zh/builder/src/echarts3/coord/cartesian/prepareCustom.js

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

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

export default function (coordSys) {
  var rect = coordSys.grid.getRect();
  return {
    coordSys: {
      // The name exposed to user is always 'cartesian2d' but not 'grid'.
      type: 'cartesian2d',
      x: rect.x,
      y: rect.y,
      width: rect.width,
      height: rect.height
    },
    api: {
      coord: zrUtil.bind(coordSys.dataToPoint, coordSys),
      size: zrUtil.bind(dataToCoordSize, coordSys)
    }
  };
}