

   ImageID : int,

   AutoRotate : boolean

) : boolean;

public: bool IsPageImage( 

   ref int ImageID,

   bool AutoRotate

)

public:

bool IsPageImage( 

   int% ImageID,

   bool AutoRotate

)

Parameters

ImageID: Output parameter. If the currently selected page is an image-based page as defined above, this parameter returns a unique image identifier of the newly created GdPictureImage object corresponding to the embedded image. If the page is not image-based, this parameter returns 0.
Be aware that you need to release the successfully created image after being used, for the suitable method please refer to the Remarks section below.
AutoRotate: Set this parameter to true if you want to automatically rotate the created image representing by the GdPictureImage object to get the same rendering orientation (for display or print) as is the viewing mode of the current page. Otherwise set it to false.
You can use the GetPageRotation method to find out if the current page should be rotated when displayed or printed.

Return Value

true if the currently selected page is entirely image-based as defined above, otherwise false. The GetStat method can be subsequently used to determine if this method has been successful.

Remarks

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

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

Likewise just to remind you that you need to release the image, if it has been created successfully, after being used using either the ReleaseGdPictureImage method or the static DisposeImage method.

Example

How to reuse an image from the image-based page in the PDF document. The image is subsequently drawn onto a new page and saved into a new PDF document.

VB.NET
C#

Dim caption As String = "Example: IsPageImage"

Dim gdpicturePDF As GdPicturePDF = New GdPicturePDF()

Dim status As GdPictureStatus = gdpicturePDF.LoadFromFile("drawing.pdf", False)

If status = GdPictureStatus.OK Then

    status = gdpicturePDF.SelectPage(1)

    If status = GdPictureStatus.OK Then

        Dim imageID As Integer = 0

        Dim result As Boolean = gdpicturePDF.IsPageImage(imageID, True)

        status = gdpicturePDF.GetStat()

        If status = GdPictureStatus.OK Then

            If result Then

                Dim name As String = gdpicturePDF.AddImageFromGdPictureImage(imageID, False, True)

                status = gdpicturePDF.GetStat()

                If status = GdPictureStatus.OK Then

                    If gdpicturePDF.SaveToFile("drawing_duplicated.pdf") = GdPictureStatus.OK Then

                        MessageBox.Show("The image has been successfully duplicated.", caption)

                    End If

                Else

                    MessageBox.Show("The AddImageFromGdPictureImage() method has failed with the status: " + status.ToString(), caption)

                End If

                GdPictureDocumentUtilities.DisposeImage(imageID)

            Else

                MessageBox.Show("This page is not image-based.", caption)

            End If

        Else

            MessageBox.Show("The IsPageImage() method has failed with the status: " + status.ToString(), caption)

        End If

    Else

        MessageBox.Show("The SelectPage() method has failed with the status: " + status.ToString(), caption)

    End If

Else

    MessageBox.Show("The file can't be loaded.", caption)

End If

gdpicturePDF.Dispose()

string caption = "Example: IsPageImage";

GdPicturePDF gdpicturePDF = new GdPicturePDF();

GdPictureStatus status = gdpicturePDF.LoadFromFile("drawing.pdf", false);

if (status == GdPictureStatus.OK)

{

    status = gdpicturePDF.SelectPage(1);

    if (status == GdPictureStatus.OK)

    {

        int imageID = 0;

        bool result = gdpicturePDF.IsPageImage(ref imageID, true);

        status = gdpicturePDF.GetStat();

        if (status == GdPictureStatus.OK)

        {

            if (result)

            {

                string name = gdpicturePDF.AddImageFromGdPictureImage(imageID, false, true);

                status = gdpicturePDF.GetStat();

                if (status == GdPictureStatus.OK)

                {

                    if (gdpicturePDF.SaveToFile("drawing_duplicated.pdf") == GdPictureStatus.OK)

                        MessageBox.Show("The image has been successfully duplicated.", caption);

                }

                else

                {

                    MessageBox.Show("The AddImageFromGdPictureImage() method has failed with the status: " + status.ToString(), caption);

                }

                GdPictureDocumentUtilities.DisposeImage(imageID);

            }

            else

                MessageBox.Show("This page is not image-based.", caption);

        }

        else

            MessageBox.Show("The IsPageImage() method has failed with the status: " + status.ToString(), caption);

    }

    else

        MessageBox.Show("The SelectPage() method has failed with the status: " + status.ToString(), caption);

}

else

    MessageBox.Show("The file can't be loaded.", caption);

gdpicturePDF.Dispose();

Reference

GdPicturePDF Class
GdPicturePDF Members
Overload List
SelectPage Method
AddImageFromGdPictureImage(Int32,Boolean,Boolean) Method
GetPageRotation Method