Ellipse ROI

Elliptical region selection over the live image. Stats are computed over pixels that satisfy ((x-cx)/a)² + ((y-cy)/b)² ≤ 1 — not just the bounding box.

Usage

Enable the ellipse checkbox, press-drag-release to draw, then drag axis handles for single-axis stretch or diagonal handles for uniform scale. Reset centers the ellipse back to ¼ of the image. The shape switches between Circle and Ellipse automatically when width ≈ height.

Adding new stats

Stats are formatted in update_stats() of src/pystream/plugins/ellipse.py. Pixels inside the ellipse are produced by get_roi_data(image); compute your metric on that array and append a line to the displayed text.