feat: honor MIDI input notes' velocity during recording

src/components/piano-roll/PianoNote.tsx

@@ -1,20 +1,7 @@
 import React, { useState, useRef, useEffect } from 'react';
 import { PIANO_ROLL_CONSTANTS, DEBUG_MODE } from '../../constants';
 import { useProjectStore } from '../../stores/projectStore';
-
-// Purple (vel=0) → green (vel=64) → red (vel=127), matching Logic Pro
-function velocityToColor(v: number, alpha = 1): string {
-  const lerp = (a: number, b: number, t: number) => Math.round(a + (b - a) * t);
-  let r: number, g: number, b: number;
-  if (v <= 64) {
-    const t = v / 64;
-    r = lerp(123, 90, t); g = lerp(95, 176, t); b = lerp(160, 106, t);
-  } else {
-    const t = (v - 64) / 63;
-    r = lerp(90, 255, t); g = lerp(176, 85, t); b = lerp(106, 85, t);
-  }
-  return alpha === 1 ? `rgb(${r}, ${g}, ${b})` : `rgba(${r}, ${g}, ${b}, ${alpha})`;
-}
+import { velocityToColor } from '../../util/velocityColor';
 
 interface PianoNoteProps {
   id: string;

src/components/piano-roll/PianoRoll.css

@@ -418,8 +418,7 @@
 
 .piano-grid-recording-note {
   position: absolute;
-  background-color: rgba(255, 60, 60, 0.35);
-  border: 1px solid rgba(255, 60, 60, 0.85);
+  border: 1px solid transparent;
   pointer-events: none;
   z-index: 3;
 }

src/components/piano-roll/PianoRollContent.tsx

@@ -13,6 +13,7 @@ import { useNoteOperations } from '../../hooks/useNoteOperations';
 import { useNoteSelection } from '../../hooks/useNoteSelection';
 import type { KeySignature } from '../../core/KGProject';
 import type { KGAudioRegion } from '../../core/region/KGAudioRegion';
+import { velocityToColor } from '../../util/velocityColor';
 
 interface PianoRollContentProps {
   contentRef: React.MutableRefObject<HTMLDivElement | null>;
@@ -259,6 +260,8 @@ const PianoRollContent: React.FC<PianoRollContentProps> = ({
           top: (107 - note.pitch) * noteHeight,
           width: Math.max((note.endBeat - note.startBeat) * beatWidth, 4),
           height: noteHeight,
+          backgroundColor: velocityToColor(note.velocity, 0.35),
+          borderColor: velocityToColor(note.velocity, 0.85),
         }}
       />
     ));

src/core/midi-input/KGMidiInput.ts

@@ -16,7 +16,7 @@ export class KGMidiInput {
   private connectedInputs: Map<string, MIDIInput> = new Map();
 
   // Recording callbacks
-  private onRecordNoteOn: ((pitch: number) => void) | null = null;
+  private onRecordNoteOn: ((pitch: number, velocity: number) => void) | null = null;
   private onRecordNoteOff: ((pitch: number) => void) | null = null;
 
   // Private constructor to prevent direct instantiation
@@ -165,7 +165,7 @@ export class KGMidiInput {
     if (command === 0x90 && velocity > 0) {
       console.log(`MIDI Note On: pitch=${pitch}, velocity=${velocity}, channel=${channel}`);
       this.triggerNoteOn(pitch, velocity);
-      this.onRecordNoteOn?.(pitch);
+      this.onRecordNoteOn?.(pitch, velocity);
     }
     // Note Off: command = 0x80 (128) or Note On with velocity 0
     else if (command === 0x80 || (command === 0x90 && velocity === 0)) {
@@ -273,7 +273,7 @@ export class KGMidiInput {
   // ===== RECORDING =====
 
   public setRecordingCallbacks(
-    onNoteOn: ((pitch: number) => void) | null,
+    onNoteOn: ((pitch: number, velocity: number) => void) | null,
     onNoteOff: ((pitch: number) => void) | null
   ): void {
     this.onRecordNoteOn = onNoteOn;

src/stores/projectStore.ts

@@ -101,7 +101,7 @@ interface ProjectState {
   // Recording state
   isRecording: boolean;
   recordingTargetRegionId: string | null;
-  recordingNotes: Array<{ pitch: number; startBeat: number; endBeat: number }>;
+  recordingNotes: Array<{ pitch: number; startBeat: number; endBeat: number; velocity: number }>;
   recordingOriginalPlayhead: number;
 
