[GRASS-dev] display/drivers/HTMLMAP status

[Glynn Clements]

Hamish wrote:

> > > I have seen that we have
> > > display/drivers/HTMLMAP
> > > in 6.3-CVS but it miserably fails to compile.
> > > 
> > > This is the last trace:
> > > http://grass.itc.it/pipermail/grassuser/2007-January/037891.html
> > > 
> > > I think that it is a nice driver but I cannot estimate
> > > how painful an update would be.
> > 
> > As I said before, unless someone fixes d.vect to use the driver's
> > polygon-filling operations (for map areas, not just label boxes),
> > there isn't any point in having the HTMLMAP driver.
> 
> You say "unless someone fixes d.vect". Does that imply the current
> method is broken versus using the R_*() fns? Or is it just not condusive
> to a working HTMLMAP driver? Will the current d.vect method be faster
> than using lib fns which will take time rendering polygons which will
> end up being off screen?

One thing I have since noticed is that the existing method clips to
the current graphics frame, whereas R_polygon_abs() doesn't (the core
R_* functions only clip to the screen; they don't understand frames).

It's possible that was the reason for the current mechanism.

In any case, it would be straightforward to add an option to d.vect to
choose between G_plot_polygon(), R_polygon_abs() and the new
D_polygon() and D_polygon_clip() functions for rendering filled
polygons. All of those except for G_plot_polygon would work with the
HTMLMAP driver.

So, I intend to add such an option, and to resurrect the HTMLMAP
driver.

-- 
Glynn Clements <glynn at gclements.plus.com>