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chord.js
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chord.js
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d3.layout.chord = function() {
var chord = {},
chords,
groups,
matrix,
n,
padding = 0,
sortGroups,
sortSubgroups,
sortChords;
function relayout() {
var subgroups = {},
groupSums = [],
groupIndex = d3.range(n),
subgroupIndex = [],
k,
x,
x0,
i,
j;
chords = [];
groups = [];
// Compute the sum.
k = 0, i = -1; while (++i < n) {
x = 0, j = -1; while (++j < n) {
x += matrix[i][j];
}
groupSums.push(x);
subgroupIndex.push(d3.range(n));
k += x;
}
// Sort groups…
if (sortGroups) {
groupIndex.sort(function(a, b) {
return sortGroups(groupSums[a], groupSums[b]);
});
}
// Sort subgroups…
if (sortSubgroups) {
subgroupIndex.forEach(function(d, i) {
d.sort(function(a, b) {
return sortSubgroups(matrix[i][a], matrix[i][b]);
});
});
}
// Convert the sum to scaling factor for [0, 2pi].
// TODO Allow start and end angle to be specified.
// TODO Allow padding to be specified as percentage?
k = (2 * Math.PI - padding * n) / k;
// Compute the start and end angle for each group and subgroup.
x = 0, i = -1; while (++i < n) {
x0 = x, j = -1; while (++j < n) {
var di = groupIndex[i],
dj = subgroupIndex[di][j],
v = matrix[di][dj];
subgroups[di + "-" + dj] = {
index: di,
subindex: dj,
startAngle: x,
endAngle: x += v * k,
value: v
};
}
groups.push({
index: di,
startAngle: x0,
endAngle: x,
value: (x - x0) / k
});
x += padding;
}
// Generate chords for each (non-empty) subgroup-subgroup link.
i = -1; while (++i < n) {
j = i - 1; while (++j < n) {
var source = subgroups[i + "-" + j],
target = subgroups[j + "-" + i];
if (source.value || target.value) {
chords.push(source.value < target.value
? {source: target, target: source}
: {source: source, target: target});
}
}
}
if (sortChords) resort();
}
function resort() {
chords.sort(function(a, b) {
return sortChords(
(a.source.value + a.target.value) / 2,
(b.source.value + b.target.value) / 2);
});
}
chord.matrix = function(x) {
if (!arguments.length) return matrix;
n = (matrix = x) && matrix.length;
chords = groups = null;
return chord;
};
chord.padding = function(x) {
if (!arguments.length) return padding;
padding = x;
chords = groups = null;
return chord;
};
chord.sortGroups = function(x) {
if (!arguments.length) return sortGroups;
sortGroups = x;
chords = groups = null;
return chord;
};
chord.sortSubgroups = function(x) {
if (!arguments.length) return sortSubgroups;
sortSubgroups = x;
chords = null;
return chord;
};
chord.sortChords = function(x) {
if (!arguments.length) return sortChords;
sortChords = x;
if (chords) resort();
return chord;
};
chord.chords = function() {
if (!chords) relayout();
return chords;
};
chord.groups = function() {
if (!groups) relayout();
return groups;
};
return chord;
};