Add Fade-out/Fade-in animation during output-configuration change.

chromeos/display/output_configurator.h

 // 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.
 
 #ifndef CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_
 #define CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/event_types.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "chromeos/chromeos_export.h"
 
 // Forward declarations for Xlib and Xrandr.
 // This is so unused X definitions don't pollute the namespace.
 typedef unsigned long XID;
 typedef XID Window;
 typedef XID RROutput;
@@ skipping 31 matching lines @@
   STATE_DUAL_PRIMARY_ONLY,
   STATE_DUAL_SECONDARY_ONLY,
 };
 
 // This class interacts directly with the underlying Xrandr API to manipulate
 // CTRCs and Outputs.  It will likely grow more state, over time, or expose
 // Output info in other ways as more of the Chrome display code grows up around
 // it.
 class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
  public:
+  // AnimationDelegate is responsible for making visual effect around the change
+  // of output configurations.  Typically it makes fade-out the displays before
+  // the transition and fade-in again after the transition finished.
+  class AnimationDelegate {
+   public:
+    virtual ~AnimationDelegate() {}
+
+    // Called when the change of display mode is scheduled.  It will usually
+    // start fading out the displays.  It also has to run |callback| once
+    // the visual effect has finished.
+    virtual void WillDisplayModeChange(base::Closure callback) {
+      callback.Run();
+    }

[oshima, 2012/07/26 14:08:17]

move this to .cc, and forward decl base::Closure.

+
+    // Called when the change of the display mode finished.  It will usually
+    // start the fading in the displays.
+    virtual void OnDisplayModeChanged() {}
+  };
+
   OutputConfigurator();
   virtual ~OutputConfigurator();
 
   State output_state() const { return output_state_; }
 
+  void set_animation_delegate(AnimationDelegate* animation_delegate) {
+    animation_delegate_.reset(animation_delegate);
+  }
+
   // Called when the user hits ctrl-F4 to request a display mode change.
   // This method should only return false if it was called in a single-head or
   // headless mode.
   bool CycleDisplayMode();
 
   // Called when powerd notifies us that some set of displays should be turned
   // on or off.  This requires enabling or disabling the CRTC associated with
   // the display(s) in question so that the low power state is engaged.
   bool ScreenPowerSet(bool power_on, bool all_displays);
 
   // Force switching the display mode to |new_state|.  This method is used when
   // the user explicitly changes the display mode in the options UI.  Returns
   // false if it was called in a single-head or headless mode.
   bool SetDisplayMode(State new_state);
 
   // Called when an RRNotify event is received.  The implementation is
   // interested in the cases of RRNotify events which correspond to output
   // add/remove events.  Note that Output add/remove events are sent in response
   // to our own reconfiguration operations so spurious events are common.
   // Spurious events will have no effect.
   virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
 
  private:
+  // The actual task of changing display mode.  Usually this is called by the
+  // |animation_delegate_|.
+  void SetDisplayModeInternal(State new_state);
+
   // Updates |output_count_|, |output_cache_|, |mirror_supported_|,
   // |primary_output_index_|, and |secondary_output_index_| with new data.
   // Returns true if the update succeeded or false if it was skipped since no
   // actual change was observed.
   // Note that |output_state_| is not updated by this call.
   bool TryRecacheOutputs(Display* display, XRRScreenResources* screen);
 
   // Uses the data stored in |output_cache_| and the given |new_state| to
   // configure the Xrandr interface and then updates |output_state_| to reflect
   // the new state.
@@ skipping 51 matching lines @@
   int secondary_output_index_;
 
   // The base of the event numbers used to represent XRandr events used in
   // decoding events regarding output add/remove.
   int xrandr_event_base_;
 
   // The display state as derived from the outputs observed in |output_cache_|.
   // This is used for rotating display modes.
   State output_state_;
 
+  scoped_ptr<AnimationDelegate> animation_delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(OutputConfigurator);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_