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venn.js
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venn.js
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(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('d3-selection'), require('d3-transition')) :
typeof define === 'function' && define.amd ? define(['exports', 'd3-selection', 'd3-transition'], factory) :
(factory((global.venn = {}),global.d3,global.d3));
}(this, (function (exports,d3Selection,d3Transition) { 'use strict';
var SMALL = 1e-10;
/** Returns the intersection area of a bunch of circles (where each circle
is an object having an x,y and radius property) */
function intersectionArea(circles, stats) {
// get all the intersection points of the circles
var intersectionPoints = getIntersectionPoints(circles);
// filter out points that aren't included in all the circles
var innerPoints = intersectionPoints.filter(function (p) {
return containedInCircles(p, circles);
});
var arcArea = 0, polygonArea = 0, arcs = [], i;
// if we have intersection points that are within all the circles,
// then figure out the area contained by them
if (innerPoints.length > 1) {
// sort the points by angle from the center of the polygon, which lets
// us just iterate over points to get the edges
var center = getCenter(innerPoints);
for (i = 0; i < innerPoints.length; ++i ) {
var p = innerPoints[i];
p.angle = Math.atan2(p.x - center.x, p.y - center.y);
}
innerPoints.sort(function(a,b) { return b.angle - a.angle;});
// iterate over all points, get arc between the points
// and update the areas
var p2 = innerPoints[innerPoints.length - 1];
for (i = 0; i < innerPoints.length; ++i) {
var p1 = innerPoints[i];
// polygon area updates easily ...
polygonArea += (p2.x + p1.x) * (p1.y - p2.y);
// updating the arc area is a little more involved
var midPoint = {x : (p1.x + p2.x) / 2,
y : (p1.y + p2.y) / 2},
arc = null;
for (var j = 0; j < p1.parentIndex.length; ++j) {
if (p2.parentIndex.indexOf(p1.parentIndex[j]) > -1) {
// figure out the angle halfway between the two points
// on the current circle
var circle = circles[p1.parentIndex[j]],
a1 = Math.atan2(p1.x - circle.x, p1.y - circle.y),
a2 = Math.atan2(p2.x - circle.x, p2.y - circle.y);
var angleDiff = (a2 - a1);
if (angleDiff < 0) {
angleDiff += 2*Math.PI;
}
// and use that angle to figure out the width of the
// arc
var a = a2 - angleDiff/2,
width = distance(midPoint, {
x : circle.x + circle.radius * Math.sin(a),
y : circle.y + circle.radius * Math.cos(a)
});
// clamp the width to the largest is can actually be
// (sometimes slightly overflows because of FP errors)
if (width > circle.radius * 2) {
width = circle.radius * 2;
}
// pick the circle whose arc has the smallest width
if ((arc === null) || (arc.width > width)) {
arc = { circle : circle,
width : width,
p1 : p1,
p2 : p2};
}
}
}
if (arc !== null) {
arcs.push(arc);
arcArea += circleArea(arc.circle.radius, arc.width);
p2 = p1;
}
}
} else {
// no intersection points, is either disjoint - or is completely
// overlapped. figure out which by examining the smallest circle
var smallest = circles[0];
for (i = 1; i < circles.length; ++i) {
if (circles[i].radius < smallest.radius) {
smallest = circles[i];
}
}
// make sure the smallest circle is completely contained in all
// the other circles
var disjoint = false;
for (i = 0; i < circles.length; ++i) {
if (distance(circles[i], smallest) > Math.abs(smallest.radius - circles[i].radius)) {
disjoint = true;
break;
}
}
if (disjoint) {
arcArea = polygonArea = 0;
} else {
arcArea = smallest.radius * smallest.radius * Math.PI;
arcs.push({circle : smallest,
p1: { x: smallest.x, y : smallest.y + smallest.radius},
p2: { x: smallest.x - SMALL, y : smallest.y + smallest.radius},
width : smallest.radius * 2 });
}
}
polygonArea /= 2;
if (stats) {
stats.area = arcArea + polygonArea;
stats.arcArea = arcArea;
stats.polygonArea = polygonArea;
stats.arcs = arcs;
stats.innerPoints = innerPoints;
stats.intersectionPoints = intersectionPoints;
}
return arcArea + polygonArea;
}
/** returns whether a point is contained by all of a list of circles */
function containedInCircles(point, circles) {
for (var i = 0; i < circles.length; ++i) {
if (distance(point, circles[i]) > circles[i].radius + SMALL) {
return false;
}
}
