File ibus-mozc-candidate-window-qt-virtual-coordinate.patch of Package mozc

diff --git a/src/renderer/qt/qt_window_manager.cc b/src/renderer/qt/qt_window_manager.cc
index 0aceecce6..5c8662b1f 100644
--- a/src/renderer/qt/qt_window_manager.cc
+++ b/src/renderer/qt/qt_window_manager.cc
@@ -32,9 +32,9 @@
 #include <algorithm>
 #include <string>
 
+#include "absl/strings/str_cat.h"
 #include "base/logging.h"
 #include "protocol/candidates.pb.h"
-#include "absl/strings/str_cat.h"
 #include "renderer/renderer_style_handler.h"
 #include "renderer/window_util.h"
 
@@ -341,16 +341,53 @@ void FillCandidates(const commands::Candidates &candidates,
 }
 }  // namespace
 
+struct VirtualRect {
+  const QScreen* screen;
+  const Rect rect;
+
+  VirtualRect(const QScreen* screen, const Rect rect): screen(screen), rect(rect) {}
+};
+
+Rect TranslateToVirtualRectWithScreen(const QScreen *screen, const Rect& native_rect) {
+    const double device_pixel_ratio = screen->devicePixelRatio();
+    // screen_left, screen_top have the save value in both virtual and native coordinate
+    const int screen_left = screen->geometry().x();
+    const int screen_top = screen->geometry().y();
+    const int vx = (native_rect.Left() - screen_left) / device_pixel_ratio + screen_left;
+    const int vy = (native_rect.Top() - screen_top) / device_pixel_ratio + screen_top;
+
+    return Rect(vx, vy, native_rect.Width() / device_pixel_ratio, native_rect.Height() / device_pixel_ratio);
+}
+
+VirtualRect TranslateToVirtualRect(const Rect& native_rect) {
+  for (const QScreen *screen: QGuiApplication::screens()) {
+    Rect rect = TranslateToVirtualRectWithScreen(screen, native_rect);
+    const QRect screen_rect = screen->geometry();
+
+    // Use (top left) to locate a screen
+    if (screen_rect.contains(rect.Left(), rect.Top())) {
+      return VirtualRect(screen, rect);
+    }
+  }
+
+  // fall back to primary screen
+  const QScreen *screen = QGuiApplication::primaryScreen();
+  Rect point = TranslateToVirtualRectWithScreen(screen, native_rect);
+  return VirtualRect(screen, point);
+}
+
 Point QtWindowManager::GetWindowPosition(
     const commands::RendererCommand &command, const Size &win_size) {
-  const Rect preedit_rect = GetRect(command.preedit_rectangle());
-  const Point win_pos = Point(preedit_rect.Left(), preedit_rect.Bottom());
-  const Rect monitor_rect = GetMonitorRect(win_pos.x, win_pos.y);
+
+  const Rect native_preedit_rect = GetRect(command.preedit_rectangle());
+  const VirtualRect preedit_rect = TranslateToVirtualRect(native_preedit_rect);
+  const Point win_pos = Point(preedit_rect.rect.Left(), preedit_rect.rect.Bottom());
+  const Rect monitor_rect = GetRect(preedit_rect.screen->geometry());
   const Point offset_to_column1(kColumn0Width, 0);
 
   const Rect adjusted_win_geometry =
       WindowUtil::GetWindowRectForMainWindowFromTargetPointAndPreedit(
-          win_pos, preedit_rect, win_size, offset_to_column1, monitor_rect,
+          win_pos, preedit_rect.rect, win_size, offset_to_column1, monitor_rect,
           /* vertical */ false);  // Only support horizontal window yet.
   return adjusted_win_geometry.origin;
 }