Aspose.Slides contains completely different set of classes to process PPTX files. Use Aspose.Slides.Pptx.PresentationEx class.
All slides in pptx format already sorted in correct order so it’s not necessary to use GetSlideByPosition method. You can access slides directly by index:
PresentationEx pptx = new PresentationEx(…);
SlideEx slide = pptx.Slides[i];
SlideEx.GetThumbnail also known as rendering currently in development. First version will be available for public testing in September.
It should be available at the end of the next week.
The September release of Aspose.Slides for .NET is due and we will let you know as soon as it is done.
Any release date set for this yet? We’re evaluating Aspose Slides and this is a critical feature for us.
It will be available on Sunday as promised before.
how can I convert the Bitmap to a PDF ?
You need some component like Aspose.Pdf for this and an example is here. However, PPTX to PDF export will be implemented in the upcoming release which is due in one or two weeks. The issue id for this feature is 10966 and you will be informed on availability of this feature.