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This commit is contained in:
Akko
681
node_modules/earcut/src/earcut.js
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vendored
Normal file
681
node_modules/earcut/src/earcut.js
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vendored
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@@ -0,0 +1,681 @@
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'use strict';
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module.exports = earcut;
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module.exports.default = earcut;
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function earcut(data, holeIndices, dim) {
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dim = dim || 2;
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var hasHoles = holeIndices && holeIndices.length,
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outerLen = hasHoles ? holeIndices[0] * dim : data.length,
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outerNode = linkedList(data, 0, outerLen, dim, true),
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triangles = [];
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if (!outerNode || outerNode.next === outerNode.prev) return triangles;
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var minX, minY, maxX, maxY, x, y, invSize;
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if (hasHoles) outerNode = eliminateHoles(data, holeIndices, outerNode, dim);
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// if the shape is not too simple, we'll use z-order curve hash later; calculate polygon bbox
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if (data.length > 80 * dim) {
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minX = maxX = data[0];
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minY = maxY = data[1];
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for (var i = dim; i < outerLen; i += dim) {
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x = data[i];
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y = data[i + 1];
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if (x < minX) minX = x;
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if (y < minY) minY = y;
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if (x > maxX) maxX = x;
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if (y > maxY) maxY = y;
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}
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// minX, minY and invSize are later used to transform coords into integers for z-order calculation
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invSize = Math.max(maxX - minX, maxY - minY);
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invSize = invSize !== 0 ? 32767 / invSize : 0;
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}
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earcutLinked(outerNode, triangles, dim, minX, minY, invSize, 0);
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return triangles;
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}
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// create a circular doubly linked list from polygon points in the specified winding order
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function linkedList(data, start, end, dim, clockwise) {
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var i, last;
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if (clockwise === (signedArea(data, start, end, dim) > 0)) {
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for (i = start; i < end; i += dim) last = insertNode(i, data[i], data[i + 1], last);
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} else {
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for (i = end - dim; i >= start; i -= dim) last = insertNode(i, data[i], data[i + 1], last);
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}
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if (last && equals(last, last.next)) {
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removeNode(last);
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last = last.next;
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}
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return last;
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}
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// eliminate colinear or duplicate points
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function filterPoints(start, end) {
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if (!start) return start;
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if (!end) end = start;
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var p = start,
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again;
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do {
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again = false;
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if (!p.steiner && (equals(p, p.next) || area(p.prev, p, p.next) === 0)) {
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removeNode(p);
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p = end = p.prev;
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if (p === p.next) break;
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again = true;
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} else {
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p = p.next;
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}
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} while (again || p !== end);
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return end;
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}
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// main ear slicing loop which triangulates a polygon (given as a linked list)
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function earcutLinked(ear, triangles, dim, minX, minY, invSize, pass) {
