markerHelper.js

define(function (require) {

    var zrUtil = require('zrender/core/util');
    var numberUtil = require('../../util/number');

    function getPrecision(data, valueAxisDim, dataIndex) {
        var precision = -1;
        do {
            precision = Math.max(
                numberUtil.getPrecision(data.get(
                    valueAxisDim, dataIndex
                )),
                precision
            );
            data = data.stackedOn;
        } while (data);

        return precision;
    }

    function markerTypeCalculatorWithExtent(percent, data, baseAxisDim, valueAxisDim, valueIndex) {
        var extent = data.getDataExtent(valueAxisDim);
        var valueArr = [];
        var min = extent[0];
        var max = extent[1];
        var val = (max - min) * percent + min;
        var dataIndex = data.indexOfNearest(valueAxisDim, val);
        valueArr[1 - valueIndex] = data.get(baseAxisDim, dataIndex);
        valueArr[valueIndex] = data.get(valueAxisDim, dataIndex, true);

        var precision = getPrecision(data, valueAxisDim, dataIndex);
        if (precision >= 0) {
            valueArr[valueIndex] = +valueArr[valueIndex].toFixed(precision);
        }

        return valueArr;
    }

    var curry = zrUtil.curry;
    // TODO Specified percent
    var markerTypeCalculator = {
        /**
         * @method
         * @param {module:echarts/data/List} data
         * @param {string} baseAxisDim
         * @param {string} valueAxisDim
         */
        min: curry(markerTypeCalculatorWithExtent, 0),
        /**
         * @method
         * @param {module:echarts/data/List} data
         * @param {string} baseAxisDim
         * @param {string} valueAxisDim
         */
        max: curry(markerTypeCalculatorWithExtent, 1),
        /**
         * @method
         * @param {module:echarts/data/List} data
         * @param {string} baseAxisDim
         * @param {string} valueAxisDim
         */
        average: curry(markerTypeCalculatorWithExtent, 0.5)
    };

    /**
     * Transform markPoint data item to format used in List by do the following
     * 1. Calculate statistic like `max`, `min`, `average`
     * 2. Convert `item.xAxis`, `item.yAxis` to `item.value` array
     * @param  {module:echarts/data/List} data
     * @param  {module:echarts/coord/*} [coordSys]
     * @param  {Object} item
     * @return {Object}
     */
    var dataTransform = function (data, coordSys, item) {
        // 1. If not specify the position with pixel directly
        // 2. If value is not a data array. Which uses xAxis, yAxis to specify the value on each dimension
        if (isNaN(item.x) || isNaN(item.y)
            && !zrUtil.isArray(item.value)
            && coordSys
        ) {
            var valueAxisDim;
            var baseAxisDim;
            var valueAxis;
            var baseAxis;
            if (item.valueIndex != null) {
                valueAxisDim = coordSys.dimensions[item.valueIndex];
                baseAxisDim = coordSys.dimensions[1 - item.valueIndex];
                valueAxis = coordSys.getAxis(valueAxisDim);
                baseAxis = coordSys.getAxis(baseAxisDim);
            }
            else {
                baseAxis = coordSys.getBaseAxis();
                valueAxis = coordSys.getOtherAxis(baseAxis);
                baseAxisDim = baseAxis.dim;
                valueAxisDim = valueAxis.dim;
            }
            var valueIndex = item.valueIndex != null
                ? item.valueIndex
                : ((valueAxisDim === 'angle' || valueAxisDim === 'x') ? 0 : 1);
            // Clone the option
            // Transform the properties xAxis, yAxis, radiusAxis, angleAxis, geoCoord to value
            item = zrUtil.extend({}, item);
            if (item.type && markerTypeCalculator[item.type] && baseAxis && valueAxis) {
                var value = markerTypeCalculator[item.type](
                    data, baseAxis.dim, valueAxisDim, valueIndex
                );
                if (item.value != null) {
                    value.push(+item.value);
                }
                item.value = value;
            }
            else {
                var originalValue = item.value;
                // FIXME Only has one of xAxis and yAxis.
                item.value = [
                    item.xAxis != null ? item.xAxis : item.radiusAxis,
                    item.yAxis != null ? item.yAxis : item.angleAxis
                ];
                if (originalValue != null) {
                    item.value.push(+originalValue);
                }
            }
            item.__rawValue = item.value[valueIndex];
        }
        return item;
    };


    /**
     * Filter data which is out of coordinateSystem range
     * [dataFilter description]
     * @param  {module:echarts/coord/*} [coordSys]
     * @param  {Object} item
     * @return {boolean}
     */
    var dataFilter = function (coordSys, item) {
        // Alwalys return true if there is no coordSys
        return coordSys ? coordSys.containData(item.value) : true;
    };

    return {
        dataTransform: dataTransform,
        dataFilter: dataFilter
    };
});