Piano synth · minimax-m3.1-flash

Check Tone version.

Tone 14.8.49. Good. Now write index.html.

Design: one octave C4-C5, 13 notes: C4, C#4, D4, D#4, E4, F4, F#4, G4, G#4, A4, A#4, B4, C5. Computer keys A W S E D F T G Y H U J K in order.

Keys: white keys C D E F G A B C (8 white), black keys C# D# F# G# A# (5).

Layout: use absolute positioning for black keys over white keys.

Piano geometry: white key width = 100/8 = 12.5%. Black key positioned between. Use flex for white keys and absolute for black.

Simplest: container width W, white key width = W/8. Black key width = 0.6 * white width, height 60%.

Approach: .piano position relative, .white-keys flex with 8 divs, .black-keys absolute layer.

Black key positions (left offsets in units of white key width): C#4 after white index 0 → left = 1*w - bw/2... Standard: black key centered on boundary between white keys. Boundary positions: 1,2,4,5,6 (0-indexed boundaries after C, D, F, G, A). left = boundary*w - bw/2.

Note labels: white keys show name + computer key; black keys show name + key.

Voice: Tone.PolySynth with Tone.Synth, maxPolyphony 16.

Pointer events: pointerdown on key → noteOn, pointerup/pointerleave → noteOff. But requirement "Release held voices when the pointer is released outside a key or the window loses focus". Use document-level pointerup listener to release all pointer-started notes, plus window blur, plus visibilitychange.

Also prevent auto-repeat: keydown with e.repeat check.

Also handle simultaneous: mouse + computer keys.

Keyboard: map 'a','w','s','e','d','f','t','g','y','h','u','j','k' → notes.

Tone.start() on first gesture.

Let me write it.

For highlighting while held: add class 'active'.

Careful with pointer capture: when pressing on a key and dragging, mouseup outside window. Use document listeners.

Also each key element should have pointerdown handler that calls noteOn for that key's note and marks key as pointer-held. Global pointerup → release all pointer-held notes.

Let me implement notes tracking: Map from source key → note index. Use per-note count? Each note could be triggered by both mouse and keyboard simultaneously. Keep a Set of active sources per note.

Implementation:
notesState: array of {activeSources:Set, synthVoice}

Simplify: sources map: sourceId -> noteIndex. sourceId like 'kbd:a' or 'ptr:12'.

noteOn(noteIdx, sourceId): if not already, sources[noteIdx].add(sourceId), triggerAttack.
noteOff(noteIdx, sourceId): remove; if set empty, triggerRelease.

Highlight key if any source active for that note.

Black key z-order so black keys are on top and receive pointer events.

Let's write the file.

Voice: use Tone.PolySynth(Tone.Synth, {oscillator:{type:'triangle'}, envelope:{attack:0.01, decay:0.2, sustain:0.4, release:1.2}}). PolySynth triggerAttack/release with note names. Set maxPolyphony 16. Also add a Tone.Reverb for richness (works with timer clock; Reverb is fine per instructions).

Tone.getDestination(). Volume maybe -6.

Also master limiter: Tone.Destination.

Let's write.

Also handle 'AudioContext' resume. Tone.start() returns promise.

Keyboard focus: attach keydown to window.

Prevent default for space etc.? Keys are letters, fine.

Let me write the HTML.

Positioning: I'll compute black key left with percentages: boundary index b in [1,2,4,5,6], left = b*12.5% - bw/2 where bw = 7.5% (0.6*12.5). Use CSS calc: left: calc(12.5% - 3.75%).

Let's write.

Also note names: C4, C♯4 etc. Labels: for white key show "C4" and "A". Black key show "C#4" and "W". Use "♯" character? Might be safer with "C#4". I'll use "C♯4" visually? Use plain "C#4" to be safe for verification text.

Let's write the file now.

Also a small hint text and status line ("Click to enable audio").

Also the octave: C4 through C5 = 13 notes. Good.

Now also "Display the computer-key mapping." — show mapping on each key plus a legend row below.

Let me write it.

Issue: pointerenter with pointerdown — pointerenter fires on the new key while dragging but the old key's pointerleave fires releasing it. OK.

But problem: pointerdown on black key; the black key element is inside .blacks with pointer-events none on container but auto on black. Fine.

Another issue: pointerdown triggers on white key; since .blacks container is above whites with pointer-events:none, the container won't block.

Also on pointerdown I don't setPointerCapture, so pointerleave on the key works.

Let's test in browser.

Looks good. Black keys positioned correctly (C#4 between C and D etc.).

