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

ui/gfx/screen_win.cc

Index: ui/gfx/screen_win.cc
diff --git a/ui/gfx/screen_win.cc b/ui/gfx/screen_win.cc
index 3199f7acaacdd2b15c3dca37d09014dc418c2d00..86bfc3fc29df48e5ba1192c2ca93b402ece0f8bf 100644
--- a/ui/gfx/screen_win.cc
+++ b/ui/gfx/screen_win.cc
@@ -5,97 +5,160 @@
 #include "ui/gfx/screen_win.h"
 
 #include <windows.h>
-#include <stdint.h>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/hash.h"
-#include "base/logging.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/win_util.h"
+
 #include "ui/gfx/display.h"
-#include "ui/gfx/win/dpi.h"
+#include "ui/gfx/geometry/insets.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/point_conversions.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/geometry/vector2d.h"
+#include "ui/gfx/win/display_info.h"
+#include "ui/gfx/win/display_manager.h"
+#include "ui/gfx/win/rect_util.h"
+#include "ui/gfx/win/screen_win_display.h"
 
 namespace {
 
-MONITORINFOEX GetMonitorInfoForMonitor(HMONITOR monitor) {
-  MONITORINFOEX monitor_info;
-  ZeroMemory(&monitor_info, sizeof(MONITORINFOEX));
-  monitor_info.cbSize = sizeof(monitor_info);
-  GetMonitorInfo(monitor, &monitor_info);
-  return monitor_info;
-}
-
-gfx::Display GetDisplay(const MONITORINFOEX& monitor_info) {
-  int64_t id =
-      static_cast<int64_t>(base::Hash(base::WideToUTF8(monitor_info.szDevice)));
-  gfx::Rect bounds = gfx::Rect(monitor_info.rcMonitor);
-  gfx::Display display(id);
-  display.set_bounds(gfx::win::ScreenToDIPRect(bounds));
-  display.set_work_area(
-      gfx::win::ScreenToDIPRect(gfx::Rect(monitor_info.rcWork)));
-  display.SetScaleAndBounds(gfx::GetDPIScale(), bounds);
-
-  DEVMODE mode;
-  memset(&mode, 0, sizeof(DEVMODE));
-  mode.dmSize = sizeof(DEVMODE);
-  mode.dmDriverExtra = 0;
-  if (EnumDisplaySettings(monitor_info.szDevice,
-                          ENUM_CURRENT_SETTINGS,
-                          &mode)) {
-    switch (mode.dmDisplayOrientation) {
-    case DMDO_DEFAULT:
-      display.set_rotation(gfx::Display::ROTATE_0);
-      break;
-    case DMDO_90:
-      display.set_rotation(gfx::Display::ROTATE_90);
-      break;
-    case DMDO_180:
-      display.set_rotation(gfx::Display::ROTATE_180);
-      break;
-    case DMDO_270:
-      display.set_rotation(gfx::Display::ROTATE_270);
-      break;
-    default:
-      NOTREACHED();
-    }
-  }
-
-  return display;
+// Returns a point in |to_origin|'s coordinates and position scaled by
+// |scale_factor|.
+gfx::Point ScalePointRelative(const gfx::Point& from_origin,
+                              const gfx::Point& to_origin,
+                              const float scale_factor,
+                              const gfx::Point& point) {
+  gfx::Vector2d from_origin_vector(from_origin.x(), from_origin.y());
+  gfx::Vector2d to_origin_vector(to_origin.x(), to_origin.y());
+  gfx::Point scaled_relative_point(
+      gfx::ScaleToFlooredPoint(point - from_origin_vector, scale_factor));
+  return scaled_relative_point + to_origin_vector;
 }
 
-BOOL CALLBACK EnumMonitorCallback(HMONITOR monitor,
-                                  HDC hdc,
-                                  LPRECT rect,
-                                  LPARAM data) {
-  std::vector<gfx::Display>* all_displays =
-      reinterpret_cast<std::vector<gfx::Display>*>(data);
-  DCHECK(all_displays);
+std::vector<gfx::Display> ToVectorOfDisplays(
+    const std::vector<gfx::win::ScreenWinDisplay>& screen_win_displays) {
+  std::vector<gfx::Display> displays;
+  for (const auto& screen_win_display : screen_win_displays)
+    displays.push_back(screen_win_display.display());
 
