Rounding problems

[jibaku]

On some graph (using 2.0.0-dev), I've rounding problems, where I get 103.9999999999 instead of 104 etc.

The code for the rounding with 103 / 104 issue

<script src="/static/js/bootstrap.min.js"></script>

<script type="text/javascript" src="/static/js/Chart.min.js"></script>
<script type="text/javascript">
  var lineChartData = {"tension": 0, "legendTemplate": "", "type": "line", "data": {"labels": ["22/09", "23/09", "24/09", "25/09", "26/09", "27/09", "28/09", "29/09"], "datasets": [{"borderColor": "rgba(220,220,220,0.5)", "pointBorderWidth": "rgba(220,220,220,0.5)", "backgroundColor": "rgba(220,220,220,0.5)", "borderDash": [5, 5], "pointBorderColor": "rgba(220,220,220,0.5)", "pointBackgroundColor": "rgba(220,220,220,0.5)", "data": [103, 103, 103, 103, 104, 104, 104, 104], "label": "Likes"}]}, "tooltipTemplate": "", "options": {"responsive": true, "scales": {"xAxes": [{"display": true}], "yAxes": [{"display": true}]}}};
  function updateLegend() {
      $legendContainer = $('#legendContainer');
      $legendContainer.empty();
      $legendContainer.append(window.myBar.generateLegend());
  }
  window.onload = function() {

      Chart.defaults.global.elements.line.tension = 0;
      var ctx2 = document.getElementById("line").getContext("2d");
      window.myBar = new Chart(ctx2, lineChartData);
  };
</script>

[etimberg]

@jibaku we probably need a better default template function. In your case you could change the template to "<%=value.toFixed(1)%>" which would probably fix the problem

[artesea]

I've forced value.toFixed() on both tooltips (where the floats have lots of dps) and also on the axis to avoid this issue. Although it means some graphs go from 0.0 to 1000.0 whilst others are 0.0 to 1.8

[etimberg]

@artesea you could try running the ticks through a function that does something like the following.

1. Determine numerical distance between ticks
2. numDecimal = -1 * Math.floor(Math.log10(tickDistance))
3. numDecimal = Math. Max(numDecimal, 0)
4. return tickValue.toFixed(numDecimal)

That should show the best number of decimal places given the scale range

[etimberg]

Closing since #1567 was merged