Adding a watermark to a PDF file from a SharePoint Workflow

Muhimbi's has a great amount of interest from our existing PDF Converter customers for the Workflow Power Pack for SharePoint. I am not really surprised as there is a lot of of synergy between the two.

// A quick introduction for those not familiar with the product: The Muhimbi Workflow Power Pack for SharePoint allows custom C# or VB.NET code to be embedded in SharePoint Designer Workflows without the need to resort to complex Visual Studio based workflows, the development of bespoke Workflow Activities or long development cycles.

The solution presented below executes a workflow whenever a PDF file is added or updated. As part of the workflow it loads portrait and landscape based watermarks and applies the relevant template to each page of the document. The workflow author can specify if the watermark goes in the foreground or the background, the SharePoint location of the watermarks as well as the level of transparency. As the code is well documented it is easy to make further changes and customisations, e.g. the PDF file that needs to be watermarked may not be the file the workflow is acting on.


Create the workflow as follows:

1. Download and install the Muhimbi Workflow Power Pack for SharePoint.


2. Download and install the Muhimbi PDF Converter for SharePoint.
   Note that you need version 3.1.2.18 or newer, older versions do not allow watermarking.


3. Download this article’s source code and sample watermarks.


4. We need to be able to access functionality in the Muhimbi.SharePoint.DocumentConverter.PDF and System.Drawing assemblies. Add these references to the relevant Web Application using the Workflow Power Pack Central Administration screens as described in the Administration Guide. Make sure to place each reference on a new line.


5. Make sure you have the appropriate privileges to create workflows on a site collection.


6. Create a new workflow using SharePoint Designer.


7. On the Workflow definition screen associate the workflow with the Shared Documents library, tick the boxes next to both ‘Automatically start….’ options and proceed to the next screen.


8. We only want to act on files of type PDF. Although we could have put this validation in the code, in this example we use a workflow condition for it so add a Compare Any Data Source condition and:
   
   a. Click on the first value followed by the display data binding (fx) button.
   b. Select Current Item as the Source and select File Type in the Field. Click the OK button to continue.
   d. Click on the second value and enter pdf.


9. Click the Actions button and insert the Execute Custom Code action.
   


10. Optionally click parameter 1 and enter a relative or absolute destination path. Leave the parameter empty to save the watermarked file on top of the existing PDF file. For details about how paths are handled, see this post and search for the words ‘this url’.

Visit the URL for More information.  http://www.muhimbi.com/blog/2010/01/adding-watermark-to-pdf-file-from.html