MacDL MkII

User-facing desktop editor for the Line 6 DL4 MkII. It lets you:

• Connect to the pedal over MIDI (Tauri app) and see connection health
• View and tweak every knob/parameter with real-time MIDI sends
• Load/Save presets A–C (and beyond) and manage a full 128-slot preset bank
• Import/Export preset banks as JSON for backup/restore
• Inspect MIDI traffic with a debugger panel (dev/debug mode)

Prerequisites

• pnpm 8+
• Rust toolchain (via rustup) for Tauri
• On macOS, Xcode Command Line Tools are sufficient. If the build process prompts for them, accept the install; full Xcode is not required.

Setup

• Install dependencies with pnpm install (other package managers aren’t supported).
• If you switch branches or update the lockfile, rerun pnpm install to keep node_modules in sync.

Scripts

• pnpm dev – start Vite (browser preview only)
• pnpm tauri dev – run the desktop shell with hot reload (use this for real MIDI)
• pnpm build – build the Vite frontend then bundle with Tauri
• pnpm lint – run ESLint with the TypeScript rules
• pnpm test – run Vitest (supports --runInBand/-i)
• pnpm format – format with Prettier
• pnpm storybook – component catalog on port 6006 (use HOME=$(pwd) pnpm storybook -- --disable-telemetry in locked-down envs)
• pnpm storybook:build – build static Storybook

Core user flows

• Connect & monitor MIDI: launch pnpm tauri dev, select the MIDI port, watch connection status/latency in the footer.
• Tweak parameters: move knobs or use the Parameters panel sliders; values mirror the pedal and send MIDI immediately.
• Presets A/B/C: load or save the on-pedal footswitch presets directly.
• Preset Bank (128 slots): browse/search all slots, rename, tag, reorder, import/export JSON. Current preset is highlighted.
• Import/Export: export the entire bank to JSON for backup; import to restore/overwrite slots.
• Debug MIDI (dev mode): open the MIDI Debugger to see live in/out messages with filters and timestamps.

Architecture (short)

• UI: React + Tailwind/LESS modules, atomic structure in components/atoms|molecules|organisms.
• Data: model metadata in src/data (effects, mappings, selector order). Parameter labels come from parameterMappings.ts.
• State: preset bank store in src/state/usePresetBank.ts; device/preset interaction lives in src/App.tsx and hooks under src/hooks.
• Styling tokens: src/styles/tokens.less.
• Storybook: run pnpm storybook to preview UI pieces in isolation.

Contributing notes

• Keep user-facing labels/descriptions in src/data accurate to the DL4 MkII manual.
• Prefer tokenized colors/spacings and co-located .module.less styles.
• Add Storybook stories for new components so UX can be reviewed without the pedal.
• Use intent-driven comments sparingly to explain behavior, not what the code literally does.

Quick references

• Preset bank persistence: src/state/usePresetBank.ts
• Parameter labels (what the Parameters panel shows): src/data/parameterMappings.ts
• Model catalog (names, detents): src/data/effects.ts and src/data/selectorOrder.ts
• MIDI helpers: src/data/midi.ts, src/data/midiMessages.ts