cktimg — Python bindings

SPICE → schematic: get the placed schematic back as a plain Python dict to post-process. Built for the AMSNet → SPICE → cktImg → cleanup loop: AMSNet turns a schematic image into a netlist, cktImg places & routes it, and you get resolved geometry (device positions, pin coords, junctions) to clean up with SINA before re-rendering.

Install

From PyPI (once published):

pip install cktimg

The CI builds abi3 wheels for Linux/macOS/Windows + an sdist on every push (.github/workflows/python.yaml); download them from the run’s Artifacts, or pip install cktimg-*.whl directly.

Build from source

Needs the Rust toolchain and maturin:

cd export/python
pip install maturin
maturin develop --release      # builds + installs into the active venv
# or: maturin build --release   → wheel in target/wheels/

Use

import cktimg

spice = open("ota.sp").read()

# Placed schematic as a dict — the seam for cleanup.
sch = cktimg.schematic(spice)

Rail nets (vdd/vcc, gnd/vss/0) get rail devices auto-inserted (xvdd/xgnd/…) when the netlist names them but draws none.

schematic(spice) returns:

{
  "devices": [
    {
      "name": "M1", "class": "nmos", "value": "",
      "rot": 1, "mirror": False, "pos": [40, 0],
      "pins": [
        {"term": "d", "net": "out", "xy": [40, 20]},
        {"term": "g", "net": "in",  "xy": [20, 0]},
        {"term": "s", "net": "gnd", "xy": [40, -20]},
        ...
      ],
    },
    ...
  ],
  "nets": ["vdd", "gnd", "in", "out", ...],
  "wires": [
    {"net": "out", "segments": [[[40, 6], [72, 6]], ...]},   # routed polylines
    ...
  ],
  "junctions": [[120, 40], ...],
}

wires is the routed geometry SINA most likely wants to clean up — each net’s trunk + stub polylines as you’d draw them. junctions are the connection dots.

rot is 0..=3 (×90°). Coordinates are in the schematic grid (device pitch = 40). Need the raw JSON string instead of a dict? cktimg.schematic_json(spice).

AMSNet / SINA cleanup loop

import cktimg

spice = amsnet.image_to_spice("schematic.png")   # image → netlist
sch   = cktimg.schematic(spice)                   # netlist → placed geometry
sch   = sina.cleanup(sch)                          # nudge positions, fix labels, ...
# re-render however you like, or feed corrected SPICE back through cktimg

schematic() gives you everything the placer sees, so SINA can adjust device positions, relabel nets, or drop stray pins before rendering.

API