[ptx] 16 bit and float image support in nona/hugin

[Pablo d'Angelo]

On Mon, 03 May 2004, Kai-Uwe Behrmann wrote:

> Am 03.05.04, 18:58 +0200 schrieb Pablo d'Angelo:
> 
> > Ok, I'll save the tiff files like that. Internally I'll use 8 bit alpha
> > channels.
> 
> This or the bit approach, You mentioned, seems to be an clever solution
> internally.

Hmm, bits are clumsy to access in C. However, an even better approach to
store most masks would be a run length encoded image (RLE encoding every
row separately). For the typical mask the storage would only cost a few
bytes for every row.

Now we just need vigra::RLEImage.

> In CIE*Lab colorspace saved as tiff unsigned values are used for *L and
> signed values for *a and *b integers. This is the only case I am aware of.

Urgh.. lots of stuff to do with vigra's impex if we want to load these
images.

ciao
  Pablo