PDF thumbnails from VBA

I was asked to develop a form where user can see a pdf thumbnail of a pdf file. It was pretty far from what I have been developing so I decided to use "uncle" google to find a solution. There are some solutions but nothing what was expecting. You can use paid version of Adobe or free Adobe Acrobat ActiveX (Acropdf1) or some others free tools that can work along a pdf file. I tested only the free version of Acrobat ActiveX component and it was really nightmare. Then I found a C# project using the GhostScript tool for creating a pdf thumbnail. Unfortunatelly VBA cannot work with this project directly. Read more to find solution.

As I mentioned you can use the Acropdf1 activeX which is automatically installed with the Adobe Reader application.

Acropdf1.PNG, 35kB

How to add the Acropdf1 activeX on a VBA form

At the first time the activeX seemed to be a good solution but then I found two "bugs". The first one is more important than the second one. The activeX takes focus and never give it back and if you press the "TAB" key, then the whole application will crash. It's very known bug but Adobe cannot fix it for some reason. And the second bug rather behavior - of the activeX control is uncomfortable - it always takes focus and never give it back and also you don't have option to find out if a pdf document is fully loaded or not. My client was complaining about that for many times so I decided to find another solution.

I found code from Matthew Ephraim. where he uses a free tool Ghostscrip and .NETFramework 3.5 and C#. Form Visual Studio you can use his tool without any problems just include it into your project. Unfortunately we cannot use his dll directly from VBA. That was the reason why I took his code and made a little adjustment to expose methods from his project to the COM object.
Now - after registration the dll to your system - you can reference the dll as usually and use it !!! And it works great.

GhostScriptSharp_reference.PNG, 17kB

Who is interested how to create a C# dll that can work with VBA I attached the zip file with entire C# solution. Look at the Attachment section.
And who just want to use it as soon as possible, download the installer and install it. I also prepare a sample and you can find everything in the Attachment section.
The installer just check if your system contains the .NETFramework 4 and if not, it will suggest to download it and then register the dlls into your system.

Your code can look like this one
and then you can take the output file as an ordinary image file and load it - for example - to an image control.

Option Explicit
'********************************************************************************
'TestPDFThumbnailGeneration
'
' Purpose:  It uses reference to GhostscriptWrapper library.
'           From a pdf file creates a jpg file that represents a thumbnail of the pdf.
'           You can set page number and DPI quality.
'
' Inputs:   -none-
'
' Outputs:  -none-
'
' Created:  02/10/2011  Premysl Lazecky
'
' Modified: .
'
'********************************************************************************
Sub TestPDFThumbnailGeneration()

    Dim PDF             As GhostscriptWrapper
    Dim strPath         As String
    Dim strInputFile    As String

    strInputFile = "Test.pdf"
    strPath = ActiveWorkbook.Path
    If Right$(strPath, 1) <> Application.PathSeparator Then
       strPath = strPath & Application.PathSeparator
    End If

    Set PDF = New GhostscriptWrapper

    PDF.GeneratePDFThumb inputPath:=strPath & strInputFile, _
                         outputPath:=strPath & "Output.jpg", _
                         Page:=1, _
                         Width:=72, Height:=72


    Set PDF = Nothing

End Sub

As the result of this code you will get a jpg file called Output.jpg with thumbnail of defined page in the pdf file - in this case page 1 - with defined resolution.

Attachments

Installer and sample files
C# project

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(DonaldBlone, 19. 12. 2021 22:23)

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