Read and write ImageJ ROI format

Roifile is a Python library to read, write, create, and plot ImageJ ROIs, an undocumented and ImageJ application specific format to store regions of interest, geometric shapes, paths, text, and whatnot for image overlays.

Author

Christoph Gohlke

License

BSD 3-Clause

Version

2024.3.20

DOI

10.5281/zenodo.6941603

Quickstart

Install the roifile package and all dependencies from the Python Package Index:

python -m pip install -U "roifile[all]"

View overlays stored in a ROI, ZIP, or TIFF file:

python -m roifile file.roi

See Examples for using the programming interface.

Source code, examples, and support are available on GitHub.

Requirements

This revision was tested with the following requirements and dependencies (other versions may work):

• CPython 3.9.13, 3.10.11, 3.11.8, 3.12.2
• Numpy 1.26.4
• Tifffile 2024.2.12 (optional)
• Matplotlib 3.8.3 (optional)

Revisions

2024.3.20

• Fix writing generator of ROIs (#9).

2024.1.10

• Support text rotation.
• Improve text rendering.
• Avoid array copies.
• Limit size read from files.

2023.8.30

• Fix linting issues.
• Add py.typed marker.

2023.5.12

• Improve object repr and type hints.
• Drop support for Python 3.8 and numpy < 1.21 (NEP29).

2023.2.12

• Delay import of zipfile.
• Verify shape of coordinates on write.

2022.9.19

• Fix integer coordinates to -5000..60536 conforming with ImageJ (breaking).
• Add subpixel_coordinates in frompoints for out-of-range integer coordinates.

2022.7.29

• …

Refer to the CHANGES file for older revisions.

Notes

The ImageJ ROI format cannot store integer coordinate values outside the range of -5000..60536.

Refer to the ImageJ RoiDecoder.java source code for a reference implementation.

Other Python packages handling ImageJ ROIs:

• ijpython_roi
• read-roi
• napari_jroitools

Examples

Create a new ImagejRoi instance from an array of x, y coordinates:

>>> roi = ImagejRoi.frompoints([[1.1, 2.2], [3.3, 4.4], [5.5, 6.6]]) >>> roi.roitype = ROI_TYPE.POINT >>> roi.options |= ROI_OPTIONS.SHOW_LABELS

Export the instance to an ImageJ ROI formatted byte string or file:

>>> out = roi.tobytes() >>> out[:4] b'Iout' >>> roi.tofile('_test.roi')

Read the ImageJ ROI from the file and verify the content:

>>> roi2 = ImagejRoi.fromfile('_test.roi') >>> roi2 == roi True >>> roi.roitype == ROI_TYPE.POINT True >>> roi.subpixelresolution True >>> roi.coordinates() array([[1.1, 2.2], [3.3, 4.4], [5.5, 6.6]], dtype=float32) >>> roi.left, roi.top, roi.right, roi.bottom (1, 2, 7, 8)

Plot the ROI using matplotlib:

>>> roi.plot()

View the overlays stored in a ROI, ZIP, or TIFF file from a command line:

python -m roifile _test.roi