Google Timeline Chart: Color each bar individually when multiple on "same" line

Question

The Google Timeline charts seem to suggest coloring individual blocks on the timeline per the documentation: https://google-developers.appspot.com/chart/interactive/docs/gallery/timeline#ControllingColors

But there seems to be a problem when two bars "overlap" on the same line, as you can see in this fiddle: http://jsfiddle.net/7A88H/21/

Here is the key code:

dataTable.addRows([
[ 'red/green/blue', 'NAME OF BAR (should be RED) (ff0000)', new Date(1789, 3, 29), new Date(1797, 2, 3) ],
[ 'red/green/blue', 'NAME OF BAR (should be GREEN) (00ff00)', new Date(1796, 2, 3),  new Date(1801, 2, 3) ],
[ 'red/green/blue', 'NAME OF BAR (should be BLUE) (0000ff)',  new Date(1801, 2, 3),  new Date(1809, 2, 3) ]]);

var options = {
    colors: ['#ff0000', '#00ff00', '#0000ff'],
};

I tried playing with the accepted answer from this question by adding a 5th column (the color) to my data rows: Google Charts API: Add Blank Row to Timeline?

Specifically, here is the function I thought I might be able to hijack to build my hack:

(function(){                                            //anonymous self calling function to prevent variable name conficts
    var el=container.getElementsByTagName("rect");      //get all the descendant rect element inside the container      
    var width=100000000;                                //set a large initial value to width
    var elToRem=[];                                     //element would be added to this array for removal
    for(var i=0;i<el.length;i++){                           //looping over all the rect element of container
        var cwidth=parseInt(el[i].getAttribute("width"));//getting the width of ith element
        if(cwidth<width){                               //if current element width is less than previous width then this is min. width and ith element should be removed
            elToRem=[el[i]];
            width=cwidth;                               //setting the width with min width
        }
        else if(cwidth==width){                         //if current element width is equal to previous width then more that one element would be removed
            elToRem.push(el[i]);        
        }
    }
    for(var i=0;i<elToRem.length;i++)
        elToRem[i].setAttribute("fill","none"); //make invisible all the rect element which has minimum width
})();

The hope was to grab each rect (skipping the bounding ones) and filling them (with a third loop, at the end) with their appropriate colors, but I couldn't figure out how to get their associated color (which was in the row objects) from the rect objects themselves.

Answer 1

I think you will need to use the additional options:

timeline: { groupByRowLabel: false }

Because, if you go to the g-page: https://google-developers.appspot.com/chart/interactive/docs/gallery/timeline#BarsOneRow in the Bars in One Row section they show how Presidents DON'T overlap, so you can't use it in this case, but for the method you are using it, timelines do overlap so they must be in their own row. It would probably be hard to read overlapping titles anyhow.

Side note: I noticed what google is doing. It's assigning the colors left to right, then wrapping. The titles however, are not wrapping, they just go left to right. Here is a fiddle I made: https://jsfiddle.net/camp185/2Lopnnt3/2/ to show how wrapping of colors working...added more colors.