836 lines
22 KiB
JavaScript
836 lines
22 KiB
JavaScript
(function(){d3.geom = {};
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/**
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* Computes a contour for a given input grid function using the <a
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* href="http://en.wikipedia.org/wiki/Marching_squares">marching
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* squares</a> algorithm. Returns the contour polygon as an array of points.
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*
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* @param grid a two-input function(x, y) that returns true for values
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* inside the contour and false for values outside the contour.
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* @param start an optional starting point [x, y] on the grid.
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* @returns polygon [[x1, y1], [x2, y2], …]
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*/
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d3.geom.contour = function(grid, start) {
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var s = start || d3_geom_contourStart(grid), // starting point
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c = [], // contour polygon
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x = s[0], // current x position
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y = s[1], // current y position
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dx = 0, // next x direction
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dy = 0, // next y direction
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pdx = NaN, // previous x direction
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pdy = NaN, // previous y direction
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i = 0;
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do {
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// determine marching squares index
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i = 0;
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if (grid(x-1, y-1)) i += 1;
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if (grid(x, y-1)) i += 2;
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if (grid(x-1, y )) i += 4;
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if (grid(x, y )) i += 8;
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// determine next direction
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if (i === 6) {
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dx = pdy === -1 ? -1 : 1;
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dy = 0;
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} else if (i === 9) {
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dx = 0;
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dy = pdx === 1 ? -1 : 1;
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} else {
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dx = d3_geom_contourDx[i];
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dy = d3_geom_contourDy[i];
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}
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// update contour polygon
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if (dx != pdx && dy != pdy) {
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c.push([x, y]);
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pdx = dx;
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pdy = dy;
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}
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x += dx;
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y += dy;
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} while (s[0] != x || s[1] != y);
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return c;
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};
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// lookup tables for marching directions
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var d3_geom_contourDx = [1, 0, 1, 1,-1, 0,-1, 1,0, 0,0,0,-1, 0,-1,NaN],
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d3_geom_contourDy = [0,-1, 0, 0, 0,-1, 0, 0,1,-1,1,1, 0,-1, 0,NaN];
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function d3_geom_contourStart(grid) {
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var x = 0,
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y = 0;
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// search for a starting point; begin at origin
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// and proceed along outward-expanding diagonals
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while (true) {
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if (grid(x,y)) {
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return [x,y];
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}
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if (x === 0) {
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x = y + 1;
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y = 0;
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} else {
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x = x - 1;
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y = y + 1;
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}
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}
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}
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/**
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* Computes the 2D convex hull of a set of points using Graham's scanning
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* algorithm. The algorithm has been implemented as described in Cormen,
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* Leiserson, and Rivest's Introduction to Algorithms. The running time of
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* this algorithm is O(n log n), where n is the number of input points.
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*
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* @param vertices [[x1, y1], [x2, y2], …]
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* @returns polygon [[x1, y1], [x2, y2], …]
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*/
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d3.geom.hull = function(vertices) {
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if (vertices.length < 3) return [];
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var len = vertices.length,
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plen = len - 1,
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points = [],
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stack = [],
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i, j, h = 0, x1, y1, x2, y2, u, v, a, sp;
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// find the starting ref point: leftmost point with the minimum y coord
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for (i=1; i<len; ++i) {
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if (vertices[i][1] < vertices[h][1]) {
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h = i;
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} else if (vertices[i][1] == vertices[h][1]) {
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h = (vertices[i][0] < vertices[h][0] ? i : h);
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}
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}
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// calculate polar angles from ref point and sort
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for (i=0; i<len; ++i) {
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if (i === h) continue;
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y1 = vertices[i][1] - vertices[h][1];
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x1 = vertices[i][0] - vertices[h][0];
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points.push({angle: Math.atan2(y1, x1), index: i});
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}
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points.sort(function(a, b) { return a.angle - b.angle; });
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// toss out duplicate angles
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a = points[0].angle;
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v = points[0].index;
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u = 0;
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for (i=1; i<plen; ++i) {
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j = points[i].index;
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if (a == points[i].angle) {
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// keep angle for point most distant from the reference
