Call EnableNonClientDpiScaling

ui/views/win/hwnd_message_handler.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <tchar.h>
@@ skipping 311 matching lines @@
 HWNDMessageHandler::HWNDMessageHandler(HWNDMessageHandlerDelegate* delegate)
     : msg_handled_(FALSE),
       delegate_(delegate),
       fullscreen_handler_(new FullscreenHandler),
       waiting_for_close_now_(false),
       use_system_default_icon_(false),
       restored_enabled_(false),
       current_cursor_(NULL),
       previous_cursor_(NULL),
       dpi_(0),
+      called_enable_non_client_dpi_scaling_(false),
       active_mouse_tracking_flags_(0),
       is_right_mouse_pressed_on_caption_(false),
       lock_updates_count_(0),
       ignore_window_pos_changes_(false),
       last_monitor_(NULL),
       is_first_nccalc_(true),
       menu_depth_(0),
       id_generator_(0),
       in_size_loop_(false),
       touch_down_contexts_(0),
@@ skipping 13 matching lines @@
 }
 
 void HWNDMessageHandler::Init(HWND parent, const gfx::Rect& bounds) {
   TRACE_EVENT0("views", "HWNDMessageHandler::Init");
   GetMonitorAndRects(bounds.ToRECT(), &last_monitor_, &last_monitor_rect_,
                      &last_work_area_);
 
   // Create the window.
   WindowImpl::Init(parent, bounds);
 
-  if (delegate_->HasFrame() && base::win::IsProcessPerMonitorDpiAware()) {
+  if (!called_enable_non_client_dpi_scaling_ &&
+      delegate_->HasFrame() &&
+      base::win::IsProcessPerMonitorDpiAware()) {
     static auto enable_child_window_dpi_message_func = []() {
       // Derived signature; not available in headers.
       // This call gets Windows to scale the non-client area when WM_DPICHANGED
       // is fired.
       using EnableChildWindowDpiMessagePtr = LRESULT (WINAPI*)(HWND, BOOL);
       return reinterpret_cast<EnableChildWindowDpiMessagePtr>(
                  GetProcAddress(GetModuleHandle(L"user32.dll"),
                                 "EnableChildWindowDpiMessage"));
     }();
     if (enable_child_window_dpi_message_func)
@@ skipping 1412 matching lines @@
   // pixels in the (now wrong) location, and thus makes actions like resizing a
   // window from the left edge look slightly less broken.
   // We special case when left or top insets are 0, since these conditions
   // actually require another repaint to correct the layout after glass gets
   // turned on and off.
   if (insets.left() == 0 || insets.top() == 0)
     return 0;
   return mode ? WVR_REDRAW : 0;
 }
 
+LRESULT HWNDMessageHandler::OnNCCreate(LPCREATESTRUCT lpCreateStruct) {
+  SetMsgHandled(FALSE);
+  if (delegate_->HasFrame() && base::win::IsProcessPerMonitorDpiAware()) {
+    static auto enable_non_client_dpi_scaling_func = []() {
+      // Signature only available in the 10.0.14393.0 API. As of this writing,
+      // Chrome built against 10.0.10586.0.
+      using EnableNonClientDpiScalingPtr = LRESULT (WINAPI*)(HWND);
+      return reinterpret_cast<EnableNonClientDpiScalingPtr>(
+                 GetProcAddress(GetModuleHandle(L"user32.dll"),
+                                "EnableNonClientDpiScaling"));
+    }();
+    called_enable_non_client_dpi_scaling_ =
+        !!(enable_non_client_dpi_scaling_func &&
+           enable_non_client_dpi_scaling_func(hwnd()));
+  }
+  return FALSE;
+}
+
 LRESULT HWNDMessageHandler::OnNCHitTest(const gfx::Point& point) {
   if (!delegate_->HasNonClientView()) {
     SetMsgHandled(FALSE);
     return 0;
   }
 
   // Some views may overlap the non client area of the window.
   // This means that we should look for these views before handing the
   // hittest message off to DWM or DefWindowProc.
   // If the hittest returned from the search for a view returns HTCLIENT
@@ skipping 947 matching lines @@
   MONITORINFO monitor_info = {sizeof(monitor_info)};
   GetMonitorInfo(MonitorFromWindow(hwnd(), MONITOR_DEFAULTTOPRIMARY),
                  &monitor_info);
   gfx::Rect shrunk_rect(monitor_info.rcMonitor);
   shrunk_rect.set_height(shrunk_rect.height() - 1);
   background_fullscreen_hack_ = true;
   SetBoundsInternal(shrunk_rect, false);
 }
 
 }  // namespace views