Irregularly shaped hotspots on image

[Wilhelm Sanke]

On Sun Apr 22, 2007, Viktoras Didziulis viktoras at ekoinf.net wrote:

> Is there a "standard" method of setting irregularly shaped invisible
> hotspots on images displayed on a stack ?
>  
> I have a few images with lots of fish on them. Need to highlight each fish
> and display its name on mouseEnter. Now I am drawing a polygon around each
> fish, setting its tool tip to fish name and putting a script that 
> passes the
> long id of the polygon to a handler to change polygon's ink from noop to
> blend. And vice versa on mouseLeave. Additionally it displays contents of
> polygon's tooltip in a separate field (in case the tooltip does not appear
> immediately on mousenter).
>  
> The drawback of this approach is that while highlights are irregular,
> hotspots are still rectangular and sometimes hotspot of a large fish 
> blocks
> all the small fishes around. So I have to adjust ordering of polygons
> sending larger to back and bringing the smallest to front to avoid 
> blocking.
>  Are there other alternative techniques ?
>  
> Best!
> Viktoras



Your approach should indeed work even with older versions of Rev and 
Metacard, I just tested in Rev 2.6.1 and Metacard 2.6.6.
The rectangle of the irregular graphic is *not* relevant, only the 
(filled) shape of the graphic will trigger the tooltip.

An alternative approach would be not to use tooltips, but to name the 
graphics and to show and hide the names on mouseenter and mouseleave. I 
have implemented a similar way in stack "Image and Words" 
(<http://www.sanke.org/Software/ImageAndWords.zip>), created a couple of 
years ago.

Regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>