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venn diagram normalization code 
Different algorithms can produce different looking output that is equally
correct. This code attempts to remove the major differences by axis aligning
the major sets, taking the mirror image if needed, and re-arranging all the
disjoint clusters so that they are close to one another (in a rough grid
pattern).
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@benfred
benfred committed Jun 21, 2015
1 parent 3d281c9 commit 0f9b02c
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Showing 7 changed files with 791 additions and 25 deletions.
20 changes: 18 additions & 2 deletions src/diagram.js
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Expand Up @@ -5,14 +5,19 @@
height = 350,
padding = 15,
duration = 1000,
orientation = Math.PI / 2,
normalize = true,
fontSize = null,
colours = d3.scale.category10(),
layoutFunction = venn.venn;

function chart(selection) {
selection.each(function(data) {
// calculate circle position, scale to fit
var circles = venn.scaleSolution(layoutFunction(data), width, height, padding);
var solution = layoutFunction(data);
if (normalize) {
solution = venn.normalizeSolution(solution, orientation);
}
var circles = venn.scaleSolution(solution, width, height, padding);
var textCentres = computeTextCentres(circles, data);

// draw out a svg
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return chart;
};

chart.normalize = function(_) {
if (!arguments.length) return normalize;
normalize = _;
return chart;
};
chart.orientation = function(_) {
if (!arguments.length) return orientation;
orientation = _;
return chart;
};

return chart;
};
// sometimes text doesn't fit inside the circle, if thats the case lets wrap
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208 changes: 198 additions & 10 deletions src/layout.js
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Expand Up @@ -288,6 +288,201 @@
return output;
};

// orientates a bunch of circles to point in orientation
function orientateCircles(circles, orientation) {
// sort circles by size
circles.sort(function (a, b) { return b.radius - a.radius; });

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;
}
}

// rotate circles so that second largest is at an angle of 'orientation'
// from largest
if (circles.length > 1) {
var rotation = Math.atan2(circles[1].x, circles[1].y) - orientation,
c = Math.cos(rotation),
s = Math.sin(rotation), x, y;

for (i = 0; i < circles.length; ++i) {
x = circles[i].x;
y = circles[i].y;
circles[i].x = c * x - s * y;
circles[i].y = s * x + c * y;
}
}

// mirror solution if third solution is above plane specified by
// first two circles
if (circles.length > 2) {
var angle = Math.atan2(circles[2].x, circles[2].y) - orientation;
while (angle < 0) { angle += 2* Math.PI; }
while (angle > 2*Math.PI) { angle -= 2* Math.PI; }
if (angle > Math.PI) {
var slope = circles[1].y / (1e-10 + circles[1].x);
for (i = 0; i < circles.length; ++i) {
var d = (circles[i].x + slope * circles[i].y) / (1 + slope*slope);
circles[i].x = 2 * d - circles[i].x;
circles[i].y = 2 * d * slope - circles[i].y;
}
}
}
}

venn.disjointCluster = function(circles) {
// union-find clustering to get disjoint sets
circles.map(function(circle) { circle.parent = circle; });

// path compression step in union find
function find(circle) {
if (circle.parent !== circle) {
circle.parent = find(circle.parent);
}
return circle.parent;
}

function union(x, y) {
var xRoot = find(x), yRoot = find(y);
xRoot.parent = yRoot;
}

// get the union of all overlapping sets
for (var i = 0; i < circles.length; ++i) {
for (var j = i + 1; j < circles.length; ++j) {
var maxDistance = circles[i].radius + circles[j].radius;
if (venn.distance(circles[i], circles[j]) + 1e-10 < maxDistance) {
union(circles[j], circles[i]);
}
}
}

// find all the disjoint clusters and group them together
var disjointClusters = {}, setid;
for (i = 0; i < circles.length; ++i) {
setid = find(circles[i]).parent.setid;
if (!(setid in disjointClusters)) {
disjointClusters[setid] = [];
}
disjointClusters[setid].push(circles[i]);
}

// cleanup bookkeeping
circles.map(function(circle) { delete circle.parent; });

