Impossible to select the entire summary?

[Frozenlock]

For a summary of width 848, a reset (click) in the selection area will give a selection object of: max: 848.0000000000001.

However, dragging the mouse in the selection area will only give a selection of max 846.9999999999826, thus never entirely selecting the entire data set.
A selection trigger seems to give the same result: can't get up to 848.0000000000001.

[Frozenlock]

(Please keep in mind that I've never written any JS... I could be totally mistaken.)

After investigation I believe this is caused by the boundX function in selection.js (from Flotr2).

function boundX(x, graph) {
  return Math.min(Math.max(0, x), graph.plotWidth - 1);
}

The selection is set to a maximum of width - 1. In my case summary.api.flotr.selection.selection.second.x is maxed at 847, instead of the initial width of 848.

The interesting part is how this maxed width is then multiplied with the axis scale:

 setSelection: function(area, preventEvent){
    var options = this.options,
      xa = this.axes.x,
      ya = this.axes.y,
      vertScale = ya.scale,
      hozScale = xa.scale,
      selX = options.selection.mode.indexOf('x') != -1,
      selY = options.selection.mode.indexOf('y') != -1,
      s = this.selection.selection;

    this.selection.clearSelection();

    s.first.y  = boundY((selX && !selY) ? 0 : (ya.max - area.y1) * vertScale, this);
    s.second.y = boundY((selX && !selY) ? this.plotHeight - 1: (ya.max - area.y2) * vertScale, this);
    s.first.x  = boundX((selY && !selX) ? 0 : (area.x1 - xa.min) * hozScale, this);
    s.second.x = boundX((selY && !selX) ? this.plotWidth : (area.x2 - xa.min) * hozScale, this);

    this.selection.drawSelection();
    if (!preventEvent)
      this.selection.fireSelectEvent();
  },

Yet the scale in Axis.js isn't based on the width -1, but rather on the width/length directly:

 setScale : function () {
    var
      length = this.length,
      max = this.max,
      min = this.min,
      offset = this.offset,
      orientation = this.orientation,
      options = this.options,
      logarithmic = options.scaling === LOGARITHMIC,
      scale;

    if (logarithmic) {
      scale = length / (log(max, options.base) - log(min, options.base));
    } else {
      scale = length / (max - min);
    }
    this.scale = scale;

[Frozenlock]

Should I open an issue in Flotr2 instead of Envision?

[cesutherland]

Could you please fork this with your reproduction? http://jsfiddle.net/cesutherland/LurmY/49/

[Frozenlock]

The same behavior is already present in this jsfiddle.
Here is a comparison of the selections one can make on the left and right side.

Complete selection up to the 'touching' point.

The two lines never meet!

[cesutherland]

Ah, got it!

[Frozenlock]

Would you prefer if i opened this as a Flotr2 issue?

[cesutherland]

Thank you, no... it's an issue en the envision data processing. I'll take a look at it. Maybe off-by-1 heh...

[Frozenlock]

Bump!

Any changes?

[Flati]

I have found this issue in my project as well.
I collected some data that might help you:

# of points	# of points missing	px width of chart
5012	4	1356
5012	8	712
3313	2	1356
3313	5	712
1528	1	1356
1528	2	712

As you can see with the data above, it seems to be an off-by-one error.
((# of points missing) / (# of points)) * (px width of chart) is always close to 1.

I also tried this with a few smaller examples, (all the way down to 2 data points). The last data point was always missing when I tried to select some area.

As mentioned above, by @Frozenlock , when I click the summary list to reset the selection, the whole data pool is displayed.

[Flati]

I have found the off-by-one error to be in flotr2.js function called boundX.
The implementation of the function is:
return Math.min(Math.max(0, x), graph.plotWidth - 1);
where it should be:
return Math.min(Math.max(0, x), graph.plotWidth);

This is in line # 4117 in the envision.js file.

After some testing on my charts, this seems to cause no error and fixes all my problems.
I will submit a pull request when I am able.