return true;
}
/** Gets all intersection points between a bunch of circles */
function getIntersectionPoints(circles) {
var ret = [];
for (var i = 0; i < circles.length; ++i) {
for (var j = i + 1; j < circles.length; ++j) {
var intersect = circleCircleIntersection(circles[i],
circles[j]);
for (var k = 0; k < intersect.length; ++k) {
var p = intersect[k];
p.parentIndex = [i,j];
ret.push(p);
}
}
}
return ret;
}
/** Circular segment area calculation. See http://mathworld.wolfram.com/CircularSegment.html */
function circleArea(r, width) {
return r * r * Math.acos(1 - width/r) - (r - width) * Math.sqrt(width * (2 * r - width));
}
/** euclidean distance between two points */
function distance(p1, p2) {
return Math.sqrt((p1.x - p2.x) * (p1.x - p2.x) +
(p1.y - p2.y) * (p1.y - p2.y));
}
/** Returns the overlap area of two circles of radius r1 and r2 - that
have their centers separated by distance d. Simpler faster
circle intersection for only two circles */
function circleOverlap(r1, r2, d) {
// no overlap
if (d >= r1 + r2) {
return 0;
}
// completely overlapped
if (d <= Math.abs(r1 - r2)) {
return Math.PI * Math.min(r1, r2) * Math.min(r1, r2);
}
var w1 = r1 - (d * d - r2 * r2 + r1 * r1) / (2 * d),
w2 = r2 - (d * d - r1 * r1 + r2 * r2) / (2 * d);
return circleArea(r1, w1) + circleArea(r2, w2);
}
/** Given two circles (containing a x/y/radius attributes),
returns the intersecting points if possible.
note: doesn't handle cases where there are infinitely many
intersection points (circles are equivalent):, or only one intersection point*/
function circleCircleIntersection(p1, p2) {
var d = distance(p1, p2),
r1 = p1.radius,
r2 = p2.radius;
// if to far away, or self contained - can't be done
if ((d >= (r1 + r2)) || (d <= Math.abs(r1 - r2))) {
return [];
}
var a = (r1 * r1 - r2 * r2 + d * d) / (2 * d),
h = Math.sqrt(r1 * r1 - a * a),
x0 = p1.x + a * (p2.x - p1.x) / d,
y0 = p1.y + a * (p2.y - p1.y) / d,
rx = -(p2.y - p1.y) * (h / d),
ry = -(p2.x - p1.x) * (h / d);
return [{x: x0 + rx, y : y0 - ry },
{x: x0 - rx, y : y0 + ry }];
}
/** Returns the center of a bunch of points */
function getCenter(points) {
var center = {x: 0, y: 0};
for (var i =0; i < points.length; ++i ) {
center.x += points[i].x;
center.y += points[i].y;
}
center.x /= points.length;
center.y /= points.length;
return center;
}
/** finds the zeros of a function, given two starting points (which must
* have opposite signs */
function bisect(f, a, b, parameters) {
parameters = parameters || {};
var maxIterations = parameters.maxIterations || 100,
tolerance = parameters.tolerance || 1e-10,
fA = f(a),
fB = f(b),
delta = b - a;
if (fA * fB > 0) {
throw "Initial bisect points must have opposite signs";
}
if (fA === 0) return a;
if (fB === 0) return b;
for (var i = 0; i < maxIterations; ++i) {
delta /= 2;
var mid = a + delta,
fMid = f(mid);
if (fMid * fA >= 0) {
a = mid;
}
if ((Math.abs(delta) < tolerance) || (fMid === 0)) {
return mid;
}
}
return a + delta;
}
// need some basic operations on vectors, rather than adding a dependency,
// just define here
function zeros(x) { var r = new Array(x); for (var i = 0; i < x; ++i) { r[i] = 0; } return r; }
function zerosM(x,y) { return zeros(x).map(function() { return zeros(y); }); }
function dot(a, b) {
var ret = 0;
for (var i = 0; i < a.length; ++i) {
ret += a[i] * b[i];
}
return ret;
}
function norm2(a) {
return Math.sqrt(dot(a, a));
}
function scale(ret, value, c) {
for (var i = 0; i < value.length; ++i) {
ret[i] = value[i] * c;
}
}
function weightedSum(ret, w1, v1, w2, v2) {
for (var j = 0; j < ret.length; ++j) {
ret[j] = w1 * v1[j] + w2 * v2[j];
}
}
/** minimizes a function using the downhill simplex method */
function nelderMead(f, x0, parameters) {
parameters = parameters || {};
var maxIterations = parameters.maxIterations || x0.length * 200,
nonZeroDelta = parameters.nonZeroDelta || 1.05,
zeroDelta = parameters.zeroDelta || 0.001,
minErrorDelta = parameters.minErrorDelta || 1e-6,
minTolerance = parameters.minErrorDelta || 1e-5,
rho = (parameters.rho !== undefined) ? parameters.rho : 1,
chi = (parameters.chi !== undefined) ? parameters.chi : 2,
psi = (parameters.psi !== undefined) ? parameters.psi : -0.5,
sigma = (parameters.sigma !== undefined) ? parameters.sigma : 0.5,
maxDiff;
// initialize simplex.