-  MONITORINFOEX monitor_info = GetMonitorInfoForMonitor(monitor);
-  gfx::Display display = GetDisplay(monitor_info);
-  all_displays->push_back(display);
-  return TRUE;
+  return displays;
 }
 
-std::vector<gfx::Display> GetDisplays() {
-  std::vector<gfx::Display> displays;
-  EnumDisplayMonitors(NULL, NULL, EnumMonitorCallback,
-                      reinterpret_cast<LPARAM>(&displays));
-  return displays;
+inline gfx::win::DisplayManager* GetDisplayManager() {
+  return gfx::win::DisplayManager::GetInstance();
 }
 
 }  // namespace
 
 namespace gfx {
 
-ScreenWin::ScreenWin()
-    : singleton_hwnd_observer_(new SingletonHwndObserver(
-          base::Bind(&ScreenWin::OnWndProc, base::Unretained(this)))),
-      displays_(GetDisplays()) {
+ScreenWin::ScreenWin() : display_manager_(GetDisplayManager()) {
+  display_manager_->AddObserver(this);
 }
 
-ScreenWin::~ScreenWin() {}
+ScreenWin::~ScreenWin() {
+  display_manager_->RemoveObserver(this);
+}
+
+// static
+Point ScreenWin::ScreenToDIPPoint(const Point& pixel_point) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager->GetScreenWinDisplayNearestScreenPoint(pixel_point);
+  Display display = screen_win_display.display();
+  return ScalePointRelative(screen_win_display.physical_bounds().origin(),
+                            display.bounds().origin(),
+                            1.0f / display.device_scale_factor(),
+                            pixel_point);
+}
+
+// static
+Point ScreenWin::DIPToScreenPoint(const Point& dip_point) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager->GetScreenWinDisplayNearestDIPPoint(dip_point);
+  Display display = screen_win_display.display();
+  return ScalePointRelative(display.bounds().origin(),
+                            screen_win_display.physical_bounds().origin(),
+                            display.device_scale_factor(),
+                            dip_point);
+}
+
+// static
+Point ScreenWin::ClientToDIPPoint(HWND hwnd, const Point& client_point) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  float scale_factor = display_manager->GetScaleFactorForHWND(hwnd);
+  return ScaleToFlooredPoint(client_point, 1.0f / scale_factor);
+}
+
+// static
+Point ScreenWin::DIPToClientPoint(HWND hwnd, const Point& dip_point) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  float scale_factor = display_manager->GetScaleFactorForHWND(hwnd);
+  return ScaleToFlooredPoint(dip_point, scale_factor);
+}
+
+// static
+Rect ScreenWin::ScreenToDIPRect(HWND hwnd, const Rect& pixel_bounds) {
+  // It's important we scale the origin and size separately. If we instead
+  // calculated the size from the floored origin and ceiled right the size could
+  // vary depending upon where the two points land. That would cause problems
+  // for the places this code is used (in particular mapping from native window
+  // bounds to DIPs).
+  if (hwnd) {
+    return Rect(ScreenToDIPPoint(pixel_bounds.origin()),
+                ScreenToDIPSize(hwnd, pixel_bounds.size()));
+  }
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager->GetScreenWinDisplayNearestScreenRect(pixel_bounds);
+  float scale_factor = screen_win_display.display().device_scale_factor();
+  return Rect(ScreenToDIPPoint(pixel_bounds.origin()),
+              ScaleToCeiledSize(pixel_bounds.size(), 1.0f / scale_factor));
+}
+
+// static
+Rect ScreenWin::DIPToScreenRect(HWND hwnd, const Rect& dip_bounds) {
+  // See comment in ScreenToDIPRect for why we calculate size like this.
+  if (hwnd) {
+    return Rect(DIPToScreenPoint(dip_bounds.origin()),
+                DIPToScreenSize(hwnd, dip_bounds.size()));
+  }
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager->GetScreenWinDisplayNearestDIPRect(dip_bounds);
+  float scale_factor = screen_win_display.display().device_scale_factor();
+  return Rect(DIPToScreenPoint(dip_bounds.origin()),
+              ScaleToCeiledSize(dip_bounds.size(), scale_factor));
+}
+
+// static
+Rect ScreenWin::ClientToDIPRect(HWND hwnd, const Rect& pixel_bounds) {
+  // See comment in ScreenToDIPRect for why we calculate size like this.
+  return Rect(ClientToDIPPoint(hwnd, pixel_bounds.origin()),
+              ScreenToDIPSize(hwnd, pixel_bounds.size()));
+}
+
+// static
+Rect ScreenWin::DIPToClientRect(HWND hwnd, const Rect& dip_bounds) {
+  // See comment in ScreenToDIPRect for why we calculate size like this.
+  return Rect(DIPToClientPoint(hwnd, dip_bounds.origin()),
+              DIPToScreenSize(hwnd, dip_bounds.size()));
+}
+
+// static
+Size ScreenWin::ScreenToDIPSize(HWND hwnd, const Size& size_in_pixels) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  float scale_factor = display_manager->GetScaleFactorForHWND(hwnd);
+  // Always ceil sizes. Otherwise we may be leaving off part of the bounds.
+  return ScaleToCeiledSize(size_in_pixels, 1.0f / scale_factor);
+}
+
+// static
+Size ScreenWin::DIPToScreenSize(HWND hwnd, const Size& dip_size) {
+  gfx::win::DisplayManager* display_manager = GetDisplayManager();
+  float scale_factor = display_manager->GetScaleFactorForHWND(hwnd);
+  // Always ceil sizes. Otherwise we may be leaving off part of the bounds.
+  return ScaleToCeiledSize(dip_size, scale_factor);
+}
 
