en/builder/src/echarts3/coord/single/prepareCustom.js

import * as zrUtil from 'zrender/src/core/util';

function dataToCoordSize(dataSize, dataItem) {
  // dataItem is necessary in log axis.
  var axis = this.getAxis();
  var val = dataItem instanceof Array ? dataItem[0] : dataItem;
  var halfSize = (dataSize instanceof Array ? dataSize[0] : dataSize) / 2;
  return axis.type === 'category' ? axis.getBandWidth() : Math.abs(axis.dataToCoord(val - halfSize) - axis.dataToCoord(val + halfSize));
}

export default function (coordSys) {
  var rect = coordSys.getRect();
  return {
    coordSys: {
      type: 'singleAxis',
      x: rect.x,
      y: rect.y,
      width: rect.width,
      height: rect.height
    },
    api: {
      coord: zrUtil.bind(coordSys.dataToPoint, coordSys),
      size: zrUtil.bind(dataToCoordSize, coordSys)
    }
  };
}