OrdinalAxis.js 30.8 KB
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/**
 * (c) 2010-2018 Torstein Honsi
 *
 * License: www.highcharts.com/license
 */
/* eslint max-len: 0 */
'use strict';
import H from './Globals.js';
import './Axis.js';
import './Utilities.js';
import './Chart.js';
import './Series.js';
var addEvent = H.addEvent,
    Axis = H.Axis,
    Chart = H.Chart,
    css = H.css,
    defined = H.defined,
    each = H.each,
    extend = H.extend,
    noop = H.noop,
    pick = H.pick,
    Series = H.Series,
    timeUnits = H.timeUnits,
    wrap = H.wrap;

/* ****************************************************************************
 * Start ordinal axis logic                                                   *
 *****************************************************************************/


wrap(Series.prototype, 'init', function (proceed) {
    var series = this,
        xAxis;

    // call the original function
    proceed.apply(this, Array.prototype.slice.call(arguments, 1));

    xAxis = series.xAxis;

    // Destroy the extended ordinal index on updated data
    if (xAxis && xAxis.options.ordinal) {
        addEvent(series, 'updatedData', function () {
            delete xAxis.ordinalIndex;
        });
    }
});

/**
 * In an ordinal axis, there might be areas with dense consentrations of points, then large
 * gaps between some. Creating equally distributed ticks over this entire range
 * may lead to a huge number of ticks that will later be removed. So instead, break the
 * positions up in segments, find the tick positions for each segment then concatenize them.
 * This method is used from both data grouping logic and X axis tick position logic.
 */
wrap(Axis.prototype, 'getTimeTicks', function (proceed, normalizedInterval, min, max, startOfWeek, positions, closestDistance, findHigherRanks) {

    var start = 0,
        end,
        segmentPositions,
        higherRanks = {},
        hasCrossedHigherRank,
        info,
        posLength,
        outsideMax,
        groupPositions = [],
        lastGroupPosition = -Number.MAX_VALUE,
        tickPixelIntervalOption = this.options.tickPixelInterval,
        time = this.chart.time;

    // The positions are not always defined, for example for ordinal positions
    // when data has regular interval (#1557, #2090)
    if (
        (!this.options.ordinal && !this.options.breaks) ||
        !positions ||
        positions.length < 3 ||
        min === undefined
    ) {
        return proceed.call(this, normalizedInterval, min, max, startOfWeek);
    }

    // Analyze the positions array to split it into segments on gaps larger than 5 times
    // the closest distance. The closest distance is already found at this point, so
    // we reuse that instead of computing it again.
    posLength = positions.length;

    for (end = 0; end < posLength; end++) {

        outsideMax = end && positions[end - 1] > max;

        if (positions[end] < min) { // Set the last position before min
            start = end;
        }

        if (end === posLength - 1 || positions[end + 1] - positions[end] > closestDistance * 5 || outsideMax) {

            // For each segment, calculate the tick positions from the getTimeTicks utility
            // function. The interval will be the same regardless of how long the segment is.
            if (positions[end] > lastGroupPosition) { // #1475

                segmentPositions = proceed.call(this, normalizedInterval, positions[start], positions[end], startOfWeek);

                // Prevent duplicate groups, for example for multiple segments within one larger time frame (#1475)
                while (segmentPositions.length && segmentPositions[0] <= lastGroupPosition) {
                    segmentPositions.shift();
                }
                if (segmentPositions.length) {
                    lastGroupPosition = segmentPositions[segmentPositions.length - 1];
                }

                groupPositions = groupPositions.concat(segmentPositions);
            }
            // Set start of next segment
            start = end + 1;
        }

        if (outsideMax) {
            break;
        }
    }

    // Get the grouping info from the last of the segments. The info is the same for
    // all segments.
    info = segmentPositions.info;

    // Optionally identify ticks with higher rank, for example when the ticks
    // have crossed midnight.
    if (findHigherRanks && info.unitRange <= timeUnits.hour) {
        end = groupPositions.length - 1;

        // Compare points two by two
        for (start = 1; start < end; start++) {
            if (
                time.dateFormat('%d', groupPositions[start]) !==
                time.dateFormat('%d', groupPositions[start - 1])
            ) {
                higherRanks[groupPositions[start]] = 'day';
                hasCrossedHigherRank = true;
            }
        }

