A Blank Slate: Canvas
Another anticipated use for scripting is to automate the new HTML5
canvas
element. This element provides
an automatable surface for drawing on, whether itâs done by the content
creator (games, animations, etc.) or the reader (drawing or writing
surface), which is why I omitted tackling it with the rest of the
semantics and structure elements.
Although a potentially interesting element to use in ebooks, at
this time the canvas
element remains
largely a black hole to assistive technologies. A summary
of the discussions that have been taking place to fix the
accessibility problems as of writing is available on the Paciello Group
website. Fixes for these accessibility issues will undoubtedly come in
time, perhaps directly for the element or perhaps through WAI-ARIA, but
itâs too soon to say.
So is the answer to avoid the element completely until the problems are solved? It would be nice if you could, but wouldnât be realistic to expect of everyone. Using it judiciously would be a better course to steer.
For now including accessible alternatives is about all you can do.
If youâre using the element to draw graphs and charts, you could add a
description with the data using the aria-describedby
attribute and the techniques
we outlined while dealing with images. If youâre using the element for
games and the like, consider the issues we detailed at the outset of the
section in determining how much information to give.
With canvas
, we really have to wait and see, ...
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