Mathias Brandewinder on .NET, F#, VSTO and Excel development, and quantitative analysis / machine learning.
by Mathias 7. September 2010 16:56

In my previous posts, I explored how to identify text in a PowerPoint slide and use the Google .NET API to translate it; let’s put it all together in a simple VSTO add-in for PowerPoint 2007.

The translation functionality is displayed in a Custom Task Pane, where you can pick the language of origin, and the language to translate to. I used the same general design I presented in my Excel add-in tutorial, using WPF controls in the task pane with the MVVM pattern, leveraging the small yet very useful MVVM foundation framework. When running, this is how the add-in looks like:

TranslatorStart

TranslatorEnd

I added only 3 languages in there, but it is fairly easy to modify the code and get it to work with any language pair supported by Google translate.

Download code sample

by Mathias 2. September 2010 17:04

The beauty of working with a framework like .NET is that when you have a problem, chances are, someone else did before you, and might have even resolved it for you. In our last post, I explained how to find text in a PowerPoint slide using C#. My goal was to translate it using the Google Translate service, and I intended to write my own code to call the web service and retrieve the translation. Turns out, there is a .NET API for Google Translate, ready to use, which does it for you already (of course, I found that out already after rolling out my own code, which wasn’t nearly as good).

Building up where we left off, I quickly wrote this class, which will translate the slide currently in view; I think the code is self-explanatory: get the slide, create a Google translator, pass it the language of origin and of destination, and translate every chunk of text you find! The only thing I needed to do was to download GoogleTranslateAPI_0.3.1, add the dll to the project as a reference.

namespace ClearLines.PowerPointTranslator
{
   using Google.API.Translate;
   using PowerPoint = Microsoft.Office.Interop.PowerPoint;

   public class SlideTranslator
   {
      public static void TranslateSlide(Language from, Language to)
      {
         var googleTranslator = new TranslateClient("http://www.clear-lines.com");

         var powerpoint = Globals.ThisAddIn.Application;
         var slide = (PowerPoint.Slide)powerpoint.ActiveWindow.View.Slide;

         foreach (PowerPoint.Shape shape in slide.Shapes)
         {
            if (shape.HasTextFrame == Microsoft.Office.Core.MsoTriState.msoTrue)
            {
               var textFrame = shape.TextFrame;
               var textRange = textFrame.TextRange;
               TranslateTextRange(textRange, googleTranslator, from, to);
            }
         }
      }

      public static void TranslateTextRange(
         PowerPoint.TextRange textRange, 
         TranslateClient translator, 
         Language from,
         Language to)
      {
         var paragraphs = textRange.Paragraphs(-1, -1);
         foreach (PowerPoint.TextRange paragraph in paragraphs)
         {
            var text = paragraph.Text;
            text = text.Replace("\r", "");
            paragraph.Text = translator.Translate(text, from, to);
         }
      }
   }
}

Later this week, after I do some code scrubbing, I’ll post the entire VSTO solution. Until then, have fun – it’s almost the week-end!

by Mathias 21. August 2010 16:38

In a previous post, we saw how to programmatically search for text in a PowerPoint slide, by iterating over the Shapes contained in a slide, finding the ones that have a TextFrame, and accessing their TextRange property. TextRange exposes a Text property, which “represents the text contained in the specified object”.

Our goal is to translate a slide from a language to another, which means translating every chunk of text we find. However, the Text property contains a bit more than just text. Suppose you were working with a slide like the one below, which contains multiple bullet points, with various indentations:

DaftPunkSlide 

If you inspect the Text for the content area, you’ll see that it looks like this:

Work It\rMake It\rDo It\rMakes Us\rHarder\rBetter\rFaster\rStronger

At the end of each bullet point, we have a \r, which indicates a line break. If we want to maintain the formatting of our slide when we translate it, we’ll have to deal with it.

We’ll worry about the actual  translation later – for the moment we will use a fake method, which will show us what chunk of text has been translated:

public static string Translate(string text)
{
   return "Translated [" + text + "]";
}

A crude approach

A first approach would be to simply take the entire Text we find in the TextRange, manually separate it into chunks by splitting it around the carriage return character, translating the chunk, and re-composing the text, re-inserting the carriage returns.

Starting where we left off last time, let’s loop over the Shapes in the slide:

private void TranslateSlide()
{
   var powerpoint = Globals.ThisAddIn.Application;
   var presentation = powerpoint.ActivePresentation;
   var slide = (PowerPoint.Slide)powerpoint.ActiveWindow.View.Slide;
   foreach (PowerPoint.Shape shape in slide.Shapes)
   {
      if (shape.HasTextFrame == Microsoft.Office.Core.MsoTriState.msoTrue)
      {
         var textFrame = shape.TextFrame;
         var textRange = textFrame.TextRange;
         var text = textRange.Text;
         textRange.Text = CrudeApproach(text);
      }
   }
}

More...

by Mathias 8. August 2010 17:30

I am currently on a project which involves creating a PowerPoint VSTO add-in. I have very limited experience with PowerPoint automation, so before committing to the project, I thought it would be a good idea to explore a bit the object model, to gauge how difficult things could get, and I set to write a small PowerPoint add-in which would automatically translate slides. Sounds like a simple enough project, how difficult could it be?

Turns out, not too difficult, but not completely trivial either. I discovered quickly that the PowerPoint object model, unlike most Office applications, doesn’t have much (any?) documentation for the .Net developer; the best I found is the VBA PowerPoint 2007 developer reference, which gives a decent starting point to figure out what the objects are about. So I thought I would share my exploration of the PowerPoint jungle, and hopefully spare some trouble to other .Net developers.

The plan

The objective is simple: write an add-in which allows the user to

  • select a language to translate from, and a language to translate to,
  • create a duplicate of the current slide, translating all the text and keeping the layout

The plan will be to use Google Translate to perform the translation. In order to do that, we will nedd to extract out all pieces of text that require translating.

Finding all the text in a slide

Lets’ start by identifying where we have text in the current slide. Let’s first create a PowerPoint 2007 Add-in project in Visual Studio. To keep things simple for now, we will add a Ribbon control with a button, and when that button is clicked, we’ll start working on the current slide:

RibbonWithButton

Double-click on the Button (I renamed my button translateButton) to generate an event handler for the Click event, and get the current Slide:

private void translateButton_Click(object sender, RibbonControlEventArgs e)
{
   var powerpoint = Globals.ThisAddIn.Application;
   if (powerpoint.ActivePresentation.Slides.Count > 0)
   {
      var slide = (PowerPoint.Slide)powerpoint.ActiveWindow.View.Slide as PowerPoint.Slide;
   }
}

More...

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