正文
canvas_基于canvan绘制的双半圆环进度条
提示：扫一扫查出行【扫一扫了解最新限行尾号】
复制提示
效果图
实现原理：
1.使用canvas绘制两个半圆弧，底图灰色半圆弧和颜色进度圆弧。
2.利用setInterval计时器，逐步改变颜色进度条，达到进度条的效果。
效果代码：
<!DOCTYPE html>
<html> <head>
<meta charset="UTF-8">
<title></title>
</head> <body>
<canvas id="canvas" width="300" height="300">
</canvas> <script type="text/javascript">
function toCanvas(id, progress, progress2) {
//canvas进度条
var canvas = document.getElementById(id),
ctx = canvas.getContext("2d"),
percent = progress,
percent2 = progress2,
//最终百分比
circleX = canvas.width / 2, // 中心x坐标
circleY = canvas.height / 2, //中心y坐标
radius = 100, //圆环半径
lineWidth = 8, // 圆形线条的宽度
fontSize = 10; //字体大小 /*//两端圆点
function smallcircle1(cx, cy, r) {
ctx.beginPath();
ctx.lineWidth = 1;
ctx.fillStyle = '#06a8f3';
ctx.arc(cx, cy, r, Math.PI, Math.PI * 2);
ctx.fill();
} function smallcircle2(cx, cy, r) {
ctx.beginPath();
ctx.lineWidth = 1;
ctx.fillStyle = '#00f8bb';
ctx.arc(cx, cy, r, Math.PI, Math.PI * 2);
ctx.fill();
}*/ //画圆
function circle(cx, cy, r) {
ctx.beginPath();
ctx.lineWidth = lineWidth;
ctx.strokeStyle = '#eee';
ctx.arc(cx, cy, r, Math.PI, Math.PI * 2);
//ctx.arc(cx, cy, r, Math.PI * 2 / 3, Math.PI * 1 / 3);
ctx.stroke();
} //画弧线
function sector(cx, cy, r, startAngle, endAngle, anti) {
ctx.beginPath();
ctx.lineWidth = lineWidth; // 渐变色 - 可自定义
var linGrad = ctx.createLinearGradient(
circleX - radius - lineWidth, circleY, circleX + radius + lineWidth, circleY
);
linGrad.addColorStop(0.0, '#06a8f3');
linGrad.addColorStop(1.0, '#00f8bb');
ctx.strokeStyle = linGrad;
//圆弧两端的样式
ctx.lineCap = 'round';
ctx.arc(cx, cy, r, Math.PI, Math.PI * (1 + endAngle / 100));
ctx.stroke();
} //画弧线02
function sector2(cx, cy, r, startAngle, endAngle, anti) {
ctx.beginPath();
ctx.lineWidth = lineWidth; // 渐变色 - 可自定义
var linGrad = ctx.createLinearGradient(
circleX - radius - lineWidth, circleY, circleX + radius + lineWidth, circleY
);
linGrad.addColorStop(0.0, '#06a8f3');
linGrad.addColorStop(1.0, '#00f8bb');
ctx.strokeStyle = linGrad //圆弧两端的样式
ctx.lineCap = 'round';
ctx.arc(cx, cy, r * 3 / 4, Math.PI, Math.PI * (1 + endAngle / 100));
ctx.stroke();
}
//刷新
function loading() {
var percent3 = progress;
if(percent < percent2) percent = percent2;
if(process >= percent) clearInterval(circleLoading);
if(process2 >= percent) clearInterval(circleLoading);
//清除canvas内容
ctx.clearRect(0, 0, circleX * 2, circleY * 2); //中间的字
ctx.font = fontSize + 'px April';
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
ctx.fillStyle = '#999';
ctx.fillText(parseFloat(process).toFixed(0) + '%', circleX, circleY*4/5);
ctx.fillText("月度完成比",circleX, circleY); //圆形
circle(circleX, circleY, radius); //圆弧
sector(circleX, circleY, radius, Math.PI * 2 / 3, process);
sector2(circleX, circleY, radius, Math.PI * 2 / 3, process2);
//两端圆点
//smallcircle1(50 + Math.cos(2 * Math.PI / 360 * 120) * 100, 150 + Math.sin(2 * Math.PI / 360 * 120) * 100, 5);
//smallcircle2(50 + Math.cos(2 * Math.PI / 360 * (120 + process * 3)) * 100, 150 + Math.sin(2 * Math.PI / 360 * (120 + process * 3)) * 100, 5);
//控制结束时动画的速度
if(process < percent3) {
if(process / percent > 0.90) {
process += 0.30;
} else if(process / percent > 0.80) {
process += 0.55;
} else if(process / percent > 0.70) {
process += 0.75;
} else {
process += 1.0;
}
} if(process2 < percent2) {
if(process2 / percent > 0.90) {
process2 += 0.30;
} else if(process2 / percent > 0.80) {
process2 += 0.55;
} else if(process2 / percent > 0.70) {
process2 += 0.75;
} else {
process2 += 1.0;
}
} } var process = 0.0;
var process2 = 0.0; var circleLoading = window.setInterval(function() {
loading();
}, 20); }
toCanvas('canvas', 50, 80);
</script>
</body> </html>
