Re: [Gimp-developer] Show clipped and out of gamut colors using blinking colors

[Ell <ell_se yahoo com>]

On Fri, 3 Nov 2017 09:38:33 -0400
Elle Stone <ellestone ninedegreesbelow com> wrote:

> On 11/02/2017 04:21 PM, Ell via gimp-developer-list wrote:
> > On Fri, 20 Oct 2017 09:03:01 -0400
> > Elle Stone <ellestone ninedegreesbelow com> wrote:
> >   
> > > Hi All,
> > >
> > > It would be really nice to be able to click a button or have a view
> > > module option that would indicate clipped colors by coloring them
> > > in some way (perhaps black for shadows, white for highlights),
> > > with an option to make these pixels blink.  
> >
> > master has a clip-warning display filter now (commit 5b118a260b),
> > which does that.  No blinking, though :)  
>
> Hi Ell, and thank you! That clip warning display filter is really
> nice!

Yay, glad you like it :)

> Regarding the blinking, personally I don't much like blinking pixels
> - probably the only advantage of blinking is to draw attention to
> very small areas that have out of display range colors. Seeing these
> areas probably requires zooming in to 100% for just about all image
> editing softwares, so the blinking per se doesn't seem all that
> useful.

I can see how blinking, or more generally, animating the warning
(say, marching-ants style), can be useful.  The main reason why it's
not there is that the pain/gain ratio of implementing this is too
high to justify, for now anyway.

> Yesterday when I compiled GIMP the new filter was there, but nothing
> was happening on the image - not sure why. But today I updated GIMP
> again, and recompiled, and made an image that was a gradient from
> -1.0f to +2.0f. The gradient ran from the upper left to the lower
> right corner. The Clip Warning shows diagonal parallel red and black
> bars for the highlights, and diagonal parallel blue and black bars
> for the shadows.

Yeah, the filter used to run after the conversion to the monitor
profile, at which point the colors were probably already clipped.  The
last commit from today (9cd8e7f9c6) moves the filter before the monitor
transform.

> Are there supposed to be diagonal bars instead of solid blotches of
> the user-chosen warning colors? If so, how would this work with
> images with just speckles and very small areas of out of display
> range colors? I'll try to do some more experimenting later on today.

Yes, the diagonal stripes are basically a static substitute for
blinking: it's possible that your image has areas with similar color to
the warning color, but it's much less likely that these areas also have
a stripe pattern, making the warning more distinguishable.

I'm not sure why this would be specifically problematic with small
our-of-range areas (though obviously less useful in these cases.)  Note
that the size of the stripe pattern is independent of the area size, or
the zoom level, so, in particular, when you zoom in you can see the
pattern over individual pixels.

--
Ell