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