        // If the complete array has crossed midnight, we want to mark the first
        // positions also as higher rank
        if (hasCrossedHigherRank) {
            higherRanks[groupPositions[0]] = 'day';
        }
        info.higherRanks = higherRanks;
    }

    // Save the info
    groupPositions.info = info;



    // Don't show ticks within a gap in the ordinal axis, where the space between
    // two points is greater than a portion of the tick pixel interval
    if (findHigherRanks && defined(tickPixelIntervalOption)) { // check for squashed ticks

        var length = groupPositions.length,
            i = length,
            itemToRemove,
            translated,
            translatedArr = [],
            lastTranslated,
            medianDistance,
            distance,
            distances = [];

        // Find median pixel distance in order to keep a reasonably even distance between
        // ticks (#748)
        while (i--) {
            translated = this.translate(groupPositions[i]);
            if (lastTranslated) {
                distances[i] = lastTranslated - translated;
            }
            translatedArr[i] = lastTranslated = translated;
        }
        distances.sort();
        medianDistance = distances[Math.floor(distances.length / 2)];
        if (medianDistance < tickPixelIntervalOption * 0.6) {
            medianDistance = null;
        }

        // Now loop over again and remove ticks where needed
        i = groupPositions[length - 1] > max ? length - 1 : length; // #817
        lastTranslated = undefined;
        while (i--) {
            translated = translatedArr[i];
            distance = Math.abs(lastTranslated - translated);
            // #4175 - when axis is reversed, the distance, is negative but
            // tickPixelIntervalOption positive, so we need to compare the same values

            // Remove ticks that are closer than 0.6 times the pixel interval from the one to the right,
            // but not if it is close to the median distance (#748).
            if (lastTranslated && distance < tickPixelIntervalOption * 0.8 &&
                    (medianDistance === null || distance < medianDistance * 0.8)) {

                // Is this a higher ranked position with a normal position to the right?
                if (higherRanks[groupPositions[i]] && !higherRanks[groupPositions[i + 1]]) {

                    // Yes: remove the lower ranked neighbour to the right
                    itemToRemove = i + 1;
                    lastTranslated = translated; // #709

                } else {

                    // No: remove this one
                    itemToRemove = i;
                }

                groupPositions.splice(itemToRemove, 1);

            } else {
                lastTranslated = translated;
            }
        }
    }
    return groupPositions;
});

// Extend the Axis prototype
extend(Axis.prototype, /** @lends Axis.prototype */ {

    /**
     * Calculate the ordinal positions before tick positions are calculated.
     */
    beforeSetTickPositions: function () {
        var axis = this,
            len,
            ordinalPositions = [],
            uniqueOrdinalPositions,
            useOrdinal = false,
            dist,
            extremes = axis.getExtremes(),
            min = extremes.min,
            max = extremes.max,
            minIndex,
            maxIndex,
            slope,
            hasBreaks = axis.isXAxis && !!axis.options.breaks,
            isOrdinal = axis.options.ordinal,
            overscrollPointsRange = Number.MAX_VALUE,
            ignoreHiddenSeries = axis.chart.options.chart.ignoreHiddenSeries,
            isNavigatorAxis = axis.options.className === 'highcharts-navigator-xaxis',
            i,
            hasBoostedSeries;

        if (
            axis.options.overscroll &&
            axis.max === axis.dataMax &&
            (
                // Panning is an execption,
                // We don't want to apply overscroll when panning over the dataMax
                !axis.chart.mouseIsDown ||
                isNavigatorAxis
            ) && (
                // Scrollbar buttons are the other execption:
                !axis.eventArgs ||
                axis.eventArgs && axis.eventArgs.trigger !== 'navigator'
            )
        ) {
            axis.max += axis.options.overscroll;

            // Live data and buttons require translation for the min:
            if (!isNavigatorAxis && defined(axis.userMin)) {
                axis.min += axis.options.overscroll;
            }
        }

        // Apply the ordinal logic
        if (isOrdinal || hasBreaks) { // #4167 YAxis is never ordinal ?

            each(axis.series, function (series, i) {
                uniqueOrdinalPositions = [];

                if (
                    (!ignoreHiddenSeries || series.visible !== false) &&
                    (series.takeOrdinalPosition !== false || hasBreaks)
                ) {

                    // concatenate the processed X data into the existing positions, or the empty array
                    ordinalPositions = ordinalPositions.concat(series.processedXData);
                    len = ordinalPositions.length;

