This is a scenario for alternate text on an image (for accessbility, svg:desc was already present in ODF 1.0 by the way)

1. Create a new spreadsheet
2. Add a logo
3. Add alternate text “This is a logo”
4. Save it
5. Reopen it in another implementation

• IBM Lotus Symphony 1.3
• ODF Translator for Excel

A list of known issues. Implementations not listed here may or may not work as expected. Results may vary depending on user settings and computer environment. Use at your own risk.

Note that ODF 1.1 defines two different attributes for alternate text, according to best practices. This includes svg:title for specifying the accessible name of the object and svg:desc for giving an accessible description. Typical the UI for entering svg:title will be a single-line edit control, while svg:desc may be a multiple-line edit control.

The Symphony document was written out using svg:title as a child element of draw:frame. This is correct.

Examining the output XML, it appears that the ODF Translator for Excel does not write out the alternate text at all.

And I looked at the 'rotation-angle' in the Symphony document's XML, and that appears to be correct. '90' is a valid value, since any non-negative integer is allowed.

So a few bugs to report here:

1. ODF Translator for Excel not reading svg:title
2. Excel 2007 SP2 not reading svg:title
3. ODF Translator for Excel not writing alternate text as svg:title or svg:desc
4. Gnumeric calling a rotation-angle of 90-degrees 'invalid'. [Seems to be OK in Gnumeric 1.9.8 for Windows, no warning — Bart Hanssens 2009/07/08 01:06 ]

Looking at Microsoft's implementation notes for Office 2007 SP2 it looks like svg:desc is supported, but not svg:title. Of course, having an implementation note is of little use to the blind user who has lost the alternate text for the embedded image.

I'm not sure of the underlying issue. Perhaps it is that Excel only has a single alt text field internally, and they decided to map it to svg:desc? If so, the best solution is to add support for both. But if you can't do that then you can use a heuristic like this:

1. When reading an ODF document if svg:title and svg:desc are both non-blank, then combine the two, perhaps delimited with a colon, or with a newline between the two. Don't lose user data.
2. If only one of svg:title and svg:desc is non-blank, the use it as the alt text. If you do this, then the current bug would go away, since svg:title is a single line string and can always be used where svg:desc is currently expected.

Since we want to encourage the use of both svg:title and svg:desc for the best accessibility, authoring tools should be encouraged to support both.