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x1 = vertices[v][0] - vertices[h][0];
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y1 = vertices[v][1] - vertices[h][1];
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x2 = vertices[j][0] - vertices[h][0];
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y2 = vertices[j][1] - vertices[h][1];
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if ((x1*x1 + y1*y1) >= (x2*x2 + y2*y2)) {
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points[i].index = -1;
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} else {
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points[u].index = -1;
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a = points[i].angle;
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u = i;
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v = j;
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}
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} else {
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a = points[i].angle;
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u = i;
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v = j;
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}
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}
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// initialize the stack
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stack.push(h);
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for (i=0, j=0; i<2; ++j) {
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if (points[j].index !== -1) {
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stack.push(points[j].index);
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i++;
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}
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}
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sp = stack.length;
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// do graham's scan
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for (; j<plen; ++j) {
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if (points[j].index === -1) continue; // skip tossed out points
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while (!d3_geom_hullCCW(stack[sp-2], stack[sp-1], points[j].index, vertices)) {
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--sp;
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}
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stack[sp++] = points[j].index;
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}
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// construct the hull
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var poly = [];
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for (i=0; i<sp; ++i) {
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poly.push(vertices[stack[i]]);
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}
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return poly;
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}
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// are three points in counter-clockwise order?
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function d3_geom_hullCCW(i1, i2, i3, v) {
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var t, a, b, c, d, e, f;
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t = v[i1]; a = t[0]; b = t[1];
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t = v[i2]; c = t[0]; d = t[1];
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t = v[i3]; e = t[0]; f = t[1];
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return ((f-b)*(c-a) - (d-b)*(e-a)) > 0;
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}
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// Note: requires coordinates to be counterclockwise and convex!
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d3.geom.polygon = function(coordinates) {
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coordinates.area = function() {
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var i = 0,
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n = coordinates.length,
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a = coordinates[n - 1][0] * coordinates[0][1],
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b = coordinates[n - 1][1] * coordinates[0][0];
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while (++i < n) {
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a += coordinates[i - 1][0] * coordinates[i][1];
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b += coordinates[i - 1][1] * coordinates[i][0];
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}
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return (b - a) * .5;
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};
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coordinates.centroid = function(k) {
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var i = -1,
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n = coordinates.length,
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x = 0,
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y = 0,
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a,
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b = coordinates[n - 1],
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c;
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if (!arguments.length) k = -1 / (6 * coordinates.area());
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while (++i < n) {
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a = b;
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b = coordinates[i];
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c = a[0] * b[1] - b[0] * a[1];
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x += (a[0] + b[0]) * c;
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y += (a[1] + b[1]) * c;
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}
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return [x * k, y * k];
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};
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// The Sutherland-Hodgman clipping algorithm.
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coordinates.clip = function(subject) {
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var input,
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i = -1,
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n = coordinates.length,
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j,
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m,
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a = coordinates[n - 1],
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b,
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c,
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d;
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while (++i < n) {
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input = subject.slice();
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subject.length = 0;
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b = coordinates[i];
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c = input[(m = input.length) - 1];
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j = -1;
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while (++j < m) {
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d = input[j];
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if (d3_geom_polygonInside(d, a, b)) {
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if (!d3_geom_polygonInside(c, a, b)) {
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subject.push(d3_geom_polygonIntersect(c, d, a, b));
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}
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subject.push(d);
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} else if (d3_geom_polygonInside(c, a, b)) {
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subject.push(d3_geom_polygonIntersect(c, d, a, b));
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}
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c = d;
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}
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a = b;
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}
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return subject;
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};
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return coordinates;
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};
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function d3_geom_polygonInside(p, a, b) {
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return (b[0] - a[0]) * (p[1] - a[1]) < (b[1] - a[1]) * (p[0] - a[0]);
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}
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// Intersect two infinite lines cd and ab.
