pub fn take_draw_extent() -> Option<DrawExtent>Expand description
Take the extent of the most recent measured draw, leaving the slot
empty. None when no line scene has drawn since the diagnostic was enabled
(or when it is off) — distinct from a recorded draw whose
fraction is None because nothing was drawn.
A frame usually holds one line draw (scenes::shares_resources forbids
two roster line scenes in a frame), and then “the most recent draw” is
“this frame’s figure”. A preset may layer a second line scene (Plan 0076)
through its own per-preset LineRenderer
(scenes::create_layer_scene) — the layer draws after the main
scene, so on a layered line-on-line preset this slot holds the layer’s
figure. The harness reads this around single-figure captures; a consumer
measuring a layered preset must know which draw it is measuring.