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if (!ear) return;
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// interlink polygon nodes in z-order
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if (!pass && invSize) indexCurve(ear, minX, minY, invSize);
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var stop = ear,
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prev, next;
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// iterate through ears, slicing them one by one
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while (ear.prev !== ear.next) {
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prev = ear.prev;
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next = ear.next;
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if (invSize ? isEarHashed(ear, minX, minY, invSize) : isEar(ear)) {
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// cut off the triangle
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triangles.push(prev.i / dim | 0);
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triangles.push(ear.i / dim | 0);
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triangles.push(next.i / dim | 0);
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removeNode(ear);
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// skipping the next vertex leads to less sliver triangles
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ear = next.next;
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stop = next.next;
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continue;
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}
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ear = next;
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// if we looped through the whole remaining polygon and can't find any more ears
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if (ear === stop) {
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// try filtering points and slicing again
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if (!pass) {
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earcutLinked(filterPoints(ear), triangles, dim, minX, minY, invSize, 1);
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// if this didn't work, try curing all small self-intersections locally
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} else if (pass === 1) {
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ear = cureLocalIntersections(filterPoints(ear), triangles, dim);
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earcutLinked(ear, triangles, dim, minX, minY, invSize, 2);
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// as a last resort, try splitting the remaining polygon into two
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} else if (pass === 2) {
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splitEarcut(ear, triangles, dim, minX, minY, invSize);
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}
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break;
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}
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}
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}
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// check whether a polygon node forms a valid ear with adjacent nodes
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function isEar(ear) {
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var a = ear.prev,
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b = ear,
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c = ear.next;
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if (area(a, b, c) >= 0) return false; // reflex, can't be an ear
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// now make sure we don't have other points inside the potential ear
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var ax = a.x, bx = b.x, cx = c.x, ay = a.y, by = b.y, cy = c.y;
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// triangle bbox; min & max are calculated like this for speed
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var x0 = ax < bx ? (ax < cx ? ax : cx) : (bx < cx ? bx : cx),
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y0 = ay < by ? (ay < cy ? ay : cy) : (by < cy ? by : cy),
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x1 = ax > bx ? (ax > cx ? ax : cx) : (bx > cx ? bx : cx),
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y1 = ay > by ? (ay > cy ? ay : cy) : (by > cy ? by : cy);
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var p = c.next;
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while (p !== a) {
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if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 &&
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pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) &&
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area(p.prev, p, p.next) >= 0) return false;
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p = p.next;
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}
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return true;
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}
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function isEarHashed(ear, minX, minY, invSize) {
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var a = ear.prev,
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b = ear,
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c = ear.next;
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if (area(a, b, c) >= 0) return false; // reflex, can't be an ear
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var ax = a.x, bx = b.x, cx = c.x, ay = a.y, by = b.y, cy = c.y;
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// triangle bbox; min & max are calculated like this for speed
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var x0 = ax < bx ? (ax < cx ? ax : cx) : (bx < cx ? bx : cx),
