Step 3 of 4 of topology construction. From How To Infer Topology.
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November 8, 2019 07:36
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Ring Cutting
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| license: gpl-3.0 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!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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