mbostock · September 12, 2018 10:53
diff --git a/.block b/.block
 license: gpl-3.0
diff --git a/README.md b/README.md
diff --git a/index.html b/index.html
 <!DOCTYPE html>
 <meta charset="utf-8">
 <style>

 .mesh {
  fill: none;
  stroke: #333;
  stroke-width: .5px;
  stroke-linejoin: round;
 }

 .play circle {
  fill: white;
  stroke: black;
  stroke-width: 3px;
 }

 .play:hover path {
  fill: red;
 }

 .play.mousedown circle {
  fill: red;
 }

 .play.mousedown path {
  fill: white;
 }

 .play rect {
  fill: none;
  pointer-events: all;
  cursor: pointer;
 }

 .arc {
  fill: none;
  stroke-width: 3px;
  stroke-linejoin: round;
  stroke-linecap: round;
  stroke: red;
 }

 .duplicate.arc {
  stroke: blue;
 }

 </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;

 var color = d3.scale.category10();

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

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

 d3.json("us.json", function(error, us) {
  if (error) throw error;

  svg.append("path")
      .datum(topojson.mesh(us))
      .attr("class", "mesh")
      .attr("d", path);

  var play = svg.append("g")
      .attr("class", "play");

  play.append("circle")
      .attr("r", 45)
      .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

  play.append("path")
      .attr("d", "M-22,-30l60,30l-60,30z")
      .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")scale(.7)");

  play.append("rect")
      .attr("width", width)
      .attr("height", height)
      .on("mousedown", function() {
        play.classed("mousedown", true);
        d3.select(window).on("mouseup", function() { play.classed("mousedown", false); });
      })
      .on("click", function() {
        resetAll();
        animation();
      });

  function resetAll() {
    play.style("display", null);
  }

  function animation() {
    play.style("display", "none");

    var results = [],
        indexes = d3.set();

    us.objects.states.geometries.forEach(function(d) {
      if (d.type === "Polygon") extractPolygon(d.arcs);
      else d.arcs.forEach(extractPolygon);
    });

    results.reverse();

    function extractPolygon(arcs) {
      arcs.forEach(extractRing);
    }

    function extractRing(arcs) {
      for (var i = 0, n = arcs.length; i < n; ++i) {
        var index = arcs[i];
        if (index < 0) index = ~index;
        results.push({
          coordinates: arc(index),
          duplicate: indexes.has(index)
        });
        indexes.add(index);
      }
    }

    function arc(index) {
      var x = 0, y = 0, arc = us.arcs[index < 0 ? ~index : index].map(function(point) {
        return [
          (x += point[0]) * us.transform.scale[0] + us.transform.translate[0],
          (y += point[1]) * us.transform.scale[1] + us.transform.translate[1]
        ];
      });
      return index < 0 ? arc.reverse() : arc;
    }

    var interval = setInterval(function() {
      var result = results.pop();
      if (!result) return clearInterval(interval), setTimeout(resetAll, 750);
      svg.append("path")
          .datum({type: "LineString", coordinates: result.coordinates})
          .attr("d", path)
          .attr("class", result.duplicate ? "duplicate arc" : "arc")
        .transition()
          .duration(500)
          .style("stroke-opacity", 0)
          .remove();
    }, 100);
  }
 });

 </script>
diff --git a/thumbnail.png b/thumbnail.png
diff --git a/us.json b/us.json
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>

	.mesh {
	fill: none;
	stroke: #333;
	stroke-width: .5px;
	stroke-linejoin: round;
	}

	.play circle {
	fill: white;
	stroke: black;
	stroke-width: 3px;
	}

	.play:hover path {
	fill: red;
	}

	.play.mousedown circle {
	fill: red;
	}

	.play.mousedown path {
	fill: white;
	}

	.play rect {
	fill: none;
	pointer-events: all;
	cursor: pointer;
	}

	.arc {
	fill: none;
	stroke-width: 3px;
	stroke-linejoin: round;
	stroke-linecap: round;
	stroke: red;
	}

	.duplicate.arc {
	stroke: blue;
	}

	</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;

	var color = d3.scale.category10();

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

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

	d3.json("us.json", function(error, us) {
	if (error) throw error;

	svg.append("path")
	.datum(topojson.mesh(us))
	.attr("class", "mesh")
	.attr("d", path);

	var play = svg.append("g")
	.attr("class", "play");

	play.append("circle")
	.attr("r", 45)
	.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

	play.append("path")
	.attr("d", "M-22,-30l60,30l-60,30z")
	.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")scale(.7)");

	play.append("rect")
	.attr("width", width)
	.attr("height", height)
	.on("mousedown", function() {
	play.classed("mousedown", true);
	d3.select(window).on("mouseup", function() { play.classed("mousedown", false); });
	})
	.on("click", function() {
	resetAll();
	animation();
	});

	function resetAll() {
	play.style("display", null);
	}

	function animation() {
	play.style("display", "none");

	var results = [],
	indexes = d3.set();

	us.objects.states.geometries.forEach(function(d) {
	if (d.type === "Polygon") extractPolygon(d.arcs);
	else d.arcs.forEach(extractPolygon);
	});

	results.reverse();

	function extractPolygon(arcs) {
	arcs.forEach(extractRing);
	}

	function extractRing(arcs) {
	for (var i = 0, n = arcs.length; i < n; ++i) {
	var index = arcs[i];
	if (index < 0) index = ~index;
	results.push({
	coordinates: arc(index),
	duplicate: indexes.has(index)
	});
	indexes.add(index);
	}
	}

	function arc(index) {
	var x = 0, y = 0, arc = us.arcs[index < 0 ? ~index : index].map(function(point) {
	return [
	(x += point[0]) * us.transform.scale[0] + us.transform.translate[0],
	(y += point[1]) * us.transform.scale[1] + us.transform.translate[1]
	];
	});
	return index < 0 ? arc.reverse() : arc;
	}

	var interval = setInterval(function() {
	var result = results.pop();
	if (!result) return clearInterval(interval), setTimeout(resetAll, 750);
	svg.append("path")
	.datum({type: "LineString", coordinates: result.coordinates})
	.attr("d", path)
	.attr("class", result.duplicate ? "duplicate arc" : "arc")
	.transition()
	.duration(500)
	.style("stroke-opacity", 0)
	.remove();
	}, 100);
	}
	});

	</script>