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function d3_geom_polygonIntersect(c, d, a, b) {
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var x1 = c[0], x2 = d[0], x3 = a[0], x4 = b[0],
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y1 = c[1], y2 = d[1], y3 = a[1], y4 = b[1],
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x13 = x1 - x3,
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x21 = x2 - x1,
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x43 = x4 - x3,
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y13 = y1 - y3,
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y21 = y2 - y1,
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y43 = y4 - y3,
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ua = (x43 * y13 - y43 * x13) / (y43 * x21 - x43 * y21);
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return [x1 + ua * x21, y1 + ua * y21];
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}
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// Adapted from Nicolas Garcia Belmonte's JIT implementation:
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// http://blog.thejit.org/2010/02/12/voronoi-tessellation/
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// http://blog.thejit.org/assets/voronoijs/voronoi.js
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// See lib/jit/LICENSE for details.
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// Notes:
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//
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// This implementation does not clip the returned polygons, so if you want to
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// clip them to a particular shape you will need to do that either in SVG or by
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// post-processing with d3.geom.polygon's clip method.
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//
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// If any vertices are coincident or have NaN positions, the behavior of this
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// method is undefined. Most likely invalid polygons will be returned. You
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// should filter invalid points, and consolidate coincident points, before
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// computing the tessellation.
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/**
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* @param vertices [[x1, y1], [x2, y2], …]
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* @returns polygons [[[x1, y1], [x2, y2], …], …]
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*/
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d3.geom.voronoi = function(vertices) {
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var polygons = vertices.map(function() { return []; });
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d3_voronoi_tessellate(vertices, function(e) {
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var s1,
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s2,
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x1,
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x2,
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y1,
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y2;
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if (e.a === 1 && e.b >= 0) {
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s1 = e.ep.r;
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s2 = e.ep.l;
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} else {
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s1 = e.ep.l;
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s2 = e.ep.r;
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}
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if (e.a === 1) {
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y1 = s1 ? s1.y : -1e6;
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x1 = e.c - e.b * y1;
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y2 = s2 ? s2.y : 1e6;
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x2 = e.c - e.b * y2;
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} else {
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x1 = s1 ? s1.x : -1e6;
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y1 = e.c - e.a * x1;
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x2 = s2 ? s2.x : 1e6;
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y2 = e.c - e.a * x2;
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}
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var v1 = [x1, y1],
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v2 = [x2, y2];
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polygons[e.region.l.index].push(v1, v2);
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polygons[e.region.r.index].push(v1, v2);
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});
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// Reconnect the polygon segments into counterclockwise loops.
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return polygons.map(function(polygon, i) {
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var cx = vertices[i][0],
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cy = vertices[i][1];
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polygon.forEach(function(v) {
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v.angle = Math.atan2(v[0] - cx, v[1] - cy);
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});
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return polygon.sort(function(a, b) {
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return a.angle - b.angle;
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}).filter(function(d, i) {
