/**
 * 水滴形状
 * @module zrender/shape/Ellipse
 * @example
 *   var Ellipse = require('zrender/shape/Ellipse');
 *   var shape = new Ellipse({
 *       style: {
 *           x: 100,
 *           y: 100,
 *           a: 40,
 *           b: 20,
 *           brushType: 'both',
 *           color: 'blue',
 *           strokeColor: 'red',
 *           lineWidth: 3,
 *           text: 'Ellipse'
 *       }    
 *   });
 *   zr.addShape(shape);
 */

/**
 * @typedef {Object} IEllipseStyle
 * @property {number} x 圆心x坐标
 * @property {number} y 圆心y坐标
 * @property {number} a 横轴半径
 * @property {number} b 纵轴半径
 * @property {string} [brushType='fill']
 * @property {string} [color='#000000'] 填充颜色
 * @property {string} [strokeColor='#000000'] 描边颜色
 * @property {string} [lineCape='butt'] 线帽样式，可以是 butt, round, square
 * @property {number} [lineWidth=1] 描边宽度
 * @property {number} [opacity=1] 绘制透明度
 * @property {number} [shadowBlur=0] 阴影模糊度，大于0有效
 * @property {string} [shadowColor='#000000'] 阴影颜色
 * @property {number} [shadowOffsetX=0] 阴影横向偏移
 * @property {number} [shadowOffsetY=0] 阴影纵向偏移
 * @property {string} [text] 图形中的附加文本
 * @property {string} [textColor='#000000'] 文本颜色
 * @property {string} [textFont] 附加文本样式，eg:'bold 18px verdana'
 * @property {string} [textPosition='end'] 附加文本位置, 可以是 inside, left, right, top, bottom
 * @property {string} [textAlign] 默认根据textPosition自动设置，附加文本水平对齐。
 *                                可以是start, end, left, right, center
 * @property {string} [textBaseline] 默认根据textPosition自动设置，附加文本垂直对齐。
 *                                可以是top, bottom, middle, alphabetic, hanging, ideographic
 */
module.exports = function (require) {
  var Base = require('./Base');
  /**
   * @alias module:zrender/shape/Ellipse
   * @constructor
   * @extends module:zrender/shape/Base
   * @param {Object} options
   */


  var Ellipse = function (options) {
    Base.call(this, options);
    /**
     * 椭圆绘制样式
     * @name module:zrender/shape/Ellipse#style
     * @type {module:zrender/shape/Ellipse~IEllipseStyle}
     */

    /**
     * 椭圆高亮绘制样式
     * @name module:zrender/shape/Ellipse#highlightStyle
     * @type {module:zrender/shape/Ellipse~IEllipseStyle}
     */
  };

  Ellipse.prototype = {
    type: 'ellipse',

    /**
     * 构建椭圆的Path
     * @param {CanvasRenderingContext2D} ctx
     * @param {module:zrender/shape/Ellipse~IEllipseStyle} style
     */
    buildPath: function (ctx, style) {
      var k = 0.5522848;
      var x = style.x;
      var y = style.y;
      var a = style.a;
      var b = style.b;
      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();
    },

    /**
    /**
     * 计算返回椭圆包围盒矩形。
     * @param {module:zrender/shape/Ellipse~IEllipseStyle} style
     * @return {module:zrender/shape/Base~IBoundingRect}
     */
    getRect: function (style) {
      if (style.__rect) {
        return style.__rect;
      }

      var lineWidth;

      if (style.brushType == 'stroke' || style.brushType == 'fill') {
        lineWidth = style.lineWidth || 1;
      } else {
        lineWidth = 0;
      }

      style.__rect = {
        x: Math.round(style.x - style.a - lineWidth / 2),
        y: Math.round(style.y - style.b - lineWidth / 2),
        width: style.a * 2 + lineWidth,
        height: style.b * 2 + lineWidth
      };
      return style.__rect;
    }
  };

  require('../tool/util').inherits(Ellipse, Base);

  return Ellipse;
}(require);