E4 · Fretboard pictograph renderer + convention spec

[ophiocus]

Part of the Chord-chart video generator epic (parent #2).

Scope

The load-bearing visual decision. Two deliverables:

1. The convention spec — document the fretboard-diagram visual language this feature uses (string order, fret window, markers). Standard six-string fretboard diagram, one guitar, EADGBE.
2. The renderer — given an E3 voicing, draw one correct fretboard frame.

Convention (proposed v1 — confirm mock before build)

• Six strings, horizontal neck by default; low E to high E ordered per house style (to confirm).
• Fret window sized to the voicing; nut shown when in first position.
• Markers: fret dots for fingered notes, O above open strings, X above muted strings.
• Open house-style questions parked for the operator: colour-per-finger vs monochrome, right- vs left-handed, horizontal vs vertical neck.

Done when

A given voicing renders to a single correct fretboard frame, and the convention is written down in this issue (so E5 and future work render consistently).

Dependencies

None to start (spec + renderer can be built against sample voicings). Consumes E3's voicing contract at integration; feeds E5.

Labels: chord-video, enhancement, prio:P1