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y0 = ay < by ? (ay < cy ? ay : cy) : (by < cy ? by : cy),
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x1 = ax > bx ? (ax > cx ? ax : cx) : (bx > cx ? bx : cx),
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y1 = ay > by ? (ay > cy ? ay : cy) : (by > cy ? by : cy);
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// z-order range for the current triangle bbox;
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var minZ = zOrder(x0, y0, minX, minY, invSize),
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maxZ = zOrder(x1, y1, minX, minY, invSize);
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var p = ear.prevZ,
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n = ear.nextZ;
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// look for points inside the triangle in both directions
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while (p && p.z >= minZ && n && n.z <= maxZ) {
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if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 && p !== a && p !== c &&
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pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) && area(p.prev, p, p.next) >= 0) return false;
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p = p.prevZ;
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if (n.x >= x0 && n.x <= x1 && n.y >= y0 && n.y <= y1 && n !== a && n !== c &&
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pointInTriangle(ax, ay, bx, by, cx, cy, n.x, n.y) && area(n.prev, n, n.next) >= 0) return false;
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n = n.nextZ;
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}
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// look for remaining points in decreasing z-order
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while (p && p.z >= minZ) {
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if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 && p !== a && p !== c &&
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pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) && area(p.prev, p, p.next) >= 0) return false;
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p = p.prevZ;
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}
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// look for remaining points in increasing z-order
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while (n && n.z <= maxZ) {
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if (n.x >= x0 && n.x <= x1 && n.y >= y0 && n.y <= y1 && n !== a && n !== c &&
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pointInTriangle(ax, ay, bx, by, cx, cy, n.x, n.y) && area(n.prev, n, n.next) >= 0) return false;
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n = n.nextZ;
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}
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return true;
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}
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// go through all polygon nodes and cure small local self-intersections
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function cureLocalIntersections(start, triangles, dim) {
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var p = start;
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do {
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var a = p.prev,
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b = p.next.next;
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if (!equals(a, b) && intersects(a, p, p.next, b) && locallyInside(a, b) && locallyInside(b, a)) {
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triangles.push(a.i / dim | 0);
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triangles.push(p.i / dim | 0);
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triangles.push(b.i / dim | 0);
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// remove two nodes involved
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removeNode(p);
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removeNode(p.next);
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p = start = b;
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}
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p = p.next;
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} while (p !== start);
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return filterPoints(p);
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}
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// try splitting polygon into two and triangulate them independently
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function splitEarcut(start, triangles, dim, minX, minY, invSize) {
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// look for a valid diagonal that divides the polygon into two
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var a = start;
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do {
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var b = a.next.next;
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while (b !== a.prev) {
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if (a.i !== b.i && isValidDiagonal(a, b)) {
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// split the polygon in two by the diagonal
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var c = splitPolygon(a, b);
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// filter colinear points around the cuts
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a = filterPoints(a, a.next);
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c = filterPoints(c, c.next);
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// run earcut on each half
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earcutLinked(a, triangles, dim, minX, minY, invSize, 0);
