Re: [Gimp-developer] Configurable target selection by the "Auto" button on the Levels dialog

[Rodrigo Severo <rodrigo fabricadeideias com>]

Liam,


First of all, thanks for your time and input on this matter.

On Mon, Jun 15, 2015 at 2:10 PM, Liam R. E. Quin <liam holoweb net> wrote:
> On Sun, 2015-06-14 at 19:05 -0300, Rodrigo Severo wrote:
> > Hi,
> >
> >
> > The "Auto" button on the Levels dialog has a fixed behaviour today
> > (which I don't know exactly which is).
>
> The source code is available -- essentially it stretches contrast in
> each R, G, B channel separately. If you press Auto and then open as
> curves, you can see. The end points are, however, a few percent in
> from the ends, limiting its usefulness in a professional setting.

So you agree that the behaviour of the "Auto" button should be at
least changed, if not configurable ;)

> > Its behaviour should be configurable by the user.
> The point of it is that it "just works". An auto button should not be
> configured.

Why not? It certainly should have a reasonable default but why not be
configurable?

The "Auto" here refers to automatically choosing the black, white (and
grey?) points. This wouldn't be changed at all.

The configuration would allow the user to choose another way to for
Gimp to choose these points. But they would still be chose
automatically

> I think really what you are asking for is a "stretch contrast" filter
> that has configurable black and white points.

That would be the poor version of my idea.

If we have configurable black and white points on Levels (and
hopefully in Curves also) the auto setting could be the first step on
a much more refined Levels or Curves setting.

> Note that you can already configure the black and white points in
> levels using the eye dropper.

I know how to manually choose the black and white points. But is there
a way to configure the way Gimp automatically chooses them for me?

> > The user interface for this functionality could be accessed by the
> user double clicking the "Auto" button.
>
> That would be a "no" :-)  There aren't any other buttons that behave
> differently when you double-click on them (and actually for good
> reason, as no-one would ever guess it, and because it would mean every
> button would have to wait to see whether the user double-clicked
> before doing anything, giving a UI feeling of slowness.

I think you might be right. Do you have another suggestion on how to
access configurable values for these buttons? If this were to be
implemented, I believe these configurations should be accessible
straight from the Levels dialog.

> I'm supportive of being able to set the levels/auto clipping
> percentage, perhaps in the Colours/Map/Stretch Contrast GEGL filter.

I think this is a good idea. I just think that not having this kind of
configuration also on the Levels dialog stiffens Gimp interface
unnecessarily.

What do you think?


Regards,

Rodrigo Severo