laya-coreui-es
Version:
laya核心库、ui库es版本，剔除了媒体、TTF等功能。基于 LayaAir-release_2.12.0 修改
108 lines (107 loc) • 3.85 kB
JavaScript
import { Point } from "./Point";
import { Utils } from "../utils/Utils";
export class GrahamScan {
static multiply(p1, p2, p0) {
return ((p1.x - p0.x) * (p2.y - p0.y) - (p2.x - p0.x) * (p1.y - p0.y));
}
static dis(p1, p2) {
return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
}
static _getPoints(count, tempUse = false, rst = null) {
if (!GrahamScan._mPointList)
GrahamScan._mPointList = [];
while (GrahamScan._mPointList.length < count)
GrahamScan._mPointList.push(new Point());
if (!rst)
rst = [];
rst.length = 0;
if (tempUse) {
GrahamScan.getFrom(rst, GrahamScan._mPointList, count);
}
else {
GrahamScan.getFromR(rst, GrahamScan._mPointList, count);
}
return rst;
}
static getFrom(rst, src, count) {
var i;
for (i = 0; i < count; i++) {
rst.push(src[i]);
}
return rst;
}
static getFromR(rst, src, count) {
var i;
for (i = 0; i < count; i++) {
rst.push(src.pop());
}
return rst;
}
static pListToPointList(pList, tempUse = false) {
var i, len = pList.length / 2, rst = GrahamScan._getPoints(len, tempUse, GrahamScan._tempPointList);
for (i = 0; i < len; i++) {
rst[i].setTo(pList[i + i], pList[i + i + 1]);
}
return rst;
}
static pointListToPlist(pointList) {
var i, len = pointList.length, rst = GrahamScan._temPList, tPoint;
rst.length = 0;
for (i = 0; i < len; i++) {
tPoint = pointList[i];
rst.push(tPoint.x, tPoint.y);
}
return rst;
}
static scanPList(pList) {
return Utils.copyArray(pList, GrahamScan.pointListToPlist(GrahamScan.scan(GrahamScan.pListToPointList(pList, true))));
}
static scan(PointSet) {
var i, j, k = 0, top = 2, tmp, n = PointSet.length, ch;
var _tmpDic = {};
var key;
ch = GrahamScan._temArr;
ch.length = 0;
n = PointSet.length;
for (i = n - 1; i >= 0; i--) {
tmp = PointSet[i];
key = tmp.x + "_" + tmp.y;
if (!(key in _tmpDic)) {
_tmpDic[key] = true;
ch.push(tmp);
}
}
n = ch.length;
Utils.copyArray(PointSet, ch);
for (i = 1; i < n; i++)
if ((PointSet[i].y < PointSet[k].y) || ((PointSet[i].y == PointSet[k].y) && (PointSet[i].x < PointSet[k].x)))
k = i;
tmp = PointSet[0];
PointSet[0] = PointSet[k];
PointSet[k] = tmp;
for (i = 1; i < n - 1; i++) {
k = i;
for (j = i + 1; j < n; j++)
if ((GrahamScan.multiply(PointSet[j], PointSet[k], PointSet[0]) > 0) || ((GrahamScan.multiply(PointSet[j], PointSet[k], PointSet[0]) == 0) && (GrahamScan.dis(PointSet[0], PointSet[j]) < GrahamScan.dis(PointSet[0], PointSet[k]))))
k = j;
tmp = PointSet[i];
PointSet[i] = PointSet[k];
PointSet[k] = tmp;
}
ch = GrahamScan._temArr;
ch.length = 0;
if (PointSet.length < 3) {
return Utils.copyArray(ch, PointSet);
}
ch.push(PointSet[0], PointSet[1], PointSet[2]);
for (i = 3; i < n; i++) {
while (ch.length >= 2 && GrahamScan.multiply(PointSet[i], ch[ch.length - 1], ch[ch.length - 2]) >= 0)
ch.pop();
PointSet[i] && ch.push(PointSet[i]);
}
return ch;
}
}
GrahamScan._tempPointList = [];
GrahamScan._temPList = [];
GrahamScan._temArr = [];