Description

Adds a targeted follow-up for expanded shell commands rendered inside Warp Agent CLI blocks. Top-level terminal blocks already receive a viewport-clipped row range, but inline TerminalBlockRows::Content previously walked every retained command/output row and column on each paint while the nested paint surface discarded offscreen writes.

This change exposes the element-local visible row window from TuiPaintSurface, intersects terminal block painting with that window, and translates the source-row and cursor origins before rendering. Inline command paint work is now proportional to the visible viewport rather than total retained output; the same intersection applies defensively to already-preclipped top-level terminal blocks. Regression coverage verifies nested clip coordinates and exact inline terminal row-window rendering.

Benchmark at 120×50 with a fixed 50-row viewport versus stack PR 3:

• Expanded inline terminal content, 100 retained rows: 61.6 → 30.9 µs/frame (50% faster, 2.0×).
• Expanded inline terminal content, 1,000 retained rows: 123.8 → 36.1 µs/frame (71% faster, 3.4×).
• Baseline paint cost doubles from 100 to 1,000 retained rows; the clipped implementation remains close to the fixed viewport cost.

Agent conversation: https://staging.warp.dev/conversation/963ead54-9843-4cc1-8d8b-dbf695ee7046

Linked Issue

N/A — Warp Agent CLI transcript rendering performance.

Testing

• cargo nextest run -p warpui_core --features tui -E 'test(visible_rows_are_relative_to_the_element_origin) | test(widget_renders_only_visible_rows) | test(nested_surface_clip_contains_cells_styles_and_widgets)' — 3 passed.

• cargo nextest run -p warp_tui -E 'test(terminal_block::tests)' — 10 passed.

• cargo bench -p warp_tui --features test-util --bench transcript_bench -- 'tui_terminal_block/clipped_content'

• ./script/format

• I have manually tested my changes locally with ./script/run-tui

Agent Mode

• Warp Agent Mode - This PR was created via Warp's AI Agent Mode

CHANGELOG-NONE

Co-Authored-By: Oz oz-agent@warp.dev