CV Annotate Points

Manual point input: run the workflow once to load the image into the node, then LEFT-CLICK the preview to add a point (drag to move it), SHIFT+CLICK to remove the nearest one. Once the outline is closed (3 or more points) a click is INSERTED into the nearest edge - the highlighted one - so a shape can be refined where it is wrong instead of in click order; ALT+CLICK appends at the end instead. The points are stored normalized (0-1 of the image size) in the 'points' field - editable by hand too - and come out in pixel coordinates, in ring order. The mask output fills the polygon the points enclose (3 or more, any count). Pair with 'CV Quad Warp' (4 corners), 'CV Select Component At Point' (a seed), 'OpenCV Draw Points', ... Zero points is a valid output (count = 0).