EPUB 2: accessible math

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Hello everyone,

we have to create a fully accessible EPUB2 with plenty of math formulas - about 300 - of various levels of complexity. Since we cannot use MathML, we are thinking to go with .png images and alt text, avoiding tables and tricks like ASCII square root symbol combined with {text-decoration:overline} for long square roots. Also, since the book is in Italian, the alt text should be in this language too - so we can't use the automatic descriptions of the formulas that some softwares can provide only in English. We have also considered SVG but we are not quite sure yet.

We were wondering if there could be better ways. Can you share some advices, resources, and such?

Thanks a lot!

Only some ideas to test:

Within EPUB2 you can switch to alternatives, therefore you can use for example embedded MathML, but with an SVG or XHTML alternative.
(unfortunately according to my tests of viewers based on Gecko, WebKit etc, there seems to be a tendency to ignore such EPUB specific accessibility features, therefore one should add a hyperlink to an alternative presentation as well instead of relying on the assumption, that such essential features of EPUB 2 are really implemented ;o)

SVG sounds better than PNG for this purpose.
In theory viewers are required to interpret embedded SVG and SVG has more build in accessibility features than PNG, an author can use.
Within the SVG there should be a text alternative as plain text or XHTML for the graphics for people without the capability to see something.

And often/usually authors use LaTex expressions as text alternatives for formulas offered as graphics or inaccessible pixel images, because typically such books or scientific articles with lots of formulas are written anyway with LaTex and output in Postscript (but as we all know, formats like Postscript or PDF have accessibility issues as well) - I think, it is ok, to add a Postscript or PDF variant as an alternative view of the complete book as well, one only has to provide the XHTML+SVG variant as an accessible alternative.

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