Re: [Gimp-developer] Need help for gegl translation

[Julien Hardelin <jm hard wanadoo fr>]

Thank you, Peter.


Le 27/08/2016 à 13:28, Peter O'Regan a écrit :
> Hi Julien,
>
> I'm not in front of the reference right now, but from the context you've
> provided it appears Vis would be shorthand for visibility. I'd guess that's
> dealing with some layer order drawing rules.
>
> Aux pad is an auxiliary input to the gegl chain. If you envision the
> tree-like structure connecting processing elements, the Aux pad wouldn't be
> connected along the main input / output line. Instead it could be from
> anywhere in the pipeline (including an independent element or self
> sufficient generator like white noise) . Pad is a synonym for the
> connection point which comes from circuit board terminology.
>
> 50% gray is a color reference that is standard terminology in image
> processing. Because we as humans don't perceive contrast linearly, 50% gray
> does not correspond to the midpoint of the color scale (e.g. 127/255 if you
> were in 8-bits). You can read a bit more about it here:
> https://en.m.wikipedia.org/wiki/Middle_gray
>
> Hope that helps!
>
> Peter
>
> On Aug 27, 2016 5:31 AM, "Julien Hardelin" <jhardlin orange fr> wrote:
>
> > To translate gegl correctly, I need to understand. And I don't understand
> > well some strings, not finding explanations on the Web:
> >
> > -/"how wide peel off bands for ink order vis"/
> >
> > What is "vis"?
> >
> > - "/Do a chain of operations, with key=value pairs after each operation
> > name to "//
> > //"set properties. And aux=[ source filter ] for specifying a chain with a
> > "//
> > //"source as something connected to an aux pad."/
> >
> > "aux pad" : auxiliary tablet computer?
> >
> > - /"Changes the light level and contrast. This operation operates in
> > linear "//
> > //"light, 'contrast' is a scale factor around 50%% gray, and 'brightness'
> > a "//
> > //"constant offset to apply after contrast scaling."/
> >
> > "50%% gray": 50%?
> >
> > I hope I don't disturb you too much.
> >
> > Julien Hardelin
> >
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