使用javascript读取波形文件数据，并生成动态的波形图

代码如下：

// HTML5 Canvas 动态波形生成器
// 使用JS读取波形文件并生成动态波形

// 创建Canvas并设置上下文
const canvas = document.createElement('canvas');
canvas.width = 800;
canvas.height = 400;
document.body.appendChild(canvas);
const ctx = canvas.getContext('2d');

// 波形数据
let waveform = [];

// 加载波形文件数据
async function loadWaveformData(url) {
  try {
    const response = await fetch(url);
    if (!response.ok) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    const arrayBuffer = await response.arrayBuffer();
    const audioContext = new AudioContext();
    const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);
    waveform = audioBuffer.getChannelData(0); // 获取左声道数据
    console.log('Waveform data loaded:', waveform);
    drawWaveform();
  } catch (error) {
    console.error('Error loading waveform data:', error);
  }
}

// 动态波形绘制参数
const waveParams = {
  sampleRate: 800, // 每帧波形的采样点数
  offset: 0, // 动态偏移
  speed: 2 // 波形滚动速度
};

// 动态绘制波形
function drawWaveform() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  ctx.beginPath();

  const step = Math.max(1, Math.floor(waveform.length / waveParams.sampleRate)); // 每步采样间隔
  const centerY = canvas.height / 2;

  for (let i = 0; i < canvas.width; i++) {
    const sampleIndex = (waveParams.offset + i * step) % waveform.length;
    const sampleValue = waveform[Math.floor(sampleIndex)];
    const y = centerY + sampleValue * centerY; // 将样本值映射到画布高度
    if (i === 0) {
      ctx.moveTo(i, y);
    } else {
      ctx.lineTo(i, y);
    }
  }

  ctx.strokeStyle = '#007BFF';
  ctx.lineWidth = 2;
  ctx.stroke();

  waveParams.offset += waveParams.speed; // 波形滚动

  requestAnimationFrame(drawWaveform);
}

// 加载波形文件（将 `example.wav` 替换为你的文件路径）
loadWaveformData('example.wav');