Method doRender

packages/pi-tui/src/tui.ts:1264–1774

()

	}

	private doRender(): void {
		if (this.stopped) return;
		const width = this.terminal.columns;
		const height = this.terminal.rows;
		const widthChanged = this.previousWidth !== 0 && this.previousWidth !== width;
		const heightChanged = this.previousHeight !== 0 && this.previousHeight !== height;
		const previousBufferLength = this.previousHeight > 0 ? this.previousViewportTop + this.previousHeight : height;
		let prevViewportTop = heightChanged ? Math.max(0, previousBufferLength - height) : this.previousViewportTop;
		let viewportTop = prevViewportTop;
		let hardwareCursorRow = this.hardwareCursorRow;
		const computeLineDiff = (targetRow: number): number => {
			const currentScreenRow = hardwareCursorRow - prevViewportTop;
			const targetScreenRow = targetRow - viewportTop;
			return targetScreenRow - currentScreenRow;
		};

		// Render all components to get new lines
		let newLines = this.render(width);

		// Composite overlays into the rendered lines (before differential compare)
		if (this.overlayStack.length > 0) {
			newLines = this.compositeOverlays(newLines, width, height);
		}

		// Extract cursor position before applying line resets (marker must be found first)
		const cursorPos = this.extractCursorPosition(newLines, height);

		// Never write a line wider than the terminal: truncate defensively
		// instead of crashing. Extremely narrow terminals can make
		// components overflow by a column (e.g. wide graphemes at width 1).
		// applyLineResets() runs afterwards, so truncated lines still get
		// their trailing reset and cannot leak styles.
		for (let i = 0; i < newLines.length; i++) {
			const line = newLines[i]!;
			if (isImageLine(line)) continue;
			const lineWidth = asciiVisibleWidth(line, width) ?? visibleWidth(line);
			if (lineWidth > width) {
				newLines[i] = sliceByColumn(line, 0, width, true);
			}
		}

		newLines = this.applyLineResets(newLines);

		// Helper to clear scrollback and viewport and render all new lines
		const fullRender = (clear: boolean): void => {
			this.fullRedrawCount += 1;
			let buffer = "\x1b[?2026h"; // Begin synchronized output
			if (clear) {
				buffer += this.deleteKittyImages(this.previousKittyImageIds);
				buffer += "\x1b[2J\x1b[H\x1b[3J"; // Clear screen, home, then clear scrollback
			}
			for (let i = 0; i < newLines.length; i++) {
				if (i > 0) buffer += "\r\n";
				const line = newLines[i]!;
				const isImage = isImageLine(line);
				const imageReservedRows = isImage ? this.getKittyImageReservedRows(newLines, i) : 1;
				if (imageReservedRows > 1 && imageReservedRows <= height) {
					for (let row = 1; row < imageReservedRows; row++) {