   // Undo/redo state
@@ -199,7 +199,7 @@ interface ProjectState {
 }
 
 // Module-level recording state (not reactive — only used for timing during active recording)
-let _recordingActiveNotes: Map<number, number> = new Map(); // pitch → region-relative startBeat
+let _recordingActiveNotes: Map<number, { startBeat: number; velocity: number }> = new Map(); // pitch → note-on data
 let _recordingRegionStartBeat: number = 0;
 
 function getRecordingLoopEndBeatRelative(): number | null {
@@ -883,18 +883,23 @@ export const useProjectStore = create<ProjectState>((set, get) => {
       };
 
       KGMidiInput.instance().setRecordingCallbacks(
-        (pitch: number) => {
+        (pitch: number, velocity: number) => {
           const beat = buildCorrectedBeat();
-          _recordingActiveNotes.set(pitch, beat);
+          _recordingActiveNotes.set(pitch, { startBeat: beat, velocity });
         },
         (pitch: number) => {
           const endBeat = buildCorrectedBeat();
-          const startBeat = _recordingActiveNotes.get(pitch);
-          if (startBeat !== undefined) {
+          const activeNote = _recordingActiveNotes.get(pitch);
+          if (activeNote !== undefined) {
             _recordingActiveNotes.delete(pitch);
-            const finalizedEndBeat = finalizeRecordedNote(startBeat, endBeat);
+            const finalizedEndBeat = finalizeRecordedNote(activeNote.startBeat, endBeat);
             set(state => ({
-              recordingNotes: [...state.recordingNotes, { pitch, startBeat, endBeat: finalizedEndBeat }],
+              recordingNotes: [...state.recordingNotes, {
+                pitch,
+                startBeat: activeNote.startBeat,
+                endBeat: finalizedEndBeat,
+                velocity: activeNote.velocity,
+              }],
             }));
           }
         }
@@ -925,8 +930,13 @@ export const useProjectStore = create<ProjectState>((set, get) => {
       const correctionBeats = (playbackDelaySec + recordingOffsetSec) * (bpm / 60);
       const endBeatForHeld = KGAudioInterface.instance().getTransportPosition() - correctionBeats - _recordingRegionStartBeat;
 
-      _recordingActiveNotes.forEach((startBeat, pitch) => {
-        finalNotes.push({ pitch, startBeat, endBeat: finalizeRecordedNote(startBeat, endBeatForHeld) });
+      _recordingActiveNotes.forEach((activeNote, pitch) => {
+        finalNotes.push({
+          pitch,
+          startBeat: activeNote.startBeat,
+          endBeat: finalizeRecordedNote(activeNote.startBeat, endBeatForHeld),
+          velocity: activeNote.velocity,
+        });
       });
       _recordingActiveNotes.clear();
 
@@ -938,7 +948,7 @@ export const useProjectStore = create<ProjectState>((set, get) => {
           startBeat: n.startBeat,
           endBeat: n.endBeat,
           pitch: n.pitch,
-          velocity: 127,
+          velocity: n.velocity,
         }));
         const command = new CreateNotesCommand(noteData);
         KGCore.instance().executeCommand(command);
@@ -1272,4 +1282,3 @@ export const useProjectStore = create<ProjectState>((set, get) => {
 
 
 
-

src/test/integration/store/project-store-sync.integration.test.ts

@@ -349,7 +349,7 @@ describe('Project Store Synchronization Integration Tests', () => {
       expect(noteOff).toBeTypeOf('function');
 
       act(() => {
-        noteOn?.(60);
+        noteOn?.(60, 96);
         noteOff?.(60);
       });
 
