From 703ea9aacdc98b68e45d92f74ad3256e12ffe364 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 16 Sep 2021 13:16:13 +0300
Subject: [PATCH] Apply scale keeping window center in place.

---
 Telegram/SourceFiles/window/main_window.cpp | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/Telegram/SourceFiles/window/main_window.cpp b/Telegram/SourceFiles/window/main_window.cpp
index 7c9cf878a2..66f5e31300 100644
--- a/Telegram/SourceFiles/window/main_window.cpp
+++ b/Telegram/SourceFiles/window/main_window.cpp
@@ -445,10 +445,15 @@ Core::WindowPosition MainWindow::positionFromSettings() const {
 		return position;
 	}
 	const auto scaleFactor = cScale() / float64(position.scale);
-	position.x *= scaleFactor;
-	position.y *= scaleFactor;
-	position.w *= scaleFactor;
-	position.h *= scaleFactor;
+	if (scaleFactor != 1.) {
+		// Change scale while keeping the position center in place.
+		position.x += position.w / 2;
+		position.y += position.h / 2;
+		position.w *= scaleFactor;
+		position.h *= scaleFactor;
+		position.x -= position.w / 2;
+		position.y -= position.h / 2;
+	}
 	return position;
 }