186 lines
3.9 KiB
Plaintext
186 lines
3.9 KiB
Plaintext
/**
|
|
* @file 路径相关的函数集合
|
|
* @author mengke01(kekee000@gmail.com)
|
|
*/
|
|
|
|
import {getPointHash} from './util';
|
|
|
|
/**
|
|
* 对路径进行插值，补全省略的点
|
|
*
|
|
* @param {Array} path 路径
|
|
* @return {Array} 路径
|
|
*/
|
|
export function interpolate(path) {
|
|
const newPath = [];
|
|
for (let i = 0, l = path.length; i < l; i++) {
|
|
const next = i === l - 1 ? 0 : i + 1;
|
|
newPath.push(path[i]);
|
|
// 插值
|
|
if (!path[i].onCurve && !path[next].onCurve) {
|
|
newPath.push({
|
|
x: (path[i].x + path[next].x) / 2,
|
|
y: (path[i].y + path[next].y) / 2,
|
|
onCurve: true
|
|
});
|
|
}
|
|
}
|
|
|
|
return newPath;
|
|
}
|
|
|
|
|
|
/**
|
|
* 去除路径中的插值点
|
|
*
|
|
* @param {Array} path 路径
|
|
* @return {Array} 路径
|
|
*/
|
|
export function deInterpolate(path) {
|
|
const newPath = [];
|
|
|
|
for (let i = 0, l = path.length; i < l; i++) {
|
|
const next = i === l - 1 ? 0 : i + 1;
|
|
const prev = i === 0 ? l - 1 : i - 1;
|
|
// 插值
|
|
if (
|
|
!path[prev].onCurve && path[i].onCurve && !path[next].onCurve
|
|
&& Math.abs(2 * path[i].x - path[prev].x - path[next].x) < 0.001
|
|
&& Math.abs(2 * path[i].y - path[prev].y - path[next].y) < 0.001
|
|
) {
|
|
continue;
|
|
}
|
|
|
|
newPath.push(path[i]);
|
|
}
|
|
|
|
return newPath;
|
|
}
|
|
|
|
|
|
/**
|
|
* 判断路径的方向是否顺时针
|
|
*
|
|
* see:
|
|
* http://debian.fmi.uni-sofia.bg/~sergei/cgsr/docs/clockwise.htm
|
|
*
|
|
* @param {Array} path 路径
|
|
* @return {number} 0 无方向 1 clockwise, -1 counter clockwise
|
|
*/
|
|
export function isClockWise(path) {
|
|
|
|
if (path.length < 3) {
|
|
return 0;
|
|
}
|
|
|
|
let zCount = 0;
|
|
for (let i = 0, l = path.length; i < l; i++) {
|
|
const cur = path[i];
|
|
const prev = i === 0 ? path[l - 1] : path[i - 1];
|
|
const next = i === l - 1 ? path[0] : path[i + 1];
|
|
const z = (cur.x - prev.x) * (next.y - cur.y)
|
|
- (cur.y - prev.y) * (next.x - cur.x);
|
|
|
|
if (z < 0) {
|
|
zCount--;
|
|
}
|
|
else if (z > 0) {
|
|
zCount++;
|
|
}
|
|
}
|
|
|
|
return zCount === 0
|
|
? 0
|
|
: zCount < 0 ? 1 : -1;
|
|
}
|
|
|
|
/**
|
|
* 获取路径哈希
|
|
*
|
|
* @param {Array} path 路径数组
|
|
* @return {number} 哈希值
|
|
*/
|
|
export function getPathHash(path) {
|
|
let hash = 0;
|
|
const seed = 131;
|
|
|
|
path.forEach(p => {
|
|
hash = 0x7FFFFFFF & (hash * seed + getPointHash(p) + (p.onCurve ? 1 : 0));
|
|
});
|
|
|
|
return hash;
|
|
}
|
|
|
|
|
|
/**
|
|
* 移除重复点
|
|
*
|
|
* @param {Array} points 点集合
|
|
* @return {Array} 移除后点集合
|
|
*/
|
|
export function removeOverlapPoints(points) {
|
|
const hash = {};
|
|
const ret = [];
|
|
for (let i = 0, l = points.length; i < l; i++) {
|
|
const hashcode = points[i].x * 31 + points[i].y;
|
|
if (!hash[hashcode]) {
|
|
ret.push(points[i]);
|
|
hash[hashcode] = 1;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* 对path进行双向链表连接
|
|
*
|
|
* @param {Array} path 轮廓数组
|
|
* @return {Array} path
|
|
*/
|
|
export function makeLink(path) {
|
|
for (let i = 0, l = path.length; i < l; i++) {
|
|
const cur = path[i];
|
|
const prev = i === 0 ? path[l - 1] : path[i - 1];
|
|
const next = i === l - 1 ? path[0] : path[i + 1];
|
|
cur.index = i;
|
|
cur.next = next;
|
|
cur.prev = prev;
|
|
}
|
|
|
|
return path;
|
|
}
|
|
|
|
/**
|
|
* 对path进行缩放
|
|
*
|
|
* @param {Array} path 轮廓数组
|
|
* @param {number} ratio 缩放大小
|
|
*
|
|
* @return {Array} path
|
|
*/
|
|
export function scale(path, ratio) {
|
|
for (let i = 0, l = path.length; i < l; i++) {
|
|
const cur = path[i];
|
|
cur.x *= ratio;
|
|
cur.y *= ratio;
|
|
}
|
|
|
|
return path;
|
|
}
|
|
|
|
|
|
export function clone(path) {
|
|
return path ? path.map(p => {
|
|
const newP = {
|
|
x: p.x,
|
|
y: p.y
|
|
};
|
|
|
|
if (p.onCurve) {
|
|
newP.onCurve = true;
|
|
}
|
|
|
|
return newP;
|
|
}) : path;
|
|
}
|