Webaudio音频可视化器，对数刻度x轴

Question

此代码绘制画布对象中频率数据的线性序列。如何在webaudio上下文中使用 getByteFrequencyData 在对数X轴上显示频率？

var analyser = audioContext.createAnalyser();
[...]
frameLooper(); 

function frameLooper(){
    window.requestAnimationFrame(frameLooper);
    fbc_array = new Uint8Array(analyser.frequencyBinCount);
    analyser.getByteFrequencyData(fbc_array);
    canvas.width = fbc_array.length;
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    bar_width = 2;

    for (var i = 0; i < fbc_array.length; i++) {
        bar_x = i;
        bar_height = -fbc_array[i];
        ctx.fillRect(bar_x, canvas.height, bar_width, bar_height);
    }
}