关于javascript:canvas-垂直背景图滚动

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想找游戏相干素材

<!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>canvas 垂直背景图滚动 </title>
</head>
<body>
  <canvas id="canvas" width="480" height="720">
    你的浏览器不反对 canvas，请降级你的浏览器。</canvas>
  <script>
    const canvas = document.getElementById('canvas')
    let ctx = canvas.getContext("2d")

    var offSetY = 0;
    var image = new Image(); // 创立图片元素
    image.onload = function(){bgMove(image);
    }
    image.src = 'images/bg.jpg';

    function bgMove() {
      // 记录状态
      ctx.save();
      ctx.clearRect(0, 0, canvas.width, canvas.height);
      ctx.translate(0, offSetY);
      ctx.drawImage(image, 0, 0);
      ctx.drawImage(image, 0, -canvas.height);
      // 判断 offSetY 偏移量
      offSetY += 0.2;
      if(offSetY >= canvas.height) {offSetY = 0;}
      ctx.restore();
      window.requestAnimationFrame(bgMove);
    }
  </script>
</body>
</html>

图片能够在这里找背景图片地址

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