Signal meters dB indication

I've noticed that the signal level meters we have now can't be used to provide any measurment, because they lack any dB(FS?) indication. Here's my idea to solve this.


Follows mouse, so no extra screen space is used when not needed.

The selected level is indicated by white lines inside the meter, outside a 1-pixel wide dotted line
The background is 50% black with 2 pixels margin from the text, ending on the dotted line. The text should be 2 pixels from the meter (so the black baground touches it).

Also: what is the relationship between the fader dB scale and the meter's scale?
Are they the same? That'd simplify things I guess...

PS: I've found an issue that's related: #1022

Start by reviewing the existing signal meters, the fader dB scale, and related issue #1022; the payload names no files or tests. Compare the proposed mockup and determine how the two scales relate. Done means the meter provides a mouse-following dB indication with the described marker and background treatment.

Written by the indexing model from the issue text.