Open Presentation in JavaScript

Besides creating PowerPoint presentations from scratch, Aspose.Slides allows you to open existing presentations. After you load a presentation, you can get information about the presentation, edit the presentation (content on its slides), add new slides or remove existing ones, etc.

Open Presentation

To open an existing presentation, you simply have to instantiate the Presentation class and pass the file path (of the presentation you want to open) to its constructor.

This JavaScript code shows you how to open a presentation and also find out the number of slides it contains:

// Instantiates the Presentation class and passes the file path to its constructor
var pres = new aspose.slides.Presentation("Presentation.pptx");
try {
    // Prints the total number of slides present in the presentation
    console.log(pres.getSlides().size());
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Open Password Protected Presentation

When you have to open a password-protected presentation, you can pass the password through the getPassword method (from the LoadOptions class) to decrypt the presentation and load the presentation. This JavaScript code demonstrates the operation:

var loadOptions = new aspose.slides.LoadOptions();
loadOptions.setPassword("YOUR_PASSWORD");
var pres = new aspose.slides.Presentation("pres.pptx", loadOptions);
try {
    // Do some work with the decrypted presentation
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Open Large Presentation

Aspose.Slides provides options (the getBlobManagementOptions method in particular) under the LoadOptions class to allow you to load large presentations.

This JavaScript demonstrates an operation in which a large presentation (say 2GB in size) is loaded:

var loadOptions = new aspose.slides.LoadOptions();
loadOptions.getBlobManagementOptions().setPresentationLockingBehavior(aspose.slides.PresentationLockingBehavior.KeepLocked);
loadOptions.getBlobManagementOptions().setTemporaryFilesAllowed(true);
loadOptions.getBlobManagementOptions().setMaxBlobsBytesInMemory(0);
var pres = new aspose.slides.Presentation("veryLargePresentation.pptx", loadOptions);
try {
    // The large presentation has been loaded and can be used, but the memory consumption is still low.
    // makes changes to the presentation.
    pres.getSlides().get_Item(0).setName("Very large presentation");
    // The presentation will be saved to the other file. The memory consumption stays low during the operation
    pres.save("veryLargePresentation-copy.pptx", aspose.slides.SaveFormat.Pptx);
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Info

To circumvent certain limitations when interacting with a stream, Aspose.Slides may copy the stream’s content. Loading a large presentation through its stream will result in the copying of the presentation’s contents and cause slow loading. Therefore, when you intend to load a large presentation, we strongly recommend that you use the presentation file path and not its stream.

When you want to create a presentation that contains large objects (video, audio, big images, etc.), you can use the Blob facility to reduce memory consumption.

Load Presentation

Aspose.Slides provides ResourceLoadingCallback with a single method to allow you to manage external resources. This JavaScript code shows you how to use the IResourceLoadingCallback class:

var opts = new aspose.slides.LoadOptions();
opts.setResourceLoadingCallback(java.newInstanceSync("ImageLoadingHandler"));
var pres = new aspose.slides.Presentation("presentation.pptx", opts);

You will need to implement ImageLoadingHandler in Java, compile it, and add it to the module location \aspose.slides.via.java\lib.

class ImageLoadingHandler implements IResourceLoadingCallback
{
    public int resourceLoading(IResourceLoadingArgs args)
    {
        if (args.getOriginalUri().endsWith(".jpg"))
        {
            try // loads substitute image
            {
                byte[] imageBytes = Files.readAllBytes(new File("aspose-logo.jpg").toPath());
                    args.setData(imageBytes);
                return ResourceLoadingAction.UserProvided;
            } catch (RuntimeException ex) {
                return ResourceLoadingAction.Skip;
            }  catch (IOException ex) {
                ex.printStackTrace();
                }
            } else if (args.getOriginalUri().endsWith(".png")) {
                // sets substitute url
                args.setUri("http://www.google.com/images/logos/ps_logo2.png");
            return ResourceLoadingAction.Default;
            }
            // skips all other images
        return ResourceLoadingAction.Skip;
        }
    }

Load Presentation Without Embedded Binary Objects

The PowerPoint presentation can contain the following types of the embedded binary objects:

• VBA Project (Presentation.VbaProject);
• OLE Object embedded data (OleEmbeddedDataInfo.getEmbeddedFileData);
• ActiveX Control binary data (Control.getActiveXControlBinary);

Using the LoadOptions.setDeleteEmbeddedBinaryObjects property, you can load the presentation without any embedded binary objects.

This property can be useful for removing potentially malicious binary content.

The code demonstrates how to load and save a presentation without any malware content:

var loadOptions = new aspose.slides.LoadOptions();
loadOptions.setDeleteEmbeddedBinaryObjects(true);
var pres = new aspose.slides.Presentation("malware.ppt", loadOptions);
try {
    pres.save("clean.ppt", aspose.slides.SaveFormat.Ppt);
} finally {
    if (pres != null) {
        pres.dispose();
    }
}

Open and Save Presentation

Steps to Open and Save Presentation:

1. Create an instance of the Presentation class and pass the file you want to open.
2. Save the presentation.

// Instantiates a Presentation object that represents a PPT file
var pres = new aspose.slides.Presentation();
try {
    // ...do some work here...
    // Saves your presentation to a file
    pres.save("demoPass.pptx", aspose.slides.SaveFormat.Pptx);
} finally {
    if (pres != null) {
        pres.dispose();
    }
}