Method extractCursorPosition

packages/pi-tui/src/tui.ts:1244–1262

* Find and extract cursor position from rendered lines. * Searches for CURSOR_MARKER, calculates its position, and strips it from the output. * Only scans the bottom terminal height lines (visible viewport). * @param lines - Rendered lines to search * @param height - Terminal height (visible

(lines: string[], height: number)

	 * @returns Cursor position { row, col } or null if no marker found
	 */
	private extractCursorPosition(lines: string[], height: number): { row: number; col: number } | null {
		// Only scan the bottom `height` lines (visible viewport)
		const viewportTop = Math.max(0, lines.length - height);
		for (let row = lines.length - 1; row >= viewportTop; row--) {
			const line = lines[row]!;
			const markerIndex = line.indexOf(CURSOR_MARKER);
			if (markerIndex !== -1) {
				// Calculate visual column (width of text before marker)
				const beforeMarker = line.slice(0, markerIndex);
				const col = visibleWidth(beforeMarker);

				// Strip marker from the line
				lines[row] = line.slice(0, markerIndex) + line.slice(markerIndex + CURSOR_MARKER.length);

				return { row, col };
			}
		}
		return null;
	}

	private doRender(): void {
		if (this.stopped) return;