a7ce677ac3
This brings the terminal element's viewport culling in line with the editor optimization in PR #44995 and the fix in PR #45077. ## Problem When a terminal is inside a scrollable container (e.g., the Agent Panel thread view), it would render ALL cells during prepaint, even when the terminal was entirely outside the viewport. This caused unnecessary CPU usage when multiple terminal tool outputs existed in the Agent Panel. ## Solution Calculate the intersection of the terminal's bounds with the current content_mask (the visible viewport after all parent clipping). If the intersection has zero area, skip all cell processing entirely. ### Three code paths 1. **Offscreen** (`intersection.size <= 0`): Early exit, process 0 cells 2. **Fully visible** (`intersection == bounds`): Fast path, stream cells directly (no allocation) 3. **Partially clipped**: Group cells by line, skip/take visible rows only ### Key insight: filter by screen position, not buffer coordinates The previous approach tried to filter cells by `cell.point.line` (terminal buffer coordinates), which breaks in Scrollable mode where cells can have negative line numbers for scrollback history. The new approach filters by **screen position** using `chunk_by(line).skip(N).take(M)`, which works regardless of the actual line numbers because we're filtering on enumerated line group index. ## Testing Added comprehensive unit tests for: - Screen-position filtering with positive lines (Inline mode) - Screen-position filtering with negative lines (Scrollable mode with scrollback) - Edge cases (skip all, positioning math) - Unified filtering works for both modes Manually verified: - Terminal fully visible (no clipping) ✓ - Terminal clipped from top/bottom ✓ - Terminal completely outside viewport ✓ - Scrollable terminals with scrollback history ✓ - Selection/interaction still works ✓ Release Notes: - Improved Agent Panel performance when terminals are scrolled offscreen. /cc @as-cii
Design notes:
This crate is split into two conceptual halves:
- The terminal.rs file and the src/mappings/ folder, these contain the code for interacting with Alacritty and maintaining the pty event loop. Some behavior in this file is constrained by terminal protocols and standards. The Zed init function is also placed here.
- Everything else. These other files integrate the
Terminalstruct created in terminal.rs into the rest of GPUI. The main entry point for GPUI is the terminal_view.rs file and the modal.rs file.
ttys are created externally, and so can fail in unexpected ways. However, GPUI currently does not have an API for models than can fail to instantiate. TerminalBuilder solves this by using Rust's type system to split tty instantiation into a 2 step process: first attempt to create the file handles with TerminalBuilder::new(), check the result, then call TerminalBuilder::subscribe(cx) from within a model context.
The TerminalView struct abstracts over failed and successful terminals, passing focus through to the associated view and allowing clients to build a terminal without worrying about errors.
#Input
There are currently many distinct paths for getting keystrokes to the terminal:
-
Terminal specific characters and bindings. Things like ctrl-a mapping to ASCII control character 1, ANSI escape codes associated with the function keys, etc. These are caught with a raw key-down handler in the element and are processed immediately. This is done with the
try_keystroke()method on Terminal -
GPU Action handlers. GPUI clobbers a few vital keys by adding bindings to them in the global context. These keys are synthesized and then dispatched through the same
try_keystroke()API as the above mappings -
IME text. When the special character mappings fail, we pass the keystroke back to GPUI to hand it to the IME system. This comes back to us in the
View::replace_text_in_range()method, and we then send that to the terminal directly, bypassingtry_keystroke(). -
Pasted text has a separate pathway.
Generally, there's a distinction between 'keystrokes that need to be mapped' and 'strings which need to be written'. I've attempted to unify these under the '.try_keystroke()' API and the .input() API (which try_keystroke uses) so we have consistent input handling across the terminal