Piano synth · deepseek-v4.1-flash

Let me build this. First check the directory and tone.min.js.

Let me write the app. I'll build a piano with one octave C4-C5 (13 notes including C5). White keys: C D E F G A B C. Black keys: C# D# F# G# A#.

Layout: proper piano keyboard. I'll use a container with white keys flex, and black keys absolutely positioned.

Key mapping: A=C4, W=C#4, S=D4, E=D#4, D=E4, F=F4, T=F#4, G=G4, Y=G#4, H=A4, U=A#4, J=B4, K=C5.

Use PolySynth with Tone.Synth ADSR to support polyphony. Actually Tone.PolySynth(Tone.Synth, {envelope:...}). Trigger attack/release.

Prevent auto-repeat: track held keys set.

Pointer down on key -> noteOn; pointerup/leave -> noteOff. Handle pointerup outside via window pointerup. Window blur -> release all.

Audio context start via user gesture: on first interaction call Tone.start().

Let me write it.

For pointer events on keys: mousedown/touchstart. Use pointerdown on key, pointerup on window, pointerleave on key. Also pointercancel.

Simplest: attach pointerdown to each key => start note. Attach pointerup/pointerleave on each key => release. And window pointerup => release all active pointer notes. Track active pointer keys.

Let me implement the "held" state with map note->count? Better: for keyboard, set of held physical keys; for pointer, set of active pointer note.

I'll maintain active voices: Map note -> numberOfSources? Simpler: functions noteOn(note), noteOff(note). Keep a Set of active notes. noteOn only if not active. noteOff only if active. That prevents duplicate sustained voices.

But mouse and keyboard may overlap; fine.

Display labels on white keys (C4, D4...) and black keys maybe label the computer key. Show mapping: I'll put note label and key label on each.

Let me create nice CSS.

Let me write the file.

Let me run in browser and inspect.

The piano renders correctly. Note the black key positions: I see C#4 between C4 and D4, D#4, then F#4, G#4, A#4 — correct. Good.

Now test interaction: click start, press keys. Let me click Enable Audio then keyboard.

Audio active, C4 highlighted (the confirmation blip was captured mid-press). No console errors after activation. Now test keyboard press. Let me press keys. The browser tool has "key" action. Let me press "a" and check highlighting, then release.

Actually the browser tool's key action may send a click/keypress. Let me try pressing 'a'.

The key action probably sent a complete keypress (down+up), so C4 no longer highlighted. The Enable Audio button has focus ring. I can't easily test held state with the single key action because it's press+release. Let me verify the handler logic by reading code — already reasonable.

Let me test clicking on a key (pointerdown/up). The click action does down+up. Let me click D4.

Actually a better verification of the highlight would be to use motion or drag. Let me do a drag from C4 to D4 to test drag playing. But drag ends with pointerup releasing.

Let me just test a click on E4 and check no console errors. Also test multiple simultaneous via keyboard is hard.

The key action did register — no errors. But did it play? The key handler uses e.code. The browser tool's key action—does it send code "KeyA"? Possibly. If it sent only key 'a', codeToKey handles e.key fallback. Good.

Let me verify by dispatching synthetic events via inspect? Not available. I'll trust the code. But let me quickly test through browser "type" maybe not.

Actually I can check that keydown worked by temporarily... no. Let me at least verify mapping function handles lowercase. It does.

Let me test a click on a white key to ensure pointer handlers work, checking console for errors.

Click on D4 (x=560 is around D4, which spans ~551-617). No console errors. Since it's a click (down+up), highlight already released.

No new console errors after interactions. The only warnings are the initial AudioContext warning before gesture, which is expected and fine.

Everything looks good. Let me do a final quick check of the file for any issues. The black key positioning: for first black key C#4, whiteCount=1 after C4 added, left = 1*66-21 = 45. C4 spans 0-66, so C#4 at 45-87, centered on boundary at 66. Good.

One thing: `e.target.closest` — target could be the span inside key; closest works. Good.

Potential issue: pointerleave with e.buttons check—on touch, buttons may be 0 during drag? Actually pointer capture is set on keyboardEl, so pointerleave may not fire while captured. Fine.

`Tone.PolySynth(Tone.Synth, {...})` — constructor signature in v14.8 is PolySynth(voice, options). Good.

The `synth` is created in ensureStarted before Tone.start resolves. Fine.

Note: In ensureStarted, I set started=true then call Tone.start. But makeSynth creates node before context resumed — okay, Tone handles it.

Also on keydown before gesture, noteOn calls ensureStarted which calls Tone.start() within keydown user gesture — good.

I think we're done. Let me confirm file exists and report.