（H5前端CAD平台）在线CAD如何实现图形识别功能

前言

CAD图形识别功能可帮助用户快速识别和提取CAD图纸中的各种图形，从而加速设计过程。
可应用在识别与分类阶段，自动识别图纸中的不同元素，通过特定特征进行区分，减少了手动分类的工作量；也可应用在数量统计阶段，统计图纸中各种构件的数量用于预算；还可运用在图纸定位和应用阶段，快速定位图纸上的特定元素，便于快速查找和修改。

mxcad为用户提供了图形识别功能和API，用户可根据自身需求对该功能进行拓展或二次开发，更详细文档关注公Z号：梦想云图网页CAD。

图形识别步骤

1. 打开mxcad在线示例demo：demo.mxdraw3d.com:3000/mxcad/

2. 点击【工具(A)】菜单栏，找到图形识别功能，选择【图形识别】按钮，如下图：

3. 根据命令行提示，点击鼠标左键点选图元或拉框选择需要识别的图形（图形识别功能目前支持识别直线类、多段线类、弧线类、圆类，以及块这五类图元），如下图：

4. 点击右键结束选择后，在弹出的图形识别框内设置查找图形详情，设置图形名称可方便后续查找已识别图形；设置重新选择图形时，会覆盖当前选中图形；设置区域查找时，需要用户框选查找范围，若未框选范围则会默认为全图纸查找图形，如下图：

5. 在图形识别框内点击【开始识别】按钮，开始在目标范围内查找图形，并将查找结果展示在图形识别列表中。点击图形识别列表下的坐标对应的【查看】按钮会自动定位到对应的图形位置，并圈选出目标图形，如下图：

6.当识别多个图形后，可点击目标图形统计表格对应的操作列中的【详情】按钮查看识别详情，图形坐标列表将转换为该目标图形的识别结果，如下图：

识别注意事项：

如果需要识别的图形较为复杂，为保证识别速度与精度，我们需尽可能查找图形中的特殊部分而不是选取整个图形（图形对象过多时可能会导致卡顿，影响用户使用效率）。
图形识别支持区域选择，用户可根据自身需求精确定位图形筛选区域。

功能开发

mxcad 图形识别功能中运用的核心思想是通过[McDbEntity]实体中每个实体的特征在图纸中进行查找，查找的实体中包括了[直线类]、[多段线类]、[弧线类]、[圆类]，以及[块]。