@@ -365,6 +365,7 @@ describe('Project Store Synchronization Integration Tests', () => {
       expect(mockAudioInterface.stopPlayback).toHaveBeenCalled();
       expect(setRecordingCallbacksSpy).toHaveBeenLastCalledWith(null, null);
       expect(testRegion.getNotes()).toHaveLength(1);
+      expect(testRegion.getNotes()[0].getVelocity()).toBe(96);
     });
 
     it('should cut a held looped recording note at the loop end when note off arrives after wrap', async () => {
@@ -400,7 +401,7 @@ describe('Project Store Synchronization Integration Tests', () => {
       const noteOff = setRecordingCallbacksSpy.mock.calls.at(-1)?.[1];
 
       act(() => {
-        noteOn?.(60);
+        noteOn?.(60, 72);
         noteOff?.(60);
       });
 
@@ -412,6 +413,50 @@ describe('Project Store Synchronization Integration Tests', () => {
       expect(notes).toHaveLength(1);
       expect(notes[0].getStartBeat()).toBeCloseTo(15);
       expect(notes[0].getEndBeat()).toBeCloseTo(16);
+      expect(notes[0].getVelocity()).toBe(72);
+    });
+
+    it('should preserve velocity when finalizing a held recording note on stop', async () => {
+      const testTrack = new KGMidiTrack('Recording Track', 0, 'acoustic_grand_piano');
+      const testRegion = new KGMidiRegion('record-region', 'track-0', 0, 'Recording Region', 16, 16);
+      testTrack.addRegion(testRegion);
+      testProject.setTracks([testTrack]);
+
+      await act(async () => {
+        await useProjectStore.getState().loadProject(testProject);
+      });
+
+      const core = KGCore.instance();
+      vi.spyOn(core, 'startPlaying').mockResolvedValue(undefined);
+      vi.spyOn(mockAudioInterface, 'getTransportPosition')
+        .mockReturnValueOnce(5)
+        .mockReturnValueOnce(6.5);
+      const setRecordingCallbacksSpy = vi.spyOn(KGMidiInput.instance(), 'setRecordingCallbacks');
+      const { setActiveRegionId, setPlayheadPosition, startRecording, stopTransport } = useProjectStore.getState();
+
+      act(() => {
+        setActiveRegionId(testRegion.getId());
+        setPlayheadPosition(4);
+      });
+
+      await act(async () => {
+        await startRecording();
+      });
+
+      const noteOn = setRecordingCallbacksSpy.mock.calls.at(-1)?.[0];
+      expect(noteOn).toBeTypeOf('function');
+
+      act(() => {
+        noteOn?.(60, 48);
+      });
+
+      await act(async () => {
+        await stopTransport();
+      });
+
+      const notes = testRegion.getNotes();
+      expect(notes).toHaveLength(1);
+      expect(notes[0].getVelocity()).toBe(48);
     });
   });
 

src/util/velocityColor.ts

@@ -0,0 +1,23 @@
+// Purple (vel=0) -> green (vel=64) -> red (vel=127), matching the piano roll note colors.
+export function velocityToColor(v: number, alpha = 1): string {
+  const clampedVelocity = Math.max(0, Math.min(127, v));
+  const lerp = (a: number, b: number, t: number) => Math.round(a + (b - a) * t);
+
+  let r: number;
+  let g: number;
+  let b: number;
+
+  if (clampedVelocity <= 64) {
+    const t = clampedVelocity / 64;
+    r = lerp(123, 90, t);
+    g = lerp(95, 176, t);
+    b = lerp(160, 106, t);
+  } else {
+    const t = (clampedVelocity - 64) / 63;
+    r = lerp(90, 255, t);
+    g = lerp(176, 85, t);
+    b = lerp(106, 85, t);
+  }
+
+  return alpha === 1 ? `rgb(${r}, ${g}, ${b})` : `rgba(${r}, ${g}, ${b}, ${alpha})`;
+}