From d33021773c7cacfe6c34f55581ed55bc4b521850 Mon Sep 17 00:00:00 2001
From: Pavel Djundik <xPaw@users.noreply.github.com>
Date: Tue, 5 Feb 2019 23:15:47 +0200
Subject: [PATCH] Fix up textarea growing to avoid rounding issues in Chrome

---
 client/css/style.css |  2 +-
 client/js/lounge.js  | 13 ++++++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/client/css/style.css b/client/css/style.css
index 326c42ff..9bfe5149 100644
--- a/client/css/style.css
+++ b/client/css/style.css
@@ -1983,7 +1983,7 @@ part/quit messages where we don't load previews (adds a blank line otherwise) */
 	min-height: 19px; /* Required when computing input height at char deletion */
 	height: 19px;
 	max-height: 95px; /* min-height/height x number of lines maximum */
-	line-height: 19px /* should match height */;
+	line-height: 19px; /* should match height */
 	outline: none;
 	margin: 5px;
 	padding: 0;
diff --git a/client/js/lounge.js b/client/js/lounge.js
index fb5ec550..1167af3a 100644
--- a/client/js/lounge.js
+++ b/client/js/lounge.js
@@ -82,23 +82,22 @@ $(function() {
 	});
 
 	function resetInputHeight(input) {
-		input.style.height = input.style.minHeight;
+		input.style.height = "";
 	}
 
 	const input = $("#input")
 		.on("input", function() {
 			const style = window.getComputedStyle(this);
+			const lineHeight = parseFloat(style.lineHeight, 10) || 1;
 
 			// Start by resetting height before computing as scrollHeight does not
 			// decrease when deleting characters
 			resetInputHeight(this);
 
-			this.style.height = Math.min(
-				Math.round(window.innerHeight - 100), // prevent overflow
-				this.scrollHeight
-				+ Math.round(parseFloat(style.borderTopWidth) || 0)
-				+ Math.round(parseFloat(style.borderBottomWidth) || 0)
-			) + "px";
+			// Use scrollHeight to calculate how many lines there are in input, and ceil the value
+			// because some browsers tend to incorrently round the values when using high density
+			// displays or using page zoom feature
+			this.style.height = Math.ceil(this.scrollHeight / lineHeight) * lineHeight + "px";
 
 			chat.find(".chan.active .chat").trigger("keepToBottom"); // fix growing
 		});