perf(chat): lay out and draw only the visible chat thread rows

Every frame the open chat thread handled all N messages: grouping flags
from two day keys each, a measuring layout of every body, then the
draw, which laid every body out a second time and ran the bubble, hover
and popup code, however few rows were on screen.

The thread now keeps a layout cache: grouping flags, each body's
wrapped size (keyed by message, so only new or re-wrapped bodies are
measured) and each row's height, with prefix offsets. A frame binary-
searches the visible range and submits those rows plus any failed send
(Retry stays reachable with Tab), the row being drag-selected and the
row whose context menu is open; one spacer stands in for each skipped
run, and scrolling to the newest message works as before.

- Rows are rebuilt when the chat store changes or when the wrap width,
  fonts, font size, DPI scale, rasterizer density or compact mode
  change. Fonts are keyed by FontId, so a font reload at the same size
  (the colour-emoji toggle) re-measures. A rebuild is O(N), about
  0.5-1 ms at 3000 messages.
- Grouping flags are recomputed on a data change and once a minute,
  together with util::refreshTimezone(), so a system timezone change
  reaches chat timestamps within a minute.

Rows above the visible range are now one spacer of their summed
heights, so the visible rows no longer move by a pixel each time a row
above them crosses the top of the app window. Debug builds log once if
a cached wrap width or row height ever disagrees with the live layout.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

This commit is contained in:

DanS

2026-10-10 09:50:03 -05:00

co-authored by

Claude Opus 5.5

parent a69380817e

commit 4a95d9ecb7

4 changed files with 393 additions and 21 deletions

									
										CMakeLists.txt
									
		+1
		
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				@@ -664,6 +664,7 @@ set(APP_HEADERS

				    src/ui/windows/balance_address_list.h

				    src/ui/windows/balance_recent_tx.h

				    src/ui/windows/balance_lerp.h

				    src/ui/windows/chat_thread_layout.h

				    src/ui/windows/balance_tab_helpers.h

				    src/ui/windows/send_tab.h

				    src/ui/windows/receive_tab.h