Example: GDS → ROOM → text dump

The gds_to_room program — layout import workflow

Schematic import from Qucs: Qucs example.

1. Build (VS Code)

Ctrl+Shift+B → choose a task:

Task	Output
Build: Static Libraries (.a)	`build/libroom.a`, `build/libroom_utils.a`
Build: All Targets	Libraries + `gds_to_room.exe`, `make_sample_gds.exe`
Install: Libraries + Headers	`install/` prefix for other projects
Example: Build & Run Full Demo	Sample GDS → `output/sample.room`

2. Build (command line)

cmake -S . -B build -G "MinGW Makefiles"
cmake --build build --target room room_utils

On first cmake configure, Cap'n Proto is built into third_party/capnp-install/ automatically. Sample layout GDS can come from the IHP Open Source PDK (sg13g2) or make_sample_gds.

3. Link from another project

# after: VS Code task "Install: Libraries + Headers"
list(APPEND CMAKE_PREFIX_PATH "C:/path/to/Room/install")
find_package(ROOM REQUIRED)

add_executable(my_app main.cpp)
target_link_libraries(my_app PRIVATE ROOM::room_utils)
target_include_directories(my_app PRIVATE ${ROOM_INCLUDE_DIRS})
# also link capnp + kj from third_party/capnp-install/lib

4. Sample GDS

.\build\make_sample_gds.exe testdata\sample.gds

Creates a minimal GDS with cells INV and TOP.

5. Import

.\build\gds_to_room.exe testdata\sample.gds output\sample.room output\sample.txt

Argument	Description
`input.gds`	Input GDSII file
`output.room`	Binary ROOM file (Cap'n Proto)
`dump.txt`	Text dump (optional; defaults to `output.room.txt`)

6. Example source

Source file: examples/gds_to_room/main.cpp

#include "database.h"
#include "gds_importer.h"
#include "text_dump.h"

room::GdsImporter importer;
room::Database db = importer.importFile("testdata/sample.gds");

db.saveToFile("output/sample.room");

room::TextDumper dumper;
dumper.dumpToFile(db, "output/sample.txt");

// round-trip check
room::Database reloaded = room::Database::loadFromFile("output/sample.room");

Core headers are under src/ (database.h, …). Utility headers are under utils/ (gds_importer.h, text_dump.h). CMake adds both directories to the include path for linked targets.

7. Data flow

GDS file │ ▼ GdsImporter::importFile() │ STRNAME, BOUNDARY, PATH, SREF, TEXT, UNITS … ▼ Database → Lib → Cell → CellContent(layout).payload.layout.block │ ├─► Database::saveToFile() → sample.room └─► TextDumper::dumpToFile() → sample.txt

8. GDS → ROOM mapping

GDS record	ROOM
STRNAME	Cell
LAYER + DATATYPE	LayerSpec in Lib::layers()
BOUNDARY / BOX	Shape::Polygon
PATH	Shape::Path
TEXT	Shape::Text
SREF	Instance
UNITS	`CellContent::dbuPerMicron()`

9. Sample dump output

=== ROOM text dump ===
version: 1.0
generator: ROOM GdsImporter
lib: gds_import
layers: 3
cells: 2

cell "TOP"
  type layout dbuPerMicron=1000.000
  bbox=(0,0)-(5000,5000)
  shapes=2 instances=1 nets=0
    shape path layer=L2/D0 width=200 points=2
    shape text layer=L3/D0 "TOPCELL" at (100,100)
    instance -> "INV" at (2000,2000)

Limitations

AREF is not expanded into geometry
Only ViewType::Layout is imported from GDS
GDS user properties (PROPATTR/PROPVALUE) map to gds.prop.<attr> on cells, shapes, and instances