Re: DOCBOOK: alternative text for images in docbook

[Stefan Seefeld <seefeld at sympatico dot ca>]

Anahi Olives/UPC wrote:
> Hi,
>
> I would like to know if there is any docbook element that allows to 
show an
> alternative text for images and media objects (the text that is shown 
when
> the mouse is on the image). I saw that equations have an "alt" element to
> do that, but what about figures, imageobjects, videoobjects, ... Is it
> possible to use callouts for this? I'm not sure of understand what 
callouts
> really do. Please, is there any way to do this with docbook. Thanks.

little clarification: the 'alt' element is used as an *alternative*, 
i.e. when displaying the image content doesn't work (because it can't
be loaded, for example). The stuff displayed in a tooltip when the mouse 
is over the image is the 'title'.

That said, you should really distinguish 'media objects' and 'images':
The whole point of introducing 'mediaobject' is (as far as I understand)
to let the renderer / transformation tool choose which format best fits
the output medium. Have a look at

http://www.docbook.org/tdg/en/html/imageobject.html

So a single 'mediaobject' may include several 'imageobjects', as well
as a 'textobject'. It's the latter that that is put into the 'alt' 
attribute in the html output.

Thus, you don't need to do anything special about figures, as figures
may just include mediaobjects themselfs, so the above applies.

Stefan