var N = x0.length,
simplex = new Array(N + 1);
simplex[0] = x0;
simplex[0].fx = f(x0);
simplex[0].id = 0;
for (var i = 0; i < N; ++i) {
var point = x0.slice();
point[i] = point[i] ? point[i] * nonZeroDelta : zeroDelta;
simplex[i+1] = point;
simplex[i+1].fx = f(point);
simplex[i+1].id = i+1;
}
function updateSimplex(value) {
for (var i = 0; i < value.length; i++) {
simplex[N][i] = value[i];
}
simplex[N].fx = value.fx;
}
var sortOrder = function(a, b) { return a.fx - b.fx; };
var centroid = x0.slice(),
reflected = x0.slice(),
contracted = x0.slice(),
expanded = x0.slice();
for (var iteration = 0; iteration < maxIterations; ++iteration) {
simplex.sort(sortOrder);
if (parameters.history) {
// copy the simplex (since later iterations will mutate) and
// sort it to have a consistent order between iterations
var sortedSimplex = simplex.map(function (x) {
var state = x.slice();
state.fx = x.fx;
state.id = x.id;
return state;
});
sortedSimplex.sort(function(a,b) { return a.id - b.id; });
parameters.history.push({x: simplex[0].slice(),
fx: simplex[0].fx,
simplex: sortedSimplex});
}
maxDiff = 0;
for (i = 0; i < N; ++i) {
maxDiff = Math.max(maxDiff, Math.abs(simplex[0][i] - simplex[1][i]));
}
if ((Math.abs(simplex[0].fx - simplex[N].fx) < minErrorDelta) &&
(maxDiff < minTolerance)) {
break;
}
// compute the centroid of all but the worst point in the simplex
for (i = 0; i < N; ++i) {
centroid[i] = 0;
for (var j = 0; j < N; ++j) {
centroid[i] += simplex[j][i];
}
centroid[i] /= N;
}
// reflect the worst point past the centroid and compute loss at reflected
// point
var worst = simplex[N];
weightedSum(reflected, 1+rho, centroid, -rho, worst);
reflected.fx = f(reflected);
// if the reflected point is the best seen, then possibly expand
if (reflected.fx < simplex[0].fx) {
weightedSum(expanded, 1+chi, centroid, -chi, worst);
expanded.fx = f(expanded);
if (expanded.fx < reflected.fx) {
updateSimplex(expanded);
} else {
updateSimplex(reflected);
}
}
// if the reflected point is worse than the second worst, we need to
// contract
else if (reflected.fx >= simplex[N-1].fx) {
var shouldReduce = false;
if (reflected.fx > worst.fx) {
// do an inside contraction
weightedSum(contracted, 1+psi, centroid, -psi, worst);
contracted.fx = f(contracted);
if (contracted.fx < worst.fx) {
updateSimplex(contracted);
} else {
shouldReduce = true;
}
} else {
// do an outside contraction
weightedSum(contracted, 1-psi * rho, centroid, psi*rho, worst);
contracted.fx = f(contracted);
if (contracted.fx < reflected.fx) {
updateSimplex(contracted);
} else {
shouldReduce = true;
}
}
if (shouldReduce) {
// if we don't contract here, we're done
if (sigma >= 1) break;
// do a reduction
for (i = 1; i < simplex.length; ++i) {
weightedSum(simplex[i], 1 - sigma, simplex[0], sigma, simplex[i]);
simplex[i].fx = f(simplex[i]);
}
}
} else {
updateSimplex(reflected);
}
}
simplex.sort(sortOrder);
return {fx : simplex[0].fx,
x : simplex[0]};
