Manage Presentation Placeholders in JavaScript

Change Text in Placeholder

Using Aspose.Slides for Node.js via Java, you can find and modify placeholders on slides in presentations. Aspose.Slides allows you to make changes to the text in a placeholder.

Prerequisite: You need a presentation that contains a placeholder. You can create such a presentation in the standard Microsoft PowerPoint app.

This is how you use Aspose.Slides to replace the text in the placeholder in that presentation:

1. Instantiate the Presentation class. and pass the presentation as an argument.
2. Get a slide reference through its index.
3. Iterate through the shapes to find the placeholder.
4. Typecast the placeholder shape to an AutoShape and change the text using the TextFrame associated with the AutoShape.
5. Save the modified presentation.

This JavaScript code shows how to change the text in a placeholder:

// Instantiates a Presentation class
var pres = new aspose.slides.Presentation("ReplacingText.pptx");
try {
    // Accesses the first slide
    var sld = pres.getSlides().get_Item(0);
    // Iterates through shapes to find the placeholder
    for (let i = 0; i < sld.getShapes().size(); i++) {
        let shp = sld.getShapes().get_Item(i);
        if (shp.getPlaceholder() != null) {
            // Changes the text in each placeholder
            shp.getTextFrame().setText("This is Placeholder");
        }
    }
    // Saves the presentation to disk
    pres.save("output.pptx", aspose.slides.SaveFormat.Pptx);
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Set Prompt Text in Placeholder

Standard and pre-built layouts contain placeholder prompt texts such as Click to add a title or Click to add a subtitle. Using Aspose.Slides, you can insert your preferred prompt texts into placeholder layouts.

This JavaScript code shows you how to set the prompt text in a placeholder:

var pres = new aspose.slides.Presentation("Presentation.pptx");
try {
    var slide = pres.getSlides().get_Item(0);
    // Iterates through the slide
    for (let i = 0; i < slide.getSlide().getShapes().size(); i++) {
        let shape = slide.getSlide().getShapes().get_Item(i);
        if ((shape.getPlaceholder() != null) && (java.instanceOf(shape, "com.aspose.slides.AutoShape"))) {
            var text = "";
            // PowerPoint displays "Click to add title"
            if (shape.getPlaceholder().getType() == aspose.slides.PlaceholderType.CenteredTitle) {
                text = "Add Title";
            } else // Adds subtitle
            if (shape.getPlaceholder().getType() == aspose.slides.PlaceholderType.Subtitle) {
                text = "Add Subtitle";
            }
            shape.getTextFrame().setText(text);
            console.log("Placeholder with text: " + text);
        }
    }
    pres.save("Placeholders_PromptText.pptx", aspose.slides.SaveFormat.Pptx);
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Set Placeholder Image Transparency

Aspose.Slides allows you to set the transparency of the background image in a text placeholder. By adjusting the transparency of the picture in such a frame, you can make the text or the image stand out (depending on the text’s and picture’s colors).

This JavaScript code shows you how to set the transparency for a picture background (inside a shape):

var presentation = new aspose.slides.Presentation("example.pptx");
var shape = presentation.getSlides().get_Item(0).getShapes().get_Item(0);
var operationCollection = shape.getFillFormat().getPictureFillFormat().getPicture().getImageTransform();
for (var i = 0; i < operationCollection.size(); i++) {
    if (java.instanceOf(operationCollection.get_Item(i), "com.aspose.slides.AlphaModulateFixed")) {
        var alphaModulate = operationCollection.get_Item(i);
        var currentValue = 100 - alphaModulate.getAmount();
        console.log("Current transparency value: " + currentValue);
        var alphaValue = 40;
        alphaModulate.setAmount(100 - alphaValue);
    }
}
presentation.save("example_out.pptx", aspose.slides.SaveFormat.Pptx);

FAQ

What is a base placeholder, and how is it different from a local shape on a slide?

A base placeholder is the original shape on a layout or master that the slide’s shape inherits from—type, position, and some formatting come from it. A local shape is independent; if there’s no base placeholder, inheritance doesn’t apply.

How can I update all titles or captions across a presentation without iterating over every slide?

Edit the corresponding placeholder on the layout or the master. Slides based on those layouts/that master will automatically inherit the change.

How do I control the standard header/footer placeholders—date & time, slide number, and footer text?

Use the HeaderFooter managers at the appropriate scope (normal slides, layouts, master, notes/handouts) to turn those placeholders on or off and to set their content.