Magnifier: Prevent the cursor jumping on HiDPI display.

ash/magnifier/magnification_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/magnifier/magnification_controller.h"
 
 #include "ash/ash_root_window_transformer.h"
 #include "ash/display/display_controller.h"
 #include "ash/display/display_manager.h"
 #include "ash/shell.h"
@@ skipping 25 matching lines @@
 const float kNonMagnifiedScale = 1.0f;
 
 const float kInitialMagnifiedScale = 2.0f;
 const float kScrollScaleChangeFactor = 0.05f;
 
 // Threadshold of panning. If the cursor moves to within pixels (in DIP) of
 // |kPanningMergin| from the edge, the view-port moves.
 const int kPanningMergin = 100;
 
 void MoveCursorTo(aura::RootWindow* root_window,
-                  const gfx::Point root_location) {
+                  const gfx::Point& root_location) {
   gfx::Point3F host_location_3f(root_location);
-  root_window->layer()->transform().TransformPoint(host_location_3f);
+  root_window->GetRootTransform().TransformPoint(host_location_3f);
   root_window->MoveCursorToHostLoation(
       gfx::ToCeiledPoint(host_location_3f.AsPointF()));

[oshima, 2013/04/30 23:03:07]

We have this rounding issue because we're converting the coordinate
back and force. For m29, I'd like to change our cursor control
code so that it controls in host coordinates and convert to Root only
when necessary (say making decision).

 }
 
 }  // namespace
 
 namespace ash {
 
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationControllerImpl:
 
 class MagnificationControllerImpl : virtual public MagnificationController,
@@ skipping 558 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
 // static
 MagnificationController* MagnificationController::CreateInstance() {
   return new MagnificationControllerImpl();
 }
 
 }  // namespace ash