Expose waveform data to controllerscripts

[mixxxbot]

Reported by: Swiftb0y Date: 2020-03-22T16:34:50Z Status: New Importance: Undecided Launchpad Issue: lp1868483

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There has been an increasingly large amount of new mid- to high-end controllers that are able to show a tracks waveform on its screen. It is currently impossible for Controller mappings to make use of that functionality, since the waveform data is not retrievable in the controller environment.

[mixxxbot]

Duplicate of mixxxdj/mixxx#8695

[Swiftb0y]

imo not quite the same. The referenced issue is about rendering some UI and then exposing the image data to the JS so it can be transferred to the controller in the appropriate format (see screens on traktor hardware), while this issue is just about exposing the raw waveform data so it can be transformed in whatever form the hardware needs to render it (see pioneer hardware). While the end-user experience is similar, the implementation would be quite different.