Canvas 通过改变渐变色渐变百分比位置做飞线效果
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Canvas 通过改变渐变色渐变百分比位置做飞线效果</title>
</head>
<body>
<canvas id="myCanvas" width="700" height="700" style="border:1px solid #d3d3d3;">
您的浏览器不支持 HTML5 canvas 标签。
</canvas>
<canvas id="myCanvas2" width="700" height="700" style="border:1px solid #d3d3d3;">
您的浏览器不支持 HTML5 canvas 标签。
</canvas>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js"></script>
<script>
$(function () {
var myAction = {};
$.extend(myAction, {
getWidth: function (pointA, pointB) {
var xWidth = (pointA.x - pointB.x) * (pointA.x - pointB.x);
var yWidth = (pointA.y - pointB.y) * (pointA.y - pointB.y)
var edgeWidth = Math.sqrt( xWidth + yWidth );
return 100 / edgeWidth ;
},
initCanvas1: function () {
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var start = 0;
var pointA = {
x: 0,
y: 100
};
var pointB = {
x: 700,
y: 100
};
var width = myAction.getWidth(pointA, pointB);
function auto() {
ctx.beginPath();
ctx.moveTo(0, 100);
ctx.lineTo(700, 100);
var grd = ctx.createLinearGradient(pointA.x, pointA.y, pointB.x, pointB.y);
grd.addColorStop(0, "#5BC0DE");
grd.addColorStop(start, "#5BC0DE");
grd.addColorStop(start + (width / 2), "#ffff00");
grd.addColorStop(start + width, "#5BC0DE");
grd.addColorStop(1, "#5BC0DE");
ctx.lineWidth = 5;
ctx.strokeStyle = grd;
ctx.stroke();
console.log(start + width)
ctx.closePath();
if (start + width + 0.02 >= 1) {
start = 0;
} else {
start = start + 0.02;
}
setTimeout(function() {
auto();
}, 100);
}
auto();
},
initCanvas2: function () {
var c = document.getElementById("myCanvas2");
var ctx = c.getContext("2d");
var start = 0;
var pointA = {
x: 0,
y: 0
};
var pointB = {
x: 700,
y: 700
};
var width = myAction.getWidth(pointA, pointB);
function auto() {
ctx.beginPath();
var grd = ctx.createLinearGradient(pointA.x, pointA.y, pointB.x, pointB.y);
grd.addColorStop(0, "#5BC0DE");
grd.addColorStop(start, "#5BC0DE");
grd.addColorStop(start + (width / 2), "#ffff00");
grd.addColorStop(start + width, "#5BC0DE");
grd.addColorStop(1, "#5BC0DE");
ctx.lineWidth = 5;
ctx.strokeStyle = grd;
ctx.moveTo(0, 0);
ctx.lineTo(700, 700);
ctx.stroke();
ctx.closePath();
if (start + width + 0.02 >= 1) {
start = 0;
} else {
start = start + 0.02;
}
setTimeout(function() {
auto();
}, 100);
}
auto();
}
});
var init = function () {
myAction.initCanvas1();
myAction.initCanvas2();
}();
});
</script>
<script>
</script>
</body>
</html>
转载自：https://blog.csdn.net/xutongbao/article/details/82023196
