From 713165e4064c5addb72693432272b895dc84b0ab Mon Sep 17 00:00:00 2001
From: "trop[bot]" <37223003+trop[bot]@users.noreply.github.com>
Date: Mon, 28 Apr 2025 22:07:15 -0500
Subject: [PATCH] fix: fullscreen fillet / recovery is incorrect (#46847)

* fix: fullscreen fillet / recovery is incorrect

Signed-off-by: ZOY\zoy-l <zoy-l@outlook.com>

Co-authored-by: ZOY\zoy-l <zoy-l@outlook.com>

* fix: maintain frameless consistency on windows 11

Co-authored-by: ZOY\zoy-l <zoy-l@outlook.com>

* fix: maintain frameless consistency on windows 11

Co-authored-by: ZOY\zoy-l <zoy-l@outlook.com>

* chore: modify the comments

Co-authored-by: ZOY\zoy-l <zoy-l@outlook.com>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: ZOY\zoy-l <zoy-l@outlook.com>
---
 shell/browser/native_window_views.cc | 37 +++++++++++++++++++---------
 shell/browser/native_window_views.h  |  3 +++
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/shell/browser/native_window_views.cc b/shell/browser/native_window_views.cc
index 6a19a0768853..689e7f13df8e 100644
--- a/shell/browser/native_window_views.cc
+++ b/shell/browser/native_window_views.cc
@@ -374,14 +374,17 @@ NativeWindowViews::NativeWindowViews(const gin_helper::Dictionary& options,
       frame_style |= WS_MINIMIZEBOX;
     if (maximizable_)
       frame_style |= WS_MAXIMIZEBOX;
-    // We should not show a frame for transparent window.
-    if (!thick_frame_)
-      frame_style &= ~(WS_THICKFRAME | WS_CAPTION);
-    ::SetWindowLong(GetAcceleratedWidget(), GWL_STYLE, frame_style);
 
-    bool rounded_corner = true;
-    options.Get(options::kRoundedCorners, &rounded_corner);
-    SetRoundedCorners(rounded_corner);
+    // We should not show a frame for transparent window.
+    if (!thick_frame_) {
+      frame_style &= ~(WS_THICKFRAME | WS_CAPTION);
+      rounded_corner_ = false;
+    } else {
+      options.Get(options::kRoundedCorners, &rounded_corner_);
+    }
+
+    ::SetWindowLong(GetAcceleratedWidget(), GWL_STYLE, frame_style);
+    SetRoundedCorners(rounded_corner_);
   }
 
   LONG ex_style = ::GetWindowLong(GetAcceleratedWidget(), GWL_EXSTYLE);
@@ -646,10 +649,12 @@ void NativeWindowViews::SetEnabledInternal(bool enable) {
 void NativeWindowViews::Maximize() {
 #if BUILDFLAG(IS_WIN)
   if (IsTranslucent()) {
-    // If a window is translucent but not transparent on Windows,
-    // that means it must have a backgroundMaterial set.
-    if (!transparent())
+    // Semi-transparent windows with backgroundMaterial not set to 'none', and
+    // not fully transparent, require manual handling of rounded corners when
+    // maximized.
+    if (rounded_corner_)
       SetRoundedCorners(false);
+
     restore_bounds_ = GetBounds();
     auto display = display::Screen::GetScreen()->GetDisplayNearestWindow(
         GetNativeWindow());
@@ -678,7 +683,8 @@ void NativeWindowViews::Unmaximize() {
     NotifyWindowUnmaximize();
     if (transparent()) {
       UpdateThickFrame();
-    } else {
+    }
+    if (rounded_corner_) {
       SetRoundedCorners(true);
     }
     return;
@@ -724,7 +730,8 @@ void NativeWindowViews::Restore() {
     NotifyWindowRestore();
     if (transparent()) {
       UpdateThickFrame();
-    } else {
+    }
+    if (rounded_corner_) {
       SetRoundedCorners(true);
     }
     return;
@@ -758,6 +765,12 @@ void NativeWindowViews::SetFullScreen(bool fullscreen) {
     NotifyWindowLeaveFullScreen();
   }
 
+  // If round corners are enabled,
+  // they need to be set based on whether the window is fullscreen.
+  if (rounded_corner_) {
+    SetRoundedCorners(!fullscreen);
+  }
+
   // For window without WS_THICKFRAME style, we can not call SetFullscreen().
   // This path will be used for transparent windows as well.
   if (!thick_frame_) {
diff --git a/shell/browser/native_window_views.h b/shell/browser/native_window_views.h
index 2d23a020f115..620a5a346d3c 100644
--- a/shell/browser/native_window_views.h
+++ b/shell/browser/native_window_views.h
@@ -286,6 +286,9 @@ class NativeWindowViews : public NativeWindow,
   HWND legacy_window_ = nullptr;
   bool layered_ = false;
 
+  // This value is determined when the window is created.
+  bool rounded_corner_ = true;
+
   // Set to true if the window is always on top and behind the task bar.
   bool behind_task_bar_ = false;