Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
511 views
in Technique[技术] by (71.8m points)

d3.js - D3 update pie data with zero values

I am updating a pie chart with a dynamic JSON feed. My update function is below

function updateChart(data) {
arcs.data(pie(data)); // recompute angles, rebind data

arcs.transition()
    .ease("elastic")
    .duration(1250)
    .attrTween("d", arcTween)

sliceLabel.data(pie(data));

sliceLabel.transition()
    .ease("elastic").duration(1250)
    .attr("transform", function (d) {
    return "translate(" + arc2.centroid(d) + ")";
})
    .style("fill-opacity", function (d) {
    return d.value == 0 ? 1e-6 : 1;
});
}

function arcTween(a) {
var i = d3.interpolate(this._current, a);
this._current = i(0);
return function (t) {
    return arc(i(t));
};

When the JSON has 0 values for all objects, the arcs and labels disappear. Exactly what I want to happen.

The problem is when I pass a new JSON after one that was full of zeros, the labels come back and tween etc but the arcs never redraw.

Any suggestions on correcting my update function so that the arcs redraw correctly after they their d values have been pushed to zero?

-- edit --

Lars suggested below that I use the .enter() exactly in the same way as I did when I created the graph. I tried doing this but the results did not change. See new update function below.

this.updatePie = function updateChart(data) {
arcs.data(pie(data))
    .enter()
    .append("svg:path")
        .attr("stroke", "white")
        .attr("stroke-width", 0.5)
        .attr("fill", function (d, i) {
        return color(i);
})
    .attr("d", arc)
    .each(function (d) {
    this._current = d
})
arcs.transition()
    .ease("elastic")
    .duration(1250)
    .attrTween("d", arcTween)
sliceLabel.data(pie(data));
sliceLabel.transition()
    .ease("elastic").duration(1250)
    .attr("transform", function (d) {
    return "translate(" + arc2.centroid(d) + ")";
})
    .style("fill-opacity", function (d) {
    return d.value == 0 ? 1e-6 : 1;
});
}
function arcTween(a) {
var i = d3.interpolate(this._current, a);
this._current = i(0);
return function (t) {
    return arc(i(t));
};
}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

You've actually hit a bug in D3 there -- if everything is zero, the pie layout returns angles of NaN, which cause errors when drawing the paths. As a workaround, you can check whether everything is zero and handle this case separately. I've modified your change function as follows.

if(data.filter(function(d) { return d.totalCrimes > 0; }).length > 0) {
  path = svg.selectAll("path").data(pie(data));
  path.enter().append("path")
      .attr("fill", function(d, i) { return color(d.data.crimeType); })
      .attr("d", arc)
      .each(function(d) { this._current = d; });
  path.transition().duration(750).attrTween("d", arcTween); // redraw the arcs
} else {
  path.remove();
}

Complete jsbin here.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...