                    // remove duplicates (#1588)
                    ordinalPositions.sort(function (a, b) {
                        return a - b; // without a custom function it is sorted as strings
                    });

                    overscrollPointsRange = Math.min(
                        overscrollPointsRange,
                        pick(
                            // Check for a single-point series:
                            series.closestPointRange,
                            overscrollPointsRange
                        )
                    );

                    if (len) {

                        i = 0;
                        while (i < len - 1) {
                            if (
                                ordinalPositions[i] !== ordinalPositions[i + 1]
                            ) {
                                uniqueOrdinalPositions.push(
                                    ordinalPositions[i + 1]
                                );
                            }
                            i++;
                        }

                        // Check first item:
                        if (
                            uniqueOrdinalPositions[0] !== ordinalPositions[0]
                        ) {
                            uniqueOrdinalPositions.unshift(
                                ordinalPositions[0]
                            );
                        }

                        ordinalPositions = uniqueOrdinalPositions;
                    }
                }

                if (series.isSeriesBoosting) {
                    hasBoostedSeries = true;
                }

            });

            if (hasBoostedSeries) {
                ordinalPositions.length = 0;
            }

            // cache the length
            len = ordinalPositions.length;

            // Check if we really need the overhead of mapping axis data against the ordinal positions.
            // If the series consist of evenly spaced data any way, we don't need any ordinal logic.
            if (len > 2) { // two points have equal distance by default
                dist = ordinalPositions[1] - ordinalPositions[0];
                i = len - 1;
                while (i-- && !useOrdinal) {
                    if (ordinalPositions[i + 1] - ordinalPositions[i] !== dist) {
                        useOrdinal = true;
                    }
                }

                // When zooming in on a week, prevent axis padding for weekends even though the data within
                // the week is evenly spaced.
                if (
                    !axis.options.keepOrdinalPadding &&
                    (
                        ordinalPositions[0] - min > dist ||
                        max - ordinalPositions[ordinalPositions.length - 1] > dist
                    )
                ) {
                    useOrdinal = true;
                }
            } else if (axis.options.overscroll) {
                if (len === 2) {
                    // Exactly two points, distance for overscroll is fixed:
                    overscrollPointsRange = ordinalPositions[1] - ordinalPositions[0];
                } else if (len === 1) {
                    // We have just one point, closest distance is unknown.
                    // Assume then it is last point and overscrolled range:
                    overscrollPointsRange = axis.options.overscroll;
                    ordinalPositions = [ordinalPositions[0], ordinalPositions[0] + overscrollPointsRange];
                } else {
                    // In case of zooming in on overscrolled range, stick to the old range:
                    overscrollPointsRange = axis.overscrollPointsRange;
                }
            }

            // Record the slope and offset to compute the linear values from the array index.
            // Since the ordinal positions may exceed the current range, get the start and
            // end positions within it (#719, #665b)
            if (useOrdinal) {

                if (axis.options.overscroll) {
                    axis.overscrollPointsRange = overscrollPointsRange;
                    ordinalPositions = ordinalPositions.concat(axis.getOverscrollPositions());
                }

                // Register
                axis.ordinalPositions = ordinalPositions;

                // This relies on the ordinalPositions being set. Use Math.max
                // and Math.min to prevent padding on either sides of the data.
                minIndex = axis.ordinal2lin( // #5979
                    Math.max(
                        min,
                        ordinalPositions[0]
                    ),
                    true
                );
                maxIndex = Math.max(axis.ordinal2lin(
                    Math.min(
                        max,
                        ordinalPositions[ordinalPositions.length - 1]
                    ),
                    true
                ), 1); // #3339

                // Set the slope and offset of the values compared to the indices in the ordinal positions
                axis.ordinalSlope = slope = (max - min) / (maxIndex - minIndex);
                axis.ordinalOffset = min - (minIndex * slope);

            } else {
                axis.overscrollPointsRange = pick(axis.closestPointRange, axis.overscrollPointsRange);
                axis.ordinalPositions = axis.ordinalSlope = axis.ordinalOffset = undefined;
            }
        }

        axis.isOrdinal = isOrdinal && useOrdinal; // #3818, #4196, #4926
        axis.groupIntervalFactor = null; // reset for next run
    },
    /**
     * Translate from a linear axis value to the corresponding ordinal axis position. If there
     * are no gaps in the ordinal axis this will be the same. The translated value is the value
     * that the point would have if the axis were linear, using the same min and max.
     *
     * @param Number val The axis value
     * @param Boolean toIndex Whether to return the index in the ordinalPositions or the new value
     */
    val2lin: function (val, toIndex) {
        var axis = this,
            ordinalPositions = axis.ordinalPositions,
            ret;

        if (!ordinalPositions) {
            ret = val;

