🚧 wip: idea for text viewer

2022-09-30 02:04:16 +00:00 · 2022-09-30 02:04:16 +00:00 · 90a8efea71
parent 4307a199bc
commit 90a8efea71
2 changed files with 156 additions and 0 deletions
--- a/scope/index.html
+++ b/scope/index.html
@ -0,0 +1,30 @@
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width, initial-scale=1" />
+<link href="data:image/x-icon;base64,AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAlJSUAAGIAAP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAIiIiIgAAAAAAAAAgAAAAAAAAAAAAADIiIiIi
+IiIjMhERERERESMyERERERERIzIREREREREjMhERIRERESMyERIiIiERIzIRESEREREjMhERERER
+ESMyERERERERIzIREREREREjMiIiIiIiIiMAAAAAAAAAAAAAAAAAAAAAAAAAAIABAACAAQAAgAEA
+AIABAACAAQAAgAEAAIABAACAAQAAgAEAAIABAACAAQAA" rel="icon" type="image/x-icon" />
+<style>
+	body {
+		font-family: sans-serif;
+	}
+	#JNG5U2EX {
+		border: solid black 1px;
+	}
+</style>
+<title>Scope</title>
+</head>
+<body>
+<pre id="JNG5U2EX"></pre>
+<button onclick="cursor_left ()">Left</button>
+<button onclick="cursor_right ()">Right</button>
+<button onclick="cursor_up ()">Up</button>
+<button onclick="cursor_down ()">Down</button>
+<pre id="XDHSIT76"></pre>
+<script src="scope.js"></script> 
+</body>
+</html>
--- a/scope/scope.js
+++ b/scope/scope.js
@ -0,0 +1,126 @@
+const sync_max = 512;
+
+const textarea = document.getElementById ("JNG5U2EX");
+const debug_text = document.getElementById ("XDHSIT76");
+
+textarea.innerText = "Loading...";
+
+let page = "";
+let offset = 0;
+
+function line_start_before (page, offset) {
+	const sync_start = Math.max (sync_max, offset) - sync_max;
+	
+	for (let i = offset; i >= sync_start; i--) {
+		const c = page.charAt (i);
+		if (c == '\n') {
+			return i + 1;
+		}
+	}
+	
+	return null;
+}
+
+function line_start_after (page, offset)
+{
+	for (let i = offset; i < offset + sync_max; i++) {
+		const c = page.charAt (i);
+		if (c == '\n') {
+			return i + 1;
+		}
+	}
+	
+	return null;
+}
+
+function layout_text (page, offset) {
+	const width = 120;
+	const height = 24;
+	
+	const line_start = line_start_before (page, offset) || 0;
+	
+	// Compute layout
+	
+	let lines = Array ();
+	let line = "";
+	
+	for (let i = line_start; i < page.length; i++) {
+		if (lines.length >= height) {
+			break;
+		}
+		if (line.length >= width) {
+			lines.push (line);
+			line = "";
+		}
+		
+		const c = page.charAt (i);
+		
+		if (c == '\n') {
+			lines.push (line);
+			line = "";
+		}
+		else {
+			line = line + page.charAt (i);
+		}
+	}
+	
+	return lines.join ('\n');
+}
+
+function repaint (offset) 
+{
+	textarea.innerText = layout_text (page, offset);
+	debug_text.innerText = "Offset: " + offset + "\n";
+}
+
+async function async_main () 
+{
+	let file_length = null;
+	
+	{
+		const resp = await fetch ("log.txt", {
+			"method": "HEAD",
+		});
+		
+		file_length = resp.headers.get ("content-length");
+	}
+	
+	const resp = await fetch ("log.txt", {
+		"headers": {
+			"range": "bytes=0-65535",
+		},
+	});
+	
+	page = await resp.text ();
+	
+	repaint (offset);
+}
+
+async_main ().then (
+	function (val) {},
+	function (err) {}
+);
+
+function cursor_left () 
+{
+	offset = Math.max (1, offset) - 1;
+	repaint (offset);
+}
+
+function cursor_right () 
+{
+	offset += 1;
+	repaint (offset);
+}
+
+function cursor_up () 
+{
+	offset = line_start_before (page, offset - 2) || 0;
+	repaint (offset);
+}
+
+function cursor_down () 
+{
+	offset = line_start_after (page, offset);
+	repaint (offset);
+}