Hello.Say we have a PDF with one page whose /Resources dictionary contains the /XObject dictionary referring to a Form XObject. Both the page's and the Form XObject's streams contain a marked content sequence. Sure, the Form XObject has its own StructParents (plural) key.Every marked sequence of the Form XObject's content is referred to by structure elements via /MRC (PDF Specification paragraph 14.7.4.2).For the Adobe Acrobat Accessibility Full Check everything is fine as long as:the page's content contains some text (Tj);the page's content consumes some Image XObject (Do);the Form XObject's content contains some text (Tj);the Form XObject's content consumes some other Form XObject (Do), in turn containing only some text (Tj).Instead if the Form XObject's content consumes some other Image XObject (Do), the Full Check complains that such images are not properly tagged ('Other elements alternate text - Failed').Instead the PAC3 Checker is happy.Curiously, asking Adobe Acrobat to tag such images does nothing.Please, consider that in my case extracting the Form XObject's content to put in directly in the page's content is not an option.Considering the mismatch between the Adobe Full Check and PAC3, I need help to understand if the Adobe Full Check is right or not.Thank you all.

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Form XObject containing Image XObject causes 'Other elements alternate text - Failed'

Forum|Forum|8 years ago
January 31, 2018
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Hello.

Say we have a PDF with one page whose /Resources dictionary contains the /XObject dictionary referring to a Form XObject. Both the page's and the Form XObject's streams contain a marked content sequence. Sure, the Form XObject has its own StructParents (plural) key.

Every marked sequence of the Form XObject's content is referred to by structure elements via /MRC (PDF Specification paragraph 14.7.4.2).

For the Adobe Acrobat Accessibility Full Check everything is fine as long as:

the page's content contains some text (Tj);
the page's content consumes some Image XObject (Do);
the Form XObject's content contains some text (Tj);
the Form XObject's content consumes some other Form XObject (Do), in turn containing only some text (Tj).

Instead if the Form XObject's content consumes some other Image XObject (Do), the Full Check complains that such images are not properly tagged ('Other elements alternate text - Failed').

Instead the PAC3 Checker is happy.

Curiously, asking Adobe Acrobat to tag such images does nothing.

Please, consider that in my case extracting the Form XObject's content to put in directly in the page's content is not an option.

Considering the mismatch between the Adobe Full Check and PAC3, I need help to understand if the Adobe Full Check is right or not.

Thank you all.

Standards and accessibility

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R

renatom83808386Author

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How to involve an Adobe Escalation Manager to investigate on such issues?

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And now, the third unexpected behavior, this time for the loud reader. The problem is about the 'read on mouse click' feature.

Say we have a Form XObject (A) containing a marked content sequence made of some texts (Tj), each enclosed in a BDC-EMC block.

If the Form XObject (A) contains all the text directly, everything is OK, indeed we can click on each text, that text only will be surrounded by a black rectangle and the lour reader reads it only.

Instead, if even one only text is contained as pure text (i.e. not a marked content sequence) in an inner Form XObject (B), all the text content of the Form XObject (A) is treated as a whole block, indeed clicking on any text, all the Form XObject (A) content will be surrounded by a black rectangle and the lour reader reads the last text.

I can provide PDF samples for every case.

To summarize the thread, there are three unexpected behaviors about Form XObject-s:

if a Form XObject's content consumes some other Image XObject (Do), the Accessibility Full check complain about 'Other elements alternate text - Failed';
PreFlight ignores the /StructParents key when it handles the MCIDs of a page and of Form XObjects' consumed by the page;
if in a Form XObject's content a marked block consumes a pure text contained in an inner Form XObject (Do), the lour reader does not handle properly the feature 'read on mouse click' for the every text of the first Form XObject, direct or nested.

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Again: how to involve an Adobe Escalation Manager to investigate on such issues?