Standardize resolution of images in PDF

[lbleicher]

Hi All-

I have an application that must receive scanned documents at various resolutions, and I want to standardize (at 150dpi) the images. There is one image per page.

I have tried the following:

Code: Select all

        If InputPDF.LoadFromFile(pdfPath, False) = GdPicture.GdPictureStatus.OK Then
            For i As Integer = 1 To InputPDF.GetPageCount()
                'j2kPath = Mid(pdfPath, 1, Len(pdfPath) - 4) & "pg" & i & ".j2k"
                InputPDF.SelectPage(i)
                rastPage = InputPDF.RenderPageToGdPictureImage(150, False)
                Dim image_res_name As String = InputPDF.AddImageFromGdPictureImage(rastPage, False, False)
                myPage.ReleaseGdPictureImage(rastPage)
                executedGdPCmd = InputPDF.ClearPageContent()
                InputPDF.SetOrigin(PdfOrigin.PdfOriginTopLeft)
                InputPDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitInch)
                InputPDF.DrawImage(image_res_name, 0, 0, 8.5, 11)
                ' myPage.SaveAsJ2K(rastPage, j2kPath, 32)
            Next i
            InputPDF.SaveToFile(OutputFilePath)
        Else
            'report out reason for problem.
            Dim errCode As Integer = InputPDF.GetStat()
              ...
        End If
        InputPDF.CloseDocument()

However, this simply gives ma a blank PDF that is larger (in bytes on disk) than the original. What am I doing wrong?

I am able to write to disk the individual pages as j2ks, so the rasterization seems to work.

Thanks for your help,
Leo

[Loïc]

Hi Leo,

This problem will be solved in the next release.
Waiting for, a workaround consists to comment this line:

InputPDF.SetOrigin(PdfOrigin.PdfOriginTopLeft)

With best regards,

Loïc

[Loïc]

Hi,

By the way, I suggest you to start a new PDF from scratch to reduce the output file size.

Kind regards,

Loïc

[lbleicher]

Hi Loic-

Thanks for the quick and helpful response.

I now have a working module:

Code: Select all

 executedGdPCmd = OutputPDF.NewPDF(True)  'Should make PDF/A file

        'get some info about the document
        If InputPDF.LoadFromFile(pdfPath, False) = GdPicture.GdPictureStatus.OK Then
            For i As Integer = 1 To InputPDF.GetPageCount()
                InputPDF.SelectPage(i)
                pageImages = InputPDF.GetPageImageCount()
                If pageImages = 1 Then
                    curPageImage = InputPDF.ExtractPageImage(1)
                    inPgPD = myPage.GetBitDepth(curPageImage)
                    inPgHP = myPage.GetHeight(curPageImage)
                    inPgHI = myPage.GetHeightInches(curPageImage)
                    inPgWP = myPage.GetWidth(curPageImage)
                    inPgWI = myPage.GetWidthInches(curPageImage)
                    myPage.ReleaseGdPictureImage(curPageImage)

                    hDPI = inPgHP / inPgHI
                    wDPI = inPgWP / inPgWI
                    curDPI = System.Math.Max(hDPI, wDPI)

                    newDPI = System.Math.Min(curDPI, 150)
                Else
                    newDPI = 150
                End If
                rastPage = InputPDF.RenderPageToGdPictureImage(newDPI, False)
                executedGdPCmd = myPage.ConvertTo1Bpp(rastPage)

                Dim image_res_name As String = OutputPDF.AddImageFromGdPictureImage(rastPage, False, False)
                myPage.ReleaseGdPictureImage(rastPage)
                ' NOT NEEDED InputPDF.SetOrigin(PdfOrigin.PdfOriginTopLeft)
                OutputPDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitInch)
                OutputPDF.NewPage(inPgWI, inPgHI)
                OutputPDF.DrawImage(image_res_name, 0, 0, inPgWI, inPgHI)
            Next i
            OutputPDF.SaveToFile(OutputFilePath)
        Else
            'report out reason for problem.
            Dim errCode As Integer = InputPDF.GetStat()
        End If
        InputPDF.CloseDocument()


However, I now have a new problem. Acrobat Professional v8 thinks that the resulting document '...is damaged and needs repair.'


The PDF/A report says the following:

Creation Date mismatch between Document Info and XMP metadata
Document is damaged and needs repair
PDF contains data after end of file marker
Document information
File name: "1013288_Compress.pdf"
Path: "D:\Clients\AcclerysServices\DuPont\TestDataSourceFolder\Confidential"
PDF version number: "1.4"
File size 246.06 KB (251968 Bytes)
Creator: "GdPicture Managed PDF Plugin"
Producer: "GdPicture Managed PDF Plugin Ver. 1.000014"
Created: "11/7/2011 4:06 PM"
Trapping: "Unknown"
Additional actions: Not present
Number of plates: 1
Names of plates: "(Black) "
Environment
Preflight, 8.1.0 (237)
Acrobat version: 8.10
Operating system: Microsoft Windows Home Edition (Build 7600)

Any idea what might cause all these PDF/A issues (in Acrobat's estimation) on a newly created file?

Thanks,
Leo

[Loïc]

Hi Leo,

Please replace:

Code: Select all

OutputPDF.NewPage(inPgWI, inPgHI) 
OutputPDF.DrawImage(image_res_name, 0, 0, inPgWI, inPgHI)

by:

Code: Select all

OutputPDF.NewPage(inPgWI, inPgHI)
OutputPDF.SelectPage(i)
OutputPDF.DrawImage(image_res_name, 0, 0, inPgWI, inPgHI)

Also, you should check the return value of the function you are using, that will help you to catch error and get some useful information.

Kind regards,

Loïc