 HWND ScreenWin::GetHWNDFromNativeView(NativeView window) const {
   NOTREACHED();
@@ -111,7 +174,7 @@ gfx::Point ScreenWin::GetCursorScreenPoint() {
   POINT pt;
   GetCursorPos(&pt);
   gfx::Point cursor_pos_pixels(pt);
-  return gfx::win::ScreenToDIPPoint(cursor_pos_pixels);
+  return ScreenToDIPPoint(cursor_pos_pixels);
 }
 
 gfx::NativeWindow ScreenWin::GetWindowUnderCursor() {
@@ -121,7 +184,7 @@ gfx::NativeWindow ScreenWin::GetWindowUnderCursor() {
 }
 
 gfx::NativeWindow ScreenWin::GetWindowAtScreenPoint(const gfx::Point& point) {
-  gfx::Point point_in_pixels = gfx::win::DIPToScreenPoint(point);
+  gfx::Point point_in_pixels = DIPToScreenPoint(point);
   return GetNativeWindowFromHWND(WindowFromPoint(point_in_pixels.ToPOINT()));
 }
 
@@ -130,7 +193,7 @@ int ScreenWin::GetNumDisplays() const {
 }
 
 std::vector<gfx::Display> ScreenWin::GetAllDisplays() const {
-  return displays_;
+  return ToVectorOfDisplays(display_manager_->GetScreenWinDisplays());
 }
 
 gfx::Display ScreenWin::GetDisplayNearestWindow(gfx::NativeView window) const {
@@ -141,45 +204,26 @@ gfx::Display ScreenWin::GetDisplayNearestWindow(gfx::NativeView window) const {
     // scaling factor.
     return GetPrimaryDisplay();
   }
-
-  MONITORINFOEX monitor_info;
-  monitor_info.cbSize = sizeof(monitor_info);
-  GetMonitorInfo(MonitorFromWindow(window_hwnd, MONITOR_DEFAULTTONEAREST),
-                 &monitor_info);
-  return GetDisplay(monitor_info);
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager_->GetScreenWinDisplayNearestHWND(window_hwnd);
+  return screen_win_display.display();
 }
 
