Refactor Windows DPI Point, Rect, and Size for Multiple Monitor DPI Awareness

ui/gfx/win/display_manager.h

+// Copyright 2016 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.
+
+#ifndef UI_GFX_WIN_DISPLAY_MANAGER_H_
+#define UI_GFX_WIN_DISPLAY_MANAGER_H_
+
+#include <windows.h>
+#include <memory>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "base/observer_list.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/gfx_export.h"
+
+namespace gfx {
+
+class Point;
+class Rect;
+class ScreenWin;
+class SingletonHwndObserver;
+
+namespace win {
+
+class DisplayManagerObserver;
+class DisplayInfo;
+class ScreenWinDisplay;
+
+// Holds all of the ScreenWinDisplays corresponding to a Windows HMONITOR.
+class GFX_EXPORT DisplayManager {
+ public:
+  static DisplayManager* GetInstance();
+
+  void AddObserver(DisplayManagerObserver* observer);
+  void RemoveObserver(DisplayManagerObserver* observer);
+
+  const std::vector<ScreenWinDisplay>& GetScreenWinDisplays();
+  ScreenWinDisplay GetScreenWinDisplay(const MONITORINFOEX& monitor_info) const;
+  ScreenWinDisplay GetScreenWinDisplayNearestHWND(HWND hwnd) const;
+  ScreenWinDisplay GetScreenWinDisplayNearestScreenRect(
+      const Rect& screen_rect) const;
+  ScreenWinDisplay GetScreenWinDisplayNearestScreenPoint(
+      const Point& screen_point) const;
+  ScreenWinDisplay GetScreenWinDisplayNearestDIPRect(const Rect& dip_rect)
+      const;
+  ScreenWinDisplay GetScreenWinDisplayNearestDIPPoint(const Point& dip_point)
+      const;
+  ScreenWinDisplay GetPrimaryScreenWinDisplay() const;
+  float GetScaleFactorForHWND(HWND hwnd) const;
+  float GetScaleFactorForScreenPoint(const Point& screen_point) const;
+
+  // For Unit Tests.
+  virtual MONITORINFOEX MonitorInfoFromScreenPoint(
+      const gfx::Point& screen_point) const;
+  virtual MONITORINFOEX MonitorInfoFromScreenRect(const gfx::Rect& screen_rect)
+      const;
+  virtual MONITORINFOEX MonitorInfoFromWindow(HWND hwnd) const;
+  virtual HWND GetRootWindow(HWND hwnd) const;
+
+ protected:
+  friend std::default_delete<DisplayManager>;
+
+  static void SetInstanceForTesting(scoped_ptr<DisplayManager> display_manager);
+
+  DisplayManager();
+  virtual ~DisplayManager();
+
+  void UpdateFromDisplayInfos(const std::vector<DisplayInfo>& display_infos);
+
+ private:
+  void WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
+
+  scoped_ptr<gfx::SingletonHwndObserver> singleton_hwnd_observer_;
+  base::ObserverList<DisplayManagerObserver, true> observer_list_;
+  std::vector<ScreenWinDisplay> screen_win_displays_;
+
+  DISALLOW_COPY_AND_ASSIGN(DisplayManager);
+};
+
+}  // namespace win
+}  // namespace gfx
+
+#endif  // UI_GFX_WIN_DISPLAY_MANAGER_H_