D3Js圆环图，避免标签文字叠加

Question

In my project I have big mount of different charts, everything handled with D3Js. One of charts should to be donut type with labels. So based on this tutorial I made this graph . As you can see sometimes (depends on data) label text goes overlay's.

My question is there any way to make it like in example below, based on highcharts from here :

Thanks.

Answer 1

I think there is a solution for the problem of labels getting overlapped, using contraint relaxing when you call the label up at: Solving D3 Label Placement with Constraint Relaxing .

I had a quick look at the labels here and it seems to work. This is my modified code snippet here:

alpha = 0.5;
spacing = 5;

function relax() {
again = false;
text.each(function (d, i) {
    a = this;
    da = d3.select(a);
    y1 = da.attr("y");
    text.each(function (d, j) {
        b = this;
        // a & b are the same element and don't collide.
        if (a == b) return;
        db = d3.select(b);
        // a & b are on opposite sides of the chart and
        // don't collide
        if (da.attr("text-anchor") != db.attr("text-anchor")) return;
        // Now let's calculate the distance between
        // these elements. 
        y2 = db.attr("y");
        deltaY = y1 - y2;

        // If spacing is greater than our specified spacing,
        // they don't collide.
        if (Math.abs(deltaY) > spacing) return;

        // If the labels collide, we'll push each 
        // of the two labels up and down a little bit.
        again = true;
        sign = deltaY > 0 ? 1 : -1;
        adjust = sign * alpha;
        da.attr("y",+y1 + adjust);
        db.attr("y",+y2 - adjust);   
    });

});

if(again) {
    setTimeout(relax,20)
}
}

relax();

fiddle

Just follow the next step in the tutorial linked above for updating the polylines to follow the labels to their new positions. Good luck!