sveinn-steinarsson / highcharts-downsample Goto Github PK

Looks like something has changed either in highcharts core library or plugin handler.

The below fiddle fails to downsample:
http://jsfiddle.net/6meqb9d0/33/

I need to be able to use navigator and custom buttons to zoom into data.

I noticed threshold setting is applied for entire data set length, so while zoomed I need to calculate desirable threshold points count... And hook into setExtremes event to update series objects.

But it seems when doing Point update and redrawing the chart, new threshold value doesn't apply? I perhaps need to resort into removing and inserting new series' to chart...

var calcZoomedDownsampleThreshold = function(dataMin, dataMax, min, max) {
    var verticalPixels = window.innerWidth - 120;
    if ( ! _.isUndefined(dataMin) && ! _.isUndefined(dataMax) && ! _.isUndefined(min) && ! _.isUndefined(max) ) {
        var dataSpanSeconds = Math.floor((dataMax - dataMin) / 1000),
            zoomSpanSeconds = Math.floor((max - min) / 1000);
        console.log(Math.round(verticalPixels * dataSpanSeconds / zoomSpanSeconds));
        return Math.round(verticalPixels * dataSpanSeconds / zoomSpanSeconds);
    } else {
        return verticalPixels;
    }
};

xAxis: {
    type: 'datetime',
    events: {
        setExtremes: function (e) {
            chart.series[0].update({ downsample: { threshold: calcZoomedDownsampleThreshold(this.dataMin, this.dataMax, e.min, e.max) } }, false);
            chart.series[1].update({ downsample: { threshold: calcZoomedDownsampleThreshold(this.dataMin, this.dataMax, e.min, e.max) } }, false);
            chart.redraw();
        }
    }
},

Hello Sveinn,

First of all, thanks for sharing your work on LTTB algorithm. It is exactly what I am looking for to plot large data size in Microsoft Chart Component. Here is the link to my implementation in GitHub MSChartExtension/DownSampling.cs.

On top of that, I made some further improvement to address the limitation of your original LTTB algorithm to take into consideration with data with non fixed X. I wrote the description of the changes here: Implementation of Downsampling Algorithm in MSChart Extension

I would like to seek your kindness to review and comment on my work.
I am appreciate if my work is up to standard to be listed in your list of LTTB adaptation.

Should you have any questions, you can also contact me at [email protected].
Hope to hear from you soon.

Regards,
Code Artist

First off, thanks a lot for this plugin and your work on downsampling.
I've used your plugin extensively and just recently experienced a issue with it:
When downsampling discrete time series (series with null values) the gaps sometimes get sampled out. The desired functionality would be for null values to go untouched so gaps in the series are displayed correctly.

I am using your plugin to Downsample chart data. However, I am not able to figure out on downsampling data when a point is added to the chart.

Need help on this http://jsfiddle.net/FMJAL/86/

Regards,
Ashwin