下列为基于mxcad 封装的图形识别类SearchSamePattern用户可根据该类的使用方法利用 mxcad 进行二次开发，代码如下：

import {
DxfCode, McCmColor, McDbArc, McDbBlockReference, McDbCircle, McDbLine, McDbPolyline, McDbWipeout, McGePoint3d,
McGePoint3dArray, McGeVector3d, MxCADResbuf, MxCADSelectionSet, MxCADUtility, MxCpp
} from "mxcad";
import { MxFun } from "mxdraw";
export class SearchSamePattern {
/** 识别图元数 */
private objectCount: number = 0;
/** 选择图形集合 Map*/
private selectObjects: any;
private dTol = 0.000001;
/**
* pt1:左下角
* pt2:右上角
* pt3:左上角
* pt4:右下角
*/
private pt1: McGePoint3d;
private pt2: McGePoint3d;
private pt3: McGePoint3d;
private pt4: McGePoint3d;//包围盒大小
private pl: McDbPolyline;
/** 识别图形类名集合 [string] */
private classNames: any
/** 识别图形图片地址 */
private patternImgUrl: String
/** 识别对象详情 Map*/
private objectsDetails: any = {};
// 下列为识别结果数据
/** 识别后的图形位置数组集合 */;
private graphBoxsPos: any[] = [];
private formPt: McGePoint3d;
private toPt: McGePoint3d;
/** 点精度值 */
private dTolPt: any;
/** 识别后图形列表 */
private patternList: any = {};
/** 选择的图形集合 */
public setSelectset(ss: MxCADSelectionSet): Promise {
if (!ss?.count()) return;
const mxcad = MxCpp.getCurrentMxCAD();
// 获取当前图纸的空间块表记录包围盒
const { maxPt, minPt } = mxcad.getDatabase().currentSpace.getBoundingBox();
const currentDrawOrder = mxcad.getDatabase().currentSpace.getMinMaxDrawOrder()
const n = MxFun.screenCoordLong2Doc(Math.abs(maxPt.x - minPt.x));
minPt.x -= n; minPt.y -= n; maxPt.x += n; maxPt.y += n;
let points = new McGePoint3dArray();
points.append(minPt);
points.append(new McGePoint3d(minPt.x, maxPt.y, 0));
points.append(new McGePoint3d(maxPt.x, maxPt.y, 0));
points.append(new McGePoint3d(maxPt.x, minPt.y, 0));
this.objectCount = ss.count();
// 获取遮罩层drawOrder
let wipeout = new McDbWipeout
wipeout.setVertices(points);
const wipeoutId = mxcad.drawEntity(wipeout);
const e = wipeoutId.getMcDbEntity();
e.drawOrder = currentDrawOrder.maxDrawOrder + 1;
this.selectObjects = {};
const oldDrawOder = [];
ss.forEach(id => {
const ent = id.getMcDbEntity();
/** 记录识别图形的信息 */
if (!this.selectObjects[ent.objectName]) this.selectObjects[ent.objectName] = [];
this.selectObjects[ent.objectName].push(ent);
if (ent.objectName === 'McDbLine') {
if (!this.objectsDetails['McDbLine']) this.objectsDetails['McDbLine'] = [];
this.objectsDetails['McDbLine'].push({ entity: ent, length: (ent as McDbLine).getLength().val });
} else if (ent.objectName === 'McDbArc') {
if (!this.objectsDetails['McDbArc']) this.objectsDetails['McDbArc'] = [];
const length = (ent as McDbArc).getLength().val;
const { bugle } = this.getBugle((ent as McDbArc), length)
this.objectsDetails['McDbArc'].push({ entity: ent, length, bugle });
} else if (ent.objectName === 'McDbCircle') {
if (!this.objectsDetails['McDbCircle']) this.objectsDetails['McDbCircle'] = [];
const radius = (ent as McDbCircle).radius;
this.objectsDetails['McDbCircle'].push({ entity: ent, radius });
} else if (ent.objectName === 'McDbBlockReference') {
if (!this.objectsDetails['McDbBlockReference']) this.objectsDetails['McDbBlockReference'] = [];
const blkName = (ent as McDbBlockReference).blockName;
this.objectsDetails['McDbBlockReference'].push({ entity: ent, blkName });
} else if (ent.objectName === 'McDbPolyline') {
if (!this.objectsDetails['McDbPolyline']) this.objectsDetails['McDbPolyline'] = [];
const length = (ent as McDbPolyline).getLength().val;
this.objectsDetails['McDbPolyline'].push({ entity: ent, length });
}
/** 渲染顺序 */
oldDrawOder.push({ obj: ent, drawOrder: ent.drawOrder });
ent.drawOrder = e.drawOrder + 1;
const { maxPt, minPt } = ent.getBoundingBox();
if (!this.pt1 || !this.pt2) {
this.pt1 = minPt;
this.pt2 = maxPt;
} else {
if (minPt.x < this.pt1.x) this.pt1.x = minPt.x;
