iris
e9a6562dc6
Iris, correcting the previous commit: "Why does the mask matter at all. If you want a mask then you add .masked(). It should just prevent rows that aren't in its region at all from drawing ... Just like the opt in scrollable, masking should be opt in." So `LazySpan` sets no mask. It culls -- a row entirely outside the box it was offered is never drawn, which `intersects_viewport` already did -- and draws a straddling row in full, because virtualisation decides which rows and never how much of one. Cutting off that overhang is `.masked()`, added by whoever wants it. The transcript wants it (it is a list under a header bar) and opts back in; the benchmark does not and needs no ceremony. `top_edge.rs` goes back to reading the mask the list *inherited*, which is now also the test that the transcript is still asking for one. The previous commit had the span mask itself, which fixes the panic and is still the widget deciding what is not its to decide.