}
/// searches along line 'pk' for a point that satifies the wolfe conditions
/// See 'Numerical Optimization' by Nocedal and Wright p59-60
/// f : objective function
/// pk : search direction
/// current: object containing current gradient/loss
/// next: output: contains next gradient/loss
/// returns a: step size taken
function wolfeLineSearch(f, pk, current, next, a, c1, c2) {
var phi0 = current.fx, phiPrime0 = dot(current.fxprime, pk),
phi = phi0, phi_old = phi0,
phiPrime = phiPrime0,
a0 = 0;
a = a || 1;
c1 = c1 || 1e-6;
c2 = c2 || 0.1;
function zoom(a_lo, a_high, phi_lo) {
for (var iteration = 0; iteration < 16; ++iteration) {
a = (a_lo + a_high)/2;
weightedSum(next.x, 1.0, current.x, a, pk);
phi = next.fx = f(next.x, next.fxprime);
phiPrime = dot(next.fxprime, pk);
if ((phi > (phi0 + c1 * a * phiPrime0)) ||
(phi >= phi_lo)) {
a_high = a;
} else {
if (Math.abs(phiPrime) <= -c2 * phiPrime0) {
return a;
}
if (phiPrime * (a_high - a_lo) >=0) {
a_high = a_lo;
}
a_lo = a;
phi_lo = phi;
}
}
return 0;
}
for (var iteration = 0; iteration < 10; ++iteration) {
weightedSum(next.x, 1.0, current.x, a, pk);
phi = next.fx = f(next.x, next.fxprime);
phiPrime = dot(next.fxprime, pk);
if ((phi > (phi0 + c1 * a * phiPrime0)) ||
(iteration && (phi >= phi_old))) {
return zoom(a0, a, phi_old);
}
if (Math.abs(phiPrime) <= -c2 * phiPrime0) {
return a;
}
if (phiPrime >= 0 ) {
return zoom(a, a0, phi);
}
phi_old = phi;
a0 = a;
a *= 2;
}
return a;
}
function conjugateGradient(f, initial, params) {
// allocate all memory up front here, keep out of the loop for perfomance
// reasons
var current = {x: initial.slice(), fx: 0, fxprime: initial.slice()},
next = {x: initial.slice(), fx: 0, fxprime: initial.slice()},
yk = initial.slice(),
pk, temp,
a = 1,
maxIterations;
params = params || {};
maxIterations = params.maxIterations || initial.length * 20;
current.fx = f(current.x, current.fxprime);
pk = current.fxprime.slice();
scale(pk, current.fxprime,-1);
for (var i = 0; i < maxIterations; ++i) {
a = wolfeLineSearch(f, pk, current, next, a);
// todo: history in wrong spot?
if (params.history) {
params.history.push({x: current.x.slice(),
fx: current.fx,
fxprime: current.fxprime.slice(),
alpha: a});
}
if (!a) {
// faiiled to find point that satifies wolfe conditions.
// reset direction for next iteration
scale(pk, current.fxprime, -1);
} else {
// update direction using Polak–Ribiere CG method
weightedSum(yk, 1, next.fxprime, -1, current.fxprime);
var delta_k = dot(current.fxprime, current.fxprime),
beta_k = Math.max(0, dot(yk, next.fxprime) / delta_k);
weightedSum(pk, beta_k, pk, -1, next.fxprime);
temp = current;
current = next;
next = temp;
}
if (norm2(current.fxprime) <= 1e-5) {
break;
}
}
if (params.history) {
params.history.push({x: current.x.slice(),
fx: current.fx,
fxprime: current.fxprime.slice(),
alpha: a});
}
return current;
}
/** given a list of set objects, and their corresponding overlaps.