if (minPt.y < this.pt1.y) this.pt1.y = minPt.y;
if (maxPt.x > this.pt2.x) this.pt2.x = maxPt.x;
if (maxPt.y > this.pt2.y) this.pt2.y = maxPt.y;
}
});
this.classNames = Object.keys(this.selectObjects);
/**
* 计算包围盒其他两个角点
*/
this.pt3 = new McGePoint3d(this.pt1.x, this.pt2.y);
this.pt4 = new McGePoint3d(this.pt2.x, this.pt1.y);
/** 绘制识别图形包围盒 */
this.pl = new McDbPolyline()
this.pl.addVertexAt(this.pt1);
this.pl.addVertexAt(this.pt3);
this.pl.addVertexAt(this.pt2);
this.pl.addVertexAt(this.pt4);
this.pl.isClosed = true;
const num = MxFun.screenCoordLong2Doc(10);
this.pt1.x -= num; this.pt1.y -= num; this.pt2.x += num; this.pt2.y += num;
// 生成预览图
let w = Math.abs(this.pt1.x - this.pt2.x);
let h = Math.abs(this.pt1.y - this.pt2.y);
if (w < 1 || h < 1) return;
let jpg_width = 300;
let jpg_height = 240;
return new Promise((resolve, reject) => {
MxFun.getCurrentDraw().createCanvasImageData(
(imageData: String) => {
this.patternImgUrl = imageData;
// 恢复绘制顺序
oldDrawOder.forEach(item => {
item.obj.drawOrder = item.drawOrder;
})
wipeoutId.erase();
resolve(imageData)
},
{
width: jpg_width, // 图片宽
height: jpg_height, // 图片高
range_pt1: this.pt1.toVector3(), // 截图范围角点1
range_pt2: this.pt2.toVector3(), // 截图范围角点2
}
);
});
};
// 开始识别图形
/**
* 1.查找初始包围盒
* 2.筛选符合条件的包围盒
* 3.比较包围盒内的每一个图元与需要识别的图元是否匹配
*/
public identifyGraphics(corner1?: McGePoint3d, corner2?: McGePoint3d): any {
/** 记录图形缩略图 */
this.patternList.patternImgUrl = this.patternImgUrl;
/**初始化图形位置列表 */
this.graphBoxsPos.length = 0;
const mxcad = MxCpp.getCurrentMxCAD();
this.dTolPt = mxcad.mxdraw.viewCoordLong2Cad(0.5);// 设置精度值
if (!this.classNames) return;
const array = this.classNames.map(name => this.selectObjects[name].length);
const minIndex = array.findIndex(element => element === Math.min(...array));
const str = this.classNames[minIndex];
/** 识别块 */
if (str === 'McDbBlockReference') {
const refBlk = this.selectObjects['McDbBlockReference'][0].clone() as McDbBlockReference;
const blkName = refBlk.blockName; // 图块名
const { position } = this.getBlkMidPt(refBlk);
this.formPt = position;
const rotate = refBlk.rotation;
// 设置图块过滤器
const filter = new MxCADResbuf([DxfCode.kEntityType, "INSERT"])
const ss = new MxCADSelectionSet()
if (corner1 && corner2) {
// 局部选择
ss.crossingSelect(corner1.x, corner1.y, corner2.x, corner2.y, filter);
} else {
// 全局选择
ss.allSelect(filter);
};
// 筛选出符合条件的块
const boxs: any[] = [];
ss.forEach(id => {
const _blk = id.getMcDbEntity().clone() as McDbBlockReference;
/** 块名相等=》计算旋转角度=》计算包围盒大小 */
if (blkName === _blk.blockName) {
const _rotate = _blk.rotation;
const angle = rotate >= 0 ? _rotate - rotate : rotate - _rotate;
const { position: _position, minPt, maxPt } = this.getBlkMidPt(_blk);
if (this.classNames.length === 1) {
this.toPt = _position;
this.identificationBBox(minPt, maxPt, 0)
} else {
// 平移旋转初始包围盒。计算出最新包围盒的大小
const _pl = this.pl.clone() as McDbPolyline;
_pl.move(this.formPt, _position);
_pl.rotate(_position, angle);
let x = [], y = [];
for (let i = 0; i < _pl.numVerts(); i++) {
const pt = _pl.getPointAt(i).val;
x.push(pt.x);
y.push(pt.y);
}
const _minPt = new McGePoint3d(Math.min(...x) - 1, Math.min(...y) - 1);
const _maxPt = new McGePoint3d(Math.max(...x) + 1, Math.max(...y) + 1);
const res = boxs.filter(item => {
let ret1 = _minPt.distanceTo(item.pt1) < this.dTolPt && _maxPt.distanceTo(item.pt2) < this.dTolPt
let ret2 = _minPt.distanceTo(item.pt2) < this.dTolPt && _maxPt.distanceTo(item.pt1) < this.dTolPt
return ret1 || ret2
})
if (!res.length) {
boxs.push({ pt1: _minPt, pt2: _maxPt });
this.toPt = _position;
// MxCpp.getCurrentMxCAD().drawLine(_maxPt.x, _maxPt.y, _minPt.x, _minPt.y);
this.identificationBBox(_minPt, _maxPt, angle);
