Translate 1 pixel not 1 dip when rotating the display.

ash/display/display_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/display/display_controller.h"
 
 #include <algorithm>
 #include <map>
 
 #include "ash/ash_root_window_transformer.h"
@@ skipping 124 matching lines @@
     return;
   root_window->SetProperty(kRotationPropertyKey, info.rotation());
 #endif
   gfx::Transform rotate;
   // TODO(oshima): Manually complute the inverse of the
   // rotate+translate matrix to compensate for computation error in
   // the inverted matrix. Ideally, SkMatrix should have special
   // case handling for rotate+translate case. crbug.com/222483.
   gfx::Transform reverse_rotate;
 
-  // The origin is (0, 0), so the translate width/height must be reduced by 1.
+  // The origin is (0, 0), so the translate width/height must be reduced by
+  // 1 pixel.
+  float one_pixel = 1.0f / display.device_scale_factor();
   switch (info.rotation()) {
     case gfx::Display::ROTATE_0:
       break;
     case gfx::Display::ROTATE_90:
-      rotate.Translate(display.bounds().height() - 1, 0);
+      rotate.Translate(display.bounds().height() - one_pixel, 0);
       rotate.Rotate(90);
       // Rotate 270 instead of 90 as it will cause calcuration error.
       reverse_rotate.Rotate(270);
-      reverse_rotate.Translate(-(display.bounds().height() - 1), 0);
+      reverse_rotate.Translate(-(display.bounds().height() - one_pixel), 0);
       break;
     case gfx::Display::ROTATE_270:
-      rotate.Translate(0, display.bounds().width() - 1);
+      rotate.Translate(0, display.bounds().width() - one_pixel);
       rotate.Rotate(270);
       reverse_rotate.Rotate(90);
-      reverse_rotate.Translate(0, -(display.bounds().width() - 1));
+      reverse_rotate.Translate(0, -(display.bounds().width() - one_pixel));
       break;
     case gfx::Display::ROTATE_180:
-      rotate.Translate(display.bounds().width() - 1,
-                       display.bounds().height() - 1);
+      rotate.Translate(display.bounds().width() - one_pixel,
+                       display.bounds().height() - one_pixel);
       rotate.Rotate(180);
       reverse_rotate.Rotate(180);
-      reverse_rotate.Translate(-(display.bounds().width() - 1),
-                               -(display.bounds().height() - 1));
+      reverse_rotate.Translate(-(display.bounds().width() - one_pixel),
+                               -(display.bounds().height() - one_pixel));
       break;
   }
   scoped_ptr<aura::RootWindowTransformer> transformer(
       new AshRootWindowTransformer(root_window,
                                    rotate,
                                    reverse_rotate,
                                    info.GetOverscanInsetsInPixel(),
                                    info.ui_scale()));
   root_window->SetRootWindowTransformer(transformer.Pass());
 }
@@ skipping 759 matching lines @@
 }
 
 void DisplayController::OnFadeOutForSwapDisplayFinished() {
 #if defined(OS_CHROMEOS)
   SetPrimaryDisplay(ScreenAsh::GetSecondaryDisplay());
   Shell::GetInstance()->output_configurator_animation()->StartFadeInAnimation();
 #endif
 }
 
 }  // namespace ash