Multiple OBJR when Link span more than one line

[rosana_10]

I am testing PDF link functionality in iPhone and Android devices, in particular links that span more than one line and have multiple OBJR annotations versus links that have only one OBJR annotation.

On a desktops/laptops computers, when PDFs are opened in Acrobat Reader, and users who can’t use the mouse use keyboard to navigate the links, multiple OBJR annotations causes extra tabbing. So, I usually make sure the Links have only one OBJR .

However, on mobile devices, these links are accessed via gestures, and activated with tapping (the navigation on mobile devices is different than on desktops/laptops).

These are my questions:

• Is it considered best practice to remove extra OBJRs to avoid excessive tabbing in oder provide a better user experience?
• Does removing extra OBJR causes any accessibility issues for sighted users when PDFs are viewed on the browser?
• Has anyone seen any issues if only one OBJR annotation is used for the links when they span more than one line?  I am not asking about screen reader users; I am interested in sighted users who are able to see the links. In my opinion, if sighted users selected the section of the link that does not have an OBJR, since the links are blue and underlined, they could easily move to another section of that hyperlink to activate it. So, I am not sure that having one OBJR will create a barrier for sighted uses on mobile devices on when viewing PDFs on browsers. For example:
  "This is a test www.xxx.com/this-is-a-test/this-links-does-not/
  links.com. There is more text here, this is just a sample."
  <P> "This is a test:
       <Link> 
             OBJR
             www.xxx.com/this-is-a-test/this-link-does-not/links.com
  There is more text here, this is just a sample." 
  Note: the longer section of the link will be tabbable item.

• Is there any writing guidance that says that single OBJR annotation will cause issues if PDFs are accessed in mobile devices or when viewed on browsers?
• Has anyone done this type of research? If so, could you please share the findings or documentation?

Thanks in advance, Rosana.

[S. S]

Hi @rosana_10,

Hope you are doing well. Thanks for writing in!

Answering your questions point by point below:

Best Practices for OBJR Annotations

• Reducing Excessive Tabbing: It is generally considered best practice to minimize the use of multiple OBJR annotations. This helps reduce excessive tabbing, enhancing the overall user experience by making navigation more straightforward and intuitive.
• Accessibility for Sighted Users: Removing extra OBJRs typically does not create significant accessibility issues for sighted users. Suppose a link is visually clear (e.g., blue and underlined). In that case, users should be able to quickly identify and click on it, even if only one OBJR annotation covers the entire link.
• Single OBJR for Multi-line Links: Using a single OBJR for links that span multiple lines generally works well for sighted users. They can select any part of the link to activate it, and the visual cues (color and underline) should be sufficient to indicate it's a clickable link.

For mobile users, the key points are:

• Touch Target Size: Ensure that the OBJR encompasses the whole clickable area of the link. A well-implemented single OBJR should not create barriers if the link is touchable.
• Visual Clarity: If the link is visually distinct and the user can easily tap on it, a single OBJR should not pose problems.

Guidance and Research

While specific studies focused on OBJR annotations may be limited, general accessibility principles apply:

• WCAG and PDF/UA Guidelines: provide best practices for accessible documents, emphasizing straightforward navigation and identifiable links.
• User Testing: Conducting tests with sighted users can yield insights into their experiences with PDF navigation and OBJR usage.

In summary, using a single OBJR annotation for links is likely to improve the experience of sighted users on mobile devices or browsers. For more comprehensive insights, consider investigating user feedback and accessibility testing specific to your audience.

Hope this helps.

-Souvik

[rosana_10]

Thanks! See this comment from https://pdfa.org/wp-content/uploads/2019/06/TaggedPDFBestPracticeGuideSyntax.pdf:

"In the case where a single <Link> structure element encloses multiple link annotations, and where all link annotations have identical targets, and if it is semantically correct to do so, representing a single link to the user is likely to deliver a better user experience."

This is what I usaully do then links span more than one line. Would you agree with this assessment?

Neither WCAG nor PDF/UA Guidelines says having multliple OBJRs is a 508 defect. However,  removing extra OBJR nested under the <Link> and just keeping one OBJR will provide a better user experience, right? 

Let me know your thougths on this approach.

[S. S]

@rosana_10,

I agree with the assessment that consolidating multiple link annotations into a single <Link> structure element can enhance the user experience, especially when they share identical targets. This approach simplifies navigation and clarifies it for users, particularly those using assistive technologies.

While WCAG and PDF/UA guidelines may not explicitly label multiple OBJRs as a defect, streamlining them by removing redundant ones and retaining a single OBJR can lead to a more straightforward and cohesive experience. Fewer objects can reduce confusion and make the document easier to interact with.

Overall, consolidating the links is a sound practice if the content is semantically correct and the links function as intended. Just ensure that the final structure maintains accessibility and clarity for all users.

-Souvik