Layers and Properties

Layer management, color, linetype, extended data, and more.

Layer Management

Create Layers

const { Engine } = vjcad;

// Method 1: use Engine.createLayer (recommended)
const layer = Engine.createLayer("AnnotationLayer", {
    color: 1,              // Color index
    lineType: "CONTINUOUS",
    layerOn: true,         // Whether visible
    isFrozen: false,       // Whether frozen
    isLocked: false        // Whether locked
});

// Method 2: use doc.layers.addlayer
const doc = Engine.currentDoc;
if (!doc.layers.itemByName("ConstructionLayer")) {
    doc.layers.addlayer("ConstructionLayer", true, 3);  // Name, visible, color
}

// Method 3: auto-named layer
const autoLayer = Engine.createLayer();  // Automatically named "Layer1", "Layer2", etc.

Switch Layers

// Get current layer
const currentLayer = Engine.getCurrentLayer();

// Switch to specified layer
Engine.setCurrentLayer("LayerA");

// Access current layer name
const layerName = Engine.currentDoc.CLAYER;

Get Layers

// Get all layers
const layers = Engine.getLayers();
layers.forEach(layer => {
    console.log(`${layer.name}: color=${layer.color}, visible=${layer.layerOn}`);
});

// Get layer by name
const layer = Engine.getLayerByName("AnnotationLayer");

// Check whether layer exists
const exists = !!Engine.currentDoc.layers.itemByName("BuildingLayer");

Layer Visibility

const layer = Engine.getLayerByName("LayerName");

// Turn layer off/on
layer.layerOn = false;   // Off (invisible, but still participates in regeneration)
layer.layerOn = true;    // On
Engine.regen(true);      // Must re-render

Layer Freezing

const layer = Engine.getLayerByName("LayerName");

// Freeze/unfreeze layer
layer.isFrozen = true;   // Frozen (invisible, does not participate in regeneration)
layer.isFrozen = false;  // Unfrozen
Engine.regen(true);

// Note: layer 0 and the current layer cannot be frozen

Layer Locking

const layer = Engine.getLayerByName("LayerName");

// Lock/unlock layer
layer.isLocked = true;   // Locked (visible but not selectable or editable)
layer.isLocked = false;  // Unlocked

Layer State Comparison

State	Visible	Selectable	Editable	Participates in Regeneration
Normal	✓	✓	✓	✓
Off (layerOn=false)	✗	✗	✗	✓
Frozen (isFrozen=true)	✗	✗	✗	✗
Locked (isLocked=true)	✓	✗	✗	✓

Get Entities by Layer

// Get all entities on a specified layer
const buildingEntities = Engine.getEntities(ent => ent.layer === "BuildingLayer");

// Get entities on multiple layers
const multiLayerEntities = Engine.getEntities(ent => 
    ent.layer === "BuildingLayer" || ent.layer === "AnnotationLayer"
);

---

Color Settings

Color Index

const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();  // Must be called first

// ACI color index
line.color = 1;      // Red
line.color = 2;      // Yellow
line.color = 3;      // Green
line.color = 4;      // Cyan
line.color = 5;      // Blue
line.color = 6;      // Magenta
line.color = 7;      // White

// Special values
line.color = 256;    // ByLayer
line.color = 0;      // ByBlock

Engine.addEntities(line);

RGB True Color

const { ColorConverter } = vjcad;

// Method 1: use hexadecimal directly (with marker bit)
line.color = 0x1000000 + 0xFF8000;  // Orange

// Method 2: use ColorConverter
line.color = ColorConverter.createRgbColorIndex(0x800080);  // Purple

// Method 3: use RGB components
line.color = ColorConverter.createRgbColorIndexFromComponents(255, 192, 203);  // Pink

// Method 4: use hex string
line.color = ColorConverter.createRgbColorIndexFromHexStr("#FFD700");  // Gold

Current System Color

// Set current drawing color
Engine.CECOLOR = 1;  // Red

// Entity uses current color
const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();
line.color = Engine.CECOLOR;

---

Linetype Settings

Common Linetypes

const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();

line.lineType = "CONTINUOUS";  // Continuous (default)
line.lineType = "HIDDEN";      // Dashed
line.lineType = "CENTER";      // Center line
line.lineType = "PHANTOM";     // Phantom line
line.lineType = "DASHED";      // Short dashed line

// Linetype scale
line.lineTypeScale = 1.0;      // Default
line.lineTypeScale = 0.5;      // Denser
line.lineTypeScale = 2.0;      // Sparser

