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https://github.com/anewusername/klamath
https://github.com/anewusername/klamath
Last synced: 4 days ago
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- Host: GitHub
- URL: https://github.com/anewusername/klamath
- Owner: anewusername
- License: gpl-3.0
- Created: 2024-03-30T23:26:18.000Z (8 months ago)
- Default Branch: master
- Last Pushed: 2024-07-30T11:55:24.000Z (4 months ago)
- Last Synced: 2024-07-30T13:44:32.531Z (4 months ago)
- Language: Python
- Size: 89.8 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# klamath README
`klamath` is a Python module for reading and writing to the GDSII file format.
The goal is to keep this library simple:
- Map data types directly wherever possible.
* Presents an accurate representation of what is saved to the file.
* Avoids excess copies / allocations for speed.
* No "automatic" error checking, except when casting datatypes.
If data integrity checks are provided at all, they must be
explicitly run by the caller.
- Low-level functionality is first-class.
* Meant for use-cases where the caller wants to read or write
individual GDS records.
* Offers complete control over the written file.
- Opinionated and limited high-level functionality.
* Discards or ignores rarely-encountered data types.
* Keeps functions simple and reusable.
* Only de/encodes the file format, doesn't provide tools to modify
the data itself.
* Still requires explicit values for most fields.
- No compilation
* Uses `numpy` for speed, since it's commonly available / pre-built.
* Building this library should not require a compiler.
`klamath` was built to provide a fast and versatile GDS interface for
[masque](https://mpxd.net/code/jan/masque), which provides higher-level
tools for working with hierarchical design data and supports multiple
file formats.
### Alternatives
- [gdspy](https://github.com/heitzmann/gdspy)
* Provides abstractions and methods for working with design data
outside of the I/O process (e.g. polygon clipping).
* Requires compilation (C++) to build from source.
* Focused on high-level API
- [python-gdsii](https://pypi.org/project/python-gdsii)
* Pure-python implementation. Can easily be altered to use `numpy`
for speed, but is limited by object allocation overhead.
* Focused on high-level API
### Links
- [Source repository](https://mpxd.net/code/jan/klamath)
- [PyPI](https://pypi.org/project/klamath)
- [Github mirror](https://github.com/anewusername/klamath)
## Installation
Requirements:
* python >= 3.11
* numpy
Install with pip:
```bash
pip3 install klamath
```
Alternatively, install from git
```bash
pip3 install git+https://mpxd.net/code/jan/klamath.git@release
```
## Examples
### Low-level
Filter which polygons are read based on layer:
```python3
import io
import klamath
from klamath import records
from klamath.record import Record
def read_polygons(stream, filter_layer_tuple=(4, 5)):
"""
Given a stream positioned at the start of a record,
return the vertices of all BOUNDARY records which match
the provided `filter_layer_tuple`, up to the next
ENDSTR record.
"""
polys = []
while True:
size, tag = Record.read_header(stream)
stream.seek(size, io.SEEK_CUR) # skip to next header
if tag == records.ENDEL.tag:
break # If ENDEL, we are done
if tag != records.BOUNDARY.tag:
continue # Skip until we find a BOUNDARY
layer = records.LAYER.skip_and_read(stream)[0] # skip to LAYER
dtype = records.DATATYPE.read(stream)[0]
if (layer, dtype) != filter_layer_tuple:
continue # Skip reading XY unless layer matches
xy = XY.read(stream).reshape(-1, 2)
polys.append(xy)
return polys
```
### High-level
Write an example GDS file:
```python3
import klamath
from klamath.elements import Boundary, Text, Path, Reference
stream = open('example.gds', 'wb')
header = klamath.library.FileHeader(
name=b'example',
meters_per_db_unit=1e-9, # 1 nm DB unit
user_units_per_db_unit=1e-3) # 1 um (1000nm) display unit
header.write(stream)
elements_A = [
Boundary(layer=(4, 18),
xy=[[0, 0], [10, 0], [10, 20], [0, 20], [0, 0]],
properties={1: b'prop1string', 2: b'some other string'}),
Text(layer=(5, 5),
xy=[[5, 10]],
string=b'center position',
properties={}, # Remaining args are set to default values
presentation=0, # and will be omitted when writing
angle_deg=0,
invert_y=False,
width=0,
path_type=0,
mag=1),
Path(layer=(4, 20),
xy=[[0, 0], [10, 10], [0, 20]],
path_type=0,
width=0,
extension=(0, 0), # ignored since path_type=0
properties={}),
]
klamath.library.write_struct(stream, name=b'my_struct', elements=elements_A)
elements_top = [
Reference(struct_name=b'my_struct',
xy=[[30, 30]],
colrow=None, # not an array
angle_deg=0,
invert_y=True,
mag=1.5,
properties={}),
Reference(struct_name=b'my_struct',
colrow=(3, 2), # 3x2 array at (0, 50)
xy=[[0, 50], [60, 50], [30, 50]], # with basis vectors
angle_deg=30, # [20, 0] and [0, 30]
invert_y=False,
mag=1,
properties={}),
]
klamath.library.write_struct(stream, name=b'top', elements=elements_top)
klamath.records.ENDLIB.write(stream, None)
stream.close()
```
Read back the file:
```python3
import klamath
stream = open('example.gds', 'rb')
header = klamath.library.FileHeader.read(stream)
structs = {}
struct = klamath.library.try_read_struct(stream)
while struct is not None:
name, elements = struct
structs[name] = elements
struct = klamath.library.try_read_struct(stream)
stream.close()
print(structs)
```
Read back a single struct by name:
```python3
import klamath
stream = open('example.gds', 'rb')
header = klamath.library.FileHeader.read(stream)
struct_positions = klamath.library.scan_structs(stream)
stream.seek(struct_positions[b'my_struct'])
elements_A = klamath.library.try_read_struct(stream)
stream.close()
print(elements_A)
```