Question

I am using Flot to create graphs.
This is my Code here jsFiddle code

function drawSeriesHook(plot, canvascontext, series) {
var ctx = canvascontext,
    plotOffset = plot.offset(),
    labelText = 'VALUE', // customise this text, maybe to series.label
    points = series.datapoints.points,
    ps = series.datapoints.pointsize,
    xaxis = series.xaxis,
    yaxis = series.yaxis,
    textWidth, textHeight, textX, textY;
// only draw label for top yellow series
if (series.color === '#F8C095') {
    ctx.save();
    ctx.translate(plotOffset.left, plotOffset.top);

    ctx.lineWidth = series.bars.lineWidth;

    ctx.fillStyle = '#000'; // customise the colour here
    for (var i = 0; i < points.length; i += ps) {
        if (points[i] == null) continue;

        textWidth = ctx.measureText(labelText).width; // measure how wide the label will be
        textHeight = parseInt(ctx.font); // extract the font size from the context.font string
        textX = xaxis.p2c(points[i] + series.bars.barWidth / 2) - textWidth / 2;
        textY = yaxis.p2c(points[i + 1]) - textHeight / 2;
        ctx.fillText(labelText, textX, textY); // draw the label
    }
    ctx.restore();
}
}

1. In My drawseriesHook function i need to get the x axis labels like Data1,Data2,Data3,Data4
2. Is there any way to uniquely identify the last data item without using series.label & series.color.Currently i have identified it by modifying the series.color in the function

Answer 1

1.) Ok, I think you want to set labelText for each bar. Add the following line in the for-loop:

labelText = series.xaxis.ticks[i / ps].label;

Also see the updated example.

2.) You can add own values to data, e.g. to mark the last one:

var data = [
    {
        label : 'Used',
        color : '#EF7816',
        data : [ [ 1, 85], [ 2, 50 ], [ 3, 18], [ 4, 8 ] ],
        last : false
    },
    ...
    {
        color : '#F8C095',
        data : [ [ 1, 12], [ 2, 10], [ 3, 3], [ 4, 2] ],
        last : true
    }
];

In your hook you can check the flag:

if (series.last) { ...

Also see the next updated example.