Rendering of imageobjectco

[Chris Ridd <chrisridd@mac.com>]

We're using 'imageobjectco's in our manuals (we must have sinned greatly in our previous lives), and I'm wondering if there is a better way to render them.

Currently they're a bit of a no-op - the default rendering in FO is identical to an imageobject. For HTML the default rendering is also of an image but it also sets up an HTML imagemap.

Neither of these actually draw the callout bugs, which bothers me :-)

I think I have a solution though that will work for HTML and FO. I have a rough and a bit broken prototype for HTML conversion that essentially converts to this:

  <div style="...">

    <span style="...">1</span>

    <span style="...">2</span>

    (etc)

  </div>

where the outer 'div' has this CSS style:

  background: url(path/to/image) no-repeat;

  position: relative;

  width: (width of the image)px;

  height: (height of the image)px;

so the image gets drawn in the background, unfortunately only at full 1:1 resolution. (There may be some CSS extensions to do the scaling.) There's a 'span' for each bug, and they each have this CSS style:

  display: inline;

  position: absolute;

  top: (pixel offset from top of image via area coords)px;

  left: (pixel offset from left of image via area coords)px;

The content of the span elements would be the appropriate Unicode character for the bug, or an image, both as at present. I'm not sure if they have hyperlink semantics - should they jump to the calloutlist? That's probably doable.

I *think* the same sort of structure will work for FO, as FO seems to support the same sort of CSS styling that I'm proposing to use for the HTML.

I haven't got an FO prototype yet. My HTML prototype is still just an ugly hack to the rather long process.image template.

The disadvantage of this scheme is that the image might not get printed as it is "background", and semantically it feels a bit weird.

But on the upside this feels like a semi-sane way to do callouts. You don't need to pre-render the callouts into the images at all (we do that for FO, and I'd need to do that for HTML too) and you get nice pretty bugs (if you use the Unicode bug style).

Does anyone have any thoughts? Is this a bad idea?

Chris