From 8ed8bbad3e83f46d43f464a5be7b3fe53a897508 Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cdo@wip.sh>
Date: Mon, 2 Mar 2026 15:49:21 +0000
Subject: [PATCH] Set output rows based on window size

---
 emu.js | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/emu.js b/emu.js
index 933e8a8..bfbaf8f 100644
--- a/emu.js
+++ b/emu.js
@@ -13,7 +13,6 @@ const PERIPHS_SIZE = 69; // Nice
 const POLL_INTERVAL_MS = 20;
 
 const COLS = 80;
-const ROWS = 36;
 const TAB_WIDTH = 8;
 
 const CURSOR_IDLE_TIME_MS = 1000;
@@ -36,8 +35,9 @@ class Emulator {
 		this.rx_queue = [];
 		this.timer = setInterval(() => this.poll(), POLL_INTERVAL_MS);
 
+		this.rows = this.max_rows();
 		this.grid = Array.from(
-			{ length: ROWS },
+			{ length: this.rows },
 			() => new Array(COLS).fill(' '));
 		this.cursor = { x: 0, y: 0 };
 		this.range = {
@@ -47,6 +47,7 @@ class Emulator {
 		this.idle_timer = null;
 		this.input_enable = false;
 		document.addEventListener('keydown', (e) => this.handle_keydown(e));
+		window.addEventListener('resize', () => this.handle_resize());
 
 		this.worker = new Worker('boot.js');
 		this.worker.postMessage(this.mem);
@@ -142,7 +143,7 @@ class Emulator {
 			this.cursor_move(1, 0);
 		} else if (e.key == 'Enter') {
 			this.cursor.y = this.range.end.y + 1;
-			if (this.cursor.y >= ROWS)
+			while (this.cursor.y >= this.rows)
 				this.scroll();
 			this.cursor.x = 0;
 			this.submit_line();
@@ -228,7 +229,7 @@ class Emulator {
 	next_cell(cell) {
 		if (cell.x < COLS - 1)
 			return { x: cell.x + 1, y: cell.y };
-		else if (cell.y < ROWS - 1)
+		else if (cell.y < this.rows - 1)
 			return { x: 0, y: cell.y + 1 };
 		else
 			return null;
@@ -295,6 +296,30 @@ class Emulator {
 		this.range.start.y -= 1;
 		this.range.end.y -= 1;
 	}
+
+	max_rows() {
+		const style = getComputedStyle(this.output);
+		const line_height = parseFloat(style.lineHeight);
+		const margin_top = parseFloat(style.marginTop);
+		const margin_bottom = parseFloat(style.marginBottom);
+
+		const viewport_height = window.innerHeight;
+		const output_height = viewport_height - margin_top - margin_bottom;
+		return Math.floor(output_height / line_height) - 1;
+	}
+
+	handle_resize() {
+		this.rows = this.max_rows();
+		while (this.grid.length < this.rows)
+			this.grid.push(new Array(COLS).fill(' '));
+		while (this.grid.length > this.rows) {
+			this.grid.shift()
+			this.cursor.y -= 1;
+			this.range.start.y -= 1;
+			this.range.end.y -= 1;
+		}
+		this.flush_output();
+	}
 }
 
 window.addEventListener('DOMContentLoaded', () => {