cut-demo/src/Nest/Core/Path.ts

import { Box2 } from "../Common/Box2";
import { clipperCpp } from "../Common/ClipperCpp";
import { NestFiler } from "../Common/Filer";
import { Point } from "../Common/Point";
import { equaln } from "../Common/Util";
import { Vector2 } from "../Common/Vector2";

/**
 * 轮廓路径类
 * 可以求NFP，和保存NFPCahce
 * 因为NFP结果是按照最低点移动的,所以将点旋转后,按照盒子将点移动到0点.
 */
export class Path
{
    Id: number;
    Points: Point[];
    OutsideNFPCache: { [key: number]: Point[][]; } = {};
    InsideNFPCache: { [key: number]: Point[][]; } = {};

    constructor(origionPoints?: Point[], rotation: number = 0)
    {
        if (origionPoints)
            this.Init(origionPoints, rotation);
    }

    Origion: Path;
    //点表在旋转后的原始最小点.使用这个点将轮廓移动到0点
    OrigionMinPoint: Vector2;
    Rotation: number;

    Size: Vector2;//序列化
    Init(origionPoints: Point[], rotation: number)
    {
        this.Rotation = rotation;
        if (rotation === 0)
            this.Points = origionPoints.map(p => { return { ...p }; });
        else
        {
            let c = Math.cos(rotation);
            let s = Math.sin(rotation);

            let npts: Point[] = [];
            for (let p of origionPoints)
            {
                let x = p.x;
                let y = p.y;
                const x1 = x * c - y * s;
                const y1 = x * s + y * c;
                npts.push({ x: x1, y: y1 });
            }
            this.Points = npts;
        }

        let box = new Box2();
        let v2 = new Vector2();
        for (let p of this.Points)
        {
            v2.x = p.x;
            v2.y = p.y;
            box.expandByPoint(v2);
        }

        this.OrigionMinPoint = box.min;
        this.Size = box.max.sub(box.min);

        for (let p of this.Points)
        {
            p.x -= box.min.x;
            p.y -= box.min.y;
        }
    }

    GetNFPs(path: Path, outside: boolean): Point[][]
    {
        // 寻找内轮廓时,面积应该比本path小,这个判断移交给使用者自己判断
        // if (!outside && this.Area < path.Area) return [];
        let nfps = clipperCpp.lib.minkowskiSumPath(this.BigIntPoints, path.MirrorPoints, true);
        nfps = nfps.filter((nfp) =>
        {
            let area = Area(nfp);
            if (area > 1) return outside;//第一个不一定是外轮廓,但是面积为正时肯定为外轮廓
            if (Math.abs(area) < 10) return false;//应该不用在移除这个了

            let { x, y } = nfp[0];
            if (outside)
            {
                if (this.Area > path.Area)
                {
                    let p = { x: path.InPoint.x + x, y: path.InPoint.y + y };
                    if (p.x < 0 || p.y < 0 || p.x > this.BigSize.x || p.y > this.BigSize.y)
                        return true;
                    let dir = clipperCpp.lib.pointInPolygon(p, this.BigIntPoints);
                    return dir === 0;
                }
                else
                {
                    let p = { x: this.InPoint.x - x, y: this.InPoint.y - y };
                    if (p.x < 0 || p.y < 0 || p.x > path.BigSize.x || p.y > path.BigSize.y)
                        return true;
                    let dir = clipperCpp.lib.pointInPolygon(p, path.BigIntPoints);
                    return dir === 0;
                }
            }
            else
            {
                let p = { x: path.InPoint.x + x, y: path.InPoint.y + y };
                if (p.x < 0 || p.y < 0 || p.x > this.BigSize.x || p.y > this.BigSize.y)
                    return false;
                let dir = clipperCpp.lib.pointInPolygon(p, this.BigIntPoints);
                return dir === 1;
            }
        });
        return nfps;
    }

    GetOutsideNFP(path: Path): Point[][]
    {
        let nfps = this.OutsideNFPCache[path.Id];
        if (nfps) return nfps;

        if (this.IsRect && path.IsRect)
        {
            let [ax, ay] = [this.Size.x * 1e4, this.Size.y * 1e4];
            let [bx, by] = [path.Size.x * 1e4, path.Size.y * 1e4];
            nfps = [[
                { x: -bx, y: -by },
                { x: ax, y: -by },
                { x: ax, y: ay },
                { x: -bx, y: ay },
            ]];
        }
        else
            nfps = this.GetNFPs(path, true);
        this.OutsideNFPCache[path.Id] = nfps;
        //虽然有这种神奇的特性，但是好像并不会提高性能。
        // path.OutsideNFPCache[this.id] = (this, nfps.map(nfp =>
        // {
        //     return nfp.map(p =>
        //     {
        //         return { x: -p.x, y: -p.y };
        //     });
        // }));
        return nfps;
    }
    GetInsideNFP(path: Path): Point[][]
    {
        if (path.Area > this.Area) return;
        let nfp = this.InsideNFPCache[path.Id];
        if (nfp) return nfp;

        let nfps: Point[][];
        if (this.IsRect)
        {
            let [ax, ay] = [this.Size.x * 1e4, this.Size.y * 1e4];
            let [bx, by] = [path.Size.x * 1e4, path.Size.y * 1e4];

            if (ax === bx) ax += 1;
            if (ay === by) ay += 1;

            if (bx > ax || by > ay)
                return;
            nfps = [[
                { x: 0, y: 0 },
                { x: ax - bx, y: 0 },
                { x: ax - bx, y: ay - by },
                { x: 0, y: ay - by }
            ]];
        }
        else
            nfps = this.GetNFPs(path, false);

        if (path.Id !== undefined)
            this.InsideNFPCache[path.Id] = nfps;
        return nfps;
    }

    private _InPoint: Point;

