html5做旋转太极图 HTML5 Canvas旋转动画的2个代码例子（一个旋转的太极图效果）...

效果图：

方法一：

your browser does not support the canvas tag

var deg = 0;

var r = 30;

var rl = 100;

function drawTaiji() {

var canvas = document.getElementById('myCanvas');

var context = canvas.getContext('2d');

var colorA = "rgb(0, 0, 0)";

var colorB = "red";

var px =Math.sin(deg)*r;

var py =Math.cos(deg)*r;

context.clearRect(0, 0, 300, 300);

context.beginPath();

context.fillStyle = colorA;

context.arc(rl, rl, 60, 0.5 * Math.PI +deg, 1.5 * Math.PI +deg, true);

context.closePath();

context.fill();

context.fillStyle = colorB;

context.beginPath();

context.arc(rl, rl, 60, 1.5* Math.PI +deg, 0.5 * Math.PI +deg, true);

context.closePath();

context.fill();

context.fillStyle = colorB;

context.beginPath();

context.arc(rl+px, rl-py, 30, 0.5 * Math.PI + deg, 1.5 * Math.PI + deg, true);

context.closePath();

context.fill();

context.fillStyle = colorA;

context.beginPath();

context.arc(rl-px, rl+py, 30, 1.5 * Math.PI + deg, 0.5 * Math.PI + deg, true);

context.closePath();

context.fill();

context.fillStyle = colorA;

context.beginPath();

context.arc(rl+px, rl-py, 8, 0, 2 * Math.PI, true);

context.closePath();

context.fill();

context.fillStyle = colorB;

context.beginPath();

context.arc(rl-px, rl+py, 8, 0, 2 * Math.PI, true);

context.closePath();

context.fill();

deg +=0.1;

}

setInterval(drawTaiji, 100);

方法二：

your browser does not support the canvas tag

var canvas = document.getElementById('myCanvas');

var ctx = canvas.getContext("2d");

var angle = 0;

var count = 360;

var clrA = '#000';

var clrB = 'red';

function taiji(x, y, radius, angle, wise) {

angleangle = angle || 0;

wisewise = wise ? 1 : -1;

ctx.save();

ctx.translate(x, y);

ctx.rotate(angle);

ctx.fillStyle = clrA;

ctx.beginPath();

ctx.arc(0, 0, radius, 0, Math.PI, true);

ctx.fill();

ctx.beginPath();

ctx.fillStyle = clrB;

ctx.arc(0, 0, radius, 0, Math.PI, false);

ctx.fill();

ctx.fillStyle = clrB;

ctx.beginPath();

ctx.arc(wise * -0.5 * radius, 0, radius / 2, 0, Math.PI * 2, true);

ctx.fill();

ctx.beginPath();

ctx.fillStyle = clrA;

ctx.arc(wise * +0.5 * radius, 0, radius / 2, 0, Math.PI * 2, false);

ctx.arc(wise * -0.5 * radius, 0, radius / 10, 0, Math.PI * 2, true);

ctx.fill();

ctx.beginPath();

ctx.fillStyle = clrB;

ctx.arc(wise * +0.5 * radius, 0, radius / 10, 0, Math.PI * 2, true);

ctx.fill();

ctx.restore();

}

loop = setInterval(function () {

beginTag = true;

ctx.clearRect(0, 0, canvas.width, canvas.height);

taiji(200, 200, 50, Math.PI * (angle / count) * 2, true);

//taiji(350, 350, 50, Math.PI * ((count - angle) / count) * 2, false);

angle = (angle + 5) % count;

}, 50);