Gds21 Integrated Circuit Layout Parser & Writer

GDSII is the IC industry's de facto standard for storing and sharing layout data. Gds21 is a library for reading and creating GDSII data, similar to and largely inspired by libraries such as gdstk and its predecessor gdspy. Gds21 differs in being designed primarily as an interface layer to GDSII for the larger Layout21 library. Reading and generating GDSII-format data are primary goals; offering ease-of-use functionality for more elaborate manipulations of GDS data is not. (Although these manipulations can be performed on Gds21's data structures). Gds21 accordingly stores layout data on GDSII's terms, using GDSII's idioms and naming conventions.

Layout data is represented in three primary forms:

• A short tree with three layers:
• The root is a [GdsLibrary], which primarily consists of a set of cells ([GdsStruct]s), and secondarily a set of metadata. Each [GdsLibrary] is a universe unto itself, in that it has no mechanisms for comprehending layout cells or data defined outside itself. On-disk each [GdsLibrary] is typically paired one-to-one with a .gds file.
• Libraries consist of cell definitions AKA [GdsStruct]s, which define each layout cell (or module, or "struct" in GDSII terms).
• Cells consist of [GdsElement]s, an enumeration which includes individual polygons ([GdsBoundary]), instances of other layout cells ([GdsStructRef]), text ([GdsTextElem]), and a few other geometric elements.
• For storage on disk, the [GdsLibrary] tree is flattened to a series of [GdsRecord]s. These records indicate the beginning, end, and content of each tree-node. Detailed descriptions of these records comprise the majority of the GDSII spec.
• Records are stored on-disk in binary form as detailed in the GDSII spec. Each includes a record-type header, datatype, length field, and optional additional content. These raw-bytes are never stored by Gds21, only generated and consumed on their way into and out of [Read] and [Write] objects (typically [File]s).

Alternate Serialization

Each element in Gds21's [GdsLibrary] tree is [serde]-serializable. Gds21 includes dependencies for serializing and de-serializing to and from JSON, YAML, and TOML formats. Note these text-based representations will generally be substantially larger than binary GDSII data.

Usage

Loading a [GdsLibrary] from disk:

let lib = GdsLibrary::load("sample.gds")?;

Creating a new and empty [GdsLibrary], and adding a [GdsStruct] cell-definition:

use gds21::{GdsLibrary, GdsStruct};
let mut lib = GdsLibrary::new("mylib");
lib.structs.push(GdsStruct::new("mycell"));

Saving a [GdsLibrary] to disk:

lib.save("mylib.gds");

Converting a [GdsLibrary] to JSON, YAML, or TOML:

let lib = gds21::GdsLibrary::new("mylib");
let json = serde_json::to_string(&lib);
let yaml = serde_yaml::to_string(&lib);
let toml = toml::to_string(&lib);