flot-charting-plugin

A Flot plugin to make charting easy and efficient.

What is a chart

A chart takes as input data points at different times, accumulates them into an internal buffer (called a history buffer) of certain size and shows them as a continuous graph.

How to use

Once included in the webpage the plugin is activated by specifying a history buffer to use as a data series

    var buffer = new HistoryBuffer(256, 1); // 256 samples, and a single data serie.
 
    plot = $.plot("#placeholder", [], {
        series: {
            historyBuffer: buffer,
            lines: {
                show: true
            }
    };

Then you add data to the history buffer

    buffer.push(7); // append a number to the buffer
    buffer.appendArray([1, 2, 3, 4]); // or append an array to the buffer

A chart redraw is automatically scheduled in the next Animation Frame on any history buffer change.

History Buffer

A history buffer is a data structure designed to accelerate common operations needed by charting.

See HistoryBuffer.md

Performance considerations

Insertion of an element into a history buffer is a constant time operation O(1). Appending an array of length n to a history buffer is a linear time operation O(n).

The complexity of drawing a chart of width P pixels with a history buffer of length N, of which M are newly added elements is O(p)*O(log(N))*O(M logM)