Interacting with the data point - flot

Question

I'm using this site as a reference: http://astro.unl.edu/naap/hr/animations/hrExplorer.html

I need to add a pointer "x" as the link and manipulate slide the pointer should move the x and y axis.

See my code: http://jsfiddle.net/2Xn9f/4/

Understand?

Can you help me?

Answer 1

First off, you want a cross. In the flot API , it actually gives us that function!

function cross(ctx, x, y, radius, shadow) {
    var size = radius * Math.sqrt(Math.PI) / 2;
    ctx.moveTo(x - size, y - size);
    ctx.lineTo(x + size, y + size);
    ctx.moveTo(x - size, y + size);
    ctx.lineTo(x + size, y - size);
}

So that part is easy enough. Then, if you want to be able to slide it around the graph, you can create some jQuery UI sliders that control x and y, and have it replot every time a slider is moved:

$('#xslide').slider({
    value: 1,
    min: 0,
    max: 2,
    step: 0.1,
    slide: function(e, ui) {
        plotSlide([[ui.value, $('#yslide').slider('value')]]);
    }
});

Where plotSlide does something like this:

function plotSlide(data2) {
    $.plot($("#chart1"), [{
        data: data1},
    {
        data: data2,
        color: 'red',
        points: {
            show: true,
            symbol: cross
        },
        lines: {
            show: false
        }
    }], 
    options1);
}

See it in action here: http://jsfiddle.net/ryleyb/2Xn9f/5/