Problems when displaying tooltips of multiple series

[vitorbaptista]

Hi,

This is the problem I'm facing:

Note that, even though there're two bars: Foo and Bar, the tooltip calls them Foo in both cases.

I reproduced this in a fiddle at http://jsfiddle.net/vitorbaptista/vPGH6/1/. It basically creates two series:

var values1 = [ ["Foo", 5] ];
var values2 = [ ["Bar", 10] ];

var options = {
  // Set up bars, set mode as category, etc. Nothing special.
};

var plotObj = $.plot( $("#bars"),
  [
      { data: values1, label: "Series 1"},
      { data: values2, label: "Series 2"}      
  ],
  options );

The problem comes from FlotTooltip.stringFormat, specially from https://github.com/krzysu/flot.tooltip/blob/master/js/jquery.flot.tooltip.js#L225-L229

// change x from number to given label, if given
if(typeof item.series.xaxis.ticks !== 'undefined') {
  if(item.series.xaxis.ticks.length > item.dataIndex && !this.isTimeMode('xaxis', item))
    content = content.replace(xPattern, item.series.xaxis.ticks[item.dataIndex].label);
}

What this does, AFAIK, is get the tick indexed at item.dataIndex's label and replace it at %x. The problem is that, in this case, item.dataIndex is always 0, because both values have a single data array. As the label at the tick indexed at 0 is Foo, this is what we get.

I couldn't understand why this code exists. At that point, the correct label is already in the x and y variables, configured in https://github.com/krzysu/flot.tooltip/blob/master/js/jquery.flot.tooltip.js#L175-L182.

Is this the expected behavior? Am I doing something wrong?

Thanks!

[krzysu]

Hi, that feature was written by one of the contributors (see v0.6.4 https://github.com/krzysu/flot.tooltip#v064), so I don't quite know what is that about.
Maybe here you can find some more info #18 or just ask @Lukindo or @LoicUV

[lmacko]

The multiBar chart doesn't check whether you use same indexes on x-axis. It doesn't reorder the values or adds missing. That's why the plugin shows wrong labels.

The solutions I suggest:
-merge series to one [ ["Foo", 5],["Bar", 10] ]
-add missing elements to both series
var values1=[ ["Foo", 5],["Bar", 0] ]; var values1=[ ["Foo", 0],["Bar", 0] ]

ad Why that code exists,
yes, you're right the label is in x and y, however you have to somehow transfer the label value to format string (to the place where user want it to be shown)

[krzysu]

thank you @Lukindo for the answer!

[vitorbaptista]

Hi all,

Thanks for your comments! They were very useful.

I think I might have found the solution. Basically, the problem is that we're using only item.dataIndex to find the current item. That works if there's a single series plotted, but will break apart if there're multiple series. The problem is that item.dataIndex is the index relative to the item's data only, which may (or may not) be all that's on the graph.

But the item also have item.seriesIndex. As far as I can see, to get the item's tick, we should be doing item.seriesIndex + item.dataIndex, and not only item.dataIndex.

In my previous example, we had two series:

var values1 = [ ["Foo", 5] ];
var values2 = [ ["Bar", 10] ];

The Foo item will end up with { dataIndex: 0, seriesIndex: 0, ... }, and Bar will have { dataIndex: 0, seriesIndex: 1, ... }, and the ticks array will be [ { label: "Foo", v: 0 }, { label: "Bar", v: 1 } ].

So, if we change the code to use item.dataIndex + item.seriesIndex, as in:

if(typeof item.series.xaxis.ticks !== 'undefined') {
    var index = item.dataIndex + item.seriesIndex;
    if(item.series.xaxis.ticks.length > index && !this.isTimeMode('xaxis', item))
        content = content.replace(xPattern, item.series.xaxis.ticks[index].label);
}

Everything works as expected.

I tested the same code but using the data from #18:

data: [ [0, 450], [1, 550], [2, 320], [3, 700] ],
xaxis: {
     ticks: [
       [0, "great"],
       [1, "greater"],
       [2, "greatest"]
     ]
}   

And everything worked fine as well. In this case, as there's only one series, every item's seriesIndex is 0.

Does it sound right? I'd be happy to submit a pull request with these changes if you agree.

[vitorbaptista]

Ah! If that helps to debug this proposal, there's a jsfiddle with the updated code at http://jsfiddle.net/vitorbaptista/vPGH6/3/

[krzysu]

Hi, if you tested that both use cases work good, then just send pull request. Thanks!

[Roundaround]

Reopened this issue because of the discussion on pull request #66.

[michpetrov]

The fix expects the ticks of n-th series to be offset by n, that can work with series that form triangular matrices but not it in general. The code should be reverted and instead user should be required to supply series that are aligned into a matrix, e.g.

var values1 = [ ["Foo", 5], null ];
var values2 = [ null, ["Bar", 10] ];

[vitorbaptista]

@michpetrov Could you create a jsfiddle showing an example where the current code breaks? You could edit http://jsfiddle.net/vitorbaptista/vPGH6/1/, but you'll need to update flot.tooltip's code there (as it's from before this patch was applied)

[michpetrov]

@vitorbaptista http://jsfiddle.net/vPGH6/17/

with a set of

var values1 = [ ["Foo", 5], ["Foobar", 6] ];
var values2 = [ ["Bar", 10] ];

the tickIndex for the last bar would have to be 2, but it is only 1.

Or maybe a better example would be

var values1 = [ ["Foo", 5], ["Bar", 6] ];
var values2 = [ ["Foo", 2], ["Bar", 3] ];

In this case item.dataIndex + item.seriesIndex doesn't make sense, since the series have no offset.