The counters now say which half is left. Re-recording is rare -- 157 row
display lists in a minute of scrolling, 407ms in total -- while the
frame's draw phase sits at 7.9ms. Since that phase also carries Compose's
own measurement, what is left is laying text out: shaping glyphs, on the
thread drawing the frame, and none of it timed by anything here.
The window moved in one step, so every step boundary shaped two screens
of markdown inside a single frame, a page landing did the same, and
opening a session did seventeen screens of it in one. It now walks
towards its target a couple of rows a frame. That does not make the work
cheaper and is not meant to: it stops it arriving together, which is the
difference between a frame that is late and a frame that is missed by
ten.
What is on screen is never amortised. The visible range goes up in the
frame it is needed whatever else is pending, and only the margin being
read *towards* is spread out -- so this cannot show anybody a gap, which
is the failure the last two changes in this area both had.
Diagnosis and the ordering from the ai-app-2-6d session, whose test this
follows: records small and draw high means shaping rather than recording.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
irisandClaude Opus 5
94b1509733