        } else {

            var ordinalLength = ordinalPositions.length,
                i,
                distance,
                ordinalIndex;

            // first look for an exact match in the ordinalpositions array
            i = ordinalLength;
            while (i--) {
                if (ordinalPositions[i] === val) {
                    ordinalIndex = i;
                    break;
                }
            }

            // if that failed, find the intermediate position between the two nearest values
            i = ordinalLength - 1;
            while (i--) {
                if (val > ordinalPositions[i] || i === 0) { // interpolate
                    distance = (val - ordinalPositions[i]) / (ordinalPositions[i + 1] - ordinalPositions[i]); // something between 0 and 1
                    ordinalIndex = i + distance;
                    break;
                }
            }
            ret = toIndex ?
                ordinalIndex :
                axis.ordinalSlope * (ordinalIndex || 0) + axis.ordinalOffset;
        }
        return ret;
    },
    /**
     * Translate from linear (internal) to axis value
     *
     * @param Number val The linear abstracted value
     * @param Boolean fromIndex Translate from an index in the ordinal positions rather than a value
     */
    lin2val: function (val, fromIndex) {
        var axis = this,
            ordinalPositions = axis.ordinalPositions,
            ret;

        if (!ordinalPositions) { // the visible range contains only equally spaced values
            ret = val;

        } else {

            var ordinalSlope = axis.ordinalSlope,
                ordinalOffset = axis.ordinalOffset,
                i = ordinalPositions.length - 1,
                linearEquivalentLeft,
                linearEquivalentRight,
                distance;


            // Handle the case where we translate from the index directly, used only
            // when panning an ordinal axis
            if (fromIndex) {

                if (val < 0) { // out of range, in effect panning to the left
                    val = ordinalPositions[0];
                } else if (val > i) { // out of range, panning to the right
                    val = ordinalPositions[i];
                } else { // split it up
                    i = Math.floor(val);
                    distance = val - i; // the decimal
                }

            // Loop down along the ordinal positions. When the linear equivalent of i matches
            // an ordinal position, interpolate between the left and right values.
            } else {
                while (i--) {
                    linearEquivalentLeft = (ordinalSlope * i) + ordinalOffset;
                    if (val >= linearEquivalentLeft) {
                        linearEquivalentRight = (ordinalSlope * (i + 1)) + ordinalOffset;
                        distance = (val - linearEquivalentLeft) / (linearEquivalentRight - linearEquivalentLeft); // something between 0 and 1
                        break;
                    }
                }
            }

            // If the index is within the range of the ordinal positions, return the associated
            // or interpolated value. If not, just return the value
            return distance !== undefined && ordinalPositions[i] !== undefined ?
                ordinalPositions[i] + (distance ? distance * (ordinalPositions[i + 1] - ordinalPositions[i]) : 0) :
                val;
        }
        return ret;
    },
    /**
     * Get the ordinal positions for the entire data set. This is necessary in chart panning
     * because we need to find out what points or data groups are available outside the
     * visible range. When a panning operation starts, if an index for the given grouping
     * does not exists, it is created and cached. This index is deleted on updated data, so
     * it will be regenerated the next time a panning operation starts.
     */
    getExtendedPositions: function () {
        var axis = this,
            chart = axis.chart,
            grouping = axis.series[0].currentDataGrouping,
            ordinalIndex = axis.ordinalIndex,
            key = grouping ? grouping.count + grouping.unitName : 'raw',
            overscroll = axis.options.overscroll,
            extremes = axis.getExtremes(),
            fakeAxis,
            fakeSeries;

        // If this is the first time, or the ordinal index is deleted by updatedData,
        // create it.
        if (!ordinalIndex) {
            ordinalIndex = axis.ordinalIndex = {};
        }


        if (!ordinalIndex[key]) {

            // Create a fake axis object where the extended ordinal positions are emulated
            fakeAxis = {
                series: [],
                chart: chart,
                getExtremes: function () {
                    return {
                        min: extremes.dataMin,
                        max: extremes.dataMax + overscroll
                    };
                },
                options: {
                    ordinal: true
                },
                val2lin: Axis.prototype.val2lin, // #2590
                ordinal2lin: Axis.prototype.ordinal2lin // #6276
            };