updates the (x, y, radius) attribute on each set such that their positions
roughly correspond to the desired overlaps */
function venn(areas, parameters) {
parameters = parameters || {};
parameters.maxIterations = parameters.maxIterations || 500;
var initialLayout = parameters.initialLayout || bestInitialLayout;
var loss = parameters.lossFunction || lossFunction;
// add in missing pairwise areas as having 0 size
areas = addMissingAreas(areas);
// initial layout is done greedily
var circles = initialLayout(areas, parameters);
// transform x/y coordinates to a vector to optimize
var initial = [], setids = [], setid;
for (setid in circles) {
if (circles.hasOwnProperty(setid)) {
initial.push(circles[setid].x);
initial.push(circles[setid].y);
setids.push(setid);
}
}
var solution = nelderMead(
function(values) {
var current = {};
for (var i = 0; i < setids.length; ++i) {
var setid = setids[i];
current[setid] = {x: values[2 * i],
y: values[2 * i + 1],
radius : circles[setid].radius,
// size : circles[setid].size
};
}
return loss(current, areas);
},
initial,
parameters);
// transform solution vector back to x/y points
var positions = solution.x;
for (var i = 0; i < setids.length; ++i) {
setid = setids[i];
circles[setid].x = positions[2 * i];
circles[setid].y = positions[2 * i + 1];
}
return circles;
}
var SMALL$1 = 1e-10;
/** Returns the distance necessary for two circles of radius r1 + r2 to
have the overlap area 'overlap' */
function distanceFromIntersectArea(r1, r2, overlap) {
// handle complete overlapped circles
if (Math.min(r1, r2) * Math.min(r1,r2) * Math.PI <= overlap + SMALL$1) {
return Math.abs(r1 - r2);
}
return bisect(function(distance$$1) {
return circleOverlap(r1, r2, distance$$1) - overlap;
}, 0, r1 + r2);
}
/** Missing pair-wise intersection area data can cause problems:
treating as an unknown means that sets will be laid out overlapping,
which isn't what people expect. To reflect that we want disjoint sets
here, set the overlap to 0 for all missing pairwise set intersections */
function addMissingAreas(areas) {
areas = areas.slice();
// two circle intersections that aren't defined
var ids = [], pairs = {}, i, j, a, b;
for (i = 0; i < areas.length; ++i) {
var area = areas[i];
if (area.sets.length == 1) {
ids.push(area.sets[0]);
} else if (area.sets.length == 2) {
a = area.sets[0];
b = area.sets[1];
pairs[[a, b]] = true;
pairs[[b, a]] = true;
}
}
ids.sort(function(a, b) { return a > b; });
for (i = 0; i < ids.length; ++i) {
a = ids[i];
for (j = i + 1; j < ids.length; ++j) {
b = ids[j];
if (!([a, b] in pairs)) {
areas.push({'sets': [a, b],
'size': 0});
}
}
}
return areas;
}
/// Returns two matrices, one of the euclidean distances between the sets
/// and the other indicating if there are subset or disjoint set relationships
function getDistanceMatrices(areas, sets, setids) {
// initialize an empty distance matrix between all the points
var distances = zerosM(sets.length, sets.length),
constraints = zerosM(sets.length, sets.length);
// compute required distances between all the sets such that
// the areas match
areas.filter(function(x) { return x.sets.length == 2; })
.map(function(current) {
var left = setids[current.sets[0]],
right = setids[current.sets[1]],
r1 = Math.sqrt(sets[left].size / Math.PI),
r2 = Math.sqrt(sets[right].size / Math.PI),
distance$$1 = distanceFromIntersectArea(r1, r2, current.size);
distances[left][right] = distances[right][left] = distance$$1;
// also update constraints to indicate if its a subset or disjoint
// relationship
var c = 0;
if (current.size + 1e-10 >= Math.min(sets[left].size,
sets[right].size)) {
c = 1;
} else if (current.size <= 1e-10) {
c = -1;
}
constraints[left][right] = constraints[right][left] = c;
});
return {distances: distances, constraints: constraints};
}
/// computes the gradient and loss simulatenously for our constrained MDS optimizer
function constrainedMDSGradient(x, fxprime, distances, constraints) {
var loss = 0, i;
for (i = 0; i < fxprime.length; ++i) {
fxprime[i] = 0;
}
for (i = 0; i < distances.length; ++i) {
var xi = x[2 * i], yi = x[2 * i + 1];
for (var j = i + 1; j < distances.length; ++j) {
var xj = x[2 * j], yj = x[2 * j + 1],
dij = distances[i][j],
constraint = constraints[i][j];
var squaredDistance = (xj - xi) * (xj - xi) + (yj - yi) * (yj - yi),
distance$$1 = Math.sqrt(squaredDistance),
delta = squaredDistance - dij * dij;
if (((constraint > 0) && (distance$$1 <= dij)) ||
((constraint < 0) && (distance$$1 >= dij))) {
continue;
}
