canvas 水滴图、液体进度条、仿加速球、圆球水波图

传送门：https://github.com/guoyoujin/WaterMoire
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>test</title>
    <style>
        body {
        display: flex;
        flex-flow: column wrap;
        justify-content: center;
        align-items: center;
      }
      #c {
        margin-top: 20px;      
      }
      input[type=range]::before {content: attr(min);  color: #000; padding-right: 5px;}
      input[type=range]::after { content: attr(max); color: #000; padding-left: 5px;}
    </style>
</head>

<body>
    <canvas id="c">当前浏览器不支持canvas 请升级！</canvas>
    <input type="range" name="range" min="0" max="100" step="1">
</body>
<script>
let canvas = document.getElementById("c")
let ctx = canvas.getContext("2d")
let oRange = document.getElementsByName("range")[0];
let M = Math
let Sin = M.sin
let Cos = M.cos
let Sqrt = M.sqrt
let Pow = M.pow
let PI = M.PI
let Round = M.round
let oW = canvas.width = 250
let oH = canvas.height = 250
let lineWidth = 2 // 线宽
let r = (oW / 2) // 大半径
let cR = r - 10 * lineWidth
ctx.beginPath()
ctx.lineWidth = lineWidth

// 水波动画初始参数
let axisLength = 2 * r - 16 * lineWidth // Sin 图形长度
let unit = axisLength / 9 // 波浪宽
let range = .4 // 浪幅
let nowrange = range
let xoffset = 8 * lineWidth // x 轴偏移量
let data = ~~(oRange.value) / 100 // 数据量
let sp = 0 // 周期偏移量
let nowdata = 0
let waveupsp = 0.006 // 水波上涨速度

// 圆动画初始参数
let arcStack = [] // 圆栈
let bR = r - 8 * lineWidth
let soffset = -(PI / 2) // 圆动画起始位置
let circleLock = true // 起始动画锁

// 获取圆动画轨迹点集
for (var i = soffset; i < soffset + 2 * PI; i += 1 / (8 * PI)) {
    arcStack.push([
        r + bR * Cos(i),
        r + bR * Sin(i)
    ])
}
// 圆起始点
let cStartPoint = arcStack.shift();
ctx.strokeStyle = "#1c86d1";
ctx.moveTo(cStartPoint[0], cStartPoint[1]);
// 开始渲染
render();

function drawSine() {
    ctx.beginPath();
    ctx.save();
    var Stack = []; // 记录起始点和终点坐标
    for (var i = xoffset; i <= xoffset + axisLength; i += 20 / axisLength) {
        var x = sp + (xoffset + i) / unit;
        var y = Sin(x) * nowrange;
        var dx = i;
        var dy = 2 * cR * (1 - nowdata) + (r - cR) - (unit * y);
        ctx.lineTo(dx, dy);
        Stack.push([dx, dy])
    }
    // 获取初始点和结束点
    var startP = Stack[0]
    var endP = Stack[Stack.length - 1]
    ctx.lineTo(xoffset + axisLength, oW);
    ctx.lineTo(xoffset, oW);
    ctx.lineTo(startP[0], startP[1])
    ctx.fillStyle = "#fbec99";
    ctx.fill();
    ctx.restore();
}

function drawText() {
    ctx.globalCompositeOperation = 'source-over';
    var size = 0.4 * cR;
    ctx.font = 'bold ' + size + 'px Microsoft Yahei';
    let txt = (nowdata.toFixed(2) * 100).toFixed(0) + '`%';
    var fonty = r + size / 2;
    var fontx = r - size * 0.8;
    ctx.fillStyle = "#f6b71e";
    ctx.textAlign = 'center';
    ctx.fillText(txt, r + 5, r + 20)
}
//最外面淡黄色圈
function drawCircle() {
    ctx.beginPath();
    ctx.lineWidth = 15;
    ctx.strokeStyle = '#fff89d';
    ctx.arc(r, r, cR + 7, 0, 2 * Math.PI);
    ctx.stroke();
    ctx.restore();
}
//灰色圆圈
function grayCircle() {
    ctx.beginPath();
    ctx.lineWidth = 10;
    ctx.strokeStyle = '#eaeaea';
    ctx.arc(r, r, cR - 5, 0, 2 * Math.PI);
    ctx.stroke();
    ctx.restore();
    ctx.beginPath();
}
//橘黄色进度圈
function orangeCircle() {
    ctx.beginPath();
    ctx.strokeStyle = '#fbdb32';
    //使用这个使圆环两端是圆弧形状
    ctx.lineCap = 'round';
    ctx.arc(r, r, cR - 5, 0 * (Math.PI / 180.0) - (Math.PI / 2), (nowdata * 360) * (Math.PI / 180.0) - (Math.PI / 2));
    ctx.stroke();
    ctx.save()
}
//裁剪中间水圈
function clipCircle() {
    ctx.beginPath();
    ctx.arc(r, r, cR - 10, 0, 2 * Math.PI, false);
    ctx.clip();
}
//渲染canvas
function render() {
    ctx.clearRect(0, 0, oW, oH);
    //最外面淡黄色圈
    drawCircle();
    //灰色圆圈  
    grayCircle();
    //橘黄色进度圈
    orangeCircle();
    //裁剪中间水圈  
    clipCircle();
    // 控制波幅
    oRange.addEventListener("change", function() {
        data = ~~(oRange.value) / 100;
    }, 0);
    if (data >= 0.85) {
        if (nowrange > range / 4) {
            var t = range * 0.01;
            nowrange -= t;
        }
    } else if (data <= 0.1) {
        if (nowrange < range * 1.5) {
            var t = range * 0.01;
            nowrange += t;
        }
    } else {
        if (nowrange <= range) {
            var t = range * 0.01;
            nowrange += t;
        }
        if (nowrange >= range) {
            var t = range * 0.01;
            nowrange -= t;
        }
    }
    if ((data - nowdata) > 0) {
        nowdata += waveupsp;
    }
    if ((data - nowdata) < 0) {
        nowdata -= waveupsp
    }
    sp += 0.07;
    // 开始水波动画
    drawSine();
    // 写字
    drawText();
    requestAnimationFrame(render)
}
</script>
来源：oschina
链接：https://my.oschina.net/u/4387790/blog/3600209
标签
cos
FLEX