feat: static color coding for key column

[danferns]

Hi! I just got the core of this feature working and I'm seeking feedback.

A small rectangle is drawn next to the Key label in the Library. The color of the rectangle is based on the Key of the track.

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I'm concerned about the method used for finding the track's key. Right now, I'm using KeyUtils::guessKeyFromText on the Key string, but I don't think that'll work if the user sets custom Key Notation.

I want to use the value in ColumnCache::COLUMN_LIBRARYTABLE_KEY_ID. But I haven't been able to figure out how to access this column from the QModelIndex& index that is passed into KeyDelegate::paintItem. I'm not sure if the column is even available.

Is there a place where I can see how the index is structured?

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Once complete, this will resolve #7810.

[Swiftb0y]

Once complete, this will resolve https://github.com/mixxxdj/mixxx/issues/7810.

I don't think so. That issue requests to color the key depending on how compatible it is to the currently playing track.

[Swiftb0y]

I'm concerned about the method used for finding the track's key. Right now, I'm using KeyUtils::guessKeyFromText on the Key string, but I don't think that'll work if the user sets custom Key Notation.

Probably not. You should store the underlying mixxx::track::io::key::ChromaticKey in the cell when its text gets set. You can use a custom item role for that (I think, I'm not much into Qt MV programming tbh).

[danferns]

Thank you so much @Swiftb0y for the feedback! Preferences for key color palettes is definitely in the plans. I will apply the requested changes and try the item role method.

[daschuer]

Can you update the screenshot in the initial description of this PR? This way it is more significant if one is later following links from the Changelog.

[daschuer]

Is the draft state still correct or is it ready for final review and tests?

[danferns]

Is the draft state still correct or is it ready for final review and tests?

Yes, I am not done yet. I still have to read the Key Colors setting and only render the rectangle if it is enabled.

Also I'd like to squash a couple of commits before review, at least the one which was failing to build.

[danferns]

I want to read the setting using ConfigKey("[Config]", "KeyColorsEnabled") inside KeyUtils::keyToColor (if key colors are disabled, return an invalid color). But to do that, I would need access to the pConfig variable inside keyutils.cpp.

I see that the pConfig is passed around in class constructors. Is there a way to access it directly?

Should I go about this in some other way entirely?

[Swiftb0y]

I don't think accessing the config in the KeyUtils is a good idea. Can you share a little more insight on what you're trying to accomplish? Then we can brainstorm together.

[danferns]

Can you share a little more insight on what you're trying to accomplish?

I have added a preference setting to enable/disable Key Colors. It is called KeyColorsEnabled and I put it under the [Config] group. It is defined inside ColorPaletteSettings.

Now, I want to display the key colors only when this setting is on.

Initially, I was trying to do this preference check inside KeyDelegate. But then I noticed that the KeyUtils::keyToString function is already aware of the user's chosen notation (it doesn't need to be passed in explicitly). So I thought maybe KeyUtils::keyToColor should also do the same, and access the user settings on it's own.

Should the check instead be done inside KeyDelegate?

[Swiftb0y]

Thanks for the explanation. I think that check should stay inside KeyDelegate. The static data in KeyUtils is ugly and its usefulness is questionable IMO.

[danferns]

Got it, thank you!