Histogram for part of an image ?

[Bernard]

When a mask is active, the brightness curve will influence the image according to the white and black amounts, that's ok, but (I think) the histogram displayed is always relative to the complete image with 100% amount.
I would like to work on a specific part of an image, and I need the histogram of that part only, ignoring (ie amount 0%) the rest.
How can I achieve that ?
Bernard

[jsachs]

There is no specific feature that does this, but you can make a copy of the image and use the mask with the Composite Transformation (and a solid overlay color) to make the masked area black and then ignore the spike in the histogram at zero.

[Bernard]

Thanks Jonathan, I will try that.
What I want to do is to work brightness and contrast separately for the foreground and the background.
Of course I can do that with a mask (and the inverted mask) looking visually at the result, but without the help of the histogram.
Would it be possible to have a 'masked histogram' that would ignore the part where the amount is 0% ?
Bernard

[jsachs]

I am looking at implementing this feature - it is a little tricky.

[jsachs]

It turns out I was able to add this feature to Brightness Curve, Color Curves, and Color Balance. I was not possible to add it to the histogram tool without a major rewrite. The new code should appear in the next regular update.

[Bernard]

Jonathan,
That's absolutely fantastic !
Thank you so much for your support and such a quick answer !
I am waiting for the next update....

My best wishes for the new year to you and Kiril.
Bernard

[jsachs]

I just got the histogram tool to work also.

[Bob Walker]

Jonathan,

Thanks a lot for working this out. It's a very useful enhancement, and I look forward to using it.

Bob W

[couman]

Jonathan,

Thanks a lot for working this out. It's a very useful enhancement, and I look forward to using it.

Bob W

Yes, indeed. Thank you

[Bernard]

Thank you Jonathan !
Bernard