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earcutLinked(c, triangles, dim, minX, minY, invSize, 0);
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return;
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}
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b = b.next;
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}
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a = a.next;
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} while (a !== start);
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}
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// link every hole into the outer loop, producing a single-ring polygon without holes
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function eliminateHoles(data, holeIndices, outerNode, dim) {
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var queue = [],
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i, len, start, end, list;
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for (i = 0, len = holeIndices.length; i < len; i++) {
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start = holeIndices[i] * dim;
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end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
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list = linkedList(data, start, end, dim, false);
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if (list === list.next) list.steiner = true;
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queue.push(getLeftmost(list));
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}
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queue.sort(compareX);
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// process holes from left to right
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for (i = 0; i < queue.length; i++) {
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outerNode = eliminateHole(queue[i], outerNode);
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}
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return outerNode;
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}
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function compareX(a, b) {
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return a.x - b.x;
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}
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// find a bridge between vertices that connects hole with an outer ring and and link it
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function eliminateHole(hole, outerNode) {
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var bridge = findHoleBridge(hole, outerNode);
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if (!bridge) {
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return outerNode;
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}
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var bridgeReverse = splitPolygon(bridge, hole);
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// filter collinear points around the cuts
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filterPoints(bridgeReverse, bridgeReverse.next);
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return filterPoints(bridge, bridge.next);
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}
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// David Eberly's algorithm for finding a bridge between hole and outer polygon
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function findHoleBridge(hole, outerNode) {
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var p = outerNode,
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hx = hole.x,
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hy = hole.y,
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qx = -Infinity,
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m;
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// find a segment intersected by a ray from the hole's leftmost point to the left;
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// segment's endpoint with lesser x will be potential connection point
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do {
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if (hy <= p.y && hy >= p.next.y && p.next.y !== p.y) {
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var x = p.x + (hy - p.y) * (p.next.x - p.x) / (p.next.y - p.y);
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if (x <= hx && x > qx) {
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qx = x;
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m = p.x < p.next.x ? p : p.next;
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if (x === hx) return m; // hole touches outer segment; pick leftmost endpoint
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}
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}
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p = p.next;
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} while (p !== outerNode);
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if (!m) return null;
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// look for points inside the triangle of hole point, segment intersection and endpoint;
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// if there are no points found, we have a valid connection;
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// otherwise choose the point of the minimum angle with the ray as connection point
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var stop = m,
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mx = m.x,
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my = m.y,
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tanMin = Infinity,
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tan;
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p = m;
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do {
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if (hx >= p.x && p.x >= mx && hx !== p.x &&