loss += 2 * delta * delta;
fxprime[2*i] += 4 * delta * (xi - xj);
fxprime[2*i + 1] += 4 * delta * (yi - yj);
fxprime[2*j] += 4 * delta * (xj - xi);
fxprime[2*j + 1] += 4 * delta * (yj - yi);
}
}
return loss;
}
/// takes the best working variant of either constrained MDS or greedy
function bestInitialLayout(areas, params) {
var initial = greedyLayout(areas, params);
var loss = params.lossFunction || lossFunction;
// greedylayout is sufficient for all 2/3 circle cases. try out
// constrained MDS for higher order problems, take its output
// if it outperforms. (greedy is aesthetically better on 2/3 circles
// since it axis aligns)
if (areas.length >= 8) {
var constrained = constrainedMDSLayout(areas, params),
constrainedLoss = loss(constrained, areas),
greedyLoss = loss(initial, areas);
if (constrainedLoss + 1e-8 < greedyLoss) {
initial = constrained;
}
}
return initial;
}
/// use the constrained MDS variant to generate an initial layout
function constrainedMDSLayout(areas, params) {
params = params || {};
var restarts = params.restarts || 10;
// bidirectionally map sets to a rowid (so we can create a matrix)
var sets = [], setids = {}, i;
for (i = 0; i < areas.length; ++i ) {
var area = areas[i];
if (area.sets.length == 1) {
setids[area.sets[0]] = sets.length;
sets.push(area);
}
}
var matrices = getDistanceMatrices(areas, sets, setids),
distances = matrices.distances,
constraints = matrices.constraints;
// keep distances bounded, things get messed up otherwise.
// TODO: proper preconditioner?
var norm = norm2(distances.map(norm2))/(distances.length);
distances = distances.map(function (row) {
return row.map(function (value) { return value / norm; });});
var obj = function(x, fxprime) {
return constrainedMDSGradient(x, fxprime, distances, constraints);
};
var best, current;
for (i = 0; i < restarts; ++i) {
var initial = zeros(distances.length*2).map(Math.random);
current = conjugateGradient(obj, initial, params);
if (!best || (current.fx < best.fx)) {
best = current;
}
}
var positions = best.x;
// translate rows back to (x,y,radius) coordinates
var circles = {};
for (i = 0; i < sets.length; ++i) {
var set = sets[i];
circles[set.sets[0]] = {
x: positions[2*i] * norm,
y: positions[2*i + 1] * norm,
radius: Math.sqrt(set.size / Math.PI)
};
}
if (params.history) {
for (i = 0; i < params.history.length; ++i) {
scale(params.history[i].x, norm);
}
}
return circles;
}
/** Lays out a Venn diagram greedily, going from most overlapped sets to
least overlapped, attempting to position each new set such that the
overlapping areas to already positioned sets are basically right */
function greedyLayout(areas, params) {
var loss = params && params.lossFunction ? params.lossFunction : lossFunction;
// define a circle for each set
var circles = {}, setOverlaps = {}, set;
for (var i = 0; i < areas.length; ++i) {
var area = areas[i];
if (area.sets.length == 1) {
set = area.sets[0];
circles[set] = {x: 1e10, y: 1e10,
rowid: circles.length,
size: area.size,
radius: Math.sqrt(area.size / Math.PI)};
setOverlaps[set] = [];
}
}
areas = areas.filter(function(a) { return a.sets.length == 2; });
// map each set to a list of all the other sets that overlap it
for (i = 0; i < areas.length; ++i) {
var current = areas[i];
var weight = current.hasOwnProperty('weight') ? current.weight : 1.0;
var left = current.sets[0], right = current.sets[1];
// completely overlapped circles shouldn't be positioned early here
if (current.size + SMALL$1 >= Math.min(circles[left].size,
circles[right].size)) {
weight = 0;
}
setOverlaps[left].push ({set:right, size:current.size, weight:weight});
setOverlaps[right].push({set:left, size:current.size, weight:weight});
}
// get list of most overlapped sets
var mostOverlapped = [];
for (set in setOverlaps) {
if (setOverlaps.hasOwnProperty(set)) {
var size = 0;
for (i = 0; i < setOverlaps[set].length; ++i) {
size += setOverlaps[set][i].size * setOverlaps[set][i].weight;
}
mostOverlapped.push({set: set, size:size});
}
}
// sort by size desc
function sortOrder(a,b) {
return b.size - a.size;
}
mostOverlapped.sort(sortOrder);
// keep track of what sets have been laid out
var positioned = {};
function isPositioned(element) {
return element.set in positioned;
}
// adds a point to the output
function positionSet(point, index) {
circles[index].x = point.x;
circles[index].y = point.y;
positioned[index] = true;
}
// add most overlapped set at (0,0)
positionSet({x: 0, y: 0}, mostOverlapped[0].set);
// get distances between all points. TODO, necessary?