            // Add the fake series to hold the full data, then apply processData to it
            each(axis.series, function (series) {
                fakeSeries = {
                    xAxis: fakeAxis,
                    xData: series.xData.slice(),
                    chart: chart,
                    destroyGroupedData: noop
                };

                fakeSeries.xData = fakeSeries.xData.concat(axis.getOverscrollPositions());

                fakeSeries.options = {
                    dataGrouping: grouping ? {
                        enabled: true,
                        forced: true,
                        approximation: 'open', // doesn't matter which, use the fastest
                        units: [[grouping.unitName, [grouping.count]]]
                    } : {
                        enabled: false
                    }
                };
                series.processData.apply(fakeSeries);


                fakeAxis.series.push(fakeSeries);
            });

            // Run beforeSetTickPositions to compute the ordinalPositions
            axis.beforeSetTickPositions.apply(fakeAxis);

            // Cache it
            ordinalIndex[key] = fakeAxis.ordinalPositions;
        }
        return ordinalIndex[key];
    },

    /**
     * Get ticks for an ordinal axis within a range where points don't exist.
     * It is required when overscroll is enabled. We can't base on points,
     * because we may not have any, so we use approximated pointRange and
     * generate these ticks between <Axis.dataMax, Axis.dataMax + Axis.overscroll>
     * evenly spaced. Used in panning and navigator scrolling.
     *
     * @returns positions {Array} Generated ticks
     * @private
     */
    getOverscrollPositions: function () {
        var axis = this,
            extraRange = axis.options.overscroll,
            distance = axis.overscrollPointsRange,
            positions = [],
            max = axis.dataMax;

        if (H.defined(distance)) {
            // Max + pointRange because we need to scroll to the last

            positions.push(max);

            while (max <= axis.dataMax + extraRange) {
                max += distance;
                positions.push(max);
            }

        }

        return positions;
    },

    /**
     * Find the factor to estimate how wide the plot area would have been if ordinal
     * gaps were included. This value is used to compute an imagined plot width in order
     * to establish the data grouping interval.
     *
     * A real world case is the intraday-candlestick
     * example. Without this logic, it would show the correct data grouping when viewing
     * a range within each day, but once moving the range to include the gap between two
     * days, the interval would include the cut-away night hours and the data grouping
     * would be wrong. So the below method tries to compensate by identifying the most
     * common point interval, in this case days.
     *
     * An opposite case is presented in issue #718. We have a long array of daily data,
     * then one point is appended one hour after the last point. We expect the data grouping
     * not to change.
     *
     * In the future, if we find cases where this estimation doesn't work optimally, we
     * might need to add a second pass to the data grouping logic, where we do another run
     * with a greater interval if the number of data groups is more than a certain fraction
     * of the desired group count.
     */
    getGroupIntervalFactor: function (xMin, xMax, series) {
        var i,
            processedXData = series.processedXData,
            len = processedXData.length,
            distances = [],
            median,
            groupIntervalFactor = this.groupIntervalFactor;

        // Only do this computation for the first series, let the other inherit it (#2416)
        if (!groupIntervalFactor) {

            // Register all the distances in an array
            for (i = 0; i < len - 1; i++) {
                distances[i] = processedXData[i + 1] - processedXData[i];
            }

            // Sort them and find the median
            distances.sort(function (a, b) {
                return a - b;
            });
            median = distances[Math.floor(len / 2)];

            // Compensate for series that don't extend through the entire axis extent. #1675.
            xMin = Math.max(xMin, processedXData[0]);
            xMax = Math.min(xMax, processedXData[len - 1]);

            this.groupIntervalFactor = groupIntervalFactor = (len * median) / (xMax - xMin);
        }

        // Return the factor needed for data grouping
        return groupIntervalFactor;
    },

