Lock Rotation when screen is manually rotated

ash/wm/maximize_mode/maximize_mode_controller.cc

 // Copyright 2014 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/wm/maximize_mode/maximize_mode_controller.h"
 
 #include "ash/accelerometer/accelerometer_controller.h"
 #include "ash/display/display_manager.h"
 #include "ash/shell.h"
 #include "ash/wm/maximize_mode/maximize_mode_event_blocker.h"
@@ skipping 120 matching lines @@
   }
 
   // Compute the angle between the base and the lid.
   float angle = ClockwiseAngleBetweenVectorsInDegrees(base_flattened,
       lid_flattened, hinge_vector);
 
   // Toggle maximize mode on or off when corresponding thresholds are passed.
   // TODO(flackr): Make MaximizeModeController own the MaximizeModeWindowManager
   // such that observations of state changes occur after the change and shell
   // has fewer states to track.
+  DisplayManager* display_manager =
+      Shell::GetInstance()->display_manager();
+  gfx::Display::Rotation current_rotation = display_manager->GetDisplayInfo(
+      gfx::Display::InternalDisplayId()).rotation();
+
   if (maximize_mode_engaged &&
       angle > kFullyOpenAngleErrorTolerance &&
       angle < kExitMaximizeModeAngle) {
+    if (!rotation_locked_ && current_rotation != gfx::Display::ROTATE_0) {
+      display_manager->SetDisplayRotation(gfx::Display::InternalDisplayId(),
+          gfx::Display::ROTATE_0);
+    }
+    rotation_locked_ = false;

[flackr, 2014/05/05 20:53:56]

What if we don't reset the rotation lock on exiting touchview, and additionally
lock rotation when entering touchview with a rotated screen. This would cover
most of the use cases (i.e. enter touchview, lock at ROTATE_0 and exit and enter
would still be locked, similarly manually rotating to !0 would lock).

[jonross, 2014/05/06 15:07:54]

Done.

     Shell::GetInstance()->EnableMaximizeModeWindowManager(false);
     event_blocker_.reset();
   } else if (!maximize_mode_engaged &&
       angle > kEnterMaximizeModeAngle) {
+    rotation_locked_ =  current_rotation != gfx::Display::ROTATE_0;

[flackr, 2014/05/05 20:53:56]

This seems like a good heuristic for manual external rotations done before
entering touchview, but what if we set the rotation while in touchview or want
to lock to ROTATE_0? It should probably be a property on the display which we
could also save with the display config. This could be deferred with a TODO
reference to a bug.

[jonross, 2014/05/06 15:07:54]

Filed: https://code.google.com/p/chromium/issues/detail?id=370443

Will add the todo.

     Shell::GetInstance()->EnableMaximizeModeWindowManager(true);
     event_blocker_.reset(new MaximizeModeEventBlocker);
   }
 }
 
 void MaximizeModeController::HandleScreenRotation(const gfx::Vector3dF& lid) {
   bool maximize_mode_engaged =
       Shell::GetInstance()->IsMaximizeModeWindowManagerEnabled();
 
+  if (!maximize_mode_engaged || rotation_locked_)
+    return;
+
   DisplayManager* display_manager =
       Shell::GetInstance()->display_manager();
   gfx::Display::Rotation current_rotation = display_manager->GetDisplayInfo(
       gfx::Display::InternalDisplayId()).rotation();
 
-  // If maximize mode is not engaged, ensure the screen is not rotated and
-  // do not rotate to match the current device orientation.
-  if (!maximize_mode_engaged) {
-    if (current_rotation != gfx::Display::ROTATE_0) {
-      // TODO(flackr): Currently this will prevent setting a manual rotation on
-      // the screen of a device with an accelerometer, this should only set it
-      // back to ROTATE_0 if it was last set by the accelerometer.
-      // Also, SetDisplayRotation will save the setting to the local store,
-      // this should be stored in a way that we can distinguish what the
-      // rotation was set by.
-      display_manager->SetDisplayRotation(gfx::Display::InternalDisplayId(),
-                                          gfx::Display::ROTATE_0);
-    }
-    rotation_locked_ = false;
-    return;
-  }
-
-  if (rotation_locked_)
-    return;
-
   // After determining maximize mode state, determine if the screen should
   // be rotated.
   gfx::Vector3dF lid_flattened(lid.x(), lid.y(), 0.0f);
   float lid_flattened_length = lid_flattened.Length();
   // When the lid is close to being flat, don't change rotation as it is too
   // sensitive to slight movements.
   if (lid_flattened_length < kMinimumAccelerationScreenRotation)
     return;
 
   // The reference vector is the angle of gravity when the device is rotated
@@ skipping 35 matching lines @@
   // When exiting maximize mode return rotation to 0. When entering, rotate to
   // match screen orientation.
   if (new_rotation == gfx::Display::ROTATE_0 ||
       maximize_mode_engaged) {
     display_manager->SetDisplayRotation(gfx::Display::InternalDisplayId(),
                                         new_rotation);
   }
 }
 
 }  // namespace ash