 gfx::Display ScreenWin::GetDisplayNearestPoint(const gfx::Point& point) const {
-  gfx::Point point_in_pixels = gfx::win::DIPToScreenPoint(point);
-  POINT initial_loc = { point_in_pixels.x(), point_in_pixels.y() };
-  HMONITOR monitor = MonitorFromPoint(initial_loc, MONITOR_DEFAULTTONEAREST);
-  MONITORINFOEX mi;
-  ZeroMemory(&mi, sizeof(MONITORINFOEX));
-  mi.cbSize = sizeof(mi);
-  if (monitor && GetMonitorInfo(monitor, &mi)) {
-    return GetDisplay(mi);
-  }
-  return gfx::Display();
+  gfx::Point screen_point(DIPToScreenPoint(point));
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager_->GetScreenWinDisplayNearestScreenPoint(screen_point);
+  return screen_win_display.display();
 }
 
 gfx::Display ScreenWin::GetDisplayMatching(const gfx::Rect& match_rect) const {
-  RECT other_bounds_rect = match_rect.ToRECT();
-  MONITORINFOEX monitor_info = GetMonitorInfoForMonitor(MonitorFromRect(
-      &other_bounds_rect, MONITOR_DEFAULTTONEAREST));
-  return GetDisplay(monitor_info);
+  gfx::win::ScreenWinDisplay screen_win_display =
+      display_manager_->GetScreenWinDisplayNearestScreenRect(match_rect);
+  return screen_win_display.display();
 }
 
 gfx::Display ScreenWin::GetPrimaryDisplay() const {
-  MONITORINFOEX mi = GetMonitorInfoForMonitor(
-      MonitorFromWindow(NULL, MONITOR_DEFAULTTOPRIMARY));
-  gfx::Display display = GetDisplay(mi);
-  // TODO(kevers|girard): Test if these checks can be reintroduced for high-DIP
-  // once more of the app is DIP-aware.
-  if (GetDPIScale() == 1.0) {
-    DCHECK_EQ(GetSystemMetrics(SM_CXSCREEN), display.size().width());
-    DCHECK_EQ(GetSystemMetrics(SM_CYSCREEN), display.size().height());
-  }
-  return display;
+  return display_manager_->GetPrimaryScreenWinDisplay().display();
 }
 
 void ScreenWin::AddObserver(DisplayObserver* observer) {
@@ -190,27 +234,26 @@ void ScreenWin::RemoveObserver(DisplayObserver* observer) {
   change_notifier_.RemoveObserver(observer);
 }
 
-void ScreenWin::OnWndProc(HWND hwnd,
-                          UINT message,
-                          WPARAM wparam,
-                          LPARAM lparam) {
-  if (message != WM_DISPLAYCHANGE)
-    return;
-
-  std::vector<gfx::Display> old_displays = displays_;
-  displays_ = GetDisplays();
-
-  change_notifier_.NotifyDisplaysChanged(old_displays, displays_);
+gfx::Rect ScreenWin::ScreenToDIPRectInWindow(
+    NativeView view, const gfx::Rect& screen_rect) const {
+  HWND hwnd = view ? GetHWNDFromNativeView(view) : NULL;
+  return ScreenWin::ScreenToDIPRect(hwnd, screen_rect);
 }
 
-// static
-std::vector<gfx::Display> ScreenWin::GetDisplaysForMonitorInfos(
-    const std::vector<MONITORINFOEX>& monitor_infos) {
-  std::vector<gfx::Display> displays;
-  for (const MONITORINFOEX& monitor_info : monitor_infos)
-    displays.push_back(GetDisplay(monitor_info));
+gfx::Rect ScreenWin::DIPToScreenRectInWindow(NativeView view,
+                                             const gfx::Rect& dip_rect) const {
+  HWND hwnd = view ? GetHWNDFromNativeView(view) : NULL;
+  return ScreenWin::DIPToScreenRect(hwnd, dip_rect);
+}
 
-  return displays;
+void ScreenWin::OnDisplaysChanged(
+    const std::vector<gfx::win::ScreenWinDisplay> old_screen_win_displays,
+    const std::vector<gfx::win::ScreenWinDisplay> new_screen_win_displays) {
+  std::vector<gfx::Display> old_displays =
+      ToVectorOfDisplays(old_screen_win_displays);
+  std::vector<gfx::Display> new_displays =
+      ToVectorOfDisplays(new_screen_win_displays);
+  change_notifier_.NotifyDisplaysChanged(old_displays, new_displays);
 }
 
 }  // namespace gfx