click-to-zoom via transform

Part of a series of examples. See:

More recently, see the Zoom to Bounding Box example.

forked from mbostock's block: click-to-zoom via transform

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.background {
  fill: none;
  pointer-events: all;
}

#states {
  fill: #aaa;
}

#states .active {
  fill: orange;
}

#state-borders {
  fill: none;
  stroke: #fff;
  stroke-width: 1.5px;
  stroke-linejoin: round;
  stroke-linecap: round;
  pointer-events: none;
}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="//d3js.org/topojson.v1.min.js"></script>
<script>

var width = 960,
    height = 500,
    centered;

var projection = d3.geo.albersUsa()
    .scale(1070)
    .translate([width / 2, height / 2]);

var path = d3.geo.path()
    .projection(projection);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

svg.append("rect")
    .attr("class", "background")
    .attr("width", width)
    .attr("height", height)
    .on("click", clicked);

var g = svg.append("g");

d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json", function(error, us) {
  if (error) throw error;

g.append("g")
      .attr("id", "states")
    .selectAll("path")
      .data(topojson.feature(us, us.objects.states).features)
    .enter().append("path")
      .attr("d", path)
      .on("click", clicked);

g.append("path")
      .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
      .attr("id", "state-borders")
      .attr("d", path);
});

function clicked(d) {
  var x, y, k;

if (d && centered !== d) {
    var centroid = path.centroid(d);
    x = centroid[0];
    y = centroid[1];
    k = 4;
    centered = d;
  } else {
    x = width / 2;
    y = height / 2;
    k = 1;
    centered = null;
  }

g.selectAll("path")
      .classed("active", centered && function(d) { return d === centered; });

g.transition()
      .duration(750)
      .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")scale(" + k + ")translate(" + -x + "," + -y + ")")
      .style("stroke-width", 1.5 / k + "px");
}

</script>

https://d3js.org/d3.v3.min.js

https://d3js.org/topojson.v1.min.js