本文实例为大家分享了canvas实现水球加载动画的具体代码,供大家参考,具体内容如下
效果展示:
源码展示:
<!doctype html> <html> <head> <meta charset="utf-8"> <title>canvas实现水球加载动画</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"> <script> canvas = document.getelementbyid("c"); ctx = canvas.getcontext("2d"); orange = document.getelementsbyname("range")[0]; m = math; sin = m.sin; cos = m.cos; sqrt = m.sqrt; pow = m.pow; pi = m.pi; round = m.round; ow = canvas.width = 300; oh = canvas.height = 300; // 线宽 linewidth = 2 // 大半径 r = (ow / 2); cr = r - 8 * linewidth; ctx.beginpath(); ctx.linewidth = linewidth; // 水波动画初始参数 axislength = 2 * r - 16 * linewidth; // sin 图形长度 unit = axislength / 8; // 波浪宽 range = .2 // 浪幅 nowrange = range; xoffset = 8 * linewidth; // x 轴偏移量 data = ~~(orange.value) / 100; // 数据量 sp = 0; // 周期偏移量 nowdata = 0; waveupsp = 0.002; // 水波上涨速度 // 圆动画初始参数 arcstack = []; // 圆栈 br = r - 8 * linewidth; soffset = -(pi / 2); // 圆动画起始位置 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) ]) } cstartpoint = arcstack.shift(); // 圆起始点 ctx.strokestyle = "#1c86d1"; ctx.moveto(cstartpoint[0], cstartpoint[1]) render(); // 开始渲染 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 = "#1c86d1"; ctx.fill() ctx.restore(); } function drawtext() { ctx.globalcompositeoperation = 'source-over'; var size = 0.4 * cr; ctx.font = 'bold ' + size + 'px microsoft yahei'; txt = (nowdata.tofixed(2) * 100).tofixed(0) + '%'; var fonty = r + size / 2; var fontx = r - size * 0.8; ctx.fillstyle = "rgba(06, 85, 128, 0.8)"; ctx.filltext(txt, fontx, fonty) } function render() { ctx.clearrect(0, 0, ow, oh); if (circlelock) { if (arcstack.length) { var temp = arcstack.shift(); ctx.lineto(temp[0], temp[1]) ctx.stroke(); } else { circlelock = false; ctx.lineto(cstartpoint[0], cstartpoint[1]) ctx.stroke(); arcstack = null; ctx.globalcompositeoperation = 'destination-over'; ctx.beginpath(); ctx.linewidth = linewidth; ctx.arc(r, r, br, 0, 2 * pi, 1); ctx.beginpath(); ctx.save(); ctx.arc(r, r, r - 16 * linewidth, 0, 2 * pi, 1); ctx.restore() ctx.clip(); ctx.fillstyle = "#1c86d1"; // 初始拖拽控件 orange.addeventlistener("change", function() { data = ~~(orange.value) / 100; console.log("data=" + data) }, 0); } } else { // 开始水波动画 // 控制波幅 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; drawsine(); drawtext(); } requestanimationframe(render) } </script> <hr> <pre style="color:red"> 感: 最近贡献一下我在教学中的小案例 希望能给你一些帮助 ,希望大家继续关注我的博客 --王 </pre> </body> </html>
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