// answer: probably not
// var distances = venn.getDistanceMatrices(circles, areas).distances;
for (i = 1; i < mostOverlapped.length; ++i) {
var setIndex = mostOverlapped[i].set,
overlap = setOverlaps[setIndex].filter(isPositioned);
set = circles[setIndex];
overlap.sort(sortOrder);
if (overlap.length === 0) {
// this shouldn't happen anymore with addMissingAreas
throw "ERROR: missing pairwise overlap information";
}
var points = [];
for (var j = 0; j < overlap.length; ++j) {
// get appropriate distance from most overlapped already added set
var p1 = circles[overlap[j].set],
d1 = distanceFromIntersectArea(set.radius, p1.radius,
overlap[j].size);
// sample positions at 90 degrees for maximum aesthetics
points.push({x : p1.x + d1, y : p1.y});
points.push({x : p1.x - d1, y : p1.y});
points.push({y : p1.y + d1, x : p1.x});
points.push({y : p1.y - d1, x : p1.x});
// if we have at least 2 overlaps, then figure out where the
// set should be positioned analytically and try those too
for (var k = j + 1; k < overlap.length; ++k) {
var p2 = circles[overlap[k].set],
d2 = distanceFromIntersectArea(set.radius, p2.radius,
overlap[k].size);
var extraPoints = circleCircleIntersection(
{ x: p1.x, y: p1.y, radius: d1},
{ x: p2.x, y: p2.y, radius: d2});
for (var l = 0; l < extraPoints.length; ++l) {
points.push(extraPoints[l]);
}
}
}
// we have some candidate positions for the set, examine loss
// at each position to figure out where to put it at
var bestLoss = 1e50, bestPoint = points[0];
for (j = 0; j < points.length; ++j) {
circles[setIndex].x = points[j].x;
circles[setIndex].y = points[j].y;
var localLoss = loss(circles, areas);
if (localLoss < bestLoss) {
bestLoss = localLoss;
bestPoint = points[j];
}
}
positionSet(bestPoint, setIndex);
}
return circles;
}
/** Given a bunch of sets, and the desired overlaps between these sets - computes
the distance from the actual overlaps to the desired overlaps. Note that
this method ignores overlaps of more than 2 circles */
function lossFunction(sets, overlaps) {
var output = 0;
function getCircles(indices) {
return indices.map(function(i) { return sets[i]; });
}
for (var i = 0; i < overlaps.length; ++i) {
var area = overlaps[i], overlap;
if (area.sets.length == 1) {
continue;
} else if (area.sets.length == 2) {
var left = sets[area.sets[0]],
right = sets[area.sets[1]];
overlap = circleOverlap(left.radius, right.radius,
distance(left, right));
} else {
overlap = intersectionArea(getCircles(area.sets));
}
var weight = area.hasOwnProperty('weight') ? area.weight : 1.0;
output += weight * (overlap - area.size) * (overlap - area.size);
}
return output;
}
// orientates a bunch of circles to point in orientation
function orientateCircles(circles, orientation, orientationOrder) {
if (orientationOrder === null) {
circles.sort(function (a, b) { return b.radius - a.radius; });
} else {
circles.sort(orientationOrder);
}
var i;
// shift circles so largest circle is at (0, 0)
if (circles.length > 0) {
var largestX = circles[0].x,
largestY = circles[0].y;
for (i = 0; i < circles.length; ++i) {
circles[i].x -= largestX;
circles[i].y -= largestY;
}
}