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pointInTriangle(hy < my ? hx : qx, hy, mx, my, hy < my ? qx : hx, hy, p.x, p.y)) {
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tan = Math.abs(hy - p.y) / (hx - p.x); // tangential
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if (locallyInside(p, hole) &&
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(tan < tanMin || (tan === tanMin && (p.x > m.x || (p.x === m.x && sectorContainsSector(m, p)))))) {
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m = p;
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tanMin = tan;
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}
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}
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p = p.next;
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} while (p !== stop);
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return m;
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}
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// whether sector in vertex m contains sector in vertex p in the same coordinates
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function sectorContainsSector(m, p) {
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return area(m.prev, m, p.prev) < 0 && area(p.next, m, m.next) < 0;
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}
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// interlink polygon nodes in z-order
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function indexCurve(start, minX, minY, invSize) {
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var p = start;
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do {
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if (p.z === 0) p.z = zOrder(p.x, p.y, minX, minY, invSize);
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p.prevZ = p.prev;
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p.nextZ = p.next;
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p = p.next;
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} while (p !== start);
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|
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p.prevZ.nextZ = null;
|
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p.prevZ = null;
|
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sortLinked(p);
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}
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|
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// Simon Tatham's linked list merge sort algorithm
|
||||
// http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
|
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function sortLinked(list) {
|
||||
var i, p, q, e, tail, numMerges, pSize, qSize,
|
||||
inSize = 1;
|
||||
|
||||
do {
|
||||
p = list;
|
||||
list = null;
|
||||
tail = null;
|
||||
numMerges = 0;
|
||||
|
||||
while (p) {
|
||||
numMerges++;
|
||||
q = p;
|
||||
pSize = 0;
|
||||
for (i = 0; i < inSize; i++) {
|
||||
pSize++;
|
||||
q = q.nextZ;
|
||||
if (!q) break;
|
||||
}
|
||||
qSize = inSize;
|
||||
|
||||
while (pSize > 0 || (qSize > 0 && q)) {
|
||||
|
||||
if (pSize !== 0 && (qSize === 0 || !q || p.z <= q.z)) {
|
||||
e = p;
|
||||
p = p.nextZ;
|
||||
pSize--;
|
||||
} else {
|
||||
e = q;
|
||||
q = q.nextZ;
|
||||
qSize--;
|
||||
}
|
||||
|
||||
if (tail) tail.nextZ = e;
|
||||
else list = e;
|
||||
|
||||
e.prevZ = tail;
|
||||
tail = e;
|
||||
}
|
||||
|
||||
p = q;
|
||||
}
|
||||
|
||||
tail.nextZ = null;
|
||||
inSize *= 2;
|
||||
|
||||
} while (numMerges > 1);
|
||||
|
||||
return list;
|
||||
}
|
||||
|
||||
// z-order of a point given coords and inverse of the longer side of data bbox
|
||||
function zOrder(x, y, minX, minY, invSize) {
|
||||
// coords are transformed into non-negative 15-bit integer range
|
||||
x = (x - minX) * invSize | 0;
|
||||
y = (y - minY) * invSize | 0;
|
||||
|
||||
x = (x | (x << 8)) & 0x00FF00FF;
|
||||
x = (x | (x << 4)) & 0x0F0F0F0F;
|
||||
x = (x | (x << 2)) & 0x33333333;
|
||||
x = (x | (x << 1)) & 0x55555555;
|
||||
|
||||
y = (y | (y << 8)) & 0x00FF00FF;
|
||||
y = (y | (y << 4)) & 0x0F0F0F0F;
|
||||
y = (y | (y << 2)) & 0x33333333;
|
||||
y = (y | (y << 1)) & 0x55555555;
|
||||
|
||||
return x | (y << 1);
|
||||
}
|
||||
|
||||
// find the leftmost node of a polygon ring
|
||||
function getLeftmost(start) {
|
||||
var p = start,
|
||||
leftmost = start;
|
||||
do {
|
||||
if (p.x < leftmost.x || (p.x === leftmost.x && p.y < leftmost.y)) leftmost = p;
|
||||
p = p.next;
|
||||
} while (p !== start);
|
||||
|
||||
return leftmost;
|
||||
}
|
||||
|
||||
// check if a point lies within a convex triangle
|
||||
function pointInTriangle(ax, ay, bx, by, cx, cy, px, py) {
|
||||
return (cx - px) * (ay - py) >= (ax - px) * (cy - py) &&
|
||||
(ax - px) * (by - py) >= (bx - px) * (ay - py) &&
|
||||
(bx - px) * (cy - py) >= (cx - px) * (by - py);
|
||||
}
|
||||
|
||||
// check if a diagonal between two polygon nodes is valid (lies in polygon interior)
|
||||
function isValidDiagonal(a, b) {
|
||||
return a.next.i !== b.i && a.prev.i !== b.i && !intersectsPolygon(a, b) && // dones't intersect other edges
|
||||
(locallyInside(a, b) && locallyInside(b, a) && middleInside(a, b) && // locally visible
|
||||
(area(a.prev, a, b.prev) || area(a, b.prev, b)) || // does not create opposite-facing sectors
|
||||
equals(a, b) && area(a.prev, a, a.next) > 0 && area(b.prev, b, b.next) > 0); // special zero-length case
|
||||
}
|
||||
|
||||
// signed area of a triangle
|
||||
function area(p, q, r) {
|
||||
return (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);
|
||||
}
|
||||
|
||||
// check if two points are equal
|
||||
function equals(p1, p2) {
|
||||
return p1.x === p2.x && p1.y === p2.y;
|
||||
}
|
||||
|
||||
// check if two segments intersect
|
||||
function intersects(p1, q1, p2, q2) {
|
||||
var o1 = sign(area(p1, q1, p2));
|
||||
var o2 = sign(area(p1, q1, q2));
|
||||
