Pop-up bubble details not clear

[cylammarco]

From JMM: the pop-up bubble when mouse-over the lines is not clear what the values are. Would be nice to add more legends inside the bubble.

[blancmatter]

Looked into it briefly. There are no options making specific annotations within the 'Tooltips' (as they are called)

This example may provide a solution. https://jsfiddle.net/vgrem/5pbjz5ev/
It adds a 'listener' to the mouseover and calls a formatting function...

 google.visualization.events.addListener(chart, 'onmouseover', function(e) {
        setTooltipContent(dataTable,e.row);
    });
}


function setTooltipContent(dataTable,row) {
    if (row != null) {
        var content = '<div class="custom-tooltip" ><h1>' + dataTable.getValue(row, 0) + '</h1><div>' + dataTable.getValue(row, 1) + '</div></div>'; //generate tooltip content
        var tooltip = document.getElementsByClassName("google-visualization-tooltip")[0];
        tooltip.innerHTML = content;
    }
}

[cylammarco]

This may help:

https://developers.google.com/chart/interactive/docs/customizing_tooltip_content#custom_html_content

[blancmatter]

I looked at that link. I could see that thre are options to put tooltip text into the data as a separate column (possible, but clunky), but not to change the formating of the labelling. Also the option of JS vs HTML tooltips.

I had tried a couple of options (e.g. aggregationTarget: 'category') in the var options{}, but to avail.

[cylammarco]

something like this in a loop should work:
https://stackoverflow.com/questions/28324231/how-to-make-a-custom-tooltip-for-each-series-in-google-line-chart?rq=1

couldn't get it work in an hour, will come back to it later.