}
}
}
});
}
/** 识别弧线 */
else if (str === 'McDbArc') {
// 识别直线
const refArc = this.selectObjects['McDbArc'][0].clone() as McDbArc;
const length = refArc.getLength().val; // 弧线线长度
// 圆弧凸度
const { bugle, midPt } = this.getBugle(refArc, length);
const center = refArc.center;
const vec = center.sub(midPt);
// 设置弧线过滤器
const filter = new MxCADResbuf([DxfCode.kEntityType, "ARC"])
const ss = new MxCADSelectionSet()
if (corner1 && corner2) {
// 局部选择
ss.crossingSelect(corner1.x, corner1.y, corner2.x, corner2.y, filter);
} else {
// 全局选择
ss.allSelect(filter);
};
// 筛选出符合条件的弧线
const boxs: any[] = [];
ss.forEach(id => {
const _arc = id.getMcDbEntity().clone() as McDbArc;
const _length = _arc.getLength().val;
const { bugle: _bugle, midPt: _midPt } = this.getBugle(_arc, _length);
/** 筛选出圆弧凸度与长度相同的弧线*/
if (Math.abs(_length - length) < this.dTol && Math.abs(_bugle - bugle) < this.dTol) {
/** 分两种情况
* 1.直接旋转平移得到
* 2.镜像得到=》移动到目标位置+旋转角度+镜像翻转=》比较起始点位置
*/
// 平移+旋转
const _center = _arc.center;
const _vec = _center.sub(_midPt);
const angle = _vec.angleTo2(vec, McGeVector3d.kNegateZAxis);
// 旋转平移初始包围盒。计算出最新包围盒的大小
const _pl = this.pl.clone() as McDbPolyline;
_pl.move(midPt, _midPt);
_pl.rotate(_midPt, angle);
let x = [], y = [];
for (let i = 0; i < _pl.numVerts(); i++) {
const pt = _pl.getPointAt(i).val;
x.push(pt.x);
y.push(pt.y);
}
const _minPt = new McGePoint3d(Math.min(...x) - 1, Math.min(...y) - 1);
const _maxPt = new McGePoint3d(Math.max(...x) + 1, Math.max(...y) + 1);
const res = boxs.filter(item => {
let ret1 = _minPt.distanceTo(item.pt1) < this.dTolPt && _maxPt.distanceTo(item.pt2) < this.dTolPt
let ret2 = _minPt.distanceTo(item.pt2) < this.dTolPt && _maxPt.distanceTo(item.pt1) < this.dTolPt
let ret3 = _midPt.distanceTo(item.midPt) < this.dTolPt
return (ret1 || ret2) && ret3
})
if (!res.length) {
boxs.push({ pt1: _minPt, pt2: _maxPt, midPt: _midPt });
this.toPt = _midPt;
this.formPt = midPt;
this.identificationBBox(_minPt, _maxPt, angle);
}
}
});
}
/** 识别直线 */
else if (str === 'McDbLine') {
// 识别直线
const refLine = this.selectObjects['McDbLine'][0].clone() as McDbLine;
const length = refLine.getLength().val; // 直线长度
const vec = refLine.endPoint.sub(refLine.startPoint); // 直线角度
// 设置直线过滤器
const filter = new MxCADResbuf([DxfCode.kEntityType, "LINE"])
const ss = new MxCADSelectionSet()
if (corner1 && corner2) {
// 局部选择
ss.crossingSelect(corner1.x, corner1.y, corner2.x, corner2.y, filter);
} else {
// 全局选择
ss.allSelect(filter);
};
// 筛选出符合条件的直线
const lineArr: McDbLine[] = [];
ss.forEach(id => {
const line = id.getMcDbEntity().clone() as McDbLine;
const _length = line.getLength().val;
/**
* 1.未旋转
* 2.旋转过
*/
if (Math.abs(_length - length) < this.dTol) {
lineArr.push(line);
}
});
// 筛选出符合条件的直线后，根据包围盒范围再次筛选出符合条件的直线组合
const boxs: any[] = [];
if (lineArr.length > 0) {
lineArr.forEach((item) => {
/**
* 将要识别的图形进行平移+旋转到目标位置
*/
const ptArr = [item.startPoint, item.endPoint];
ptArr.forEach((point, index) => {
const _line = refLine.clone() as McDbLine;
_line.move(refLine.startPoint, point);
const _vec = ptArr[1 - index].sub(point);
const angle = _vec.angleTo2(vec, McGeVector3d.kNegateZAxis);
_line.rotate(point, angle)
const pt = _line.endPoint;
const _pl = this.pl.clone() as McDbPolyline;
_pl.move(refLine.startPoint, point);
_pl.rotate(point, angle);
const _refBoxPt1 = _pl.getPointAt(0).val;
const _refBoxPt2 = _pl.getPointAt(1).val;
const refVec1 = _refBoxPt1.sub(_line.startPoint);
const refVec2 = _refBoxPt2.sub(_line.startPoint);
if (pt.distanceTo(ptArr[1 - index]) < this.dTolPt && refVec1.isEqualTo(_refBoxPt1.sub(point)) && refVec2.isEqualTo(_refBoxPt2.sub(point))) {
let x = [], y = [];
for (let i = 0; i < _pl.numVerts(); i++) {