Current System Linetype

// Set current linetype
Engine.CELTYPE = "HIDDEN";

// Set current linetype scale
Engine.CELTSCALE = 1.5;

---

Lineweight Settings

const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();

// Lineweight values (unit: 0.01mm)
line.lineWeight = 0;    // Default
line.lineWeight = 15;   // 0.15mm
line.lineWeight = 30;   // 0.30mm
line.lineWeight = 50;   // 0.50mm
line.lineWeight = 100;  // 1.00mm

// Special values
line.lineWeight = -1;   // ByLayer
line.lineWeight = -2;   // ByBlock

---

Transparency Settings

const circle = new CircleEnt([50, 50], 25);
circle.setDefaults();

// Set transparency (0-100, 0=opaque, 100=fully transparent)
circle.transpMgr.setTp100(50);

// ByLayer transparency
circle.transpMgr.setValue(-1);

---

Default Properties

Set System Default Properties

// Set default values
Engine.CECOLOR = 1;            // Current color
Engine.CELTYPE = "HIDDEN";     // Current linetype
Engine.CELTSCALE = 1.5;        // Current linetype scale

Apply Default Properties to Entity

// setDefaults() applies the following system defaults:
// - Layer (CLAYER)
// - Color (CECOLOR)
// - Linetype (CELTYPE)
// - Linetype scale (CELTSCALE)

const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();  // Apply system defaults

// Important: set custom properties after setDefaults()
line.color = 3;      // Override default color

Engine.addEntities(line);

---

Extended Data (XData)

Store custom data on entities.

Set Extended Data

const line = new LineEnt([0, 0], [100, 0]);
line.setDefaults();

// Set extended data (supports any JSON object)
line.setExtData("SENSOR_DATA", {
    name: "Temperature Sensor",
    value: 25.5,
    unit: "℃",
    isActive: true,
    lastUpdate: "2026-01-29",
    config: {
        minValue: 0,
        maxValue: 100
    }
});

Engine.addEntities(line);

Read Extended Data

// Check whether extended data exists
if (line.hasExtData()) {
    // Get application name
    const appName = line.extDataAppName;  // "SENSOR_DATA"
    
    // Get extended data object (JSON already parsed automatically)
    const data = line.extData;
    console.log(data.name);   // "Temperature Sensor"
    console.log(data.value);  // 25.5
}

Modify Extended Data

// Method 1: replace completely
line.setExtData("SENSOR_DATA", {
    name: "Temperature Sensor",
    value: 30.2,
    unit: "℃"
});

// Method 2: modify based on existing data
const currentData = line.extData;
if (currentData) {
    currentData.value = 30.2;
    currentData.lastUpdate = "2026-01-30";
    line.setExtData("SENSOR_DATA", currentData);
}

Clear Extended Data

line.clearExtData();

Batch Query Entities with Extended Data

// Query all entities with extended data
const allEntities = Engine.getEntities();
const entitiesWithXData = allEntities.filter(ent => ent.hasExtData?.());

// Group by AppName
const byAppName = {};
entitiesWithXData.forEach(ent => {
    const appName = ent.extDataAppName;
    if (!byAppName[appName]) byAppName[appName] = [];
    byAppName[appName].push(ent);
});

// Query entities of a specific AppName
const sensorEntities = allEntities.filter(
    ent => ent.hasExtData?.() && ent.extDataAppName === "SENSOR_DATA"
);

Raw XData Format

// Get raw format (for debugging)
const rawXData = line.xdataRaw;
// Return format: { "1001": "AppName", "1000": "JSON string" }

Note: Extended data can be exported to DWG and loaded again; the data will be preserved.

---

File Operations

Open Local File

// Execute command
await Engine.editor.executerWithOp('OPENFROMLOCAL');

Save Local File

// Save to IndexedDB
await Engine.editor.executerWithOp('SAVELOCAL');

// Quick save and download .webcad file
await Engine.editor.executerWithOp('QSAVE');

// Save as
await Engine.editor.executerWithOp('SAVEAS');

Open Server File

await Engine.editor.executerWithOp('OPENFROMSERVER');

Save Server File

await Engine.editor.executerWithOp('SAVESERVER');

Import/Export DWG

// Import DWG
await Engine.editor.executerWithOp('IMPORTDWG');

// Export DWG
await Engine.editor.executerWithOp('EXPORTDWG');