About iterators and selection

[Boudewijn Rempt]

On Mon, 27 Sep 2004, Cyrille Berger wrote:

> > Mine too, but I didn't understand the iterator code well enough to actually
> > do something. I was rather hoping for someone else make the iterators
> > selection aware...
> If you explain me how the selections are handheld, I might be able to do it.
> We need to share some knowledge ;)
>

It's quite simple, really. Selections are just another paint device, as big
as the layer they are associated with. They hava a special color model,
alpha mask. This is almost but not quite the same as grayscale, since there
is only one channel, alpha, but there's also an associated mask color.

That's it, really, All selection tools are merely the plain tools, but they
work on selections (not that I'm done yet, some selection tools need to be converted.)

Completely transparent is completely selected; completely opaqua is completely
not selected.

Boudewijn