zh/builder/src/zrender3/graphic/shape/Trochoid.js

/**
 * 内外旋轮曲线
 * @module zrender/graphic/shape/Trochold
 */
import Path from '../Path';
var cos = Math.cos;
var sin = Math.sin;
export default Path.extend({
  type: 'trochoid',
  shape: {
    cx: 0,
    cy: 0,
    r: 0,
    r0: 0,
    d: 0,
    location: 'out'
  },
  style: {
    stroke: '#000',
    fill: null
  },
  buildPath: function (ctx, shape) {
    var x1;
    var y1;
    var x2;
    var y2;
    var R = shape.r;
    var r = shape.r0;
    var d = shape.d;
    var offsetX = shape.cx;
    var offsetY = shape.cy;
    var delta = shape.location == 'out' ? 1 : -1;

    if (shape.location && R <= r) {
      return;
    }

    var num = 0;
    var i = 1;
    var theta;
    x1 = (R + delta * r) * cos(0) - delta * d * cos(0) + offsetX;
    y1 = (R + delta * r) * sin(0) - d * sin(0) + offsetY;
    ctx.moveTo(x1, y1); // 计算结束时的i

    do {
      num++;
    } while (r * num % (R + delta * r) !== 0);

    do {
      theta = Math.PI / 180 * i;
      x2 = (R + delta * r) * cos(theta) - delta * d * cos((R / r + delta) * theta) + offsetX;
      y2 = (R + delta * r) * sin(theta) - d * sin((R / r + delta) * theta) + offsetY;
      ctx.lineTo(x2, y2);
      i++;
    } while (i <= r * num / (R + delta * r) * 360);
  }
});