From 4af9688d68fc5f15ce94d8b37b1bac8403099b26 Mon Sep 17 00:00:00 2001
From: Yohei Yukawa <yukawa@google.com>
Date: Sun, 22 Oct 2023 18:00:25 +0000
Subject: [PATCH] Fix window locations under Per-Monitor DPI in Windows

This is a minimum change to place candidate windows around the cursor
location even under Per-Monitor DPI mode in Windows.

Note that there are still known issues that 'mozc_render' continues
using the initial DPI.  Watch #831 for such remaining issues.

Closes #832.

PiperOrigin-RevId: 575633393
---
 src/renderer/win32/candidate_window.cc        | 4 ++++
 src/renderer/win32/candidate_window.h         | 2 ++
 src/renderer/win32/infolist_window.cc         | 4 ++++
 src/renderer/win32/infolist_window.h          | 2 ++
 src/renderer/win32/mozc_renderer.exe.manifest | 3 +++
 5 files changed, 15 insertions(+)

diff --git a/src/renderer/win32/candidate_window.cc b/src/renderer/win32/candidate_window.cc
index 2f0f284ce8..7377a332cf 100644
--- a/src/renderer/win32/candidate_window.cc
+++ b/src/renderer/win32/candidate_window.cc
@@ -291,6 +291,10 @@ void CandidateWindow::OnDestroy() {
   ::PostQuitMessage(0);
 }
 
+void CandidateWindow::OnDpiChanged(UINT dpiX, UINT dpiY, RECT *rect) {
+  metrics_changed_ = true;
+}
+
 BOOL CandidateWindow::OnEraseBkgnd(CDCHandle dc) {
   // We do not have to erase background
   // because all pixels in client area will be drawn in the DoPaint method.
diff --git a/src/renderer/win32/candidate_window.h b/src/renderer/win32/candidate_window.h
index 03696e4a93..2e4d58d4a6 100644
--- a/src/renderer/win32/candidate_window.h
+++ b/src/renderer/win32/candidate_window.h
@@ -77,6 +77,7 @@ class CandidateWindow : public ATL::CWindowImpl<CandidateWindow, ATL::CWindow,
   BEGIN_MSG_MAP_EX(CandidateWindow)
   MSG_WM_CREATE(OnCreate)
   MSG_WM_DESTROY(OnDestroy)
+  MSG_WM_DPICHANGED(OnDpiChanged)
   MSG_WM_ERASEBKGND(OnEraseBkgnd)
   MSG_WM_GETMINMAXINFO(OnGetMinMaxInfo)
   MSG_WM_LBUTTONDOWN(OnLButtonDown)
@@ -93,6 +94,7 @@ class CandidateWindow : public ATL::CWindowImpl<CandidateWindow, ATL::CWindow,
   ~CandidateWindow();
   LRESULT OnCreate(LPCREATESTRUCT create_struct);
   void OnDestroy();
+  void OnDpiChanged(UINT dpiX, UINT dpiY, RECT *rect);
   BOOL OnEraseBkgnd(WTL::CDCHandle dc);
   void OnGetMinMaxInfo(MINMAXINFO *min_max_info);
   void OnLButtonDown(UINT nFlags, CPoint point);
diff --git a/src/renderer/win32/infolist_window.cc b/src/renderer/win32/infolist_window.cc
index 109205ae13..f90ab18689 100644
--- a/src/renderer/win32/infolist_window.cc
+++ b/src/renderer/win32/infolist_window.cc
@@ -104,6 +104,10 @@ void InfolistWindow::OnDestroy() {
   ::PostQuitMessage(0);
 }
 
+void InfolistWindow::OnDpiChanged(UINT dpiX, UINT dpiY, RECT *rect) {
+  metrics_changed_ = true;
+}
+
 BOOL InfolistWindow::OnEraseBkgnd(CDCHandle dc) {
   // We do not have to erase background
   // because all pixels in client area will be drawn in the DoPaint method.
diff --git a/src/renderer/win32/infolist_window.h b/src/renderer/win32/infolist_window.h
index 07afbf561d..277474780d 100644
--- a/src/renderer/win32/infolist_window.h
+++ b/src/renderer/win32/infolist_window.h
@@ -70,6 +70,7 @@ class InfolistWindow : public ATL::CWindowImpl<InfolistWindow, ATL::CWindow,
 
   BEGIN_MSG_MAP_EX(InfolistWindow)
   MSG_WM_DESTROY(OnDestroy)
+  MSG_WM_DPICHANGED(OnDpiChanged)
   MSG_WM_ERASEBKGND(OnEraseBkgnd)
   MSG_WM_GETMINMAXINFO(OnGetMinMaxInfo)
   MSG_WM_SETTINGCHANGE(OnSettingChange)
@@ -83,6 +84,7 @@ class InfolistWindow : public ATL::CWindowImpl<InfolistWindow, ATL::CWindow,
   InfolistWindow &operator=(const InfolistWindow &) = delete;
   ~InfolistWindow();
   void OnDestroy();
+  void OnDpiChanged(UINT dpiX, UINT dpiY, RECT *rect);
   BOOL OnEraseBkgnd(WTL::CDCHandle dc);
   void OnGetMinMaxInfo(MINMAXINFO *min_max_info);
   void OnPaint(WTL::CDCHandle dc);
diff --git a/src/renderer/win32/mozc_renderer.exe.manifest b/src/renderer/win32/mozc_renderer.exe.manifest
index 4ceed4b592..48fde8e297 100644
--- a/src/renderer/win32/mozc_renderer.exe.manifest
+++ b/src/renderer/win32/mozc_renderer.exe.manifest
@@ -24,6 +24,9 @@
   <asmv3:application xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
     <asmv3:windowsSettings xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">
       <dpiAware>true</dpiAware>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">
+        PerMonitorV2
+      </dpiAwareness>
     </asmv3:windowsSettings>
   </asmv3:application>
 </assembly>