echarts图表清晰度问题处理

搜索：

createDom；

Layer.prototype

修改相应。

initContext: function () {
    this.ctx = this.dom.getContext('2d');

    this.ctx.dpr = this.dpr*3;
},

/**
 * 创建dom
 *
 * @inner
 * @param {string} id dom id 待用
 * @param {string} type dom type，such as canvas, div etc.
 * @param {Painter} painter painter instance
 * @param {number} number
 */
function createDom(id, type, painter, dpr) {
    var newDom = document.createElement(type);
    var width = painter.getWidth();
    var height = painter.getHeight();

    var newDomStyle = newDom.style;
    // 没append呢，请原谅我这样写，清晰~
    newDomStyle.position = 'absolute';
    newDomStyle.left = 0;
    newDomStyle.top = 0;
    newDomStyle.width = width + 'px';
    newDomStyle.height = height + 'px';
    newDom.width = width * dpr *3;
    newDom.height = height * dpr *3;

    // id不作为索引用，避免可能造成的重名，定义为私有属性
    newDom.setAttribute('data-zr-dom-id', id);
    return newDom;
}