const pt = _pl.getPointAt(i).val;
x.push(pt.x);
y.push(pt.y);
}
const _minPt = new McGePoint3d(Math.min(...x) - 1, Math.min(...y) - 1);
const _maxPt = new McGePoint3d(Math.max(...x) + 1, Math.max(...y) + 1);
const res = boxs.filter(item => {
let r1 = _minPt.distanceTo(item.pt1) < this.dTolPt && _maxPt.distanceTo(item.pt2) < this.dTolPt
let r2 = _minPt.distanceTo(item.pt2) < this.dTolPt && _maxPt.distanceTo(item.pt1) < this.dTolPt
return r1 || r2
})
if (!res.length) {
boxs.push({ pt1: _minPt, pt2: _maxPt });
this.toPt = point;
this.formPt = refLine.startPoint;
// MxCpp.getCurrentMxCAD().drawLine(_maxPt.x, _maxPt.y, _minPt.x, _minPt.y);
this.identificationBBox(_minPt, _maxPt, angle);
}
}
})
})
};
}
/** 识别圆 */
else if (str === 'McDbCircle') {
const refCricle = this.selectObjects['McDbCircle'][0].clone() as McDbCircle;
const radius = refCricle.radius; // 圆半径
// 设置圆过滤器
const filter = new MxCADResbuf([DxfCode.kEntityType, "CIRCLE"])
const ss = new MxCADSelectionSet()
if (corner1 && corner2) {
// 局部选择
ss.crossingSelect(corner1.x, corner1.y, corner2.x, corner2.y, filter);
} else {
// 全局选择
ss.allSelect(filter);
};
// 筛选出符合条件的圆
ss.forEach(id => {
const _circle = id.getMcDbEntity().clone() as McDbCircle;
const _radius = _circle.radius;
/** 筛选出圆半径相同的圆*/
if (Math.abs(_radius - radius) < this.dTol) {
const _center = _circle.center;
this.toPt = _center;
this.formPt = refCricle.center;
// 平移初始包围盒。计算出最新包围盒的大小
const _pl = this.pl.clone() as McDbPolyline;
_pl.move(this.formPt, this.toPt);
let x = [], y = [];
for (let i = 0; i < _pl.numVerts(); i++) {
const pt = _pl.getPointAt(i).val;
x.push(pt.x);
y.push(pt.y);
}
const _minPt = new McGePoint3d(Math.min(...x) - 1, Math.min(...y) - 1);
const _maxPt = new McGePoint3d(Math.max(...x) + 1, Math.max(...y) + 1);
// MxCpp.getCurrentMxCAD().drawLine(_maxPt.x, _maxPt.y, _minPt.x, _minPt.y);
this.identificationBBox(_minPt, _maxPt, 0);
}
});
}
/** 识别多段线 */
else if (str === 'McDbPolyline') {
/** 长度+顶点数+顶点对应的凸度相等=》旋转+平移后的顶点相等+有凸度线段的中点相等*/
const refPoly = this.selectObjects['McDbPolyline'][0].clone() as McDbPolyline;
const length = refPoly.getLength().val;
const { lengthArr, bugleArr, vertNum, vec, point } = this.getPlDetails(refPoly);
// 设置多段线过滤器
const filter = new MxCADResbuf([DxfCode.kEntityType, "LWPOLYLINE"])
const ss = new MxCADSelectionSet()
if (corner1 && corner2) {
// 局部选择
ss.crossingSelect(corner1.x, corner1.y, corner2.x, corner2.y, filter);
} else {
// 全局选择
ss.allSelect(filter);
};
// 筛选出符合条件的多段线
const boxs: any[] = [];
ss.forEach(id => {
const _poly = id.getMcDbEntity().clone() as McDbPolyline;
const _length = _poly.getLength().val;
/** 筛选 长度+顶点数+顶点对应的凸度 相同的多段线*/
if (Math.abs(_length - length) < this.dTol && _poly.isClosed === refPoly.isClosed) {
const { lengthArr: _lengthArr, bugleArr: _bugleArr, vertNum: _vertNum, vec: _vec, point: _point } = this.getPlDetails(_poly);
const revBugleArr = _bugleArr.map(item => item === 0 ? item : -item);
// 全等
const r1 = lengthArr.toString() === _lengthArr.toString() && bugleArr.toString() === _bugleArr.toString();
let r2 = false;
if (!r1) {
// 反向
r2 = lengthArr.toString() === [..._lengthArr].reverse().toString() && bugleArr.toString() === [...revBugleArr].reverse().toString();
}
const r3 = vertNum === _vertNum;
// 镜像
const r4 = lengthArr.toString() === _lengthArr.toString() && bugleArr.toString() === [...revBugleArr].reverse().toString();
if ((r1 || r2 || r4) && r3) {
const poly = refPoly.clone() as McDbPolyline;
const angle1 = vec.angleTo2(McGeVector3d.kXAxis, McGeVector3d.kNegateZAxis);
// 如果是反向则方向取反
const angle2 = (r2 ? _vec.negate() : _vec).angleTo2(McGeVector3d.kXAxis, McGeVector3d.kNegateZAxis);
