Before and After tool for Darktable?

Please add a before and after tool in darktable it’s better than the snapshot feature which don’t even allow zooming in. Can you guys add something like in rawtherapee?

That already exists actually

Duplicate the file. Edit the second one. Go into culling mode in lighttable. Press the Tab key to close the side menus.

then you can use Ctrl + mousewheel to zoom in and out, keep left mouse button pressed to move along the image.

  1. take a snapshot
  2. do your changes
  3. click on snapshot

you can compare the snapshot vs current.

It also exists in RT .

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He wants to pan and zoom and the snap shot is fixed only the current image will zoom…so the request is really to add the dynamic version of compare that you find in the culling view of lighttable where zoom and pan are synched and add that into the editor window…

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There’s already a feature request for this. Basically it’s not as simple as it sounds to add such a feature to the darkroom as it would require the ability to run two pixelpipes in parallel, which we can’t do right now (and if we could it would probably be sloooow).

The duplicate module in the darkroom allows you to compare duplicates with the current edit and this is the closest thing we really have to what you’re asking for. But it will not produce a comparison image that’s identical to the darkroom view due to differences in how the two images are processed, and it’s pretty slow.

Really I’d advise zooming and then creating another snapshot as you know you’re comparing like with like.

In a brain storm of some ideas to implement in darktable I wrote about this kind of feature.
The Quick compare icon.

Some kind of feature (icon) I called “Quick Compare” to show a before and after to use in darktable. An state to show the image and it previous state without use the snapshots. Just to show a comparison between the last step applied to a image with the previous one. Users don’t have to create any snapshot, but if they like to compare with another step in the process they have the snapshot module option.

but this is just an idea. Maybe devs. have other approach to this kind of request.

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As Chris mentions I think the parallel processing is the issue and it might be fantastically slow…who knows though maybe there is a way to speed it up

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As I wrote. Maybe they will have a great idea in mind. As I see some users like to have some kind of tool to compare an state with a previous one (A/B) without have to duplicate the file and use the culling mode in lighttable to see differences between images (or the same duplicated one).

If it were easy it would have been done already. We need a developer who wants it enough to suffer for it.

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Is its possible for using the code used in rawtherape.

Not sure if that’s a question or a statement but these are two entirely different applications and you can’t assume that solutions in one can just be ported to the other.

It was a question lol.

This works but not as easy as RT

I wonder if it could be scropted using Lua???

With a lua script I could take automatically take a snapshot when you open the image so you could compare any changes made to what the start was. But, it’s a snapshot and you can’t zoom or pan. The problem is running the pixel pipe and system resources. Maybe a system with multiple CPUs and GPUs could do it in a reasonable manner.

I dont think it will be slow i using a 2 core intel processor which runs RT in A/B compare mode without any visible lag.

Again, darktable is not RawTherapee. If you think you can do it though, pull requests are welcome.

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I also would like this feature, but if I don’t know how to make it and no developer is motivated I can not complain. I really appreciate the effort put in by the developers. What I would like to see is the ability to name the snapshot. I can do this when I make a new instance of a developing module so I imagine it would be possible to implement for snapshots. Snapshot really is like a before and after view so it meets my needs. Maybe if it could optionally be placed beside the image being developed it would meet the needs for a before and after view being requested by others.