[英]javascript - change speed of animation
我有一段代码。 但是我的问题是..我不知道该在哪里更改动画速度。 我试图将最后一行编辑为animate('fast'); 但没有成功..我该怎么解决? 我知道这主要是javascript,但到目前为止我没有找到这样的代码,它将在jquery中更好
$('#kim-jestesmy').waypoint(function(direction) {
var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame ||
window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
window.requestAnimationFrame = requestAnimationFrame;
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
var circles = [];
createCircle(100,100,'78', function() {
createCircle(270,100,'460', function() {
createCircle(440,100,'20', function() {
createCircle(610,100,'15', null);
});
});
});
function createCircle(x,y,text,callback) {
var radius = 75;
var endPercent = 101;
var curPerc = 0;
var counterClockwise = false;
var circ = Math.PI * 2;
var quart = Math.PI / 2;
context.lineWidth = 10;
context.strokeStyle = '#E60086';
context.shadowOffsetX = 0;
context.shadowOffsetY = 0;
function doText(context,x,y,text) {
context.lineWidth = 1;
context.fillStyle = "#919191";
context.lineStyle = "#919191";
context.font = "60px NillandBold";
context.textAlign = "center";
context.textBaseline = "middle";
context.fillText(text, x, y);
}
function animate(current) {
context.lineWidth = 10;
context.clearRect(0, 0, canvas.width, canvas.height);
context.beginPath();
context.arc(x, y, radius, -(quart), ((circ) * current) - quart, false);
context.stroke();
curPerc++;
if (circles.length) {
for (var i=0; i<circles.length; i++) {
context.lineWidth = 10;
context.beginPath();
context.arc(circles[i].x, circles[i].y, radius, -(quart), ((circ) * circles[i].curr) - quart, false);
context.stroke();
doText(context,circles[i].x,circles[i].y,circles[i].text);
}
}
if (curPerc < endPercent) {
requestAnimationFrame(function () {
animate(curPerc / 100)
});
}else{
var circle = {x:x,y:y,curr:current,text:text};
circles.push(circle);
doText(context,x,y,text);
if (callback) callback.call();
}
}
animate();
}
});
由于您不限制动画的fps,因此使用此代码将尽可能快地渲染每个帧。 如果希望更快,最简单的答案是通过将curPerc变量增加一个以上来删除帧:
function animate(current) {
context.lineWidth = 10;
context.clearRect(0, 0, canvas.width, canvas.height);
context.beginPath();
context.arc(x, y, radius, -(quart), ((circ) * current) - quart, false);
context.stroke();
curPerc += 2;
...
上面的代码将以两倍的速度完成。 如果curPerc不能平均除100(100%curPerc!= 0),则相应地更改变量endPercent。
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