C API for ocrs lib#257
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A small, stable `extern "C"` interface. `ocrs-capi` wraps `ocrs::OcrEngine` and builds as both a `cdylib` and a `staticlib`. Called it `ocrs_capi` (instead of `ocrs`) to avoid a collision with the `cdylib` from the `ocrs` crate itself. Included a README.md that explains things, and a Zig example, and unit tests.
Now the Rust source is the single source of truth for the C ABI header so it can no longer drift from the `extern "C"` signatures and `#[repr(C)]` types. Way better. - Replace hand-written `include/ocrs.h` with a cbindgen-generated header and add `cbindgen.toml` describing the output (C, OCRS_H guard, C++ extern "C" compat, `usize` to `size_t`, doc comments preserved). - Add a `header` test that regenerates the header in memory and fails if it differs from the committed file, so CI catches an API change made without regenerating. `OCRS_UPDATE_HEADER=1` rewrites it instead of comparing. The comparison tolerates CRLF and trailing whitespace for Windows checkouts. - Add a `make capi-header` target. cbindgen is a pinned, default-features-disabled dev-dependency, so compiled only for `cargo test`, so downstram consumers don't need it to build the library.
Adding tests that actually try to detect, layout, recognize path, using `ocrs_engine_get_text` and `ocrs_engine_get_text_lines` on a test image, assert substrings and non-degenerate bounding boxes. The model files are too big to commit, so they're `#[ignore]`d and using `OCRS_DETECTION_MODEL` / `OCRS_RECOGNITION_MODEL` from the env instead, skipping when unset. `make test-capi` downloads the models and runs them in release mode. The image is decoded with a new `image` dev-dependency. `lib` is added to the crate-type so the integration tests can link the crate as an rlib. This produces `libocrs_capi.rlib` and does not collide with the `ocrs` crate.
Fix warnings about safety docs reported by `make lint`. Add `# Safety` headings and regenerate the C header.
robertknight
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Jun 29, 2026
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This looks great, thank-you very much. I was able to build and run the Zig example and run the tests via make test-capi. I pushed a couple of commits to fix warnings from make lint (add # Safety headings) and a few typos.
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I wanted to play with ocrs in Zig and I noticed #2, so I went ahead and implemented it.
There's:
cbindgen(The name on the account, "p5p", is a bug by GitHub that I keep trying to get their support to resolve, but alas, no response. I can explain in more details if this is a concern. I would be happy if you can validate the name on the commits is "Sawyer X" after merging. Thank you.)