const angle = angle2 - angle1;
poly.move(point, _point);
poly.rotate(_point, angle);
poly.trueColor = new McCmColor(255, 0, 0);
let num = 0;
for (let i = 0; i < vertNum; i++) {
const pt = poly.getPointAt(i).val;
const width = poly.getWidthsAt(i);
const _pt = r2 ? _poly.getPointAt(vertNum - 1 - i).val : _poly.getPointAt(i).val;
const _width = r2 ? _poly.getWidthsAt(vertNum - 1 - i) : _poly.getWidthsAt(i);
if (pt.distanceTo(_pt) < this.dTolPt && width.val1 === _width.val1 && width.val2 === _width.val2) {
num += 1
} else {
// 两个点且反向的情况
if (vertNum === 2 && i === 0) {
const _pt1 = _poly.getPointAt(0).val;
const _pt2 = _poly.getPointAt(1).val;
const pt2 = poly.getPointAt(1).val;
const _width = _poly.getWidthsAt(0);
if (pt2.distanceTo(_pt2) < this.dTolPt && pt.distanceTo(_pt1) < this.dTolPt && width.val1 === _width.val2 && width.val2 === _width.val1) {
num += 2;
}
}
}
};
if (num === vertNum) {
// 旋转平移初始包围盒。计算出最新包围盒的大小
const _pl = this.pl.clone() as McDbPolyline;
_pl.move(point, _point);
_pl.rotate(_point, angle);
let x = [], y = [];
for (let i = 0; i < _pl.numVerts(); i++) {
const pt = _pl.getPointAt(i).val;
x.push(pt.x);
y.push(pt.y);
}
const _minPt = new McGePoint3d(Math.min(...x) - 1, Math.min(...y) - 1);
const _maxPt = new McGePoint3d(Math.max(...x) + 1, Math.max(...y) + 1);
const res = boxs.filter(item => {
let ret1 = _minPt.distanceTo(item.pt1) < this.dTolPt && _maxPt.distanceTo(item.pt2) < this.dTolPt
let ret2 = _minPt.distanceTo(item.pt2) < this.dTolPt && _maxPt.distanceTo(item.pt1) < this.dTolPt
return ret1 || ret2
})
if (!res.length) {
boxs.push({ pt1: _minPt, pt2: _maxPt });
this.toPt = _point;
this.formPt = point;
// MxCpp.getCurrentMxCAD().drawLine(_maxPt.x, _maxPt.y, _minPt.x, _minPt.y);
this.identificationBBox(_minPt, _maxPt, angle);
}
}
}
}
});
}
/** 返回识别列表 */
return this.patternList;
}
// 计算块中心点
private getBlkMidPt = (blkRef: McDbBlockReference) => {
const { minPt, maxPt } = blkRef.getBoundingBox();
const pt = minPt.clone().addvec(maxPt.sub(minPt).normalize().mult(maxPt.distanceTo(minPt) / 2))
return { position: pt, minPt, maxPt }
}
// 计算凸度
private getBugle = (arc: McDbArc, length: number) => {
const midPt = arc.getPointAtDist(length / 2).val;
const bugle = MxCADUtility.calcBulge(arc.getPointAtDist(0).val, midPt, arc.getPointAtDist(length).val).val;
return { bugle, midPt }
}
// 计算多段线的每一段线的长度和凸度
private getPlDetails = (pl: McDbPolyline) => {
const vertNum = pl.numVerts();
const lengthArr: number[] = [];
const bugleArr: number[] = [];
let point1: McGePoint3d, point2: McGePoint3d;
for (let i = 0; i < vertNum; i++) {
if (i < vertNum - 1) {
const p1 = pl.getPointAt(i).val;
const p2 = pl.getPointAt(i + 1).val;
const length = pl.getDistAtPoint(p2).val - pl.getDistAtPoint(p1).val;
const bugle = pl.getBulgeAt(i);
lengthArr.push(Number(length.toFixed(6)));
bugleArr.push(Number(bugle.toFixed(6)));
if (i === 0) {
point1 = p1;
}
if (i === vertNum - 2) {
point2 = p2;
}
}
};
const vec = point2.sub(point1)// 多段线角度
const point = point1.clone().addvec(point2.sub(point1).normalize().mult(point2.distanceTo(point1) / 2))
return { lengthArr, bugleArr, vertNum, vec, point }
}
// 将找到的实体数组与需要识别的实体数组比对
private comparisonPhysical = (objects: any, maxPt: McGePoint3d, minPt: McGePoint3d, angle: number): any => {
const calssNames = Object.keys(this.selectObjects);
if (!calssNames) return;
let num = 0;
if (calssNames.includes('McDbLine')) {
let ents = objects['McDbLine'];
const lineObjects = this.objectsDetails['McDbLine'];
for (let i = 0; i < lineObjects.length; i++) {
const element = lineObjects[i];
let _line = (element.entity as McDbLine).clone() as McDbLine;
_line.move(this.formPt, this.toPt);
_line.rotate(this.toPt, angle);
