TUI: clip inline terminal block painting

[harryalbert]

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

[harryalbert]

• TUI: skip unchanged running-command height remeasurement #14595
• TUI: clip inline terminal block painting #14594 👈 (View in Graphite)
• [3/4] TUI: reuse retained text measurements #14585 : 1 other dependent PR (#14586 )
• [2/4] TUI: bound clipped viewport painting #14582
• [1/4] TUI: add retained transcript performance benchmarks #14575
• master

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[oz-for-oss]

@harryalbert

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[oz-for-oss]

Overview

This PR optimizes TUI inline terminal block painting by exposing a visible row window from TuiPaintSurface, clipping terminal block rendering to that window, and adding targeted regression coverage plus a benchmark.

Concerns

• ⚠️ [IMPORTANT] This is a user-facing TUI rendering/performance change, but the PR description only lists automated tests and a benchmark. Repo review guidance requires acceptable TUI visual evidence for user-visible changes: a terminal transcript, a render_to_lines / TuiBuffer::to_lines snapshot diff, or a ./script/run-tui capture. Please attach one of those demonstrating inline terminal block rendering end to end.

Verdict

Found: 0 critical, 1 important, 0 suggestions

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