Create Presentations in Node.js via .NET

Overview

This article shows how to create a presentation with Aspose.Slides for Node.js via .NET, add a text box to its first slide, and save the result as a PPTX file. It also shows how to add more slides and how to switch the presentation to widescreen (16:9) slides.

The examples need a project set up as described in Installation. Save each example as a .js file in the project folder and run it from that folder with node, for example node create-presentation.js.

Create a Presentation with a Text Box

To create a presentation and put a text box on its first slide, follow these steps:

  1. Create an instance of the Presentation class. A new presentation already contains one empty slide.
  2. Get that slide from the slides collection. Collections in this package are read with get(index), and indexes start at 0.
  3. Add a rectangle with the addAutoShape method and set the text of its textFrame.
  4. Save the presentation with the save method and the SaveFormat.Pptx value.
  5. Call dispose in a finally block to release the .NET resources that back the presentation.
const { Presentation, ShapeType, SaveFormat } = require("aspose.slides.via.net");

const presentation = new Presentation();
try {
    const slide = presentation.slides.get(0);

    // The position (x, y) and the size (width, height) are in points.
    const textBox = slide.shapes.addAutoShape(ShapeType.Rectangle, 50, 50, 400, 100);
    textBox.textFrame.text = "Hello, Aspose.Slides!";

    presentation.save("new-presentation.pptx", SaveFormat.Pptx);
    console.log("Saved new-presentation.pptx");
} finally {
    presentation.dispose();
}

The script writes new-presentation.pptx to the project folder. The file has one slide with a filled rectangle whose top-left corner is 50 points from the left and top edges of the slide. The rectangle is 400 points wide and 100 points high, and its text is centered. A point is 1/72 inch. Without a license, Aspose.Slides also adds an evaluation watermark to the slide; see Licensing.

Add Slides

A new presentation has one slide. To add more, pass a layout slide to the addEmptySlide method of the slides collection. The getByType method of the layoutSlides collection returns the first layout of a given SlideLayoutType.

The following example adds two slides with the Blank layout:

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

const presentation = new Presentation();
try {
    const blankLayout = presentation.layoutSlides.getByType(SlideLayoutType.Blank);
    presentation.slides.addEmptySlide(blankLayout);
    presentation.slides.addEmptySlide(blankLayout);

    console.log("Slide count: " + presentation.slides.count);
    presentation.save("three-slides.pptx", SaveFormat.Pptx);
} finally {
    presentation.dispose();
}

The script prints Slide count: 3 and writes three-slides.pptx. The new slides are appended after the first one and contain no shapes. A new presentation always has a Blank layout, but a presentation that you open from a file may not have a layout of the requested type; in that case getByType returns null, so check the result before you pass it on.

Set the Slide Size

A new presentation uses 4:3 slides that are 720 × 540 points (10 × 7.5 inches). To create widescreen slides instead, call the setSize method of the presentation’s slideSize with a SlideSizeType value and a SlideSizeScaleType value. The scale type tells Aspose.Slides what to do with shapes that are already on the slides; DoNotScale leaves them as they are, which is the right choice for a presentation that has no content yet.

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

const presentation = new Presentation();
try {
    presentation.slideSize.setSize(SlideSizeType.Widescreen, SlideSizeScaleType.DoNotScale);

    const slideSize = presentation.slideSize.size;
    console.log(`Slide size: ${slideSize.width} x ${slideSize.height} points`);

    presentation.save("widescreen.pptx", SaveFormat.Pptx);
} finally {
    presentation.dispose();
}

The script prints Slide size: 960 x 540 points, which is 13.33 × 7.5 inches, and writes widescreen.pptx. SlideSizeType.OnScreen16x9 has the same 16:9 aspect ratio but is smaller: 720 × 405 points.

FAQ

In what units are positions and sizes measured?

In points. One inch is 72 points, so the default 4:3 slide is 720 × 540 points, and a 16:9 widescreen slide is 960 × 540 points.

Which formats can I save a new presentation to?

Any value of the SaveFormat enumeration, for example SaveFormat.Ppt for PowerPoint 97–2003, SaveFormat.Odp for OpenDocument, or SaveFormat.Pdf. For PDF output, see Convert PowerPoint to PDF.

Why does the saved presentation contain “Evaluation only” text?

Without a license, Aspose.Slides adds an evaluation watermark to the slides it saves. Apply a license as described in Licensing to remove it.

Why should I call dispose?

A Presentation object is backed by a .NET object that holds memory and other resources. Calling dispose releases them as soon as you no longer need the presentation, and calling it in a finally block releases them even when an error occurs.

Open Presentations in Node.js via .NET