I think you'll have to process the series before plotting it to add some additional line series.
For a single line series, perhaps something like this:
function rays(data) {
// Create a reference to the original data series.
var series = data[0];
for (var i=0; i<series.data.length; i++) {
// Create a new data series for each ray
// Set a label=null so these series will not show in legend
var ray = {
data: [[0,0], [series.data[i][0], series.data[i][1]]],
label: null,
points: {
show: false
}
}
// Insert the new ray series at the start of the data array
// This will make flot draw the rays under the original data series
data.unshift(ray);
}
return data;
}
Here's a working example for just the rays:
http://jsfiddle.net/vfLzp2bw/1/Here's an example including the original line extrapolated to the axes. The rays() function works a bit differently in this one by creating an entirely new data array instead of modifying the original.
http://jsfiddle.net/vfLzp2bw/