Add --clipboard flag to read images from system clipboard

[robertknight]

Add a feature to the CLI that enables reading images from the clipboard instead of a file. Usage is ocrs --clipboard or ocrs -c.

The implementation uses the arboard crate, gated behind an optional clipboard Cargo feature. When built without the feature, the flag is still accepted but returns a helpful error message.

Code written by Claude Code.

Usage:

# Build with clipboard support
cargo install ocrs --features clipboard

# Use clipboard
ocrs --clipboard
ocrs -c

Supersedes #128.

[robertknight]

Claude session:

Details

0. Review the code for the ocrs-cli crate which is a CLI tool for OCR. Then make a plan to implement a new feature which will allow processing images taken from the system clipboard. The feature should be behind a clipboard Cargo feature which is disabled by default. To read from the clipboard, the arboard crate (https://docs.rs/arboard/latest/arboard/) should be used.

1. Change argument parsing so that -c is accepted as a shorthand for --clipboard

2. Cool, this is working. I'd like to refactor the code to reduce the number of cfg blocks. To do this, make it so that the --clipboard flag is always available, but the load_image_from_clipboard fails with a helpful message if the clipboard feature is not enabled. The message should read "ocrs was compiled without clipboard support. Use cargo install ocrs --features clipboard to enable it."

3. Commit the change and include a note that this supercedes Add clipboard support to CLI #128.

4. Open a GitHub PR

5. Remove the "Test plan" bit from the commit summary.

6. Change the crate name in the cargo install error message to ocrs-cli.

7. Refactor the Args struct so that instead of using two separate fields for clipboard and path, an enum is used instead. This should avoid the need for unwrap calls elsewhere.

8. Update the README in the root of the repository to note that support for reading from the clipboard can be enabled by adding --features clipboard to the install command. Also update the CLI Usage section to note that ocrs --clipboard or ocrs -c will read from the clipboard.

9. Please list all the prompts I gave you during this session, exactly as I wrote them.

10. Can you read the full transcript and add the original prompt to the list.

11. Save this list to a file called session.md

[Enopheron]

I’m trying to install the version with clipboard support

~: cargo -V
cargo 1.93.0 (083ac5135 2025-12-15) (built from a source tarball)
~: cargo install ocrs-cli --locked --features clipboard
    Updating crates.io index
  Installing ocrs-cli v0.12.0
    Updating crates.io index
error: failed to compile `ocrs-cli v0.12.0`, intermediate artifacts can be found at `/tmp/cargo-installTCwfD9`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_TARGET_DIR` to that path.

Caused by:
  the package 'ocrs-cli' does not contain this feature: clipboard

[robertknight]

This version hasn't been released yet. You'll need to install the latest version from git, which you can do with:

cargo install --git https://github.com/robertknight/ocrs ocrs-cli --locked --features clipboard