PDF Technique 4, Test Process bullet 3
Opened this issue · 7 comments
https://www.w3.org/WAI/WCAG21/Techniques/pdf/PDF4
Reflow view does not consistently hide images marked/tagged as Artifact and should not be a test for this.
I don't recall ever seeing an artifacted image displayed in Reflow view. Do you have an example of such a document or do you know the steps to cause it to happen?
The attached PDF shows two blue boxes, both marked as artifacts when set to View> Reflow. This does not always happen but it definitely happens. This was created in Word. Acrobat continuous release 64-bit 2024.002.20991
Reflow test.pdf
Be interested to know how this shows on your system.
I don't think the blue boxes are marked as artifacts. They are output by the screen reader and the PAC also shows them
The blue boxes are marked as artifacts, but there's something wrong with them. If I un-artifact them and re-artifact them, they are not displayed in Reflow mode. The node Properties look exactly the same in both cases, so the difference is deeper in some place we can't see.
How did you artifact them? Did you mark the boxes as decorative in Word? Some time ago I did some tests in PowerPoint that showed it treats boxes with coloured backgrounds differently from boxes with no background colour. I suspect the same happens with Word. As I (vaguely) recall, it was not necessary to mark the box with no background colour as decorative, but it was necessary to mark the one with the background colour as decorative, otherwise it got treated as an image.
Actually, my last comment was not entirely true. In the original document, the four Path nodes are in a container that is shown as in the Contents panel. However, when you view the Properties, the Container Tag field is empty, which means it is not an artifact.
By contrast, after un-artifacting and re-artifacting the container, the Container Tag field is correctly set to Artifact.
So, I would say it's ok to retain the "Reflow the document and make sure the decorative image does not appear on the page" test. If containers are correctly artifacted, they will not be displayed. If they are displayed, it means they have not been artifacted correctly.
Thanks for looking into this issue.
The first PDF was made from Word but the boxes were not marked as decorative in Word. They were placed in the document header, where all content is supposedly artifacted when converted to PDF. Creating a second test file, where the boxes (still in the header) are Marked as decorative in Word does not change the outcome as the boxes still appear in Reflow view.
BTW I get no artifact or box-related error in PAC 2024 from the original file. There are other errors in the document, but they are not related to the boxes.
I get your point that these are not properly artifacted but that is what the software gives us. It's marked as decorative in Word, it's showing as an Artifact in the Content pane. And I hear no announcement re the boxes when using NVDA or Jaws—not even in Reflow view. It acts like an artifact (on my system) but still shows up in Reflow view. Yes, if one unartifacts and then reartifacts the boxes, they disappear from reflow view. But I see no change in the Contents container Properties, the Container Tag field is empty before and after this step when viewed in Acrobat. What are you using to examine this? Unfortunately, the unartifact/reartifact step is not a documented procedure as far as I know. Perhaps there should be a description of this technique on this page?
Reflow view then is the only way to determine if this is a properly formed artifact, but only one of the Procedures is required to pass this test.
Seems like this is a bug in either Word or Acrobat and should be reported. I don’t have access to Indesign to test a document created there but it would be interesting to see.
You wouldn't expect a screen reader to announce the boxes because there is nothing to announce. They don't have alternate text and they are not images - they are Paths, which are just shapes.
The behaviour of the empty Container Tag field is strange. This morning, when I created an artifact, the field showed "Artifact" and I could change it to something else. When I did exactly the same thing an hour later, the Container Tag field was greyed-out like you are seeing. A colleague verified this on another machine. But at least the boxes no longer appeared in Reflow mode. The joy of Acrobat!
Testing Reflow is problematic because no user agents support Reflow fully. Most don't support it at all. There are a couple of options (maybe more) that give different results, including:
- Test using Adobe Reader or Acrobat even though it doesn't properly support Reflow. This gets its reading order from the Content panel, so you would need to fix that, which most people don't do, not even "professional" document remediators.
- Test using VIP PDF Reader. This gets its reading order from the Tags panel and is specifically designed to work in reflow mode all the time. It doesn't display any non-text content, so your document would reflow perfectly.
There are significant bugs in all the tools we use, including Word, Acrobat and PAC 2024. This makes life very difficult.
Returning to your original question regarding Technique PDF4, I think the wording of the Reflow test in the Procedure section is adequate. If an item is not displayed in Reflow mode, it means it is correctly artifacted. This in turn means that there is no text alternative for the non-text content, which is what Technique PDF4 is all about. If an item is displayed in Reflow mode, it means it is either not artifacted or not artifacted correctly. Either way, the document needs to be fixed.
The problem is actually in the previous test, which says "Using a PDF editor, make sure the decorative image is marked as an artifact." It seems that in Acrobat, there is no way to "make sure" the decorative image is correctly marked as an artifact. The Contents panel might show an item as being artifacted, but we have shown that it might not be artifacted correctly, so you can't rely on that. The Properties dialog should show the value of the Container Tag field, but it is usually empty and greyed-out even when an item is correctly artifacted, so you can't rely on that either. A more capable PDF editor might well display the Container Tag field correctly, but I don't know of one.