add inverted noteBackgroundColor

[limse10]

Resolves: https://musescore.org/en/node/346509

This PR is separated from #16715 , preliminary discussion about this issue can be found there.

noteBackgroundColor now queries the current foreground color, so note backgrounds will always match the current score color.

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[limse10]

For further discussion, I believe it would be important for the vtests to include app-based vtests, rather than just running vtests on exported/printed scores and engravings. This would improve visibility for app-based ui issues. For example, inverted score engraving checks, as well as to verify that the app-preview and the exported scores dont have any synchronization issues (since they use different whites).

Would this be desirable/possible?

[Jojo-Schmitz]

Strange, when it was part of #16715, it caused vtests failures with some Tablature tests, it doesn't here though.
Caused be the additional code in note.cpp? IIRC that wasn't in previously.

[cbjeukendrup]

Note that this does not work when the user has chosen to use a wallpaper image instead of a plain color. But it's a big improvement already at least!

[Jojo-Schmitz]

Do wallpapers work in inverted mode at all? Should they?

[limse10]

Caused be the additional code in note.cpp? IIRC that wasn't in previously.

Yes, I added an extra check to use pure white if the score is being exported. If not exported scores will have off-white note backgrounds for tablatures

[limse10]

As for wallpapers, I would believe they wouldn't even work in normal mode, because tablature engravings draw a rectangle around the number to simulate transparency and "erase" a bit of the bar lines. Solving this problem properly would be abit more involved I believe. I can try to look into it but do share any insights you may have.

Also, what are our thoughts regarding a more comprehensive suite of vtests (as mentioned in the first comment)?

[Jojo-Schmitz]

Rebase needed

[Jojo-Schmitz]

Rebased in #22486

[RomanPudashkin]

Closing due to a long period of inactivity + @Jojo-Schmitz rebased it