Bug 164798 - Export to PDF: Repairing missing alternative text in Acrobat results to "Other elements alternative text" error
Summary: Export to PDF: Repairing missing alternative text in Acrobat results to "Othe...
Status: UNCONFIRMED
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Writer (show other bugs)
Version:
(earliest affected)
7.5.5.2 release
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords: accessibility
Depends on:
Blocks:
 
Reported: 2025-01-22 15:49 UTC by devseppala
Modified: 2025-02-19 10:06 UTC (History)
1 user (show)

See Also:
Crash report or crash signature:


Attachments
Example document with a picture of apples without alternative text. (52.77 KB, application/vnd.oasis.opendocument.text)
2025-02-18 17:37 UTC, devseppala
Details
PDF export of the example .odt document using LO 7.5.4 (27.96 KB, application/pdf)
2025-02-18 17:39 UTC, devseppala
Details
PDF export of the example .odt document using LO 25.2.0 (33.36 KB, application/pdf)
2025-02-18 17:40 UTC, devseppala
Details
Acrobat Pro screenshot of LO7.5.4 exported document before FIX (109.92 KB, image/png)
2025-02-18 17:41 UTC, devseppala
Details
Acrobat Pro screenshot of LO7.5.4 exported document before FIX, set "picture of apples" alternative text (109.88 KB, image/png)
2025-02-18 17:42 UTC, devseppala
Details
Acrobat Pro screenshot of LO 25.2.0 exported document before FIX (313.20 KB, image/png)
2025-02-18 17:43 UTC, devseppala
Details
Acrobat Pro screenshot of LO7.5.4 exported document after FIX, set "Decorative figure" option (308.37 KB, image/png)
2025-02-18 17:44 UTC, devseppala
Details

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Description devseppala 2025-01-22 15:49:54 UTC
Since LO 7.5.5, repairing missing alternative text of image in Acrobat results to Accrobat complaining about another "Other elements alternative text" error. Before LO 7.5.5, you could repair missing alternative texts of images in Acrobat just fine.

The only change in LO 7.5.5 that I can see having something to do with this is actually a fix to another accessibility problem that I had reported previously. The change is Bug 155190 - FILESAVE Acrobat Accessibility checker reports "Associated with content" error in alternative text check.

Steps to produce. 
 * Open Writer application >= 7.5.5
 * Insert image to a empty document (do NOT mark as decorative or insert alt text) 
 * export to PDF (make sure to chooce Tagged PDF - option)
 * open the exported PDF document in Acrobat Pro
 * open Accessibility tool
 * Run full check
 * From the accessibility results list, right click the "Figures Alternate text" error and choose "fix"
 * click the "Decorative Figure" option to mark the image as decorative and click "Save and Close"

Now the "Figures Alternate text" error is gone and a new "Other elements alternative text" error has appeared.
Comment 1 m_a_riosv 2025-01-23 19:56:06 UTC
Please attach a sample file, reduce the size as much as possible without private information, and paste the information in Menu/Help/About LibreOffice, there is a copy icon.
Comment 2 devseppala 2025-02-18 17:37:23 UTC
Created attachment 199282 [details]
Example document with a picture of apples without alternative text.
Comment 3 devseppala 2025-02-18 17:39:24 UTC
Created attachment 199283 [details]
PDF export of the example .odt document using LO 7.5.4
Comment 4 devseppala 2025-02-18 17:40:00 UTC
Created attachment 199284 [details]
PDF export of the example .odt document using LO 25.2.0
Comment 5 devseppala 2025-02-18 17:41:37 UTC
Created attachment 199285 [details]
Acrobat Pro screenshot of LO7.5.4 exported document before FIX
Comment 6 devseppala 2025-02-18 17:42:28 UTC
Created attachment 199286 [details]
Acrobat Pro screenshot of LO7.5.4 exported document before FIX, set "picture of apples" alternative text
Comment 7 devseppala 2025-02-18 17:43:22 UTC
Created attachment 199287 [details]
Acrobat Pro screenshot of LO 25.2.0 exported document before FIX
Comment 8 devseppala 2025-02-18 17:44:41 UTC
Created attachment 199288 [details]
Acrobat Pro screenshot of LO7.5.4 exported document after FIX, set "Decorative figure" option
Comment 9 devseppala 2025-02-18 17:47:04 UTC
First, apologies for the very late response, I was hit by a tsunami of other urgent thing to attend to and just didn't have the time progress this until now.

I uploaded requested sample files and some screenshots from Acrobat Pro UI.

One reason for the late reply was also, that I noticed that there was something funky in this situation and I wanted to investigate it by my self a little further.

After some more digging I found that not everything is OK with LibreOffice 7.5.4 PDF export either.

It happens that for PDF export file that has image without alternative text
  * For LibreOffice 7.5.4 exported file
	* FIX with Acrobat Pro works if you choose "Decorative figure" option
	* FIX with Acrobat Pro fails if you set some alternative text like "picture of apples"
		* ERROR: Associated with content

the opposite happens with with LO 25.2.0

  * For LibreOffice 25.2.0 exported file
	* FIX with Acrobat Pro fails if you choose "Decorative figure" option
		* ERROR: Other elements alternate text
	* FIX with Acrobat Pro works if you set some alternative text like "picture of apples"



SYSTEM INFORMATION FOR LO 25.2

Version: 25.2.0.3 (X86_64) / LibreOffice Community
Build ID: e1cf4a87eb02d755bce1a01209907ea5ddc8f069
CPU threads: 16; OS: Windows 11 X86_64 (10.0 build 26100); UI render: Skia/Vulkan; VCL: win
Locale: fi-FI (fi_FI); UI: en-GB
Calc: threaded

SYSTEM INFORMATION FOR LO 7.5.4

Version: 7.5.4.2 (X86_64) / LibreOffice Community
Build ID: 36ccfdc35048b057fd9854c757a8b67ec53977b6
CPU threads: 8; OS: Windows 10.0 Build 22631; UI render: Skia/Vulkan; VCL: win
Locale: fi-FI (fi_FI); UI: en-GB
Calc: CL threaded
Comment 10 devseppala 2025-02-19 10:06:37 UTC
I tested this same scenario using Word 2019 and I found out that the same problem happens with a Word 2019 generated PDF-file. With a Word 2019 exported PDF file the behaviour is the same as Writer 25.2.0, tagging image as "Decorative Image" results to the same " Other elements alternate text" error.

I also found out that with Word exported file the Figure-tag is transformed to Sect-tag and in LO Writer generated PDF file the Figure-tag is transformed to Artifact-tag by Acrobat Pro.

So this really seem to be more of an Acrobat issue than LibreOffice issue, as similar behaviour is observed with Word 2019. I don't have access to newer versions of Word or Acrobat Pro, so I would appreciate if someone could test if this bug is present in newer Acrobat Pro versions.