Re: [Gimp-developer] Pencil - Tool Options and Hardness

[Petteri Soininen <pesoini gmail com>]

To make things even more complicated, the new MyPaint brushes can have a 
pixel brush that behaves like pencil.

So if we get brush option to turn anti-aliasing off, we'll have 3 tools 
to make pixel art with..

-Petteri

On 22.6.2016 13:40, Simon Budig wrote:
> C R (cajhne gmail com) wrote:
> > > Have you actually tried to do what I outlined above?
> > Have you? lol
> > No - I haven't. It's not currently possible to turn off anti-aliasing on
> > the brush tool, so it's not possible to "test" it.
> Ah, sorry. I missed that we're discussing hypothetical future
> characteristics of the tools here. I was just looking at the current
> difference between the pencil and the paintbrush tool.
>
> > However, knowing how anti-aliasing works, your statement is incorrect...
> Well, if you choose to label the behaviour I described as
> "pixel-grid-snapping" (or the lack thereof) as "anti-aliasing" then it
> is not me who is making the error here. I actually don't think that they
> are the same.
>
> > The paintbrush tool resamples the brush when the pixel grid of the brush
> > > is not perfectly aligned to the pixel grid of the image.
> > Yes, but with anti-aliasing turned off (which you can't presently), it
> > wouldn't.
> >
> > > A perfect non-antialiased 1 pixel brush typically gets spread across
> > > four adjacent pixels in the image, assuming you're working with a high
> > > zoom level and don't specifically align the brush to the pixel grid of
> > > the image.
> > I don't know why you would assume that. :)
> > It's incorrect at any rate.
> This is *exactly* what the current paint brush tool does. And it really
> is no rocket science to test it. Just do as I explained above. I even
> did just a few moments ago, even if I knew this behaviour for years.
>
> > Anti-aliasing IS what average pixels to spread over a 4-pixel block.
> > If you turn it off (which, again, you can't currently in the brush tool),
> > and a single click with a 1px brush fills more than one pixel, then that
> > would be incorrect behaviour.
> The Pencil tool does two things (compared to the paintbrush) that are
> independent of each other:
>
> a) it thresholds the alpha channel of the brush (with a quite low
> threshold)
>
> b) it snaps the pixels of the brush to the pixels of the image, so that
> no resampling occurs.
>
> This is the *current* state of Gimp. And it has been like this for ages.
>
> If we want to put that as an option into the paintbrush (and lose the
> pencil) then describing both of these behaviours combined as
> "anti-aliasing" is IMHO misleading and wrong.
>
> Bye,
>          Simon