Christophe Viau implemented a new shape type as a D3 plugin based on superformulas.
<!DOCTYPE html>
<meta charset="utf-8">
<title>Superformula</title>
<style>
path {
stroke-width: 1.5px;
stroke: #666;
fill: #ddd;
}
#controls {
position: absolute;
width: 240px;
font: 10px sans-serif;
}
#controls span,
#controls label {
position: relative;
top: -5px;
padding: 5px;
display: inline-block;
width: 20px;
}
#controls button {
font: 10px sans-serif;
padding: 5px;
width: 70px;
}
</style>
<div id="controls"></div>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="superformula.js"></script>
<script>
var types = {
asterisk: {m: 12, n1: .3, n2: 0, n3: 10, a: 1, b: 1},
bean: {m: 2, n1: 1, n2: 4, n3: 8, a: 1, b: 1},
butterfly: {m: 3, n1: 1, n2: 6, n3: 2, a: .6, b: 1},
circle: {m: 4, n1: 2, n2: 2, n3: 2, a: 1, b: 1},
clover: {m: 6, n1: .3, n2: 0, n3: 10, a: 1, b: 1},
cloverFour: {m: 8, n1: 10, n2: -1, n3: -8, a: 1, b: 1},
cross: {m: 8, n1: 1.3, n2: .01, n3: 8, a: 1, b: 1},
diamond: {m: 4, n1: 1, n2: 1, n3: 1, a: 1, b: 1},
drop: {m: 1, n1: .5, n2: .5, n3: .5, a: 1, b: 1},
ellipse: {m: 4, n1: 2, n2: 2, n3: 2, a: 9, b: 6},
gear: {m: 19, n1: 100, n2: 50, n3: 50, a: 1, b: 1},
heart: {m: 1, n1: .8, n2: 1, n3: -8, a: 1, b: .18},
heptagon: {m: 7, n1: 1000, n2: 400, n3: 400, a: 1, b: 1},
hexagon: {m: 6, n1: 1000, n2: 400, n3: 400, a: 1, b: 1},
malteseCross: {m: 8, n1: .9, n2: .1, n3: 100, a: 1, b: 1},
pentagon: {m: 5, n1: 1000, n2: 600, n3: 600, a: 1, b: 1},
rectangle: {m: 4, n1: 100, n2: 100, n3: 100, a: 2, b: 1},
roundedStar: {m: 5, n1: 2, n2: 7, n3: 7, a: 1, b: 1},
square: {m: 4, n1: 100, n2: 100, n3: 100, a: 1, b: 1},
star: {m: 5, n1: 30, n2: 100, n3: 100, a: 1, b: 1},
triangle: {m: 3, n1: 100, n2: 200, n3: 200, a: 1, b: 1}
};
var format = d3.format(".4n");
var scale = d3.scale.linear()
.domain([-10, 20, 1000])
.range([0, 800, 1000]);
var svg = d3.select("body")
.append("svg")
.attr("width", 960)
.attr("height", 500);
var shape = d3.superformula()
.type("asterisk")
.size(100000)
.segments(3600);
var path = svg.append("path")
.attr("class", "big")
.attr("transform", "translate(480,250)")
.attr("d", shape);
var control = d3.select("#controls")
.selectAll("div")
.data(d3.entries(types.asterisk))
.enter().append("div")
.attr("id", function(d) { return d.key; });
control.append("label")
.text(function(d) { return d.key; });
control.append("input")
.attr("type", "range")
.attr("max", 1000)
.attr("min", 0)
.property("value", function(d) { return scale(d.value); })
.on("change", changed)
.on("input", changed);
control.append("span")
.text(function(d) { return format(d.value); });
d3.select("#controls")
.append("div")
.selectAll("button")
.data(d3.entries(types))
.enter().append("button")
.text(function(d) { return d.key; })
.on("click", function(d) {
for (var param in d.value) {
var control = d3.select("#" + param);
control.select("input").property("value", scale(d.value[param]));
control.select("span").text(format(d.value[param]));
shape.param(param, d.value[param]);
