origins of effect Meta knob arcs are not consistent relative to their default positions

[nvdl]

Bug Description

Mixxx 2.4.0-beta
Git Version: 2.4-beta-347-gc323d0cd54
Platform: Linux x86_64
OS: Debian 11

Some knobs do not draw the delta ring relative to their default position.

"Echo", "Moog Filter" and "Balance" in the above shots do not draw the ring relative to the default (minimal/no-effect) position.

Version

No response

OS

No response

[ronso0]

Yes, these are still dumb knobs currently. Arc origin is set in the skin (static) to either center, left or right.

To make them dynamic, i.e. aware of the effect's default Meta parameter we'd need to

• add WEffectMetaKnob, derived from WKnobComposed
• listen to EffectSlot::effectChanged in order to
• get the manifest of the loaded effect, read & store default Meta parameter
• adjust drawArc() to make use of it

Nice little weekend project for Mixxx 2.4.x : )