toneEQ: move exposure/contrast compensation sliders to advanced tab

[MStraeten]

since there're endless discussions on tweaking the tone equalizer a lowest common denominator might be simply moving the controls for mask exposure and contrast compensation to the advanced tab. since the real estate of the gui is driven by the simple tab, the additional required vertical space is taken from the graph and in masking tab there's unused space. the bar indication the spread of the histogram on masking tab is no longer needed, so removed

[jenshannoschwalm]

tested just now:

1. There is a UI gap in the masking tab -
   

as this is missing :-)

2. Not sure - shouldn't mask quantization be in the advanced tab too?

[MStraeten]

the gap is there because the minimum height of the module is determined by the sliders in simple tab.
Mask quantisation results can't be seen in the histogram graph - so it seems to be better to keep it on masking tab.
also the graph will be compressed further, if there's a further slider put on advanced graph.

the histogram representing mask bar is no longer used, since the effect of the moved sliders can be seen directly in the histogram.

[marc-fouquet]

Obviously I don't have anything working right now on my PR. Even though I haven't given up just yet, it looks like my stuff will take a lot longer.

Just for inspiration, I wanted to show what my current UI looks like, after all the discussions in that forum thread.

I went for a version, where the histogram is always visible and the tabs are placed below it. This is useful, because smoothing changes the histogram too, which is immediately visible here. I also put almost everything into collapsible sections, so people cen decide for themselves, how much vertical space they want to use.

Regarding mask quantization: I don't think that this is an option that should be placed in a prominent location. I don't think that this is widely used, I regard it as an unsuccessful attempt to have a little bit of zone system in the module.

[MStraeten]

This pr keeps the vertical space needed for the module, since there’re users running darktable on capable notebooks where screen size is limited.
this pr doesn’t want to change the UX fundamentally but is improving the users workflow in a often demanded way.

[da-phil]

Changes are looking fine for me.
Because folks have been talking about how precious vertical space was to them I wanted to ask how you feel about removing the x-axis labels of the node UI, see framed in red:

IHMO there is no real usage for it, only the y-axis labels are. However they are probably still helpful to cross-reference the sliders in the simple tab.

[MStraeten]

This pr isn’t intended to be a major change of the toneequalizer UI - so no further changes beside what’s needed to optimize the handling of the mask histogram.
There are plenty of non converging discussions on the UX of tone equalizer - so let’s keep this pr small and without scope creepers …

[TurboGit]

@MStraeten : You may want to try out #18656 (be ware that this will break all your ToneEQ presets). I think #18656 is the way to go, the auto-fit is especially fixing a itch I had for this module.