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return !i || (d.angle - polygon[i - 1].angle > 1e-10);
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});
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});
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};
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var d3_voronoi_opposite = {"l": "r", "r": "l"};
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function d3_voronoi_tessellate(vertices, callback) {
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var Sites = {
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list: vertices
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.map(function(v, i) {
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return {
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index: i,
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x: v[0],
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y: v[1]
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};
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})
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.sort(function(a, b) {
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return a.y < b.y ? -1
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: a.y > b.y ? 1
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: a.x < b.x ? -1
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: a.x > b.x ? 1
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: 0;
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}),
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bottomSite: null
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};
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var EdgeList = {
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list: [],
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leftEnd: null,
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rightEnd: null,
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init: function() {
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EdgeList.leftEnd = EdgeList.createHalfEdge(null, "l");
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EdgeList.rightEnd = EdgeList.createHalfEdge(null, "l");
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EdgeList.leftEnd.r = EdgeList.rightEnd;
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EdgeList.rightEnd.l = EdgeList.leftEnd;
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EdgeList.list.unshift(EdgeList.leftEnd, EdgeList.rightEnd);
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},
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createHalfEdge: function(edge, side) {
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return {
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edge: edge,
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side: side,
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vertex: null,
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"l": null,
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"r": null
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};
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},
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insert: function(lb, he) {
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he.l = lb;
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he.r = lb.r;
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lb.r.l = he;
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lb.r = he;
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},
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leftBound: function(p) {
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var he = EdgeList.leftEnd;
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do {
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he = he.r;
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} while (he != EdgeList.rightEnd && Geom.rightOf(he, p));
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he = he.l;
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return he;
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},
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del: function(he) {
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he.l.r = he.r;
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he.r.l = he.l;
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he.edge = null;
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},
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right: function(he) {
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return he.r;
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},
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left: function(he) {
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return he.l;
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},
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leftRegion: function(he) {
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return he.edge == null
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? Sites.bottomSite
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: he.edge.region[he.side];
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},
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rightRegion: function(he) {
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return he.edge == null
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? Sites.bottomSite
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: he.edge.region[d3_voronoi_opposite[he.side]];
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}
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};
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var Geom = {
