FpsMeter keeps the stamp before the last second, so a frame longer
than the span shows as the worst and a bar. The inspector's panel, a
second root out of the app's scope, sits in a FocusScope of its own,
so Tab goes on from Pick. EventLogger takes key downs through an
interceptor, which runs before bindings, and marks its box with a key
context to know focus is inside, so a field's Backspace and Enter log.
Tests hold the stall, Tab both ways through Pick, bound keys in a
field, a key while focus is outside, newest first and a bare border.
install_inspector draws gpui's debug inspector in Ely's look: a panel
with the picked box's source, ids and box model, and its margin,
border, padding and size drawn over the page through raise, since the
panel scrolls. FpsMeter counts frames on the executor's clock and
colors each by the frames it missed. RenderCounter counts the renders
of the view that draws it. EventLogger lists the input that reaches
what it holds, its canvas laid first so a child's stop hides nothing.
The knobs join a layout::seeded seed, so a changed starting value,
option list or range starts every setting over, and a renamed knob
no longer fails. new() refuses no knobs, twin names and a number
outside its range. Controls are keyed by knob name. The test presses
keys without a refresh, so only a notify redraws, and walks the
switch twice, the slider twice and a pick the owner takes away.
tooling::Playground lays a preview beside its knobs, each a switch, a
choice or a number that edits one property; the preview redraws from
the settings, which fail on a name or kind the knobs lack. The gallery
app is the ComponentGallery; its page 43 shows both.