Recompress existing PDFs using MRC compression in VB.NET

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'We assume that GdPicture has been correctly installed and unlocked.
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Using pdf As GdPicturePDF = New GdPicturePDF()
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    Dim status As GdPictureStatus = pdf.LoadFromFile("source.pdf", False)
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    If status = GdPictureStatus.OK Then
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        'Setting MRC options.
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        pdf.SetMRCImageBackgroundResolution(100)
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        'You can set it to true to obtain a better quality rendering, but it produces a bigger file.
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        pdf.SetMRCPreserveSmoothing(False)
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        'You can also set the compression values for images here, for example:
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        pdf.SetCompressionForBitonalImage(PdfCompression.PdfCompressionJBIG2)
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        pdf.SetCompressionForColorImage(PdfCompression.PdfCompressionJPEG2000)
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        'Using the negative value permits to specify better quality factor versus a compression rate.
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        pdf.SetJpeg2000Quality(-60)
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        Dim pageCount As Integer = pdf.GetPageCount()
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        status = pdf.GetStat()
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        Dim pageNo As Integer = 1
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        While (pageNo <= pageCount) AndAlso (status = GdPictureStatus.OK)
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            status = pdf.SelectPage(pageNo)
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            If status = GdPictureStatus.OK Then
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                'We can ignore hiddent text in the example.
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                Dim isPageImage As Boolean = pdf.IsPageImage(True)
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                status = pdf.GetStat()
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                If status = GdPictureStatus.OK Then
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                    If isPageImage Then
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                        'As the page is image-based, the image number is 1 and we can extract this image.
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                        Dim imageID As Integer = pdf.ExtractPageImage(1)
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                        status = pdf.GetStat()
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                        If status = GdPictureStatus.OK Then
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                            'Getting the resource name of the extracted image, the index of the image to be used here is 0.
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                            Dim imageResName As String = pdf.GetPageImageResName(0)
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                            status = pdf.GetStat()
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                            If status = GdPictureStatus.OK Then
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                                'The original image is replaced with the compressed image on the whole page surface here.
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                                status = pdf.ReplaceImageMRC(imageResName, imageID)
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                                'You need to dispose of the used image resource here.
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                                GdPictureDocumentUtilities.DisposeImage(imageID)
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                            End If
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                        End If
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                    End If
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                End If
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            End If
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            pageNo += 1
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        End While
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        If status = GdPictureStatus.OK Then
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            status = pdf.SaveToFile("dest.pdf", True)
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            If status = GdPictureStatus.OK Then
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                MessageBox.Show("The example has been followed successfully and the file has been saved.", "MRC Compression Example", MessageBoxButtons.OK, MessageBoxIcon.Information)
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            Else
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                MessageBox.Show("The example has been followed successfully, but the file can't be saved. Status: " + status.ToString(), "MRC Compression Example", MessageBoxButtons.OK, MessageBoxIcon.[Error])
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            End If
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        Else
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            MessageBox.Show("The example has NOT been followed successfully. Status: " + status.ToString(), "MRC Compression Example", MessageBoxButtons.OK, MessageBoxIcon.[Error])
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        End If
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    Else
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        MessageBox.Show("The file can't be loaded. Status: " + status.ToString(), "MRC Compression Example", MessageBoxButtons.OK, MessageBoxIcon.[Error])
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    End If
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End Using