    /**
     * Make the tick intervals closer because the ordinal gaps make the ticks spread out or cluster
     */
    postProcessTickInterval: function (tickInterval) {
        // Problem: https://jsfiddle.net/highcharts/FQm4E/1/
        // This is a case where this algorithm doesn't work optimally. In this case, the
        // tick labels are spread out per week, but all the gaps reside within weeks. So
        // we have a situation where the labels are courser than the ordinal gaps, and
        // thus the tick interval should not be altered
        var ordinalSlope = this.ordinalSlope,
            ret;


        if (ordinalSlope) {
            if (!this.options.breaks) {
                ret = tickInterval / (ordinalSlope / this.closestPointRange);
            } else {
                ret = this.closestPointRange || tickInterval; // #7275
            }
        } else {
            ret = tickInterval;
        }
        return ret;
    }
});

// Record this to prevent overwriting by broken-axis module (#5979)
Axis.prototype.ordinal2lin = Axis.prototype.val2lin;

// Extending the Chart.pan method for ordinal axes
wrap(Chart.prototype, 'pan', function (proceed, e) {
    var chart = this,
        xAxis = chart.xAxis[0],
        overscroll = xAxis.options.overscroll,
        chartX = e.chartX,
        runBase = false;

    if (xAxis.options.ordinal && xAxis.series.length) {

        var mouseDownX = chart.mouseDownX,
            extremes = xAxis.getExtremes(),
            dataMax = extremes.dataMax,
            min = extremes.min,
            max = extremes.max,
            trimmedRange,
            hoverPoints = chart.hoverPoints,
            closestPointRange = xAxis.closestPointRange || xAxis.overscrollPointsRange,
            pointPixelWidth = xAxis.translationSlope * (xAxis.ordinalSlope || closestPointRange),
            movedUnits = (mouseDownX - chartX) / pointPixelWidth, // how many ordinal units did we move?
            extendedAxis = { ordinalPositions: xAxis.getExtendedPositions() }, // get index of all the chart's points
            ordinalPositions,
            searchAxisLeft,
            lin2val = xAxis.lin2val,
            val2lin = xAxis.val2lin,
            searchAxisRight;

        if (!extendedAxis.ordinalPositions) { // we have an ordinal axis, but the data is equally spaced
            runBase = true;

        } else if (Math.abs(movedUnits) > 1) {

            // Remove active points for shared tooltip
            if (hoverPoints) {
                each(hoverPoints, function (point) {
                    point.setState();
                });
            }

            if (movedUnits < 0) {
                searchAxisLeft = extendedAxis;
                searchAxisRight = xAxis.ordinalPositions ? xAxis : extendedAxis;
            } else {
                searchAxisLeft = xAxis.ordinalPositions ? xAxis : extendedAxis;
                searchAxisRight = extendedAxis;
            }

            // In grouped data series, the last ordinal position represents the grouped data, which is
            // to the left of the real data max. If we don't compensate for this, we will be allowed
            // to pan grouped data series passed the right of the plot area.
            ordinalPositions = searchAxisRight.ordinalPositions;
            if (dataMax > ordinalPositions[ordinalPositions.length - 1]) {
                ordinalPositions.push(dataMax);
            }

            // Get the new min and max values by getting the ordinal index for the current extreme,
            // then add the moved units and translate back to values. This happens on the
            // extended ordinal positions if the new position is out of range, else it happens
            // on the current x axis which is smaller and faster.
            chart.fixedRange = max - min;
            trimmedRange = xAxis.toFixedRange(null, null,
                lin2val.apply(searchAxisLeft, [
                    val2lin.apply(searchAxisLeft, [min, true]) + movedUnits, // the new index
                    true // translate from index
                ]),
                lin2val.apply(searchAxisRight, [
                    val2lin.apply(searchAxisRight, [max, true]) + movedUnits, // the new index
                    true // translate from index
                ])
            );

            // Apply it if it is within the available data range
            if (
                trimmedRange.min >= Math.min(extremes.dataMin, min) &&
                trimmedRange.max <= Math.max(dataMax, max) + overscroll
            ) {
                xAxis.setExtremes(trimmedRange.min, trimmedRange.max, true, false, { trigger: 'pan' });
            }

            chart.mouseDownX = chartX; // set new reference for next run
            css(chart.container, { cursor: 'move' });
        }

    } else {
        runBase = true;
    }

    // revert to the linear chart.pan version
    if (runBase) {
        if (overscroll) {
            xAxis.max = xAxis.dataMax + overscroll;
        }
        // call the original function
        proceed.apply(this, Array.prototype.slice.call(arguments, 1));
    }
});

/* ****************************************************************************
 * End ordinal axis logic                                                   *
 *****************************************************************************/