hover.js

/**
* Copyright 2012-2019, Plotly, Inc.
* All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/

'use strict';

var scatterHover = require('../scatter/hover');
var fillText = require('../../lib').fillText;

module.exports = function hoverPoints(pointData, xval, yval, hovermode) {
    var scatterPointData = scatterHover(pointData, xval, yval, hovermode);
    if(!scatterPointData || scatterPointData[0].index === false) return;

    var newPointData = scatterPointData[0];

    // if hovering on a fill, we don't show any point data so the label is
    // unchanged from what scatter gives us - except that it needs to
    // be constrained to the trianglular plot area, not just the rectangular
    // area defined by the synthetic x and y axes
    // TODO: in some cases the vertical middle of the shape is not within
    // the triangular viewport at all, so the label can become disconnected
    // from the shape entirely. But calculating what portion of the shape
    // is actually visible, as constrained by the diagonal axis lines, is not
    // so easy and anyway we lost the information we would have needed to do
    // this inside scatterHover.
    if(newPointData.index === undefined) {
        var yFracUp = 1 - (newPointData.y0 / pointData.ya._length);
        var xLen = pointData.xa._length;
        var xMin = xLen * yFracUp / 2;
        var xMax = xLen - xMin;
        newPointData.x0 = Math.max(Math.min(newPointData.x0, xMax), xMin);
        newPointData.x1 = Math.max(Math.min(newPointData.x1, xMax), xMin);
        return scatterPointData;
    }

    var cdi = newPointData.cd[newPointData.index];

    newPointData.a = cdi.a;
    newPointData.b = cdi.b;

    newPointData.xLabelVal = undefined;
    newPointData.yLabelVal = undefined;
    // TODO: nice formatting, and label by axis title, for a, b, and c?

    var trace = newPointData.trace;
    var carpet = trace._carpet;

    var labels = trace._module.formatLabels(cdi, trace);
    newPointData.yLabel = labels.yLabel;

    delete newPointData.text;
    var text = [];

    function textPart(ax, val) {
        var prefix;

        if(ax.labelprefix && ax.labelprefix.length > 0) {
            prefix = ax.labelprefix.replace(/ = $/, '');
        } else {
            prefix = ax._hovertitle;
        }

        text.push(prefix + ': ' + val.toFixed(3) + ax.labelsuffix);
    }


    if(!trace.hovertemplate) {
        var hoverinfo = cdi.hi || trace.hoverinfo;
        var parts = hoverinfo.split('+');

        if(parts.indexOf('all') !== -1) parts = ['a', 'b', 'text'];
        if(parts.indexOf('a') !== -1) textPart(carpet.aaxis, cdi.a);
        if(parts.indexOf('b') !== -1) textPart(carpet.baxis, cdi.b);

        text.push('y: ' + newPointData.yLabel);

        if(parts.indexOf('text') !== -1) {
            fillText(cdi, trace, text);
        }

        newPointData.extraText = text.join('<br>');
    }

    return scatterPointData;
};