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<!DOCTYPE html> |
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<meta charset="utf-8"> |
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<style> |
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body { |
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font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; |
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width: 960px; |
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height: 500px; |
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position: relative; |
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} |
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form { |
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position: absolute; |
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top: 1em; |
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left: 1em; |
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} |
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path { |
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fill-rule: evenodd; |
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stroke: #333; |
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stroke-width: 2px; |
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} |
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.sun path { |
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fill: #6baed6; |
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} |
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.planet path { |
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fill: #9ecae1; |
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} |
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.annulus path { |
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fill: #c6dbef; |
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} |
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</style> |
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<form> |
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<input type="radio" name="reference" id="ref-annulus"> |
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<label for="ref-annulus">Annulus</label><br> |
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<input type="radio" name="reference" id="ref-planet" checked> |
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<label for="ref-planet">Planets</label><br> |
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<input type="radio" name="reference" id="ref-sun"> |
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<label for="ref-sun">Sun</label> |
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</form> |
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<script src="https://d3js.org/d3.v4.min.js"></script> |
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<script> |
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var width = 960, |
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height = 500, |
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radius = 80, |
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x = Math.sin(2 * Math.PI / 3), |
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y = Math.cos(2 * Math.PI / 3); |
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var offset = 0, |
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speed = 4, |
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start = Date.now(); |
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var svg = d3.select("body").append("svg") |
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.attr("width", width) |
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.attr("height", height) |
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.append("g") |
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.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")scale(.55)") |
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.append("g"); |
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var frame = svg.append("g") |
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.datum({radius: Infinity}); |
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frame.append("g") |
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.attr("class", "annulus") |
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.datum({teeth: 80, radius: -radius * 5, annulus: true}) |
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.append("path") |
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.attr("d", gear); |
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frame.append("g") |
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.attr("class", "sun") |
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.datum({teeth: 16, radius: radius}) |
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.append("path") |
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.attr("d", gear); |
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frame.append("g") |
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.attr("class", "planet") |
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.attr("transform", "translate(0,-" + radius * 3 + ")") |
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.datum({teeth: 32, radius: -radius * 2}) |
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.append("path") |
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.attr("d", gear); |
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frame.append("g") |
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.attr("class", "planet") |
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.attr("transform", "translate(" + -radius * 3 * x + "," + -radius * 3 * y + ")") |
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.datum({teeth: 32, radius: -radius * 2}) |
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.append("path") |
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.attr("d", gear); |
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frame.append("g") |
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.attr("class", "planet") |
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.attr("transform", "translate(" + radius * 3 * x + "," + -radius * 3 * y + ")") |
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.datum({teeth: 32, radius: -radius * 2}) |
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.append("path") |
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.attr("d", gear); |
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d3.selectAll("input[name=reference]") |
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.data([radius * 5, Infinity, -radius]) |
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.on("change", function(radius1) { |
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var radius0 = frame.datum().radius, angle = (Date.now() - start) * speed; |
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frame.datum({radius: radius1}); |
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svg.attr("transform", "rotate(" + (offset += angle / radius0 - angle / radius1) + ")"); |
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}); |
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d3.selectAll("input[name=speed]") |
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.on("change", function() { speed = +this.value; }); |
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function gear(d) { |
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var n = d.teeth, |
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r2 = Math.abs(d.radius), |
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r0 = r2 - 8, |
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r1 = r2 + 8, |
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r3 = d.annulus ? (r3 = r0, r0 = r1, r1 = r3, r2 + 20) : 20, |
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da = Math.PI / n, |
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a0 = -Math.PI / 2 + (d.annulus ? Math.PI / n : 0), |
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i = -1, |
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path = ["M", r0 * Math.cos(a0), ",", r0 * Math.sin(a0)]; |
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while (++i < n) path.push( |
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"A", r0, ",", r0, " 0 0,1 ", r0 * Math.cos(a0 += da), ",", r0 * Math.sin(a0), |
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"L", r2 * Math.cos(a0), ",", r2 * Math.sin(a0), |
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"L", r1 * Math.cos(a0 += da / 3), ",", r1 * Math.sin(a0), |
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"A", r1, ",", r1, " 0 0,1 ", r1 * Math.cos(a0 += da / 3), ",", r1 * Math.sin(a0), |
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"L", r2 * Math.cos(a0 += da / 3), ",", r2 * Math.sin(a0), |
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"L", r0 * Math.cos(a0), ",", r0 * Math.sin(a0)); |
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path.push("M0,", -r3, "A", r3, ",", r3, " 0 0,0 0,", r3, "A", r3, ",", r3, " 0 0,0 0,", -r3, "Z"); |
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return path.join(""); |
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} |
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d3.timer(function() { |
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var angle = (Date.now() - start) * speed, |
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transform = function(d) { return "rotate(" + angle / d.radius + ")"; }; |
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frame.selectAll("path").attr("transform", transform); |
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frame.attr("transform", transform); // frame of reference |
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}); |
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</script> |