Now click Enable Audio and test notes.

Audio active. Now press a computer key (e.g., 'a') and check highlight. The browser tool's key action: key with text? Let's use action "key" with text "a". It may send keydown/keyup. To observe highlight while held, better to use pointer down without up — but the click action does down+up quickly. Let me press key "a" and check voices count and active class.

Actually to see press-and-release highlighting, I could dispatch events via JS. Let me first test with browser key action and check the DOM state right after keydown — hard. Instead use inspect after key press to check voices = 0 (released properly) and no console errors.

Then to verify hold highlighting, I can use JS via... no eval tool. But I can use drag? drag does mousedown, move, mouseup.

Alternative: use browser action "key" with text and check screenshot mid-hold — the tool probably presses and releases.

Let me instead add a temporary test: use browser action "key" then inspect. Let's just press 'a'.

The key press focused the button (focus ring on Enable Audio) — because the keydown on "a" didn't reach? Actually the browser "key" action may focus the last-clicked element and press 'a' — keydown fired on window anyway, so should trigger. voices shows 0 after release — consistent with correct release.

But I can't confirm the attack happened. The keydown handler is on window so it fires regardless of focus. Good. However, one problem: keydown 'a' with focus on the button — 'a' doesn't activate it. Fine.

To verify press-and-release highlight and voice count, let me instrument via the debug handle. I can't eval JS directly... but I can add a temporary test page? Alternatively, use browser "key" action with a long-held key? Let's check if the browser tool supports keydown-only. The action set includes "key" only.

Better: verify via mouse drag — drag from a key to outside; during drag the key should highlight. But screenshots are taken after action completes.

Alternative approach: add temporary auto-test code that programmatically dispatches keydown without keyup, then take screenshot. I can temporarily add a test hook in the page? That would pollute the artifact. But I can add a small hidden debug: the file already exposes window.__piano. Instead of modifying index.html, I could create a separate test html that loads index.html in an iframe... complicated.

Simpler: temporarily add to index.html a query-param-driven self test? Hmm, adds code.

Alternative: use the browser tool's key action repeatedly? The tool description mentions "motion frames" for animation. Not helpful.

Actually maybe the browser tool's key action supports pressing multiple keys for chords? Not documented.

Let me instead verify by measuring audio output: I could attach an AnalyserNode in the page to check RMS while holding a key. Still requires holding.

Pragmatic verification: temporarily modify index.html to include a `?selftest=1` mode... but the runner inlines it; extra code is fine if harmless. Actually simpler: I'll temporarily create a copy test.html that loads tone.min.js and index.html content? Hmm.

Easiest: temporarily patch index.html with a script that, when URL contains "selftest", dispatches keydown events for 'a','d','g' without keyup, and reports state in the status area; take screenshot to verify highlight and voices count; then remove the patch.

But wait: reloading with ?selftest=1 — the browser tool's reload probably loads index.html without query. I could use a separate file `selftest.html` that imports the same logic? The file is self-contained; I could copy index.html to selftest.html and append the test script. Then load selftest.html via browser... does the browser tool support navigating to a URL? Probably it loads index.html only. Let me check whether the tool's inspect accepts url param — not documented.

Alternative approach: verify with the drag action! Drag starts on a key (pointerdown) and ends elsewhere (pointerup). During the drag, does the tool capture intermediate motion frames? The "motion" action captures frames of recent animation. Not applicable.

Another way: hold the pointer down by using "click" then... no.

Practical: I can test programmatically by adding a permanent, harmless diagnostic: expose __piano.debugState. Then I need to trigger a keydown without keyup. I could simulate via the browser tool: "key" action likely sends keydown+keyup. But what if I press a key while focus is on a text input? No inputs.

Hmm — what about the "drag" action: mousedown on key, move, mouseup outside. The screenshot after shows released state.

Let me try a different tactic: use the browser tool's key action and immediately inspect; but the tool returns DOM snapshot after keyup.

I think the most reliable verification of held-state is a small self-test block in index.html itself that runs on load when a flag is set, and displays results. But triggering the flag requires URL params.

Let me check: maybe the browser tool supports specifying a URL via the `text` param on "reload"? Unlikely.

Alternative: create a separate file `selftest.html` that is index.html with an extra script appended that programmatically drives the keyboard and writes results into document.title, and then... I still need to load it in the browser.

Does the browser tool load a file relative to cwd? Probably loads index.html fixed. Let's test: run the browser action "inspect" with a text param? Not documented.

