SOURCE

const canvas = document.getElementById("canvas");
canvas.width = 600;
canvas.height = 400;
const ctx = canvas.getContext("2d");

ctx.moveTo(0, 100);
ctx.lineTo(600, 100);
ctx.moveTo(0, 200);
ctx.lineTo(600, 200);
ctx.moveTo(0, 300);
ctx.lineTo(600, 300);
ctx.lineWidth = 1
ctx.strokeStyle = '#ccc'
ctx.stroke();

ctx.font = "16px PingFangSC-Regular, PingFang SC";
ctx.fillStyle = "#f00";
ctx.fillText("afgk 汉字下沉", 100, 98.4);
// y 轴位置差不多是字号的 1/10 偏差

<canvas id="canvas"></canvas>

* {
    margin: 0;
    padding: 0;
}

canvas {
    background: rgba(0, 0, 0, .05)
}