// File loader function loadMidiFile(file) if (!file
// Event Listeners selectBtn.addEventListener('click', () => fileInput.click()); fileInput.addEventListener('change', (e) => if (e.target.files.length) loadMidiFile(e.target.files[0]); ); dropZone.addEventListener('dragover', (e) => e.preventDefault(); dropZone.style.borderColor = '#2c7da0'; ); dropZone.addEventListener('dragleave', () => dropZone.style.borderColor = '#bdd3e8'; ); dropZone.addEventListener('drop', (e) => ); resetBtn.addEventListener('click', () => fileInput.value = ''; controlsSection.style.display = 'none'; setStatus("Ready — upload a MIDI file"); currentMidiData = null; parsedMidi = null; ); downloadBtn.addEventListener('click', exportAsPDF); midi to thirty dollar website
// Render piano roll on canvas function renderPianoRoll(notes, ticksPerQuarter, canvasElem) if (!notes.length) const ctx = canvasElem.getContext('2d'); ctx.clearRect(0, 0, canvasElem.width, canvasElem.height); ctx.fillStyle = "#aaa"; ctx.font = "14px Inter"; ctx.fillText("No notes to display", 20, 50); return; const width = canvasElem.width; const height = canvasElem.height; const ctx = canvasElem.getContext('2d'); ctx.clearRect(0, 0, width, height); const maxTick = Math.max(...notes.map(n => n.startTick + n.duration), 480 * 4); const ticksPerMeasure = ticksPerQuarter * 4; const maxMeasures = Math.min(8, Math.ceil(maxTick / ticksPerMeasure)); const timeRange = ticksPerMeasure * maxMeasures; const minPitch = Math.min(...notes.map(n => n.pitch), 48); const maxPitch = Math.max(...notes.map(n => n.pitch), 84); const pitchRange = maxPitch - minPitch + 1; const noteHeight = Math.min(14, (height - 60) / pitchRange); // Draw grid & labels ctx.fillStyle = "#ddd"; ctx.font = "10px monospace"; for (let i = 0; i <= maxMeasures; i++) let x = (i * ticksPerMeasure / timeRange) * width; ctx.beginPath(); ctx.strokeStyle = "#3a546d"; ctx.lineWidth = 0.7; ctx.moveTo(x, 0); ctx.lineTo(x, height); ctx.stroke(); ctx.fillStyle = "#b9d0e4"; ctx.fillText(`$i`, x+4, 18); // draw note rectangles for (let note of notes) const x = (note.startTick / timeRange) * width; const w = (note.duration / timeRange) * width; const y = ((maxPitch - note.pitch) / pitchRange) * (height - 40) + 20; ctx.fillStyle = `hsl($200 + (note.velocity * 0.5), 70%, 60%)`; ctx.fillRect(x, y, Math.max(w, 3), noteHeight-1); ctx.strokeStyle = "#ffffff80"; ctx.strokeRect(x, y, Math.max(w, 3), noteHeight-1); // pitch labels ctx.fillStyle = "#ffecb3"; ctx.font = "9px monospace"; for (let p = minPitch; p <= maxPitch; p+=2) let y = ((maxPitch - p) / pitchRange) * (height - 40) + 20 + noteHeight/2; ctx.fillText(MidiFile.pitchName ? MidiFile.pitchName(p) : `note$p`, 5, y); // File loader function loadMidiFile(file) if (
