Find the topmost node drawn under a point. The scene is compiled into a colour
pick-buffer (each grob drawn in a colour encoding its id, respecting clipping
and paint order) using the same code path that renders it, so the result is
geometry-, clip- and overlap-exact by construction. Markers and text are
matched by their bounding box; lines and segments by a small pick band. grid
ships no equivalent: grid.locator() waits for one interactive click and
returns coordinates rather than a node.
Usage
hit_test(scene, x, y, units = c("npc", "px"))Arguments
- scene
A
vl_scene().- x, y
Query point, in
units:"npc"(default; the page,0..1with y up) or"px"(device pixels, top-left origin, y down).- units
"npc"or"px".