Convert PowerPoint to PDF in Node.js via .NET

Overview

Aspose.Slides for Node.js via .NET converts PowerPoint and OpenDocument presentations to PDF without Microsoft PowerPoint. Each visible slide becomes one PDF page of the same size as the slide, and the text stays selectable and searchable. This article shows the default conversion and a conversion to PDF/A with PdfOptions.

The examples expect a presentation named sample.pptx in the project folder that you set up in Installation. Any PowerPoint presentation will do. Save each example as a .js file in the project folder and run it from that folder with node.

Convert a Presentation to PDF

To convert a presentation to PDF, follow these steps:

  1. Open the presentation by passing its path to the Presentation constructor. The same code works for PPTX, PPT, and ODP files.
  2. Call the save method with the output path and SaveFormat.Pdf.
  3. Call dispose in a finally block to release the .NET resources that back the presentation.
const { Presentation, SaveFormat } = require("aspose.slides.via.net");

const presentation = new Presentation("sample.pptx");
try {
    presentation.save("sample.pdf", SaveFormat.Pdf);
    console.log("Saved sample.pdf");
} finally {
    presentation.dispose();
}

The script writes sample.pdf to the project folder. The conversion uses default settings: every slide that is not hidden becomes a page, in slide order. Without a license, each page also shows an evaluation watermark; see Licensing.

Convert a Presentation to PDF/A

To control the output, pass a PdfOptions object as the third argument of save. The following example sets the compliance property to PdfCompliance.PdfA2b, which produces a PDF/A-2b file. PDF/A is the ISO standard for long-term archiving: among other rules, it requires every font that the document uses to be embedded in the file.

const { Presentation, SaveFormat, PdfOptions, PdfCompliance } = require("aspose.slides.via.net");

const pdfOptions = new PdfOptions();
pdfOptions.compliance = PdfCompliance.PdfA2b;

const presentation = new Presentation("sample.pptx");
try {
    presentation.save("sample-pdfa.pdf", SaveFormat.Pdf, pdfOptions);
    console.log("Saved sample-pdfa.pdf");
} finally {
    presentation.dispose();
}

The script writes sample-pdfa.pdf with the same pages as the default conversion. To confirm that a file meets the standard, check it with a PDF/A validator such as veraPDF. Other PdfCompliance values select other standards, such as PdfA1b, PdfA2a, or PdfUa for accessibility.

FAQ

How do I include hidden slides in the PDF?

Hidden slides are skipped by default. Set the showHiddenSlides property of PdfOptions to true and pass the options to save.

Can I protect the PDF with a password?

Yes. Set the password property of PdfOptions before you call save. PDF readers then ask for that password before they open the file.

Can I convert only some of the slides?

Yes. Pass an array of slide positions as the fourth argument of save. Positions start at 1, and the third argument can be null if you need no options: presentation.save("selected.pdf", SaveFormat.Pdf, null, [1, 3]) writes a PDF with the first and third slides.

Why does the text look different when I convert on Linux?

Aspose.Slides can only use fonts that are installed on the machine that runs the conversion. When a presentation uses a font that is missing, such as Calibri on a typical Linux server, Aspose.Slides uses an installed font in its place, which can change the look of the text and where lines break. Install the fonts that your presentations use to get the same result as on Windows.

Can I get the PDF as a Buffer instead of a file?

Yes. presentation.saveToBuffer(SaveFormat.Pdf) returns the PDF as a Node.js Buffer, which is convenient when you send the result in an HTTP response. It also accepts PdfOptions as its second argument.

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