aaac7fed
 liuqimichale
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/**
* 椭圆形状
* @module zrender/graphic/shape/Ellipse
*/
import Path from '../Path';
export default Path.extend({
type: 'ellipse',
shape: {
cx: 0, cy: 0,
rx: 0, ry: 0
},
buildPath: function (ctx, shape) {
var k = 0.5522848;
var x = shape.cx;
var y = shape.cy;
var a = shape.rx;
var b = shape.ry;
var ox = a * k; // 水平控制点偏移量
var oy = b * k; // 垂直控制点偏移量
// 从椭圆的左端点开始顺时针绘制四条三次贝塞尔曲线
ctx.moveTo(x - a, y);
ctx.bezierCurveTo(x - a, y - oy, x - ox, y - b, x, y - b);
ctx.bezierCurveTo(x + ox, y - b, x + a, y - oy, x + a, y);
ctx.bezierCurveTo(x + a, y + oy, x + ox, y + b, x, y + b);
ctx.bezierCurveTo(x - ox, y + b, x - a, y + oy, x - a, y);
ctx.closePath();
}
});
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