87 lines
3.9 KiB
Markdown
87 lines
3.9 KiB
Markdown
# Masque README
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Masque is a Python module for designing lithography masks.
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The general idea is to implement something resembling the GDSII file-format, but
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with some vectorized element types (eg. circles, not just polygons) and the ability
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to output to multiple formats.
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- [Source repository](https://mpxd.net/code/jan/masque)
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- [PyPI](https://pypi.org/project/masque)
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## Installation
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Requirements:
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* python >= 3.11
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* numpy
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* klamath (used for GDSII i/o)
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Optional requirements:
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* `ezdxf` (DXF i/o): ezdxf
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* `oasis` (OASIS i/o): fatamorgana
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* `svg` (SVG output): svgwrite
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* `visualization` (shape plotting): matplotlib
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* `text` (`Text` shape): matplotlib, freetype
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Install with pip:
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```bash
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pip install 'masque[oasis,dxf,svg,visualization,text]'
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```
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## Overview
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A layout consists of a hierarchy of `Pattern`s stored in a single `Library`.
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Each `Pattern` can contain `Ref`s pointing at other patterns, `Shape`s, and `Label`s.
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`masque` departs from several "classic" GDSII paradigms:
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- Layer info for `Shape`ss and `Label`s is not stored in the individual shape and label objects.
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Instead, the layer is determined by the key for the container dict (e.g. `pattern.shapes[layer]`).
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* This simplifies many common tasks: filtering `Shape`s by layer, remapping layers, and checking if
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a layer is empty.
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* Technically, this allows reusing the same shape or label object across multiple layers. This isn't
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part of the standard workflow since a mixture of single-use and multi-use shapes could be confusing.
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* This is similar to the approach used in [KLayout](https://www.klayout.de)
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- `Ref` target names are also determined in the key of the container dict (e.g. `pattern.refs[target_name]`).
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* This similarly simplifies filtering `Ref`s by target name, updating to a new target, and checking
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if a given `Pattern` is referenced.
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- `Pattern` names are set by their containing `Library` and are not stored in the `Pattern` objects.
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* This guarantees that there are no duplicate pattern names within any given `Library`.
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* Likewise, enumerating all the names (and all the `Pattern`s) in a `Library` is straightforward.
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- Each `Ref`, `Shape`, or `Label` can be repeated multiple times by attaching a `repetition` object to it.
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* This is similar to how OASIS reptitions are handled, and provides extra flexibility over the GDSII
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approach of only allowing arrays through AREF (`Ref` + `repetition`).
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- `Label`s do not have an orientation or presentation
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* This is in line with how they are used in practice, and how they are represented in OASIS.
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- Non-polygonal `Shape`s are allowed. For example, elliptical arcs are a basic shape type.
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* This enables compatibility with OASIS (e.g. circles) and other formats.
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* `Shape`s provide a `.to_polygons()` method for GDSII compatibility.
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- Most coordinate values are stored as 64-bit floats internally.
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* 1 earth radii in nanometers (6e15) is still represented without approximation (53 bit mantissa -> 2^53 > 9e15)
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* Operations that would otherwise clip/round on are still represented approximately.
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* Memory usage is usually dominated by other Python overhead.
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## Glossary
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- `Library`: A collection of named cells. OASIS or GDS "library" or file.
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- `Pattern`: A collection of geometry, text labels, and reference to other patterns.
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OASIS or GDS "Cell", DXF "Block".
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- `Ref`: A reference to another pattern. GDS "AREF/SREF", OASIS "Placement".
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- `Shape`: Individual geometric entity. OASIS or GDS "Geometry element", DXF "LWPolyline" or "Polyline".
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- `repetition`: Repetition operation. OASIS "repetition".
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GDS "AREF" is a `Ref` combined with a `Grid` repetition.
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- `Label`: Text label. Not rendered into geometry. OASIS, GDS, DXF "Text".
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- `annotation`: Additional metadata. OASIS or GDS "property".
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## TODO
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* Better interface for polygon operations (e.g. with `pyclipper`)
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- de-embedding
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- boolean ops
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* Tests tests tests
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* check renderpather
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* pather and renderpather examples
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