Style : how to add a new module instance with its own preset ?

[DaveInDev]

Is your feature request related to a problem? Please describe.
I often would like to create a style that would add a new instance of a module, without modifying the existing instances of this same module.

A simple example to illustrate :

• let says that I have some instances of "exposure" applied on my raw (with different masks).
• I would like to create a style that would add a constant -1EV exposure on the whole scene, everytime I call it.

For the moment :
I create a new instance of "exposure -1EV", and try to record it as a style.
But next time I try to apply this style, darktable will modify an existing exposure module instance, and would not create a new "exposure" instance.

Describe the solution you'd like
Maybe in the edit-style window, close to the "keep", "reset" and 'update" columns, it would be nice to have a "new" column that, if selected, would create a new instance of the selected module ?

By default this column would not be selected, thus it would not change the existing behaviour of darktable styles.

[wpferguson]

Have you tried making it a named instance?

Create a new exposure module and set it to what you want. Change the name of the exposure module to something that works for you. Make a style from it.

[DaveInDev]

I just tried it, but it does not work either.
In no case I managed to create an additional instance of an already existing module (using a style).

[ralfbrown]

@wpferguson A named instance won't generate a new instance in the pixelpipe each time the style is applied, since the second and later applications will match on that name and just update the existing instance from the first application.

For the particular case of stacking exposure adjustments, it may be easier -- and adds less clutter to the pixelpipe -- to just define a keystroke shortcut which decrements the exposure slider 1EV by setting an appropriate speed in the shortcut. That doesn't play too well with a first or focused instance that has a mask, though.

[DaveInDev]

@ralfbrown : you are right. But more than that, it does not even create one new instance when I call it. Do you manage to do it at least once ?

The stacking of exposure was just an example.
I would also use it for many other examples, and even multiple modules at once, when I do not want to overwrite already existing modules of teh same type.

[TurboGit]

@ralfbrown : Are you sure? A user named instance should be stacked on top of the current exposure instance if they don't have the same name.

I think @wpferguson is right, and I'm the author of this code :)

[DaveInDev]

@TurboGit : you're right (I'm not surprised ;-) ) : it works if you manually rename the module. My new module instance had already a name, coming from the preset I used to set it, but it was not sufficient : you must manually rename the module so that it create a new instance when called from a style.

[ralfbrown]

Yes, I was talking about manually named, not displaying the preset name -- in the latter case, the module doesn't actually have a name, it's just displaying to the user whatever preset matches (which only happens when the module does not have a name).