Mx2DNode Secondary Development API Reference (backend parametric drawing / data extraction)

Compiled from the project TypeScript source (src/mxcad/*.ts, src/sample/*.ts); all signatures and return values are subject to the source code.

I. Usage Pattern

Create a new .ts file under src/, import the modules, and use them:

import { Mx2DDraw, MxBackstage, MxFun } from "../MxFun";
import { McDbDatabase } from "../mxcad/McDbDatabase";
import { McGePoint3d } from "../mxcad/McGePoint3d";
// ... import the remaining McDb* classes you need from ../mxcad/

Typical flow (see sample/ParamDraw.ts):

// 1. Open the blank template (empty_template.dwg in the project directory)
if (!MxBackstage.openFile(Mx2DDraw.getEmptyTemplateDwgFilePath())) { /* failed */ }

// 2. Draw (see section 2)
Mx2DDraw.drawLine(new McGePoint3d([0,0,0]), new McGePoint3d([100,100,0]));

// 3. Save (DWG/DXF both fine; relative paths are relative to the project directory;
//    without a DWG license module it auto-converts via mxcadassembly)
if (!MxBackstage.writeFile("out/test.dwg")) { /* failed */ }

Mx2DDraw, MxBackstage, and MxFun are singletons (MxFun.init() is called by the mxapp.js entry point) — use them directly; do not new them.

II. Mx2DDraw — 2D Drawing Class

2.1 Pre-drawing Settings

Method	Description
setColor(r, g, b)	Set the current color (RGB 0-255)
setColorIndex(index)	Set the AutoCAD color index
setLineWeight(lineWeight)	Set line weight, takes a LineWeight enum (kLnWt025 = 0.25 mm, kLnWtByLayer = -1 follows the layer)
addLinetype(name, lineDefine) → linetype id	Add a linetype. lineDefine like "6,-10" (solid length, dash length…)
addLinetypeEx(name, lineDefine, textStyle) → linetype id	Linetype with a text definition
setLinetype(name)	Set the current linetype
setLineTypeScale(scale)	Set the current linetype scale
addLayer(name) → layer id	Add a layer
setLayer(name) → bool	Set the current layer
addTextStyle(name, shxFile, bigFontFile, xScale) → style id	Add an SHX text style
addTextStyle2(name, trueTypeFont, xScale) → style id	Add a TrueType text style (e.g. SimHei, SimSun)
setTextStyle(name) → bool	Set the current text style
addDimStyle(name, doubleData, intData, stringData, idData) → style id	Add a dimension style (fails if a same-named style already exists)
addPatternDefinition(name, definition) → bool	Add a hatch pattern definition. definition format: "((angle, xOrigin, yOrigin, dx, dy, dash1, dash2, ...))", e.g. "((45, 0,0, 0,0.125))"

2.2 Basic Primitive Drawing (all return McDbObjectId)

Method	Description
drawLine(pt1, pt2) / drawLine2(x1,y1,x2,y2)	Line
drawPoint(x, y, z=0)	Point
drawCircle(center, r) / drawCircle2(cx, cy, r)	Circle
drawArc(center, radius, startAngle, endAngle)	Arc
drawEllipse(center, majorAxisX, majorAxisY, radiusRatio) / drawEllipse2(cx,cy,cz, ...)	Ellipse
drawText(position, text, height, rotation, hMode, vMode, widthFactor=1)	Single-line text. hMode: 0 left / 1 center / 2 right; vMode: 1 bottom / 2 middle / 3 top; position may be an [x,y,z] array
drawMText(location, contents, height, width, rotation, attachment)	MText. attachment 1–9 (nine-grid from top-left to bottom-right). Supports format codes, e.g. superscript 2: "\A2;Square method: m{\H0.3x;\S 2^;}"
drawImage(position, width, height, rotation, imageFilePath)	Insert an image (JPG, etc.)
drawEntity(ent: McDbEntity)	Draw a self-constructed entity object (e.g. build a McDbLine, set its properties, then submit)
erase(id) → bool	Delete an object

2.3 Path → Primitive (the path API accumulates points first, then generates the entity)

Mx2DDraw.pathMoveToEx(new McGePoint3d([600, 3300]), 0, 0, 0.3); // start point (incl. start/end widths, bulge)
Mx2DDraw.pathLineTo(700, 3300);                                  // subsequent points
Mx2DDraw.pathLineTo(700, 3400);
Mx2DDraw.pathLineTo(600, 3300);
Mx2DDraw.pathMakeClosed();          // optional: close
Mx2DDraw.pathMakeExclude(true);     // optional: mark as an excluded region (hole)

Generated results (all return an id):

• drawPathToPolyline() → polyline
• drawPathToSpline() → spline
• drawPathToHatch(patternName = "", scale = 1) → hatch (the pattern name must be added via addPatternDefinition first; an empty string means solid fill)

2.4 Blocks

Method	Description
InsertBlock(fileName, blockName) → block table record id	Import a block definition from a DWG file (the block with the given name in the file); returns the new block record id. A relative fileName is based on the project directory
drawBlockReference(pos, blkName, scale, angleDeg) → block reference id	Insert an existing block. angle unit: degrees