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bisect: function(s1, s2) {
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var newEdge = {
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region: {"l": s1, "r": s2},
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ep: {"l": null, "r": null}
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};
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var dx = s2.x - s1.x,
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dy = s2.y - s1.y,
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adx = dx > 0 ? dx : -dx,
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ady = dy > 0 ? dy : -dy;
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newEdge.c = s1.x * dx + s1.y * dy
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+ (dx * dx + dy * dy) * .5;
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if (adx > ady) {
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newEdge.a = 1;
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newEdge.b = dy / dx;
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newEdge.c /= dx;
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} else {
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newEdge.b = 1;
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newEdge.a = dx / dy;
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newEdge.c /= dy;
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}
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return newEdge;
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},
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intersect: function(el1, el2) {
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var e1 = el1.edge,
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e2 = el2.edge;
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if (!e1 || !e2 || (e1.region.r == e2.region.r)) {
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return null;
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}
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var d = (e1.a * e2.b) - (e1.b * e2.a);
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if (Math.abs(d) < 1e-10) {
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return null;
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}
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var xint = (e1.c * e2.b - e2.c * e1.b) / d,
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yint = (e2.c * e1.a - e1.c * e2.a) / d,
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e1r = e1.region.r,
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e2r = e2.region.r,
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el,
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e;
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if ((e1r.y < e2r.y) ||
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(e1r.y == e2r.y && e1r.x < e2r.x)) {
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el = el1;
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e = e1;
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} else {
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el = el2;
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e = e2;
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}
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var rightOfSite = (xint >= e.region.r.x);
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if ((rightOfSite && (el.side === "l")) ||
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(!rightOfSite && (el.side === "r"))) {
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return null;
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}
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return {
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x: xint,
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y: yint
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};
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},
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rightOf: function(he, p) {
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var e = he.edge,
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topsite = e.region.r,
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rightOfSite = (p.x > topsite.x);
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if (rightOfSite && (he.side === "l")) {
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return 1;
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}
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if (!rightOfSite && (he.side === "r")) {
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return 0;
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}
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if (e.a === 1) {
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var dyp = p.y - topsite.y,
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dxp = p.x - topsite.x,
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fast = 0,
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above = 0;
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if ((!rightOfSite && (e.b < 0)) ||
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(rightOfSite && (e.b >= 0))) {
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above = fast = (dyp >= e.b * dxp);
|
|
} else {
|
|
above = ((p.x + p.y * e.b) > e.c);
|
|
if (e.b < 0) {
|
|
above = !above;
|
|
}
|
|
if (!above) {
|
|
fast = 1;
|
|
}
|
|
}
|
|
if (!fast) {
|
|
var dxs = topsite.x - e.region.l.x;
|
|
above = (e.b * (dxp * dxp - dyp * dyp)) <
|
|
(dxs * dyp * (1 + 2 * dxp / dxs + e.b * e.b));
|
|
|
|
if (e.b < 0) {
|
|
above = !above;
|
|
}
|
|
}
|
|
} else /* e.b == 1 */ {
|
|
var yl = e.c - e.a * p.x,
|
|
t1 = p.y - yl,
|
|
t2 = p.x - topsite.x,
|
|
t3 = yl - topsite.y;
|
|
|
|