Maybe there's a way: I can serve? No network in sandbox? Local http server on localhost might be allowed. The browser tool might only accept file:// of index.html.

Practical decision: I'll do a self-test inside index.html temporarily, then remove it. To trigger it, use a URL hash? Reload action won't include hash. But I can auto-run the self-test after a delay on every load (e.g., 800ms after load, dispatch keydown for a,d,g without keyup, then report). Then take screenshot at ~1s to see three highlighted keys and voices=3. Then remove the test code and reload to confirm clean.

But dispatching keydown synthetically also triggers ensureAudio → Tone.start() without gesture → warning. Fine, already saw warnings.

Timing: the browser tool's inspect runs after page load; the screenshot after reload happens at some time. I need the self-test state to persist long enough for the screenshot, e.g., dispatch at 600ms and never release. Then screenshot shows 3 highlighted keys with voices=3. Then remove code.

Let's do that. But the auto-repeat test too: dispatch keydown with repeat:true twice → should not create duplicate voices.

Also test window blur release: dispatch window blur event → all released.

I'll implement a temporary self-test that runs a sequence and writes results to a visible div, and logs to console so inspect shows them. Console logs will show in inspect output — good, that's a way to read results.

Plan: temporary script appended before </body>:

window.addEventListener('load', () => setTimeout(() => {
  const log = [];
  const press = (k, opts) => window.dispatchEvent(new KeyboardEvent('keydown', Object.assign({key:k, bubbles:true}, opts||{})));
  press('a'); press('d'); press('g');
  log.push('held=' + window.__piano.active().join(',') + ' voices=' + document.getElementById('voices').textContent);
  press('a', {repeat:true});
  log.push('after repeat voices=' + document.getElementById('voices').textContent);
  console.log('SELFTEST', log.join(' | '));
}, 500));

And screenshot to see highlights. Let's add it temporarily.

Also I want to verify pointer highlight & release outside. Simulate pointerdown on a key element then dispatch window pointerup, and check voices.

Let me write the temp test file as a copy: index_selftest.html? The browser loads index.html. So modify index.html temporarily, then revert. Use edit tool with a marker so I can remove.

Let's do it.

The self-test output wasn't in console yet (console shows only initial). Maybe the inspect ran before the 400ms timeout. Let's do an "inspect" action now to read the console.

All behaviors verified:
- 3 simultaneous voices (a, d, g) → voices=3
- auto-repeat ignored → voices stays 3
- keyup releases one → 2
- pointerdown on F4 → 3 and class "key white active" (highlight works)
- pointerup outside → 2 and class removed
- blur → 0 (all released)

Also self-test's keydown triggered ensureAudio which started audio — interesting, "Audio active" appeared because synthetic keydown called ensureAudio → Tone.start() succeeded? Status says "Audio active". Fine.

Note: the self-test left the keys released. Now remove the temp script and reload to confirm clean state.

One more thing: the "voices" display is a nice touch. Also should I handle multiple pointers on same key - fine.

Also check that mouse click on a key triggers audio activation through gesture: pointerdown → ensureAudio → Tone.start(). Good.

Remove temp test now.

Clean. Now do real mouse interactions: click a white key (C4) and a black key, verify audio starts and console clean.

Click on the black key C#4 at ~(240, 340).

Clicking the black key C#4 activated audio ("Audio active"), voices back to 0 after release. No errors in console.

Now test a drag from a white key to outside the piano (should release). And test computer key press. Then done.

Let me do a drag: from white key G4 (x=660,y=450) to outside (x=660,y=700).

Drag from G4 off the piano ended with voices=0 — released properly.

Also verify computer key press works in the real browser (the earlier 'a' key press before audio activation: the click focused the button; keydown 'a' on window fired). Let me confirm by pressing 'j' and checking that no error occurs and audio still fine. The state after keyup is voices 0. To verify the key press actually triggered a note, the earlier self-test already verified handler logic; plus real key press path tested indirectly. Let me do one real key press to ensure no console errors and the key doesn't scroll etc.

Also there's one issue: keydown while focus is on the "Enable Audio" button and user presses space/enter — irrelevant.

Another potential issue: pressing "a" while an input focused—no inputs.

One more: the `keyup` for a key pressed while window blurred might not fire → handled by blur releaseAll.

Let me press 'j' via the tool and inspect console.

Console clean (only the pre-gesture autoplay warnings that occurred at load before activation). All good.

One more consideration: black key label "C#4" is rendered as "C#4" — good.

Final check of file: ensure tone.min.js script tag present, no temp test. Let's grep.