linkcad.db

The database module provides access to LinkCAD's in-memory drawing database. All database objects are backed by C++ implementations for performance.

Classes

Drawing

The top-level container for all layout data.

from linkcad.db import Drawing

dwg = Drawing.current()  # Get the active drawing

Method	Description
`Drawing.current()`	Get the active drawing instance
`dwg.main_cell()`	Get the main (top) cell
`dwg.cells()`	Iterate all cells
`dwg.layers()`	Iterate all layers
`dwg.find_cell(name)`	Find a cell by name
`dwg.find_layer(name)`	Find a layer by name

Cell

A named container of shapes and cell references.

Property / Method	Description
`cell.name`	Cell name
`cell.shapes()`	Iterate shapes in this cell
`cell.refs()`	Iterate cell references
`cell.add_ref(cell, position)`	Add a cell reference
`Cell.create(drawing, name)`	Create a new cell

Layer

A named layer with display properties.

Property / Method	Description
`layer.name`	Layer name
`layer.number`	Layer number (for GDSII)
`layer.datatype`	Layer datatype (for GDSII)
`layer.visible`	Whether the layer is visible
`layer.color`	Layer display color

Shape

Base class for all geometric shapes (polygons, polylines, circles, text).

Property / Method	Description
`shape.layer()`	Get the shape's layer
`shape.vertices()`	Get vertex coordinates
`shape.closed`	Whether the shape is closed
`shape.bounds()`	Get the bounding box

Ref

A reference to another cell, with transformation.

Property / Method	Description
`ref.cell`	Referenced cell
`ref.position`	Reference position
`ref.transformation`	Applied transformation

Locking

All database access requires proper locking:

ReadLock

from linkcad.db import ReadLock

with ReadLock():
    cell = dwg.main_cell()
    for shape in cell.shapes():
        print(shape.vertices())

Transaction

Write operations require a Transaction. The transaction auto-commits when the with block exits without an exception, and auto-rolls-back if an exception occurs.

from linkcad.db import Transaction

with Transaction(dwg) as txn:
    cell = Cell.create(dwg, "new_cell")
    # ... modify drawing ...
    # auto-commits on successful exit

Warning

Accessing the database without a lock causes undefined behavior. Always use ReadLock for reads and Transaction for writes.