KLayout integration

LibMan opens layout views (gds, oas, lstr, layout / *.layout.core) in KLayout via a persistent KLayout server — a background KLayout instance that polls a JSON command file.

Tool Manager setup

Property	Typical value
Layout tool	Path to klayout (or klayout.exe)
LayoutViews	gds,oas,lstr,layout (default includes core alias for layout CORE)

Schematic/symbol views use a separate tool (e.g. Xschem via WSL); see Xschem integration.

Opening layouts

Double-click on the layout view root

Double-click the view node itself (gds, oas, lstr, or layout) — not a cell inside the expanded hierarchy.

Double-click opens KLayout and does not expand or collapse the tree node (use the arrow/disclosure control or single-click expand for hierarchy browsing).

LibMan:

1. Resolves the file path sent to KLayout (GDS/OAS/LStream directly; *.layout.core natively when the mcore streamer is installed).
2. Picks a root cell to activate (see Root cell selection).
3. Starts KLayout with the server script if needed, then sends an open command with the file and cell name.
4. On a later double-click on the same layout root while KLayout is already running, sends a select command (file is not reloaded).

Double-click on a hierarchy cell

Double-click a child cell under the layout view. LibMan always opens/selects that exact cell name.

Root cell selection

When you open the layout view root, LibMan chooses the KLayout cell as follows:

Priority	Rule	Example
1	LibMan group name (selected cell in the groups list) if that name exists in the layout file	Group sg13g2_io, GDS contains sg13g2_io → opens sg13g2_io
2	Single top cell in the file hierarchy	One wrapper cell TOP with children shown in the tree → opens TOP
3	First top cell (sorted) when several top-level cells exist	sg13g2_stdcell.layout.core with 84 stdcells, group sg13g2_stdcell not in file → opens first cell alphabetically (e.g. sg13g2_and2_1)
4	No matching cell	File opens without an explicit cell selection (KLayout default)

Hierarchy is taken from the in-memory cache when the tree was expanded; otherwise LibMan reads it synchronously from the file (GDS/OAS/LStream/CORE parsers).

This matches the tree rules for CORE layout: a single wrapper top cell is shown as its children in the UI, but KLayout still activates the real top cell when you open the layout root.

KLayout server protocol

Commands are written as JSON to a temp file (libman_klayout_cmd_<pid>.json), polled every 250 ms by an embedded Python script started with klayout -rr <script>.

Action	Fields	Behaviour
open	file, cell	Load layout into a view (same-view mode); select cell if non-empty; zoom fit
select	file, cell	Switch to an already open view; select cell; zoom fit

An .alive sidecar file reports the server PID for health checks.

CORE layout files

*.layout.core files are passed directly to KLayout (no temporary GDS export) when the mcore plugin is available. Build it from KLayout-coredb (or link integrations/klayout/mcore from CommonDB into your KLayout tree).

See also: CORE integration.

Troubleshooting

Symptom	Check
KLayout does not start	Layout tool path in Tool Manager; executable exists
File opens but wrong/empty cell	Group name may not exist in file; expand layout tree once so hierarchy cache is warm
*.layout.core not recognized	mcore streamer not installed in KLayout
Second double-click does nothing	KLayout server died; close KLayout and double-click again to restart
Double-click expands tree instead of opening	Expected: only child cells expand; layout root opens KLayout. Use the disclosure arrow to expand

More: Troubleshooting.