plotly.js/src/components/legend/defaults.js

The open source javascript graphing library that powers plotly

/**
* Copyright 2012-2020, 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 Registry = require('../../registry');
var Lib = require('../../lib');
var Template = require('../../plot_api/plot_template');

var attributes = require('./attributes');
var basePlotLayoutAttributes = require('../../plots/layout_attributes');
var helpers = require('./helpers');


module.exports = function legendDefaults(layoutIn, layoutOut, fullData) {
    var containerIn = layoutIn.legend || {};

    var legendTraceCount = 0;
    var legendReallyHasATrace = false;
    var defaultOrder = 'normal';

    for(var i = 0; i < fullData.length; i++) {
        var trace = fullData[i];

        if(!trace.visible) continue;

        // Note that we explicitly count any trace that is either shown or
        // *would* be shown by default, toward the two traces you need to
        // ensure the legend is shown by default, because this can still help
        // disambiguate.
        if(trace.showlegend || (
            trace._dfltShowLegend && !(
                trace._module &&
                trace._module.attributes &&
                trace._module.attributes.showlegend &&
                trace._module.attributes.showlegend.dflt === false
            )
        )) {
            legendTraceCount++;
            if(trace.showlegend) {
                legendReallyHasATrace = true;
                // Always show the legend by default if there's a pie,
                // or if there's only one trace but it's explicitly shown
                if(Registry.traceIs(trace, 'pie-like') ||
                    trace._input.showlegend === true
                ) {
                    legendTraceCount++;
                }
            }
        }

        if((Registry.traceIs(trace, 'bar') && layoutOut.barmode === 'stack') ||
                ['tonextx', 'tonexty'].indexOf(trace.fill) !== -1) {
            defaultOrder = helpers.isGrouped({traceorder: defaultOrder}) ?
                'grouped+reversed' : 'reversed';
        }

        if(trace.legendgroup !== undefined && trace.legendgroup !== '') {
            defaultOrder = helpers.isReversed({traceorder: defaultOrder}) ?
                'reversed+grouped' : 'grouped';
        }
    }

    var showLegend = Lib.coerce(layoutIn, layoutOut,
        basePlotLayoutAttributes, 'showlegend',
        legendReallyHasATrace && legendTraceCount > 1);

    if(showLegend === false && !containerIn.uirevision) return;

    var containerOut = Template.newContainer(layoutOut, 'legend');

    function coerce(attr, dflt) {
        return Lib.coerce(containerIn, containerOut, attributes, attr, dflt);
    }

    coerce('uirevision', layoutOut.uirevision);

    if(showLegend === false) return;

    coerce('bgcolor', layoutOut.paper_bgcolor);
    coerce('bordercolor');
    coerce('borderwidth');
    Lib.coerceFont(coerce, 'font', layoutOut.font);

    var orientation = coerce('orientation');
    var defaultX, defaultY, defaultYAnchor;

    if(orientation === 'h') {
        defaultX = 0;

        if(Registry.getComponentMethod('rangeslider', 'isVisible')(layoutIn.xaxis)) {
            defaultY = 1.1;
            defaultYAnchor = 'bottom';
        } else {
            // maybe use y=1.1 / yanchor=bottom as above
            //   to avoid https://github.com/plotly/plotly.js/issues/1199
            //   in v2
            defaultY = -0.1;
            defaultYAnchor = 'top';
        }
    } else {
        defaultX = 1.02;
        defaultY = 1;
        defaultYAnchor = 'auto';
    }

    coerce('traceorder', defaultOrder);
    if(helpers.isGrouped(layoutOut.legend)) coerce('tracegroupgap');

    coerce('itemsizing');
    coerce('itemwidth');

    coerce('itemclick');
    coerce('itemdoubleclick');

    coerce('x', defaultX);
    coerce('xanchor');
    coerce('y', defaultY);
    coerce('yanchor', defaultYAnchor);
    coerce('valign');
    Lib.noneOrAll(containerIn, containerOut, ['x', 'y']);

    var titleText = coerce('title.text');
    if(titleText) {
        coerce('title.side', orientation === 'h' ? 'left' : 'top');
        Lib.coerceFont(coerce, 'title.font', layoutOut.font);
    }
};