const indexArr: number[] = [];
const mLineArr = ents.filter((item: McDbLine, index: number) => {
if (Math.abs(element.length - item.getLength().val) < this.dTol) {
let r1 = item.startPoint.distanceTo(_line.startPoint) < this.dTolPt && item.endPoint.distanceTo(_line.endPoint) < this.dTolPt;
let r2 = item.startPoint.distanceTo(_line.endPoint) < this.dTolPt && item.endPoint.distanceTo(_line.startPoint) < this.dTolPt;
if (r1 || r2) indexArr.push(index);
return r1 || r2;
}
});
if (mLineArr.length > 0) {
num += 1;
ents.splice(indexArr[0], 1);
ents = [...ents];
} else {
break;
}
}
};
if (calssNames.includes('McDbArc')) {
let ents = objects['McDbArc'];
const arcObjects = this.objectsDetails['McDbArc'];
for (let i = 0; i < arcObjects.length; i++) {
const element = arcObjects[i];
let _arc = (element.entity as McDbArc).clone() as McDbArc;
_arc.move(this.formPt, this.toPt);
_arc.rotate(this.toPt, angle);
const startPoint = _arc.getPointAtDist(0).val;
const endPoint = _arc.getPointAtDist(element.length).val;
const indexArr: number[] = [];
const mArcArr = ents.filter((item: McDbArc, index: number) => {
const _length = item.getLength().val;
const { bugle: _bugle } = this.getBugle(item, _length)
if (Math.abs(element.length - item.getLength().val) < this.dTol && Math.abs(_bugle - element.bugle) < this.dTol) {
const _startPoint = item.getPointAtDist(0).val;
const _endPoint = item.getPointAtDist(_length).val;
let r1 = startPoint.distanceTo(_startPoint) < this.dTolPt && endPoint.distanceTo(_endPoint) < this.dTolPt;
let r2 = startPoint.distanceTo(_endPoint) < this.dTolPt && endPoint.distanceTo(_startPoint) < this.dTolPt;
if (r1 || r2) {
indexArr.push(index);
}
return r1 || r2;
}
});
if (mArcArr.length > 0) {
num += 1;
ents.splice(indexArr[0], 1);
ents = [...ents];
} else {
break;
}
}
};
if (calssNames.includes('McDbCircle')) {
let ents = objects['McDbCircle'];
const circleObjects = this.objectsDetails['McDbCircle'];
for (let i = 0; i < circleObjects.length; i++) {
const element = circleObjects[i];
let _circle = (element.entity as McDbCircle).clone() as McDbCircle;
_circle.move(this.formPt, this.toPt);
_circle.rotate(this.toPt, angle);
const center = _circle.center;
const radius = _circle.radius;
const indexArr: number[] = [];
const mCiecleArr = ents.filter((item: McDbCircle, index: number) => {
const _center = item.center;
const _radius = item.radius;
const r = Math.abs(_radius - radius) < this.dTol && center.distanceTo(_center) < this.dTolPt;
if (r) {
indexArr.push(index)
}
return r;
});
if (mCiecleArr.length > 0) {
num += 1;
ents.splice(indexArr[0], 1);
ents = [...ents];
} else {
break;
}
}
};
if (calssNames.includes('McDbBlockReference')) {
/** 平移+旋转=>比对包围盒大小+块名字 */
let ents = objects['McDbBlockReference'];
const blkObjects = this.objectsDetails['McDbBlockReference'];
for (let i = 0; i < blkObjects.length; i++) {
const element = blkObjects[i];
let _blk = (element.entity as McDbBlockReference).clone() as McDbBlockReference;
_blk.move(this.formPt, this.toPt);
_blk.rotate(this.toPt, angle);
const blkName = _blk.blockName;
const { minPt: blkMinPt, maxPt: blkMaxPt } = this.getBlkMidPt(_blk);
const indexArr: number[] = [];
const mArcArr = ents.filter((item: McDbBlockReference, index: number) => {
const _blkName = item.blockName;
if (_blkName === blkName) {
if (this.classNames.length === 1) {
indexArr.push(index);
return true
} else {
const { minPt: _blkMinPt, maxPt: _blkMaxPt } = this.getBlkMidPt(item);
let r1 = blkMinPt.distanceTo(_blkMinPt) < this.dTolPt && blkMaxPt.distanceTo(_blkMaxPt) < this.dTolPt;
if (r1) {
indexArr.push(index);
}
return r1
}
}
});
if (mArcArr.length > 0) {
num += 1;
ents.splice(indexArr[0], 1);
