From a3bcd2fac415dba704f787df5523da7400c74b42 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 10 Feb 2023 20:32:06 +0400
Subject: [PATCH] Fix rounding for maximized translucent windows.

---
 ui/platform/win/ui_window_win.cpp | 12 +++++++++++-
 ui/platform/win/ui_window_win.h   |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/ui/platform/win/ui_window_win.cpp b/ui/platform/win/ui_window_win.cpp
index da05e37..3206df8 100644
--- a/ui/platform/win/ui_window_win.cpp
+++ b/ui/platform/win/ui_window_win.cpp
@@ -274,7 +274,9 @@ void WindowHelper::updateCornersRounding() {
 	if (!::Platform::IsWindows11OrGreater()) {
 		return;
 	}
-	auto preference = _isFullScreen ? kDWMWCP_DONOTROUND : kDWMWCP_ROUND;
+	const auto preference = (_isFullScreen || _isMaximizedAndTranslucent)
+		? kDWMWCP_DONOTROUND
+		: kDWMWCP_ROUND;
 	DwmSetWindowAttribute(
 		_handle,
 		kDWMWA_WINDOW_CORNER_PREFERENCE,
@@ -372,6 +374,14 @@ void WindowHelper::init() {
 					window()->windowState() & ~Qt::WindowMaximized);
 			});
 		}
+		if (state != Qt::WindowMinimized) {
+			const auto is = (state == Qt::WindowMaximized)
+				&& window()->testAttribute(Qt::WA_TranslucentBackground);
+			if (_isMaximizedAndTranslucent != is) {
+				_isMaximizedAndTranslucent = is;
+				updateCornersRounding();
+			}
+		}
 	};
 	Ui::Connect(
 		window()->windowHandle(),
diff --git a/ui/platform/win/ui_window_win.h b/ui/platform/win/ui_window_win.h
index d3ec58d..d29fc11 100644
--- a/ui/platform/win/ui_window_win.h
+++ b/ui/platform/win/ui_window_win.h
@@ -83,6 +83,7 @@ private:
 	QMargins _marginsDelta;
 	bool _updatingMargins = false;
 	bool _isFullScreen = false;
+	bool _isMaximizedAndTranslucent = false;
 
 };