SetPrependContentMode Method (GdPicturePDF)

In This Topic

Determines if all subsequent modifications of the current page of the loaded PDF document are prepend or append. The initial value is set to false, means the prepend mode is disabled.

This method can be particularly useful if you need to append content on the background of the page, for example drawing an image behind existing text.

Syntax

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

'Declaration
 
Public Function SetPrependContentMode( _
   ByVal Enable As Boolean _
) As GdPictureStatus

public GdPictureStatus SetPrependContentMode( 
   bool Enable
)

public function SetPrependContentMode( 
    Enable: Boolean
): GdPictureStatus;

public function SetPrependContentMode( 
   Enable : boolean
) : GdPictureStatus;

public: GdPictureStatus SetPrependContentMode( 
   bool Enable
)

public:
GdPictureStatus SetPrependContentMode( 
   bool Enable
)

Parameters

Enable: Set this parameter to true, if you want to enable the prepend mode, otherwise set it to false to disable it. Initial value is false.

Return Value

A member of the GdPictureStatus enumeration. If the method has been successfully followed, then the return value is GdPictureStatus.OK.

We strongly recommend always checking this status first.

Remarks

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

Example

How to rotate the first page of an existing PDF document by an angle of 20 degrees without altering the page's content.

VB.NET
C#

Dim caption As String = "Example: SetPrependContentMode"
Dim gdpicturePDF As New GdPicturePDF()
'See the SetBlendMode() method how to create this file.
Dim status As GdPictureStatus = gdpicturePDF.LoadFromFile("test_BlendMode.pdf", False)
If status = GdPictureStatus.OK Then
    Dim pageWidth As Single = gdpicturePDF.GetPageWidth()
    status = gdpicturePDF.GetStat()
    If status <> GdPictureStatus.OK Then
        MessageBox.Show("The GetPageWidth() method has failed.", caption)
        GoTo [error]
    End If
    Dim pageHeight As Single = gdpicturePDF.GetPageHeight()
    status = gdpicturePDF.GetStat()
    If status <> GdPictureStatus.OK Then
        MessageBox.Show("The GetPageHeight() method has failed.", caption)
        GoTo [error]
    End If
            
    'The first page is selected implicitly.
    'The current measurement units are set to points and the current origin is bottom left by default.
    If (gdpicturePDF.SetPrependContentMode(True) = GdPictureStatus.OK) AndAlso
       (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, pageWidth / 2, pageHeight / 2) = GdPictureStatus.OK) AndAlso
       (gdpicturePDF.AddRotationAt(20, 0, 0) = GdPictureStatus.OK) AndAlso
       (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, -pageWidth / 2, -pageHeight / 2) = GdPictureStatus.OK) Then
        status = gdpicturePDF.SaveToFile("test_PrependMode.pdf")
        If status = GdPictureStatus.OK Then
            MessageBox.Show("The example has been followed successfully and the file has been saved.", caption)
        Else
            MessageBox.Show("The example has been followed successfully, but the file can't be saved. Status: " + status.ToString(), caption)
        End If
    Else
        MessageBox.Show("The example has not been followed successfully." + vbCrLf + "The last known status is " + gdpicturePDF.GetStat().ToString(), caption)
    End If
Else
    MessageBox.Show("The LoadFromFile() method has failed with the status: " + status.ToString(), caption)
End If
[error]:
gdpicturePDF.Dispose()

string caption = "Example: SetPrependContentMode";
GdPicturePDF gdpicturePDF = new GdPicturePDF();
//See the SetBlendMode() method how to create this file.
GdPictureStatus status = gdpicturePDF.LoadFromFile("test_BlendMode.pdf", false);
if (status == GdPictureStatus.OK)
{
    float pageWidth = gdpicturePDF.GetPageWidth();
    status = gdpicturePDF.GetStat();
    if (status != GdPictureStatus.OK)
    {
        MessageBox.Show("The GetPageWidth() method has failed.", caption);
        goto error;
    }
    float pageHeight = gdpicturePDF.GetPageHeight();
    status = gdpicturePDF.GetStat();
    if (status != GdPictureStatus.OK)
    {
        MessageBox.Show("The GetPageHeight() method has failed.", caption);
        goto error;
    }
            
    //The first page is selected implicitly.
    //The current measurement units are set to points and the current origin is bottom left by default.
    if ((gdpicturePDF.SetPrependContentMode(true) == GdPictureStatus.OK) &&
        (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, pageWidth / 2, pageHeight / 2) == GdPictureStatus.OK) &&
        (gdpicturePDF.AddRotationAt(20, 0, 0) == GdPictureStatus.OK) &&
        (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, -pageWidth / 2, -pageHeight / 2) == GdPictureStatus.OK))
    {
        status = gdpicturePDF.SaveToFile("test_PrependMode.pdf");
        if (status == GdPictureStatus.OK)
            MessageBox.Show("The example has been followed successfully and the file has been saved.", caption);
        else
            MessageBox.Show("The example has been followed successfully, but the file can't be saved. Status: " + status.ToString(), caption);
    }
    else
        MessageBox.Show("The example has not been followed successfully.\nThe last known status is " + gdpicturePDF.GetStat().ToString(), caption);
}
else
    MessageBox.Show("The LoadFromFile() method has failed with the status: " + status.ToString(), caption);
error:
gdpicturePDF.Dispose();

Reference

GdPicturePDF Class
GdPicturePDF Members
SetMeasurementUnit Method
SetOrigin Method
SetBlendMode Method
AddTransformationMatrix Method
ResetGraphicsState Method