Function getScaleExtent

libs/echarts/echarts.simple.js:37598–37737

* Get axis scale extent before niced. * Item of returned array can only be number (including Infinity and NaN).

(scale, model)

 * Item of returned array can only be number (including Infinity and NaN).
 */
function getScaleExtent(scale, model) {
    var scaleType = scale.type;

    var min = model.getMin();
    var max = model.getMax();
    var originalExtent = scale.getExtent();

    var axisDataLen;
    var boundaryGap;
    var span;
    if (scaleType === 'ordinal') {
        axisDataLen = model.getCategories().length;
    }
    else {
        boundaryGap = model.get('boundaryGap');
        if (!isArray(boundaryGap)) {
            boundaryGap = [boundaryGap || 0, boundaryGap || 0];
        }
        if (typeof boundaryGap[0] === 'boolean') {
            if (__DEV__) {
                console.warn('Boolean type for boundaryGap is only '
                    + 'allowed for ordinal axis. Please use string in '
                    + 'percentage instead, e.g., "20%". Currently, '
                    + 'boundaryGap is set to be 0.');
            }
            boundaryGap = [0, 0];
        }
        boundaryGap[0] = parsePercent$1(boundaryGap[0], 1);
        boundaryGap[1] = parsePercent$1(boundaryGap[1], 1);
        span = (originalExtent[1] - originalExtent[0])
            || Math.abs(originalExtent[0]);
    }

    // Notice: When min/max is not set (that is, when there are null/undefined,
    // which is the most common case), these cases should be ensured:
    // (1) For 'ordinal', show all axis.data.
    // (2) For others:
    //      + `boundaryGap` is applied (if min/max set, boundaryGap is
    //      disabled).
    //      + If `needCrossZero`, min/max should be zero, otherwise, min/max should
    //      be the result that originalExtent enlarged by boundaryGap.
    // (3) If no data, it should be ensured that `scale.setBlank` is set.

    // FIXME
    // (1) When min/max is 'dataMin' or 'dataMax', should boundaryGap be able to used?
    // (2) When `needCrossZero` and all data is positive/negative, should it be ensured
    // that the results processed by boundaryGap are positive/negative?

    if (min === 'dataMin') {
        min = originalExtent[0];
    }
    else if (typeof min === 'function') {
        min = min({
            min: originalExtent[0],
            max: originalExtent[1]
        });
    }