How to fill the Area between two series with multiples yAxis in HighChart?

Question

The topic of filling area between series has been discussed quite a lot. I\'ve seen some solutions using \'arearange\' series ( adding dummy serie with area ran

Answer 1

I've accepted Sebastian answer and I publish here its implementation :

I've created a function that generates a dummy series with the type 'arearange', using the data of the first series and a modified version of the data in the second series in order to map them on the main yAxis :

/**
*generate a dummy arearange series in order to fill area between our two series.
*/
function createRangeSerie(data1, min1, max1, data2, min2, max2)
{
    //we will apply a linear transfomation to values from the second series
    var b = min1-min2;
    var a = (max1 - b) / max2;

    var rangeData = [];
    $.each(data1, function(index, value) {
         var value2 = a*data2[index] + b;

        rangeData.push([value, value2]);
    });    

    //return the third series, used to fill the area between our 2 series.    
    return {
        name: 'areaRangeSerie',
        type: 'arearange',
        data: rangeData
    };
};

then I use it to add the new area in my chart as seen in this fiddle example :

http://jsfiddle.net/2me4Z/3/

Thanks again guys!

LIMITATIONS : What I was afraid of occurs : in the case I want to fill only if the first curve is under the second (or vice versa). there is a problem on the adjacent points. As you can see in the updated JSfiddle. So this solution is still not perfect, I'll improve it.

LAST VERSION : In my final version, I've added the intersection point to my arearange serie. Now the result is perfect. You can see the result an the algorithm here in this JSFiddle as you can see, I4ve changed the xAxis so I've got values for computations instead of categories.

Edit : here is the function to find the intersection point from two lines ( each defined by two points so we need 4 arguments : line1Point1 line1Point2, line2Point1, line2Point2). I don't sue pixel coordinates but I compute intersection from my x and y values since the resulting point will be mapped by the highchart library the same way.

function intersectionPoint(l1Pt1, l1Pt2, l2Pt1, l2Pt2){
    console.log(l1Pt1, l1Pt2, l2Pt1, l2Pt2);

    //compute A B and C for the first line: AX + BY = C
    A1 = l1Pt2.y-l1Pt1.y;
    B1 = l1Pt1.x-l1Pt2.x;
    C1 = A1*l1Pt1.x + B1 *l1Pt1.y;

    //compute A B and C for the second line
    A2 = l2Pt2.y - l2Pt1.y;
    B2 = l2Pt1.x - l2Pt2.x;
    C2 = A2*l2Pt1.x + B2*l2Pt1.y;

    var delta = A1*B2 - A2*B1;
    if(delta == 0) {
        console.log("Lines are parallel");
        return null;
    }
    else
    {
        return {
            x: (B2*C1 - B1*C2)/delta,
            y: (A1*C2 - A2*C1)/delta
        };    
    }

};

I'm really expecting highchart to give a full official support for it since it will become again more complex when using logarithmic axis X(