Circle-packing diagram - transition between two set of values

Question

I have a diagram very similar to circle packing

At some point, a user wants to see some different data. Obviously, a different diagram can be displayed immediately,

Answer 1

It looks that I finally resolved all issues. jsfiddle is here.

Here is the whole code (except data definition and button creation) that handles smooth circle pack layout transition:

var diameter = 500,
    format = d3.format(",d"),
    dataSource = 2;
var pack = d3.layout.pack()
    .size([diameter - 4, diameter - 4])
    .value(function(d) { return d.size; });
var svg = d3.select("body").append("svg")
    .attr("width", diameter)
    .attr("height", diameter);

var data = getData();

var vis = svg.datum(data).selectAll(".node")
    .data(pack.nodes)
   .enter()
    .append("g");

var titles = vis.append("title")
    .attr("x", function(d) { return d.x; })
    .attr("y", function(d) { return d.y; })
    .text(function(d) { return d.name +
        (d.children ? "" : ": " + format(d.value)); });

var circles = vis.append("circle")
    .attr("stroke", "black")
    .style("fill", function(d) { return !d.children ? "tan" : "beige"; })
    .attr("cx", function(d) { return d.x; })
    .attr("cy", function(d) { return d.y; })
    .attr("r", function(d) { return d.r; });

updateVis();

function updateVis() {

    if (dataSource == 0)
        pack.value(function(d) { return d.size; });
    if (dataSource == 1)
        pack.value(function(d) { return 100; });
    if (dataSource == 2)
        pack.value(function(d) { return 1 +
                 Math.floor(Math.random()*301); });

    var data1 = pack.nodes(data);

    titles.attr("x", function(d) { return d.x; })
        .attr("y", function(d) { return d.y; })
        .text(function(d) { return d.name +
            (d.children ? "" : ": " + format(d.value)); });

    circles.transition()
        .duration(5000)
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; })
        .attr("r", function(d) { return d.r; });
};