知识库

html
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    html,
    body {
      width: 100vw;
      height: 100vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
    }
  </style>
</head>

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

  <script>
    const canvas = document.getElementById('canvas')
    const context = canvas.getContext('2d')

    canvas.style.background = '#ddd'
    canvas.width = 800
    canvas.height = 800

    const drawGrid = (context, gridColor, lineWidth, gapX, gapY) => {
      const { width, height } = context.canvas

      context.lineWidth = lineWidth
      context.strokeStyle = gridColor

      // 横线
      for (let i = gapY + lineWidth; i < height; i += gapY) {
        context.beginPath()
        context.moveTo(0, i)
        context.lineTo(width, i)
        context.stroke()
      }

      // 竖线
      for (let i = gapX + lineWidth; i < width; i += gapX) {
        context.beginPath()
        context.moveTo(i, 0)
        context.lineTo(i, height)
        context.stroke()
      }
    }

    drawGrid(context, 'red', 0.5, 20, 20)
  </script>
</body>

</html>