naja-schematic (Python package)

Interactive schematic viewer for najaeda netlists: the naja-schematic WASM viewer, packaged with the Python backend that answers it from a live najaeda netlist.

pip install naja-schematic

In a notebook (Jupyter, Google Colab, VSCode)

Try it in Colab: a walkthrough of every widget feature below, runnable as is. Then a real design: a RISC-V core.

from najaeda import netlist
import naja_schematic

netlist.load_primitives("xilinx")
top = netlist.load_verilog("design.v")

naja_schematic.show()          # interactive view in the cell output

The view is answered from the netlist in the running kernel, so it shows the design as the notebook has built or edited it so far; call show() again after an edit for a fresh view. Diagnoses (e.g. from a formal equivalence check) can be overlaid:

view = naja_schematic.show()
view.annotate([{"kind": "instance", "path": ["u_sub"], "severity": "error",
                "message": "not equivalent", "source": "kepler-formal"}])
view

The view and your najaeda code can point each other at instances. show_instance() takes a najaeda Instance, a list of instance ids (as Instance.pathIDs) or a list of instance names (a plain string is one name, never split on /, since escaped names can contain it). Anonymous instances have no name to go by: reach them with an Instance or ids. The viewer opens its tree down to that instance, selects it, and draws it alone in the schematic. Each pin there is open, so you can click one to add its net and grow the schematic from the instance. In the other direction, the instance selected in the viewer (click it in the tree or the schematic) is available as a najaeda Instance:

view.show_instance(netlist.get_instance_by_path(["u_sub", "u_and"]))
view.show_instance(["u_sub", "u_and"]) # same thing

inst = view.selected                   # what the user clicked, or None
inst.get_model_name()

view.on_select(lambda inst: print("selected", inst))

naja_schematic.show(inst) (or show(["u_sub", "u_and"])) starts a new view on it. After editing or reloading the design in later cells, view.design_changed() refreshes an existing view in place.

From a shell

naja-schematic --verilog design.v --liberty cells.lib --open
naja-schematic --sv top.sv --top top --diagnosis report.json --open

serves the viewer page and its WebSocket on http://localhost:8081/ and opens it in a browser. --stdio speaks the same protocol as JSON lines on stdin/stdout instead, for a host (e.g. an editor extension) that relays messages itself. naja-schematic --help lists every option.

From an application that already holds the design

A tool that loads and edits the design itself (with najaeda or the raw naja bindings) can serve the viewer on it without loading anything:

import threading, naja_schematic

design_lock = threading.RLock()   # held by the host while it edits the design
server = naja_schematic.ViewerServer(lock=design_lock)   # port 0: any free port
server.start()
server.open_browser()             # or hand server.url to the user

server.annotate(items)            # diagnosis overlay, kept across reloads
server.show_instance([3, 7])      # instance ids, names, or a najaeda Instance
server.on_select(lambda id_path, path: print("selected", path))
with server.replacing_design():   # holds design_lock, then viewers reload
    netlist.load_verilog("other.v")
server.stop()

Viewer requests are answered on a background thread while lock is held (or pass run= to answer them on a thread of your choosing). The page's URL carries a random access token, and other web pages can't connect to the WebSocket. Once the design is replaced, anything a viewer asked about or selected in the old one is ignored, even if it arrives late or names instance ids the new design reuses.

Development

The viewer bundle (naja_schematic/static/naja-schematic.js) is built from the C++ sources, not checked in. From the repository root:

emcmake cmake -S . -B build-wasm-module -DCMAKE_BUILD_TYPE=Release -DNAJA_SCHEMATIC_WASM_MODULE=ON
cmake --build build-wasm-module
export NAJA_SCHEMATIC_BUNDLE=$PWD/build-wasm-module/naja-schematic.js   # or copy it into static/
pip install -e "python[test]" && pytest python/tests

Releases are built and published by .github/workflows/python-package.yml on a v<version> tag (e.g. v0.1.0).