Compute the convex hull of a set of points with Geometric.js.
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December 20, 2018 22:13
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Convex Hull
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <style> | |
| body { | |
| margin: 0; | |
| } | |
| polygon { | |
| fill: none; | |
| stroke: steelblue; | |
| stroke-width: 2px; | |
| } | |
| text { | |
| font-family: "Helvetica Neue", sans-serif; | |
| font-size: 16px; | |
| pointer-events: none; | |
| text-anchor: middle; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <script src="https://d3js.org/d3.v5.min.js"></script> | |
| <script src="https://unpkg.com/[email protected]/build/geometric.min.js"></script> | |
| <script> | |
| var width = window.innerWidth, height = window.innerHeight, started = false; | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var instructions = svg.append("text") | |
| .attr("x", width / 2) | |
| .attr("y", height / 2) | |
| .text("Hover anywhere to start."); | |
| var polygon = svg.append("polygon"); | |
| var points = []; | |
| svg.on("mousemove", _ => { | |
| if (!started){ | |
| instructions.transition().duration(750) | |
| .attr("x", 10) | |
| .attr("y", 20) | |
| .style("text-anchor", "start") | |
| .text("Click to reset."); | |
| started = true; | |
| } | |
| var p = [d3.event.pageX, d3.event.pageY]; | |
| points.push(p); | |
| svg.append("circle").attr("r", 2).attr("transform", "translate(" + p + ")"); | |
| polygon.attr("points", geometric.polygonHull(points)); | |
| }); | |
| svg.on("click", _ => { | |
| instructions | |
| .transition() | |
| .style("opacity", 1e-6) | |
| .remove(); | |
| d3.selectAll("circle").remove(); | |
| points = []; | |
| polygon.attr("points", null); | |
| }); | |
| </script> | |
| </body> | |
| </html> |
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