Add shortcut keys to ui scaling

ash/accelerators/accelerator_controller.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 "ash/accelerators/accelerator_controller.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 
@@ skipping 136 matching lines @@
     // rotation and position. Use replace so we only enqueue one at a time.
     active_window->layer()->GetAnimator()->
         set_preemption_strategy(ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
     active_window->layer()->GetAnimator()->StartAnimation(
         new ui::LayerAnimationSequence(
             new ash::ScreenRotation(360, active_window->layer())));
   }
   return true;
 }
 
-const gfx::Display::Rotation GetNextRotation(gfx::Display::Rotation current) {
+gfx::Display::Rotation GetNextRotation(gfx::Display::Rotation current) {
   switch (current) {
     case gfx::Display::ROTATE_0:
       return gfx::Display::ROTATE_90;
     case gfx::Display::ROTATE_90:
       return gfx::Display::ROTATE_180;
     case gfx::Display::ROTATE_180:
       return gfx::Display::ROTATE_270;
     case gfx::Display::ROTATE_270:
       return gfx::Display::ROTATE_0;
   }
   NOTREACHED() << "Unknown rotation:" << current;
   return gfx::Display::ROTATE_0;
 }
 
+float GetNextScale(float scale, bool up) {
+  // These scales are equivalent to 1024, 1280, 1600 and 1920 pixel width
+  // respectively on 2560 pixel width 2x density display.
+  static const float kScales[] = {0.8f, 1.0f, 1.25f, 1.5f};
+  static const size_t kScaleTableSize = arraysize(kScales);
+  for (size_t i = 0; i < kScaleTableSize; ++i) {
+    if (kScales[i] == scale) {
+      if (up && i != kScaleTableSize -1)

[James Cook, 2013/03/15 17:09:38]

nit: "kScaleTableSize - 1"

+        return kScales[i + 1];
+      if (!up && i != 0)
+        return kScales[i - 1];
+      return kScales[i];
+    }
+  }
+  // Fallback to 1.0f if the |scale| wasn't in the list.
+  return 1.0f;
+}
+
+bool HandleScaleUI(bool up) {
+  // UI Scaling is effective only on internal display.
+  int64 display_id = gfx::Display::InternalDisplayId();
+#if defined(OS_CHROMEOS)
+  // On linux desktop, allow ui scalacing on the first dislpay.
+  if (!base::chromeos::IsRunningOnChromeOS())
+    display_id = Shell::GetInstance()->display_manager()->first_display_id();
+#endif
+  const gfx::Display& display = Shell::GetInstance()->display_manager()->
+      GetDisplayForId(display_id);
+  const DisplayInfo& display_info = Shell::GetInstance()->display_manager()->
+      GetDisplayInfo(display);
+  Shell::GetInstance()->display_manager()->SetDisplayUIScale(
+      display.id(), GetNextScale(display_info.ui_scale(), up));
+  return true;
+}
+
 // Rotates the screen.
 bool HandleRotateScreen() {
-  aura::Window* active_window = wm::GetActiveWindow();
-  if (!active_window)
-    return false;
-  const gfx::Display& display =
-      Shell::GetScreen()->GetDisplayNearestWindow(active_window);
+  gfx::Point point = Shell::GetScreen()->GetCursorScreenPoint();
+  gfx::Display display = Shell::GetScreen()->GetDisplayNearestPoint(point);
   const DisplayInfo& display_info =
       Shell::GetInstance()->display_manager()->GetDisplayInfo(display);
   Shell::GetInstance()->display_manager()->SetDisplayRotation(
       display.id(), GetNextRotation(display_info.rotation()));
   return true;
 }
 
 bool HandleToggleDesktopBackgroundMode() {
   DesktopBackgroundController* desktop_background_controller =
       Shell::GetInstance()->desktop_background_controller();
@@ skipping 562 matching lines @@
       return true;
     }
     case WINDOW_POSITION_CENTER: {
       aura::Window* window = wm::GetActiveWindow();
       if (window) {
         wm::CenterWindow(window);
         return true;
       }
       break;
     }
+    case SCALE_UI_UP:
+      return HandleScaleUI(true /* up */);
+    case SCALE_UI_DOWN:
+      return HandleScaleUI(false /* down */);
     case ROTATE_WINDOW:
       return HandleRotateActiveWindow();
     case ROTATE_SCREEN:
       return HandleRotateScreen();
     case TOGGLE_DESKTOP_BACKGROUND_MODE:
       return HandleToggleDesktopBackgroundMode();
     case TOGGLE_ROOT_WINDOW_FULL_SCREEN:
       return HandleToggleRootWindowFullScreen();
     case DISPLAY_TOGGLE_SCALE:
-      internal::DisplayManager::ToggleDisplayScale();
+      internal::DisplayManager::ToggleDisplayScaleFactor();
       return true;
     case MAGNIFY_SCREEN_ZOOM_IN:
       return HandleMagnifyScreen(1);
     case MAGNIFY_SCREEN_ZOOM_OUT:
       return HandleMagnifyScreen(-1);
     case MEDIA_NEXT_TRACK:
       return HandleMediaNextTrack();
     case MEDIA_PLAY_PAUSE:
        return HandleMediaPlayPause();
     case MEDIA_PREV_TRACK:
@@ skipping 83 matching lines @@
     keyboard_brightness_control_delegate) {
   keyboard_brightness_control_delegate_ =
       keyboard_brightness_control_delegate.Pass();
 }
 
 bool AcceleratorController::CanHandleAccelerators() const {
   return true;
 }
 
 }  // namespace ash