Function findMainSubplot

src/plots/plots.js:972–1006

(ax, fullLayout)

};

function findMainSubplot(ax, fullLayout) {
    var mockGd = {_fullLayout: fullLayout};

    var isX = ax._id.charAt(0) === 'x';
    var anchorAx = ax._mainAxis._anchorAxis;
    var mainSubplotID = '';
    var nextBestMainSubplotID = '';
    var anchorID = '';

    // First try the main ID with the anchor
    if(anchorAx) {
        anchorID = anchorAx._mainAxis._id;
        mainSubplotID = isX ? (ax._id + anchorID) : (anchorID + ax._id);
    }

    // Then look for a subplot with the counteraxis overlaying the anchor
    // If that fails just use the first subplot including this axis
    if(!mainSubplotID || !fullLayout._plots[mainSubplotID]) {
        mainSubplotID = '';

        var counterIDs = ax._counterAxes;
        for(var j = 0; j < counterIDs.length; j++) {
            var counterPart = counterIDs[j];
            var id = isX ? (ax._id + counterPart) : (counterPart + ax._id);
            if(!nextBestMainSubplotID) nextBestMainSubplotID = id;
            var counterAx = axisIDs.getFromId(mockGd, counterPart);
            if(anchorID && counterAx.overlaying === anchorID) {
                mainSubplotID = id;
                break;
            }
        }
    }

    return mainSubplotID || nextBestMainSubplotID;
}

// This function clears any trace attributes with valType: color and
// no set dflt filed in the plot schema. This is needed because groupby (which