Title block (attribute) filling example — see drawTq in sample/ParamDraw.ts:

let id = Mx2DDraw.drawBlockReference([100,100,0], "BT", 1.0, 0.0);
let blkRef = id.getEntity() as McDbBlockReference;
blkRef.createAttribute();
for (let i = 0; i < blkRef.attributeCount; i++) {
    let attrib = blkRef.attributeItem(i);
    attrib.textString = "John Doe";   // fill in by matching attrib.tag
}

2.5 Dimensions

Method	Description
drawDimAligned(xLine1, xLine2, dimLinePoint)	Aligned dimension
drawDimRotated(xLine1, xLine2, dimLinePoint, rotation)	Rotated (linear) dimension
drawDimDiametric(chordPoint, farChordPoint, leaderLength)	Diametric dimension
drawDimRadial(center, chordPoint, leaderLength)	Radial dimension
drawDimAngular(arcPoint, xLine1, xLine2, sDimensionText)	Angular dimension

Known source issue: drawEllipseArc and drawDimAngular internally call the wrong method (a typo); verify before use or switch to the low-level API.

2.6 Database and Objects

Method	Description
currentDatabase() → McDbDatabase	The current drawing database (drawing context)
backgroundDatabase() → McDbDatabase	The database of the drawing opened in the background
objectIdToObject(id) → McDbObject|null	Convert an object id to an entity object (auto-mapped to the concrete type)
handleToObjectId(handle) / objectIdToHandle(id)	Convert between handle and id
compareObject(id1, id2) → number	Compare whether two objects are the same (0 = same)
getEmptyTemplateDwgFilePath()	Path of the blank template DWG (empty_template.dwg in the project directory)
getCurrentPath()	Current program path (project dir/../../)

III. MxBackstage — Background File Handling

Method	Description
openFile(fileName, iReadContent = 0) → bool	Open a drawing. iReadContent: 0 default; pass 67904 (kReadDefault|kReadxData) when extended data must be read
writeFile(fileName) → bool	Save as DWG/DXF/mxweb (by extension). Without a DWG write module it auto-converts via mxcadassembly
writeWebGLFile(fileName) → bool	Output the frontend display file (mxweb)
getDatabase() → McDbDatabase	Get the current drawing database
initSet(iniJson) → bool	Initialize conversion settings (JSON string; generally no need to call)

IV. McDbDatabase — Database Object

let db: McDbDatabase = new McDbDatabase();   // standalone instance (for reading another file then merging)
db.readDwgFile("a.dwg");                     // relative paths are relative to the project directory; or get it from Mx2DDraw.currentDatabase()

Method/Property	Description
readDwgFile(fileName) → bool	Load a DWG standalone into this instance (call free() when done)
getBlockTable() / getLayerTable() / getDimStyleTable() / getLineTypeTable() / getTextStyleTable()	Get each symbol table (a table object has getAll() returning an array of record ids)
currentSpace() / modelSpace() → McDbBlockTableRecord	Current space / model space
currentSpace().getBoundingBox() → [minPt, maxPt]	Bounding rectangle of the space
getUselessLayer() → id array	Unused layers
marge(database, aryLayer?) → bool	Merge another database into this one (optionally only the specified layer array)
insert(blkName, database) → bool	Insert a block from another database
getSysVarString/setSysVarString(name, val)	System variables (string)
getSysVarDouble/setSysVarDouble(name, val)	System variables (double), e.g. LTSCALE global linetype scale
getSysVarLong/setSysVarLong, getSysVarPoint/setSysVarPoint	System variables (integer/point)
Properties: currentlyColorIndex, currentlyLayerName, currentlyLineTypeName, currentlyTextStyle, currentlyTrueColor, insbase, lineTypeScale	Read/write the current drawing state
free()	Release (must be called for standalone readDwgFile instances)

LineWeight enum: kLnWt000~kLnWt211 (0/5/9/…/211), kLnWtByLayer=-1, kLnWtByBlock=-2, kLnWtByLwDefault=-3.

V. McDbEntity — Common Entity Parts

Properties and methods inherited by all concrete entities (Line/Circle/Polyline/Text/BlockReference/Dimension…):

Property/Method	Description
layer / layerId	Layer name / layer id (read-write)
color / colorIndex	Color (McCmColor) / color index (read-write)
linetype / linetypeId / linetypeScale	Linetype name / id / scale (read-write)
visible	Whether visible
textStyleId	Text style id
getGeomExtents() → [minPt, maxPt]	Geometric bounding rectangle
xdata(appName?) → MrxDbgRbList	Read all extended data
setxDataString(appName, val, index=0) / getxDataString(appName, index=0)	String extended data
setxDataDouble/ getxDataDouble, setxDataLong/getxDataLong	Double/integer extended data
explode() → id array	Explode the entity (block references, polylines, etc.)
intersectWith(ent, mode=0) → point array	Intersect with another entity

VI. Concrete Entity Classes (commonly used members)

The following members are taken from the source and sample usage; full definitions live in the corresponding src/mxcad/ files:

• McDbLine: startPoint, endPoint (McGePoint3d, read-write; with new McDbLine() assign then Mx2DDraw.drawEntity(line))
• McDbCircle: center, radius
• McDbPolyline: numVerts vertex count, getPointAt(i), getBulgeAt(i)
• McDbText: textString, position, alignmentPoint
• McDbMText: contents, getAllText()
• McDbBlockReference: position, blockName, blockTableRecordId, blockTransform, attributeCount, attributeItem(i) (returns McDbAttribute: tag, textString, position), createAttribute()
• McDbDimension / McDbAlignedDimension / McDbRotatedDimension: xLine1Point, xLine2Point, getDimVarObjectId(342/343/344) (get the dimension block)
• McDbBlockTableRecord (space/block definition): name, getAllEntity() → array of entity ids inside the block
• McDbLayerTableRecord: name, colorIndex, color, off

VII. Selection Sets and Filtering

import { MrxDbgSelSet } from "../mxcad/MrxDbgSelSet";
import { MrxDbgRbList } from "../mxcad/MrxDbgRbList";

let ss = new MrxDbgSelSet();
let filter = new MrxDbgRbList();
filter.addString("LWPOLYLINE", 5020);   // filter by type (5020 is the type code)
filter.addString("layer name", 8);        // filter by layer (8 is the layer code)
ss.allSelect(filter);                    // or selectAtPoint(pt, filter, tol)
                                          //    crossingSelect(pt1, pt2) / windowSelect(pt1, pt2)

for (let i = 0; i < ss.count; i++) {
    let ent = ss.item(i).getEntity();    // returns the concrete entity object
    if (ent instanceof McDbText) { /* ... */ }
}

MrxDbgRbList (resbuf list): count, atDouble/atLong/atString/atPoint(i), addDouble/addLong/addString/addPoint(v, dataType), itemDataType(i), removeAll().

VIII. Geometry Objects

• McGePoint3d: x/y/z (read-write); construct with new McGePoint3d() or new McGePoint3d([x,y,z]); distanceTo(pt), add(pt), sum(pt), isEqualTo(pt), transformBy(mat)
• McGeVector3d: vector
• McGeMatrix3d: matrix transformation, preMultBy(mat) pre-multiply, etc.

IX. Secondary Development Guide

1. New drawing feature: create a .ts under src/sample/, follow the TestDraw class structure of ParamDraw.ts (one primitive per draw method), register the command in MxCommand.ts

2. Data extraction feature: see GetDwgData.ts (selection set + filter + instanceof dispatch + JSON output)

   ⚠️ No existing command covers geometry extraction: getcaddata extracts text and block attributes only — there is NO existing command for geometry entities such as lines/polylines/circles; secondary development is required. Minimal example (tested: extracts all lines to JSON; 105/105 lines matched exactly against the frontend mxcad export result):

   // src/sample/GetLines.ts
   import { Mx2DDraw, MxBackstage, MxFun } from "../MxFun";
   import { McDbLine } from "../mxcad/McDbLine";
   import { MrxDbgSelSet } from "../mxcad/MrxDbgSelSet";
   import { MrxDbgRbList } from "../mxcad/MrxDbgRbList";
   
   export function getlines(param: any) {
     if (!param.file) return { code: 3, message: "param.file error" };
     if (!param.outfile) return { code: 4, message: "param.outfile error" };
     let curPath = Mx2DDraw.getCurrentPath();
     if (!MxBackstage.openFile(curPath + param.file, 67904))
       return { code: 5, message: "openFile failed" };
     let db = MxBackstage.getDatabase();
     let ids = db.modelSpace().getAllEntity();   // all entity ids in model space
     let lines: any[] = [];
     for (let i = 0; i < ids.length; i++) {
       let ent = ids[i].getObject();            // id → concrete entity object
       if (!ent) continue;
       if (ent instanceof McDbLine) {
         let line: McDbLine = ent;
         lines.push({
           type: "LINE", layer: line.layer, linetype: line.linetype,
           handle: line.handle.imp,              // handle (string)
           startPoint: { x: line.startPoint.x, y: line.startPoint.y, z: line.startPoint.z },
           endPoint: { x: line.endPoint.x, y: line.endPoint.y, z: line.endPoint.z }
         });
       }
     }
     MxFun.writeFile(curPath + param.outfile, JSON.stringify({ count: lines.length, lines }, null, 1));
     return { ret: 0, resultfile: param.outfile };
   }

   Registration and invocation: add import { getlines } from "./sample/GetLines"; and MxProcessor.addCommand("getlines", getlines) in MxCommand.ts, then after npm run build run bin\node.exe mxapp.js getlines file=t1.dwg outfile=t1_lines.json. Other entity types (circle/polyline/dimension, etc.) follow the same pattern: swap the instanceof branch + corresponding members (see section 6).

3. Cutting/export features: see CutDwg.ts (title block frame detection + sorting), ExportPdf.ts (whole-drawing PDF + title block frame localization)

4. Compilation: npm run build (tsc); after any modification you MUST recompile (the runtime executes the .js)

5. All sample code lives in the src/sample/ directory and can be copied and adapted directly