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/event_types.h"
+#include "base/observer_list.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;
 typedef XID RRCrtc;
@@ skipping 13 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:
+  class Observer {
+   public:
+    // Called when the change of the display mode finished.  It will usually
+    // start the fading in the displays.
+    virtual void OnDisplayModeChanged() = 0;
+  };
+
   explicit OutputConfigurator(bool is_extended_display_enabled);
   virtual ~OutputConfigurator();
 
   OutputState output_state() const { return output_state_; }
 
   // 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(OutputState 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;
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
  private:
   // The information we need to cache from an output to implement operations
   // such as power state but also to eliminate duplicate operations within a
   // given action (determining which CRTC to use for a given output, for
   // example).
   struct CachedOutputDescription {
     RROutput output;
     RRCrtc crtc;
     RRMode mirror_mode;
     RRMode ideal_mode;
@@ skipping 37 matching lines @@
   // doesn't match any supported state.  |output_cache_| must be up-to-date with
   // regards to the state of X or this method may return incorrect results.
   OutputState InferCurrentState(
       Display* display, XRRScreenResources* screen) const;
 
   // Scans the |output_cache_| to determine whether or not we are in a
   // "projecting" state and then calls the DBus kSetIsProjectingMethod on powerd
   // with the result.
   void CheckIsProjectingAndNotify();
 
+  // Fires OnDisplayModeChanged() event to the observers.
+  void NotifyOnDisplayChanged();
+
   // This is detected by the constructor to determine whether or not we should
   // be enabled.  If we aren't running on ChromeOS, we can't assume that the
   // Xrandr X11 extension is supported.
   // If this flag is set to false, any attempts to change the output
   // configuration to immediately fail without changing the state.
   bool is_running_on_chrome_os_;
 
   // Set to true if the extended display flag is enabled.
   const bool is_extended_display_enabled_;
 
@@ skipping 17 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.
   OutputState output_state_;
 
+  ObserverList<Observer> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(OutputConfigurator);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DISPLAY_OUTPUT_CONFIGURATOR_H_