above = (t1 * t1) > (t2 * t2 + t3 * t3);
|
|
}
|
|
return he.side === "l" ? above : !above;
|
|
},
|
|
|
|
endPoint: function(edge, side, site) {
|
|
edge.ep[side] = site;
|
|
if (!edge.ep[d3_voronoi_opposite[side]]) return;
|
|
callback(edge);
|
|
},
|
|
|
|
distance: function(s, t) {
|
|
var dx = s.x - t.x,
|
|
dy = s.y - t.y;
|
|
return Math.sqrt(dx * dx + dy * dy);
|
|
}
|
|
};
|
|
|
|
var EventQueue = {
|
|
list: [],
|
|
|
|
insert: function(he, site, offset) {
|
|
he.vertex = site;
|
|
he.ystar = site.y + offset;
|
|
for (var i=0, list=EventQueue.list, l=list.length; i<l; i++) {
|
|
var next = list[i];
|
|
if (he.ystar > next.ystar ||
|
|
(he.ystar == next.ystar &&
|
|
site.x > next.vertex.x)) {
|
|
continue;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
list.splice(i, 0, he);
|
|
},
|
|
|
|
del: function(he) {
|
|
for (var i=0, ls=EventQueue.list, l=ls.length; i<l && (ls[i] != he); ++i) {}
|
|
ls.splice(i, 1);
|
|
},
|
|
|
|
empty: function() { return EventQueue.list.length === 0; },
|
|
|
|
nextEvent: function(he) {
|
|
for (var i=0, ls=EventQueue.list, l=ls.length; i<l; ++i) {
|
|
if (ls[i] == he) return ls[i+1];
|
|
}
|
|
return null;
|
|
},
|
|
|
|
min: function() {
|
|
var elem = EventQueue.list[0];
|
|
return {
|
|
x: elem.vertex.x,
|
|
y: elem.ystar
|
|
};
|
|
},
|
|
|
|
extractMin: function() {
|
|
return EventQueue.list.shift();
|
|
}
|
|
};
|
|
|
|
EdgeList.init();
|
|
Sites.bottomSite = Sites.list.shift();
|
|
|
|
var newSite = Sites.list.shift(), newIntStar;
|
|
var lbnd, rbnd, llbnd, rrbnd, bisector;
|
|
var bot, top, temp, p, v;
|
|
var e, pm;
|
|
|
|
while (true) {
|
|
if (!EventQueue.empty()) {
|
|
newIntStar = EventQueue.min();
|
|
}
|
|
if (newSite && (EventQueue.empty()
|
|
|| newSite.y < newIntStar.y
|
|
|| (newSite.y == newIntStar.y
|
|
&& newSite.x < newIntStar.x))) { //new site is smallest
|
|
lbnd = EdgeList.leftBound(newSite);
|
|
rbnd = EdgeList.right(lbnd);
|
|
bot = EdgeList.rightRegion(lbnd);
|
|
e = Geom.bisect(bot, newSite);
|
|
bisector = EdgeList.createHalfEdge(e, "l");
|
|
EdgeList.insert(lbnd, bisector);
|
|
p = Geom.intersect(lbnd, bisector);
|
|
if (p) {
|
|
EventQueue.del(lbnd);
|
|
EventQueue.insert(lbnd, p, Geom.distance(p, newSite));
|
|
}
|
|
lbnd = bisector;
|
|
bisector = EdgeList.createHalfEdge(e, "r");
|
|
EdgeList.insert(lbnd, bisector);
|
|
p = Geom.intersect(bisector, rbnd);
|
|
if (p) {
|
|
EventQueue.insert(bisector, p, Geom.distance(p, newSite));
|
|
}
|
|
newSite = Sites.list.shift();
|
|
} else if (!EventQueue.empty()) { //intersection is smallest
|
|
lbnd = EventQueue.extractMin();
|
|
llbnd = EdgeList.left(lbnd);
|
|
rbnd = EdgeList.right(lbnd);
|
|
rrbnd = EdgeList.right(rbnd);
|
|
bot = EdgeList.leftRegion(lbnd);
|
|
top = EdgeList.rightRegion(rbnd);
|
|
v = lbnd.vertex;
|
|
Geom.endPoint(lbnd.edge, lbnd.side, v);
|
|
Geom.endPoint(rbnd.edge, rbnd.side, v);
|
|
EdgeList.del(lbnd);
|
|
EventQueue.del(rbnd);
|
|
EdgeList.del(rbnd);
|
|
pm = "l";
|
|
if (bot.y > top.y) {
|
|
temp = bot;
|
|
bot = top;
|
|
top = temp;
|
|
pm = "r";
|
|
}
|
|
e = Geom.bisect(bot, top);
|
|
bisector = EdgeList.createHalfEdge(e, pm);
|
|
EdgeList.insert(llbnd, bisector);
|
|
Geom.endPoint(e, d3_voronoi_opposite[pm], v);
|
|
p = Geom.intersect(llbnd, bisector);
|
|
if (p) {
|
|
EventQueue.del(llbnd);
|
|
EventQueue.insert(llbnd, p, Geom.distance(p, bot));
|
|
}
|
|
p = Geom.intersect(bisector, rrbnd);
|
|
if (p) {
|
|
EventQueue.insert(bisector, p, Geom.distance(p, bot));
|
|
}
|
|
} else {
|
|
break;
|
|
}
|
|
}//end while
|
|
|
|
for (lbnd = EdgeList.right(EdgeList.leftEnd);
|
|
lbnd != EdgeList.rightEnd;
|
|
lbnd = EdgeList.right(lbnd)) {
|
|
callback(lbnd.edge);
|
|
}
|
|
}
|
|
/**
|
|
* @param vertices [[x1, y1], [x2, y2], …]
|
|
* @returns triangles [[[x1, y1], [x2, y2], [x3, y3]], …]
|
|
*/
|
|
d3.geom.delaunay = function(vertices) {
|
|
var edges = vertices.map(function() { return []; }),
|
|
triangles = [];
|
|
|
|
// Use the Voronoi tessellation to determine Delaunay edges.
|
|
d3_voronoi_tessellate(vertices, function(e) {
|
|
edges[e.region.l.index].push(vertices[e.region.r.index]);
|
|
});
|
|
|
|
// Reconnect the edges into counterclockwise triangles.
|
|
edges.forEach(function(edge, i) {
|
|
var v = vertices[i],
|
|
cx = v[0],
|
|
cy = v[1];
|
|
edge.forEach(function(v) {
|
|
v.angle = Math.atan2(v[0] - cx, v[1] - cy);
|
|
});
|
|
edge.sort(function(a, b) {
|
|
return a.angle - b.angle;
|
|
});
|
|
for (var j = 0, m = edge.length - 1; j < m; j++) {
|
|
triangles.push([v, edge[j], edge[j + 1]]);
|
|
}
|
|
});
|
|
|
|
return triangles;
|
|
};
|
|
// Constructs a new quadtree for the specified array of points. A quadtree is a
|
|
// two-dimensional recursive spatial subdivision. This implementation uses
|
|
// square partitions, dividing each square into four equally-sized squares. Each
|
|
// point exists in a unique node; if multiple points are in the same position,
|
|
// some points may be stored on internal nodes rather than leaf nodes. Quadtrees
|
|
// can be used to accelerate various spatial operations, such as the Barnes-Hut
|
|
// approximation for computing n-body forces, or collision detection.
|
|
d3.geom.quadtree = function(points, x1, y1, x2, y2) {
|
|
var p,
|
|
i = -1,
|
|
n = points.length;
|
|
|
|
// Type conversion for deprecated API.
|
|
if (n && isNaN(points[0].x)) points = points.map(d3_geom_quadtreePoint);
|
|
|
|
// Allow bounds to be specified explicitly.
|
|
if (arguments.length < 5) {
|
|
if (arguments.length === 3) {
|
|
y2 = x2 = y1;
|
|
y1 = x1;
|
|
} else {
|
|
x1 = y1 = Infinity;
|
|
x2 = y2 = -Infinity;
|
|
|
|
// Compute bounds.
|
|
while (++i < n) {
|
|
p = points[i];
|
|
if (p.x < x1) x1 = p.x;
|
|
if (p.y < y1) y1 = p.y;
|
|
if (p.x > x2) x2 = p.x;
|
|
if (p.y > y2) y2 = p.y;
|
|
}
|
|
|
|
// Squarify the bounds.
