[GRASS-dev] Re: i.rgb.his/i.his.rgb and 16bit images

[Glynn Clements]

Georg Kaspar wrote:

> > ps- patch added in the trac system to allow i.rbg2his to work
> > with 11-bit data (I fixed the truncation to 255 you saw before),
> > but d.his and i.his2rgb are still 8-bit only for now.

d.his uses the maps' associated colour tables, which only support 8
bits per component, as does the display architecture, so this
restriction be changed (and mostly isn't relevant; 16-bit or
floating-point rasters work fine, so long as they have a suitable
colour table).

It seems to me that i.rgb.his and i.his.rgb would be better
implemented as scripts which use r.mapcalc. Either way, the
calculation should be performed using floating-point values in the
range 0.0 to 1.0, which conversion on input and output.

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