var o3 = sign(area(p2, q2, p1));
|
||||
var o4 = sign(area(p2, q2, q1));
|
||||
|
||||
if (o1 !== o2 && o3 !== o4) return true; // general case
|
||||
|
||||
if (o1 === 0 && onSegment(p1, p2, q1)) return true; // p1, q1 and p2 are collinear and p2 lies on p1q1
|
||||
if (o2 === 0 && onSegment(p1, q2, q1)) return true; // p1, q1 and q2 are collinear and q2 lies on p1q1
|
||||
if (o3 === 0 && onSegment(p2, p1, q2)) return true; // p2, q2 and p1 are collinear and p1 lies on p2q2
|
||||
if (o4 === 0 && onSegment(p2, q1, q2)) return true; // p2, q2 and q1 are collinear and q1 lies on p2q2
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
// for collinear points p, q, r, check if point q lies on segment pr
|
||||
function onSegment(p, q, r) {
|
||||
return q.x <= Math.max(p.x, r.x) && q.x >= Math.min(p.x, r.x) && q.y <= Math.max(p.y, r.y) && q.y >= Math.min(p.y, r.y);
|
||||
}
|
||||
|
||||
function sign(num) {
|
||||
return num > 0 ? 1 : num < 0 ? -1 : 0;
|
||||
}
|
||||
|
||||
// check if a polygon diagonal intersects any polygon segments
|
||||
function intersectsPolygon(a, b) {
|
||||
var p = a;
|
||||
do {
|
||||
if (p.i !== a.i && p.next.i !== a.i && p.i !== b.i && p.next.i !== b.i &&
|
||||
intersects(p, p.next, a, b)) return true;
|
||||
p = p.next;
|
||||
} while (p !== a);
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
// check if a polygon diagonal is locally inside the polygon
|
||||
function locallyInside(a, b) {
|
||||
return area(a.prev, a, a.next) < 0 ?
|
||||
area(a, b, a.next) >= 0 && area(a, a.prev, b) >= 0 :
|
||||
area(a, b, a.prev) < 0 || area(a, a.next, b) < 0;
|
||||
}
|
||||
|
||||
// check if the middle point of a polygon diagonal is inside the polygon
|
||||
function middleInside(a, b) {
|
||||
var p = a,
|
||||
inside = false,
|
||||
px = (a.x + b.x) / 2,
|
||||
py = (a.y + b.y) / 2;
|
||||
do {
|
||||
if (((p.y > py) !== (p.next.y > py)) && p.next.y !== p.y &&
|
||||
(px < (p.next.x - p.x) * (py - p.y) / (p.next.y - p.y) + p.x))
|
||||
inside = !inside;
|
||||
p = p.next;
|
||||
} while (p !== a);
|
||||
|
||||
return inside;
|
||||
}
|
||||
|
||||
// link two polygon vertices with a bridge; if the vertices belong to the same ring, it splits polygon into two;
|
||||
// if one belongs to the outer ring and another to a hole, it merges it into a single ring
|
||||
function splitPolygon(a, b) {
|
||||
var a2 = new Node(a.i, a.x, a.y),
|
||||
b2 = new Node(b.i, b.x, b.y),
|
||||
an = a.next,
|
||||
bp = b.prev;
|
||||
|
||||
a.next = b;
|
||||
b.prev = a;
|
||||
|
||||
a2.next = an;
|
||||
an.prev = a2;
|
||||
|
||||
b2.next = a2;
|
||||
a2.prev = b2;
|
||||
|
||||
bp.next = b2;
|
||||
b2.prev = bp;
|
||||
|
||||
return b2;
|
||||
}
|
||||
|
||||
// create a node and optionally link it with previous one (in a circular doubly linked list)
|
||||
function insertNode(i, x, y, last) {
|
||||
var p = new Node(i, x, y);
|
||||
|
||||
if (!last) {
|
||||
p.prev = p;
|
||||
p.next = p;
|
||||
|
||||
} else {
|
||||
p.next = last.next;
|
||||
p.prev = last;
|
||||
last.next.prev = p;
|
||||
last.next = p;
|
||||
}
|
||||
return p;
|
||||
}
|
||||
|
||||
function removeNode(p) {
|
||||
p.next.prev = p.prev;
|
||||
p.prev.next = p.next;
|
||||
|
||||
if (p.prevZ) p.prevZ.nextZ = p.nextZ;
|
||||
if (p.nextZ) p.nextZ.prevZ = p.prevZ;
|
||||
}
|
||||
|
||||
function Node(i, x, y) {
|
||||
// vertex index in coordinates array
|
||||
this.i = i;
|
||||
|
||||
// vertex coordinates
|
||||
this.x = x;
|
||||
this.y = y;
|
||||
|
||||
// previous and next vertex nodes in a polygon ring
|
||||
this.prev = null;
|
||||
this.next = null;
|
||||
|
||||
// z-order curve value
|
||||
this.z = 0;
|
||||
|
||||
// previous and next nodes in z-order
|
||||
this.prevZ = null;
|
||||
this.nextZ = null;
|
||||
|
||||
// indicates whether this is a steiner point
|
||||
this.steiner = false;
|
||||
}
|
||||
|
||||
// return a percentage difference between the polygon area and its triangulation area;
|
||||
// used to verify correctness of triangulation
|
||||
earcut.deviation = function (data, holeIndices, dim, triangles) {
|
||||
var hasHoles = holeIndices && holeIndices.length;
|
||||
var outerLen = hasHoles ? holeIndices[0] * dim : data.length;
|
||||
|
||||
var polygonArea = Math.abs(signedArea(data, 0, outerLen, dim));
|
||||
if (hasHoles) {
|
||||
for (var i = 0, len = holeIndices.length; i < len; i++) {
|
||||
var start = holeIndices[i] * dim;
|
||||
var end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
|
||||
polygonArea -= Math.abs(signedArea(data, start, end, dim));
|
||||
}
|
||||
}
|
||||
|
||||
var trianglesArea = 0;
|
||||
for (i = 0; i < triangles.length; i += 3) {
|
||||
var a = triangles[i] * dim;
|
||||
var b = triangles[i + 1] * dim;
|
||||
var c = triangles[i + 2] * dim;
|
||||
trianglesArea += Math.abs(
|
||||
(data[a] - data[c]) * (data[b + 1] - data[a + 1]) -
|
||||
(data[a] - data[b]) * (data[c + 1] - data[a + 1]));
|
||||
}
|
||||
|
||||
return polygonArea === 0 && trianglesArea === 0 ? 0 :
|
||||
Math.abs((trianglesArea - polygonArea) / polygonArea);
|
||||
};
|
||||
|
||||
function signedArea(data, start, end, dim) {
|
||||
var sum = 0;
|
||||
for (var i = start, j = end - dim; i < end; i += dim) {
|
||||
sum += (data[j] - data[i]) * (data[i + 1] + data[j + 1]);
|
||||
j = i;
|
||||
}
|
||||
return sum;
|
||||
}
|
||||
|
||||
// turn a polygon in a multi-dimensional array form (e.g. as in GeoJSON) into a form Earcut accepts
|
||||
earcut.flatten = function (data) {
|
||||
var dim = data[0][0].length,
|
||||
result = {vertices: [], holes: [], dimensions: dim},
|
||||
holeIndex = 0;
|
||||
|
||||
for (var i = 0; i < data.length; i++) {
|
||||
for (var j = 0; j < data[i].length; j++) {
|
||||
for (var d = 0; d < dim; d++) result.vertices.push(data[i][j][d]);
|
||||
}
|
||||
if (i > 0) {
|
||||
holeIndex += data[i - 1].length;
|
||||
result.holes.push(holeIndex);
|
||||
}
|
||||
}
|
||||
return result;
|
||||
};
|
||||
Reference in New Issue
Block a user