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@mbostock
Last active November 8, 2019 07:36
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Ring Cutting
license: gpl-3.0
<!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;
}
.before,
.after {
fill: none;
stroke-width: 3px;
stroke-linejoin: round;
stroke-linecap: round;
}
.before {
stroke: red;
}
.after {
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 cuts = [];
us.objects.states.geometries.forEach(function(d) {
if (d.type === "Polygon") extractPolygon(d.arcs);
else d.arcs.forEach(extractPolygon);
});
cuts.reverse();
function extractPolygon(arcs) {
arcs.forEach(extractRing);
}
function extractRing(arcs) {
for (var i = 1, n = arcs.length; i < n; ++i) {
cuts.push([arc(arcs[i - 1]), d3.merge(arcs.slice(i, n).map(arc))]);
}
}
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 cut = cuts.pop();
if (!cut) return clearInterval(interval), setTimeout(resetAll, 750);
var g = svg.append("g")
.attr("class", "cut");
g.selectAll("path")
.data(cut)
.enter().append("path")
.datum(function(d) { return {type: "LineString", coordinates: d}; })
.attr("d", path)
.attr("class", function(d, i) { return i ? "after" : "before"; });
g.transition()
.duration(500)
.style("stroke-opacity", 0)
.remove();
}, 100);
}
});
</script>
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