    /**
     * 用这个点来检测是否在Path内部
     */
    private get InPoint()
    {
        if (this._InPoint) return this._InPoint;
        let mp = { x: (this.Points[0].x + this.Points[1].x) / 2, y: (this.Points[0].y + this.Points[1].y) / 2 };
        let normal = new Vector2(this.Points[1].x - this.Points[0].x, this.Points[1].y - this.Points[0].y).normalize();
        // [normal.x, normal.y] = [normal.y, -normal.x];
        mp.x -= normal.y;
        mp.y += normal.x;

        mp.x *= 1e4;
        mp.y *= 1e4;
        this._InPoint = mp;
        return mp;
    }

    protected _BigIntPoints: Point[];
    get BigIntPoints()
    {
        if (this._BigIntPoints) return this._BigIntPoints;
        this._BigIntPoints = this.Points.map(p =>
        {
            return {
                x: Math.round(p.x * 1e4),
                y: Math.round(p.y * 1e4),
            };
        });
        return this._BigIntPoints;
    }

    private _BigSize: Vector2;
    get BigSize()
    {
        if (this._BigSize) return this._BigSize;
        this._BigSize = new Vector2(this.Size.x * 1e4, this.Size.y * 1e4);
        return this._BigSize;
    }

    protected _MirrorPoints: Point[];
    get MirrorPoints()
    {
        if (!this._MirrorPoints)
            this._MirrorPoints = this.BigIntPoints.map(p =>
            {
                return { x: -p.x, y: -p.y };
            });

        return this._MirrorPoints;
    }

    protected _BoundingBox: Box2;
    get BoundingBox()
    {
        if (!this._BoundingBox)
            this._BoundingBox = new Box2(new Vector2, this.Size);
        return this._BoundingBox;
    }

    protected _Area: number;
    get Area()
    {
        if (this._Area === undefined)
            this._Area = Area(this.Points);
        return this._Area;
    }
    set Area(a: number)
    {
        this._Area = a;
    }

    private _IsRect: boolean;
    get IsRect()
    {
        if (this._IsRect === undefined)
        {
            let s = this.BoundingBox.getSize(new Vector2);
            this._IsRect = equaln(this.Area, s.x * s.y, 1);
        }
        return this._IsRect;
    }

    ReadFile(file: NestFiler): void
    {
        let ver = file.Read();
        this.Id = file.Read();
        let arr = file.Read();
        this.Points = [];
        for (let i = 0; i < arr.length; i += 2)
        {
            let p = { x: arr[i], y: arr[i + 1] };
            this.Points.push(p);
        }

        this.Size = new Vector2(file.Read(), file.Read());
        this._Area = file.Read();
        let id = file.Read();
        if (id !== -1)
        {
            this.Origion = id;
            this.Rotation = file.Read();
            this.OrigionMinPoint = new Vector2(file.Read(), file.Read());
        }
    }
    WriteFile(file: NestFiler): void
    {
        file.Write(1);//ver
        file.Write(this.Id);
        let arr: number[] = [];
        for (let p of this.Points)
            arr.push(p.x, p.y);
        file.Write(arr);

        file.Write(this.Size.x);
        file.Write(this.Size.y);
        file.Write(this._Area);
        if (this.Origion && this.Origion.Id)
        {
            //如果有原始的id,则传递它,以便后续进行NFP复用.
            file.Write(this.Origion.Id);
            file.Write(this.Rotation);
            file.Write(this.OrigionMinPoint.x);
            file.Write(this.OrigionMinPoint.y);
        }
        else
            file.Write(-1);
    }
}


//点表面积
export function Area(pts: Point[]): number
{
    let cnt = pts.length;
    if (cnt < 3)
        return 0;
    let a = 0;
    for (let i = 0, j = cnt - 1; i < cnt; ++i)
    {
        a += (pts[j].x + pts[i].x) * (pts[j].y - pts[i].y);
        j = i;
    }
    return -a * 0.5;
}

/**
 * 平移点表,返回新点表
 */
export function TranslatePath(pts: Point[], p: Point): Point[]
{
    return pts.map(px =>
    {
        return { x: p.x + px.x, y: p.y + px.y };
    });
}

//缩放点表,返回原始点表
export function PathScale(pts: Point[], scale: number): Point[]
{
    for (let p of pts)
    {
        p.x *= scale;
        p.y *= scale;
    }
    return pts;
}