// return in more usable form
var ret = [];
for (setid in disjointClusters) {
if (disjointClusters.hasOwnProperty(setid)) {
ret.push(disjointClusters[setid]);
}
}
return ret;
};

function getBoundingBox(circles) {
var minMax = function(d) {
var hi = Math.max.apply(null, circles.map(
function(c) { return c[d] + c.radius; } )),
lo = Math.min.apply(null, circles.map(
function(c) { return c[d] - c.radius;} ));
return {max:hi, min:lo};
};

return {xRange: minMax('x'), yRange: minMax('y')};
}

venn.normalizeSolution = function(solution, orientation) {
orientation = orientation || Math.PI/2;

// work with a list instead of a dictionary, and take a copy so we
// don't mutate input
var circles = [], i, setid;
for (setid in solution) {
if (solution.hasOwnProperty(setid)) {
var previous = solution[setid];
circles.push({x: previous.x,
y: previous.y,
radius: previous.radius,
setid: setid});
}
}

// get all the disjoint clusters
var clusters = venn.disjointCluster(circles);

// orientate all disjoint sets, get sizes
for (i = 0; i < clusters.length; ++i) {
orientateCircles(clusters[i], orientation);
var bounds = getBoundingBox(clusters[i]);
clusters[i].size = (bounds.xRange.max - bounds.xRange.min) * (bounds.yRange.max - bounds.yRange.min);
clusters[i].bounds = bounds;
}
clusters.sort(function(a, b) { return b.size - a.size; });

// orientate the largest at 0,0, and get the bounds
circles = clusters[0];
var returnBounds = circles.bounds;

var spacing = (returnBounds.xRange.max - returnBounds.xRange.min)/50;

function addCluster(cluster, right, bottom) {
if (!cluster) return;

var bounds = cluster.bounds, xOffset, yOffset, centreing;

if (right) {
xOffset = returnBounds.xRange.max - bounds.xRange.min + spacing;
} else {
xOffset = returnBounds.xRange.max - bounds.xRange.max - spacing;
centreing = (bounds.xRange.max - bounds.xRange.min) / 2 -
(returnBounds.xRange.max - returnBounds.xRange.min) / 2;
if (centreing < 0) xOffset += centreing;
}

if (bottom) {
yOffset = returnBounds.yRange.max - bounds.yRange.min + spacing;
} else {
yOffset = returnBounds.yRange.max - bounds.yRange.max - spacing;
centreing = (bounds.yRange.max - bounds.yRange.min) / 2 -
(returnBounds.yRange.max - returnBounds.yRange.min) / 2;
if (centreing < 0) yOffset += centreing;
}

for (var j = 0; j < cluster.length; ++j) {
cluster[j].x += xOffset;
cluster[j].y += yOffset;
circles.push(cluster[j]);
}
}

var index = 1;
while (index < clusters.length) {
addCluster(clusters[index], true, false);
addCluster(clusters[index+1], false, true);
addCluster(clusters[index+2], true, true);
index += 3;

// have one cluster (in top left). lay out next three relative
// to it in a grid
returnBounds = getBoundingBox(circles);
}

// convert back to solution form
var ret = {};
for (i = 0; i < circles.length; ++i) {
ret[circles[i].setid] = circles[i];
}
return ret;
};

/** Scales a solution from venn.venn or venn.greedyLayout such that it fits in
a rectangle of width/height - with padding around the borders. also
centers the diagram in the available space at the same time */
Expand All @@ -300,19 +495,12 @@
}
}

var minMax = function(d) {
var hi = Math.max.apply(null, circles.map(
function(c) { return c[d] + c.radius; } )),
lo = Math.min.apply(null, circles.map(
function(c) { return c[d] - c.radius;} ));
return {max:hi, min:lo};
};

width -= 2*padding;
height -= 2*padding;

var xRange = minMax('x'),
yRange = minMax('y'),
var bounds = getBoundingBox(circles),
xRange = bounds.xRange,
yRange = bounds.yRange,
xScaling = width / (xRange.max - xRange.min),
yScaling = height / (yRange.max - yRange.min),
scaling = Math.min(yScaling, xScaling),
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