ents = [...ents];
} else {
return;
}
}
}
if (calssNames.includes('McDbPolyline')) {
/** 平移+旋转=>比对凸度+点位置 */
let ents = objects['McDbPolyline'];
const plObjects = this.objectsDetails['McDbPolyline'];
for (let i = 0; i < plObjects.length; i++) {
const element = plObjects[i];
let _poly = (element.entity as McDbPolyline).clone() as McDbPolyline;
_poly.move(this.formPt, this.toPt);
_poly.rotate(this.toPt, angle);
const { lengthArr, bugleArr, vertNum } = this.getPlDetails(_poly);
const indexArr: number[] = [];
const mPlArr = ents.filter((item: McDbPolyline, index: number) => {
const _length = item.getLength().val;
if (Math.abs(_length - element.length) < this.dTol && _poly.isClosed === _poly.isClosed) {
const { lengthArr: _lengthArr, bugleArr: _bugleArr, vertNum: _vertNum } = this.getPlDetails(item);
const revBugleArr = _bugleArr.map(item => item === 0 ? item : -item);
const r1 = lengthArr.toString() === _lengthArr.toString() && bugleArr.toString() === _bugleArr.toString();
let r2 = false;
if (!r1) {
r2 = lengthArr.toString() === [..._lengthArr].reverse().toString() && bugleArr.toString() === [...revBugleArr].reverse().toString();
}
const r3 = vertNum === _vertNum;
if ((r1 || r2) && r3) {
let _num = 0;
for (let i = 0; i < vertNum; i++) {
const pt = _poly.getPointAt(i).val;
const width = _poly.getWidthsAt(i);
const _pt = r2 ? item.getPointAt(vertNum - 1 - i).val : item.getPointAt(i).val;
const _width = r2 ? item.getWidthsAt(vertNum - 1 - i) : item.getWidthsAt(i);
if (pt.distanceTo(_pt) < this.dTolPt && width.val1 === _width.val1 && width.val2 === _width.val2) {
_num += 1
} else {
// 两个点且反向的情况
if (vertNum === 2 && i === 0) {
const _pt1 = item.getPointAt(0).val;
const _pt2 = item.getPointAt(1).val;
const _width = item.getWidthsAt(0);
const pt2 = _poly.getPointAt(1).val;
if (pt2.distanceTo(_pt2) < this.dTolPt && pt.distanceTo(_pt1) < this.dTolPt && width.val1 === _width.val2 && width.val2 === _width.val1) {
_num += 2;
}
}
}
};
if (_num === vertNum) {
indexArr.push(index);
}
return _num === vertNum;
}
}
});
if (mPlArr.length > 0) {
num += 1;
ents.splice(indexArr[0], 1);
ents = [...ents];
} else {
break;
}
}
}
if (num === this.objectCount) {
// 匹配成功
const pt = minPt.clone().addvec(maxPt.clone().sub(minPt).normalize().mult(minPt.distanceTo(maxPt) / 2));
const res = this.graphBoxsPos.filter(point => pt.distanceTo(point) < this.dTolPt);
if (!res.length) {
this.graphBoxsPos.push(pt)
}
};
this.patternList.graphBoxsPos = [...this.graphBoxsPos];
}
// 识别包围盒是否符合要求
private identificationBBox = (minPt: McGePoint3d, maxPt: McGePoint3d, angle: number): any => {
const _ss = new MxCADSelectionSet()
_ss.crossingSelect(minPt.x, minPt.y, maxPt.x, maxPt.y);
const boxEntity = {};
_ss.forEach(id => {
const ent = id.getMcDbEntity();
if (!boxEntity[ent.objectName]) boxEntity[ent.objectName] = [];
boxEntity[ent.objectName].push(ent);
});
let r = this.classNames.filter(name => boxEntity[name] && this.selectObjects[name].length <= boxEntity[name].length);
if (r.length === this.classNames.length) {
this.comparisonPhysical(boxEntity, maxPt, minPt, angle);
}
}
};

调用 SearchSamePattern 类，实现图形识别功能，代码如下：

/** 获取需要识别的图形 */
const getIdentificationPattern = async () => {
// 获取需要识别的图形
const ss = new MxCADSelectionSet();// 选择集
const filter = new MxCADResbuf([DxfCode.kEntityType, "LINE,ARC,CIRCLE,LWPOLYLINE,INSERT"])
if (!await ss.userSelect("请点击左键或拉框选择需要识别的图形:", filter)) return;
if (ss.count() == 0) return;
// 搜索图形
const searchPattern = new SearchSamePattern();
// 搜索图形简图地址
const patternImgUrl = await searchPattern.setSelectset(ss);
if (!patternImgUrl.value) return;
// 获取识别结果
const searchList = searchPattern.identifyGraphics();
console.log(searchList);
}