94 lines
2.9 KiB
JavaScript
94 lines
2.9 KiB
JavaScript
/**
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* @file 求路径的合并
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* 利用插值将曲线转换成直线，求解后再转换成曲线
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* @author mengke01(kekee000@gmail.com)
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*/
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define(
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function (require) {
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var Clipper = require('./join/Clipper');
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var Relation = require('./join/relation');
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var pathUtil = require('./pathUtil');
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var interpolate = pathUtil.interpolate;
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var deInterpolate = pathUtil.deInterpolate;
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var util = require('graphics/util');
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var ceilPoint = util.ceilPoint;
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var interpolatePathCrossBezier = require('./join/interpolatePathCrossBezier');
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var bezier2Segment = require('./join/bezier2Segment');
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var segment2Bezier = require('./join/segment2Bezier');
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var reducePath = require('./reducePath');
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/**
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* 求路径交集、并集、差集
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*
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* @param {Array} paths 路径集合
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* @param {number} relation 关系
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* @return {Array} 合并后的路径
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*/
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function pathJoin(paths, relation) {
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if (paths.length === 1) {
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if (relation === Relation.intersect) {
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return [];
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}
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return paths;
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}
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var i;
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var l;
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// 对路径进行插值，求舍入
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for (i = 0, l = paths.length; i < l; i++) {
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paths[i].forEach(ceilPoint);
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paths[i] = interpolate(paths[i]);
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}
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// 计算bezier、直线的交点，分割bezier曲线
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for (i = 0, l = paths.length; i < l; i++) {
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for (var j = i; j < l; j++) {
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interpolatePathCrossBezier(paths[i], paths[j]);
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}
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}
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var bezierHash = {};
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// 对曲线使用线段拟合，clipper求路径关系
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for (i = 0, l = paths.length; i < l; i++) {
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paths[i] = bezier2Segment(paths[i], bezierHash);
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}
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var clipper = new Clipper();
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clipper.addSubject(paths[0]);
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for (i = 1, l = paths.length; i < l; i++) {
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// 非相交可以不需要clip路径，相交则把最后一个路径作为相交路径
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if (relation === Relation.intersect || relation === Relation.tangency) {
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clipper.addClip(paths[i]);
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}
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else {
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clipper.addSubject(paths[i]);
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}
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}
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paths = clipper.execute(relation);
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if (Object.keys(bezierHash).length) {
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paths = segment2Bezier(paths, bezierHash);
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}
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return paths.filter(function (path) {
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return path.length > 2;
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}).map(function (path) {
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return reducePath(deInterpolate(path)).reverse();
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});
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}
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pathJoin.Relation = Relation;
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return pathJoin;
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}
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);
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