canvas環形資料效果

admin發表於2018-02-04
Canvas

分享一段程式碼例項，它利用canvas實現了環形資料效果。

程式碼例項如下:

[HTML] 純文字檢視 複製程式碼執行程式碼
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>螞蟻部落</title>
<script>
//適配
var html = document.getElementsByTagName("html")[0];
function getFontSize() {
  var width = document.documentElement.clientWidth ||
      document.body.clientWidth + "px";
  var fontSize = (100 / 750) * width;
  if (width >= 750) {
    fontSize = "100";
  }
  return fontSize;
}
html.style.fontSize = getFontSize() + "px";
window.onresize = function () {
  setTimeout(function () {
    html.style.fontSize = getFontSize() + "px";
  }, 100)
};
window.onload = function () {
  var canvas = document.getElementById("canvas");
  var ctx = canvas.getContext("2d");
  //已還金額/總金額
  var rand = 3000 / 5000 * 100;
  var angle = 0;
  var rot = 360 - rand;

  function draw(angle) {
    ctx.save();
    ctx.translate(75, 75);
    ctx.rotate(-Math.PI / 2)
    ctx.fillStyle = "#fce5cc";
    ctx.beginPath();
    ctx.arc(0, 0, 100, Math.PI / 180 * angle, Math.PI * 2, false);
    ctx.lineTo(0, 0);
    ctx.closePath();
    ctx.fill();
    ctx.restore();
  }
  var timer = setInterval(function () {
    angle += 1;
    if (angle >= rot) {
      clearInterval(timer);
    }
    ctx.clearRect(0, 0, 150, 150); //相當於初始化
    draw(angle);
  }, 5);
}
</script>
<style>
.Box {
  width: 100%;
  padding: .34rem 0;
  border-bottom: 1px solid #d7d7d7;
  background: #fff;
}
.Box .wradius {
  width: 2.52rem;
  height: 2.52rem;
  border-radius: 50%;
  background: #fce5cc;
  margin: 0 auto;
  position: relative;
}
.Box .nradius {
  width: 1.78rem;
  height: 1.78rem;
  border-radius: 50%;
  background: #3b3b3b;
  left: 50%;
  top: 50%;
  margin-top: -0.89rem;
  margin-left: -0.89rem;
  border: 2px solid #f27d00;
  position: absolute;
  text-align: center;
}
.Box p {
  font-size: .24rem;
  color: #fff;
  padding-top: .38rem;
  padding-bottom: .1rem;
}
.Box h1 {
  font-size: .48rem;
  color: #f27d00;
}
.Box .jiekxq {
  color: #f27d00;
  font-size: .28rem;
  position: relative;
  text-align: right;
  padding: 0 .3rem;
  display: block;
}
.Box .jiekxq img {
  position: absolute;
  right: 1.9rem;
  width: .3rem;
  top: .08rem;
}
.moneypice {
  padding: 0 .3rem;
  margin: .33rem 0 .2rem;
  border: 1px solid #d7d7d7;
  border-right: none;
  border-left: none;
  background: #fff;
}
.moneypice p {
  color: #161615;
  font-size: .32rem;
  border-bottom: 1px solid #d7d7d7;
  line-height: 1.1rem;
  overflow: hidden;
}
.moneypice p b {
  float: left;
}
.moneypice p span {
  color: #f27d00;
  text-align: center;
  float: left;
  width: 5rem;
  text-align: center;
}
.moneypice p img {
  float: right;
  width: .19rem;
  height: .3rem;
  margin-top: .4rem;
}
#canvas {
  background: #f27d00;
  border-radius: 50%;
  overflow: hidden;
  width: 2.52rem;
  height: 2.52rem;
}
</style>
</head>
<body>
  <div class="wrapper">
    <div class="Box">
      <div class="wradius">
        <canvas id="canvas" width="150" height="150"></canvas>
        <div class="nradius">
          <p>1111</p>
          <h1>5175</h1>
        </div>
      </div>
    </div>

  </div>
</body>
</html>

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