From d518b6abc887787ac169270cbcf71c4626e2caaf Mon Sep 17 00:00:00 2001
From: Samuel Maddock <samuel.maddock@gmail.com>
Date: Tue, 18 May 2021 21:34:40 -0400
Subject: [PATCH] fix: window bounds not scaled from screen coordinates
 (#29162)

---
 shell/browser/native_window_views.cc     | 28 ++++++++++++++----------
 shell/browser/native_window_views.h      |  4 ++++
 shell/browser/native_window_views_win.cc | 18 ++++++++-------
 3 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/shell/browser/native_window_views.cc b/shell/browser/native_window_views.cc
index 79eb4d20752d..1a855d106792 100644
--- a/shell/browser/native_window_views.cc
+++ b/shell/browser/native_window_views.cc
@@ -82,6 +82,22 @@
 
 namespace electron {
 
+#if defined(OS_WIN)
+
+// Similar to the ones in display::win::ScreenWin, but with rounded values
+// These help to avoid problems that arise from unresizable windows where the
+// original ceil()-ed values can cause calculation errors, since converting
+// both ways goes through a ceil() call. Related issue: #15816
+gfx::Rect ScreenToDIPRect(HWND hwnd, const gfx::Rect& pixel_bounds) {
+  float scale_factor = display::win::ScreenWin::GetScaleFactorForHWND(hwnd);
+  gfx::Rect dip_rect = ScaleToRoundedRect(pixel_bounds, 1.0f / scale_factor);
+  dip_rect.set_origin(
+      display::win::ScreenWin::ScreenToDIPRect(hwnd, pixel_bounds).origin());
+  return dip_rect;
+}
+
+#endif
+
 namespace {
 
 #if defined(OS_WIN)
@@ -96,18 +112,6 @@ void FlipWindowStyle(HWND handle, bool on, DWORD flag) {
   ::SetWindowLong(handle, GWL_STYLE, style);
 }
 
-// Similar to the ones in display::win::ScreenWin, but with rounded values
-// These help to avoid problems that arise from unresizable windows where the
-// original ceil()-ed values can cause calculation errors, since converting
-// both ways goes through a ceil() call. Related issue: #15816
-gfx::Rect ScreenToDIPRect(HWND hwnd, const gfx::Rect& pixel_bounds) {
-  float scale_factor = display::win::ScreenWin::GetScaleFactorForHWND(hwnd);
-  gfx::Rect dip_rect = ScaleToRoundedRect(pixel_bounds, 1.0f / scale_factor);
-  dip_rect.set_origin(
-      display::win::ScreenWin::ScreenToDIPRect(hwnd, pixel_bounds).origin());
-  return dip_rect;
-}
-
 gfx::Rect DIPToScreenRect(HWND hwnd, const gfx::Rect& pixel_bounds) {
   float scale_factor = display::win::ScreenWin::GetScaleFactorForHWND(hwnd);
   gfx::Rect screen_rect = ScaleToRoundedRect(pixel_bounds, scale_factor);
diff --git a/shell/browser/native_window_views.h b/shell/browser/native_window_views.h
index 9f62ac1ba20b..52ca6f024531 100644
--- a/shell/browser/native_window_views.h
+++ b/shell/browser/native_window_views.h
@@ -35,6 +35,10 @@ class WindowStateWatcher;
 class EventDisabler;
 #endif
 
+#if defined(OS_WIN)
+gfx::Rect ScreenToDIPRect(HWND hwnd, const gfx::Rect& pixel_bounds);
+#endif
+
 class NativeWindowViews : public NativeWindow,
                           public views::WidgetObserver,
                           public ui::EventHandler {
diff --git a/shell/browser/native_window_views_win.cc b/shell/browser/native_window_views_win.cc
index 0ff2b7ad14af..13e369c716c2 100644
--- a/shell/browser/native_window_views_win.cc
+++ b/shell/browser/native_window_views_win.cc
@@ -260,11 +260,12 @@ bool NativeWindowViews::PreHandleMSG(UINT message,
     case WM_SIZING: {
       is_resizing_ = true;
       bool prevent_default = false;
-      NotifyWindowWillResize(gfx::Rect(*reinterpret_cast<RECT*>(l_param)),
-                             &prevent_default);
+      gfx::Rect bounds = gfx::Rect(*reinterpret_cast<RECT*>(l_param));
+      HWND hwnd = GetAcceleratedWidget();
+      gfx::Rect dpi_bounds = ScreenToDIPRect(hwnd, bounds);
+      NotifyWindowWillResize(dpi_bounds, &prevent_default);
       if (prevent_default) {
-        ::GetWindowRect(GetAcceleratedWidget(),
-                        reinterpret_cast<RECT*>(l_param));
+        ::GetWindowRect(hwnd, reinterpret_cast<RECT*>(l_param));
         return true;  // Tells Windows that the Sizing is handled.
       }
       return false;
@@ -288,11 +289,12 @@ bool NativeWindowViews::PreHandleMSG(UINT message,
     case WM_MOVING: {
       is_moving_ = true;
       bool prevent_default = false;
-      NotifyWindowWillMove(gfx::Rect(*reinterpret_cast<RECT*>(l_param)),
-                           &prevent_default);
+      gfx::Rect bounds = gfx::Rect(*reinterpret_cast<RECT*>(l_param));
+      HWND hwnd = GetAcceleratedWidget();
+      gfx::Rect dpi_bounds = ScreenToDIPRect(hwnd, bounds);
+      NotifyWindowWillMove(dpi_bounds, &prevent_default);
       if (!movable_ || prevent_default) {
-        ::GetWindowRect(GetAcceleratedWidget(),
-                        reinterpret_cast<RECT*>(l_param));
+        ::GetWindowRect(hwnd, reinterpret_cast<RECT*>(l_param));
         return true;  // Tells Windows that the Move is handled. If not true,
                       // frameless windows can be moved using
                       // -webkit-app-region: drag elements.