}
path.attr("d", shape);
});
function changed(d) {
var v = scale.invert(this.value);
path.attr("d", shape.param(d.key, v));
d3.select(this.nextSibling).text(format(v));
}
</script>
(function() {
var _symbol = d3.svg.symbol(),
_line = d3.svg.line();
d3.superformula = function() {
var type = _symbol.type(),
size = _symbol.size(),
segments = size,
params = {};
function superformula(d, i) {
var n, p = _superformulaTypes[type.call(this, d, i)];
for (n in params) p[n] = params[n].call(this, d, i);
return _superformulaPath(p, segments.call(this, d, i), Math.sqrt(size.call(this, d, i)));
}
superformula.type = function(x) {
if (!arguments.length) return type;
type = d3.functor(x);
return superformula;
};
superformula.param = function(name, value) {
if (arguments.length < 2) return params[name];
params[name] = d3.functor(value);
return superformula;
};
// size of superformula in square pixels
superformula.size = function(x) {
if (!arguments.length) return size;
size = d3.functor(x);
return superformula;
};
// number of discrete line segments
superformula.segments = function(x) {
if (!arguments.length) return segments;
segments = d3.functor(x);
return superformula;
};
return superformula;
};
function _superformulaPath(params, n, diameter) {
var i = -1,
dt = 2 * Math.PI / n,
t,
r = 0,
x,
y,
points = [];
while (++i < n) {
t = params.m * (i * dt - Math.PI) / 4;
t = Math.pow(Math.abs(Math.pow(Math.abs(Math.cos(t) / params.a), params.n2)
+ Math.pow(Math.abs(Math.sin(t) / params.b), params.n3)), -1 / params.n1);
if (t > r) r = t;
points.push(t);
}
r = diameter * Math.SQRT1_2 / r;
i = -1; while (++i < n) {
x = (t = points[i] * r) * Math.cos(i * dt);
y = t * Math.sin(i * dt);
points[i] = [Math.abs(x) < 1e-6 ? 0 : x, Math.abs(y) < 1e-6 ? 0 : y];
}
return _line(points) + "Z";
}
var _superformulaTypes = {
asterisk: {m: 12, n1: .3, n2: 0, n3: 10, a: 1, b: 1},
bean: {m: 2, n1: 1, n2: 4, n3: 8, a: 1, b: 1},
butterfly: {m: 3, n1: 1, n2: 6, n3: 2, a: .6, b: 1},
circle: {m: 4, n1: 2, n2: 2, n3: 2, a: 1, b: 1},
clover: {m: 6, n1: .3, n2: 0, n3: 10, a: 1, b: 1},
cloverFour: {m: 8, n1: 10, n2: -1, n3: -8, a: 1, b: 1},
cross: {m: 8, n1: 1.3, n2: .01, n3: 8, a: 1, b: 1},
diamond: {m: 4, n1: 1, n2: 1, n3: 1, a: 1, b: 1},
drop: {m: 1, n1: .5, n2: .5, n3: .5, a: 1, b: 1},
ellipse: {m: 4, n1: 2, n2: 2, n3: 2, a: 9, b: 6},
gear: {m: 19, n1: 100, n2: 50, n3: 50, a: 1, b: 1},
heart: {m: 1, n1: .8, n2: 1, n3: -8, a: 1, b: .18},
heptagon: {m: 7, n1: 1000, n2: 400, n3: 400, a: 1, b: 1},
hexagon: {m: 6, n1: 1000, n2: 400, n3: 400, a: 1, b: 1},
malteseCross: {m: 8, n1: .9, n2: .1, n3: 100, a: 1, b: 1},
pentagon: {m: 5, n1: 1000, n2: 600, n3: 600, a: 1, b: 1},
rectangle: {m: 4, n1: 100, n2: 100, n3: 100, a: 2, b: 1},
roundedStar: {m: 5, n1: 2, n2: 7, n3: 7, a: 1, b: 1},
square: {m: 4, n1: 100, n2: 100, n3: 100, a: 1, b: 1},
star: {m: 5, n1: 30, n2: 100, n3: 100, a: 1, b: 1},
triangle: {m: 3, n1: 100, n2: 200, n3: 200, a: 1, b: 1}
};
d3.superformulaTypes = d3.keys(_superformulaTypes);
})();