|
|
var dx = x2 - x1,
|
|
dy = y2 - y1;
|
|
if (dx > dy) y2 = y1 + dx;
|
|
else x2 = x1 + dy;
|
|
}
|
|
}
|
|
|
|
// Recursively inserts the specified point p at the node n or one of its
|
|
// descendants. The bounds are defined by [x1, x2] and [y1, y2].
|
|
function insert(n, p, x1, y1, x2, y2) {
|
|
if (isNaN(p.x) || isNaN(p.y)) return; // ignore invalid points
|
|
if (n.leaf) {
|
|
var v = n.point;
|
|
if (v) {
|
|
// If the point at this leaf node is at the same position as the new
|
|
// point we are adding, we leave the point associated with the
|
|
// internal node while adding the new point to a child node. This
|
|
// avoids infinite recursion.
|
|
if ((Math.abs(v.x - p.x) + Math.abs(v.y - p.y)) < .01) {
|
|
insertChild(n, p, x1, y1, x2, y2);
|
|
} else {
|
|
n.point = null;
|
|
insertChild(n, v, x1, y1, x2, y2);
|
|
insertChild(n, p, x1, y1, x2, y2);
|
|
}
|
|
} else {
|
|
n.point = p;
|
|
}
|
|
} else {
|
|
insertChild(n, p, x1, y1, x2, y2);
|
|
}
|
|
}
|
|
|
|
// Recursively inserts the specified point p into a descendant of node n. The
|
|
// bounds are defined by [x1, x2] and [y1, y2].
|
|
function insertChild(n, p, x1, y1, x2, y2) {
|
|
// Compute the split point, and the quadrant in which to insert p.
|
|
var sx = (x1 + x2) * .5,
|
|
sy = (y1 + y2) * .5,
|
|
right = p.x >= sx,
|
|
bottom = p.y >= sy,
|
|
i = (bottom << 1) + right;
|
|
|
|
// Recursively insert into the child node.
|
|
n.leaf = false;
|
|
n = n.nodes[i] || (n.nodes[i] = d3_geom_quadtreeNode());
|
|
|
|
// Update the bounds as we recurse.
|
|
if (right) x1 = sx; else x2 = sx;
|
|
if (bottom) y1 = sy; else y2 = sy;
|
|
insert(n, p, x1, y1, x2, y2);
|
|
}
|
|
|
|
// Create the root node.
|
|
var root = d3_geom_quadtreeNode();
|
|
|
|
root.add = function(p) {
|
|
insert(root, p, x1, y1, x2, y2);
|
|
};
|
|
|
|
root.visit = function(f) {
|
|
d3_geom_quadtreeVisit(f, root, x1, y1, x2, y2);
|
|
};
|
|
|
|
// Insert all points.
|
|
points.forEach(root.add);
|
|
return root;
|
|
};
|
|
|
|
function d3_geom_quadtreeNode() {
|
|
return {
|
|
leaf: true,
|
|
nodes: [],
|
|
point: null
|
|
};
|
|
}
|
|
|
|
function d3_geom_quadtreeVisit(f, node, x1, y1, x2, y2) {
|
|
if (!f(node, x1, y1, x2, y2)) {
|
|
var sx = (x1 + x2) * .5,
|
|
sy = (y1 + y2) * .5,
|
|
children = node.nodes;
|
|
if (children[0]) d3_geom_quadtreeVisit(f, children[0], x1, y1, sx, sy);
|
|
if (children[1]) d3_geom_quadtreeVisit(f, children[1], sx, y1, x2, sy);
|
|
if (children[2]) d3_geom_quadtreeVisit(f, children[2], x1, sy, sx, y2);
|
|
if (children[3]) d3_geom_quadtreeVisit(f, children[3], sx, sy, x2, y2);
|
|
}
|
|
}
|
|
|
|
function d3_geom_quadtreePoint(p) {
|
|
return {
|
|
x: p[0],
|
|
y: p[1]
|
|
};
|
|
}
|
|
})();
|