Multipage Nested Layers: A Comparison of PDF Tools – Part 3

PDF layers, also known as optional content groups (OCGs), are a part of PDF functionality and have been around for almost 20 years. This can be extremely useful with CAD drawings, for example, allowing users to focus on those aspects of the drawing that they are particularly interested in, without being distracted by things that are not currently important.

In the previous articles in this series, we looked at how simple layers and nested layers were supported in a range of PDF viewers.

In this article, we will look at the support for multipage PDFs that contain nested layers (layer groups) in a range of PDF readers, and see why the Apryse WebViewer is a standout solution.

In the second article in this series, the sample PDF was created using ArcGIS from ESRI and contains mapping data for parts of the Western USA. That PDF, and two more for other parts of the US created in the same way, have been merged into a single three-page document (using xodo.com).

The resulting document is similar in format and data complexity to files that some customers work with. It contains three pages – each with a set of layers that relate to a single page.

As before, the Scale Bar is a great example of a layer group, consisting of the ratio text, and two scale lines – one for miles and the other for kilometers.

This allows any of those items to be hidden either separately or as a group.

In the previous article, we saw that Chrome, Edge, PDF.js Express, Aspose, PDFSimpli, and Allinpdf do not support layers, so we will not look at them again. As such, the tools used in this test are those that successfully worked with simple layers.

The following browser was evaluated:

Three within-browser (Chrome) options were reviewed:

Two standalone desktop tools were reviewed:

The following features were used to assess how well a viewer works with multipage PDFs that contain layers:

Acrobat sets the standard here. If a single page is visible (within the view), just the layers that relate to that page are available in the Layers Panel.

With Two-Page View (without scrolling), the layers for both pages are shown.

Similarly, if all three pages are visible, the layers for all pages are shown.

For this PDF and ones like it, the ability to hide unused layers is helpful. Each page has the same layer names, so it can be confusing as to which layer relates to which page.

With all of the pages visible, if the last Scale Bar is hidden from the Layers panel, then the scale bar disappears for that page exactly as expected.

Let’s look at the other viewers.

Firefox behaves entirely differently from Acrobat. In previous articles we have seen that Firefox has issues with showing nested layers. But now the number of layers becomes completely unwieldy, and it is possible to “hide” layers that are not actually visible.

Apryse WebViewer shows all of the layers even if only a single page is showing. As a result, it is possible to “hide” layers that are not actually visible, which has the potential to be very confusing.

It was difficult to evaluate PSPDFKit. The online demo either allows you to set the view to single page/two page etc., or to show layers. Although all of the layers were visible, it is not possible to rule out that if only a single page was shown, only the layers relating to that page would be visible in the Layers Panel.

However, as previously found, any attempt to toggle layer visibility results in all of the map content being hidden.

As previously reported, PDF Studio Pro does not support nested layers well.

Furthermore, in a multipage document, its Layer Panel shows all of the layers for all of the pages, making it difficult to use.

Having seen that most of the viewers are not intuitive, let’s now look at what happens if we convert a multipage document back into a single page one.

In this test, the three page document was converted back into a single page document. This was done either by:

The modified document was then viewed in Xodo.

Three types of results were found.

This is the ideal result. Only the layers that relate to the single page are present. This avoids confusion, since there is only one set of layers within the Layers Panel, so you can’t click on the “wrong one.”

This result was found for PDFs created by deleting pages using Acrobat or Xodo.

A similar PDF was also created by saving just a single page of the PDF using Apryse WebViewer.

In this case, even though two of the pages have been removed, the layers that were in those pages have been retained in the PDF. This has the potential to be very confusing, since you can select a layer for a page that is not only not visible, it doesn’t exist at all.

This result was created by PDF Studio Pro. It was also created by removing pages from the thumbnail viewer in Apryse WebViewer. (Note that this is a different result than what occurred by saving the PDF with just a single page.)

This is the worst result and was found by removing pages using PSPDFKit. All of the layers have been discarded, including those for the page that has been kept.

This could result in significant loss of functionality.

The following table summarizes the test results. If layers matter to you, you’ll want to choose a PDF viewer that has as many green cells as possible.

Check out our blog post to learn how to create new PDFs from each layer.

This is a complex niche case, which will not affect many users.

However, if you are one of those users and you have a workflow that creates multipage PDFs with nested layers, this will matter enormously.

Acrobat has the edge if it really matters that you only show the layers related to the page that is visible since it does that straight out of the box.

However, Apryse WebViewer is open source, so if you wish, you can fork the project and alter viewer behavior. Furthermore, Apryse SDK allows you to manipulate the PDF itself, offering control of the contents which may allow you to work around this complexity.

With regards to creating a single page document from a multi-page PDF that contains layers, there was no apparent difference between Acrobat, Xodo, and the Apryse WebViewer.

Once again PSPDFKit was disappointing, particularly with regard to creating single page documents since all of the layers were discarded in the process.

But don’t just take our word for it, try out the functionality at the Apryse Showcase and then have a look at the many samples that illustrate what it can do.

Alternatively, you can try out the SaaS option at Xodo.com.

When you are ready to get started, see the documentation for the SDK to get going quickly. Don’t forget, you can also reach out to us on Discord if you have any issues.