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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "ui/gfx/display_change_notifier.h"
      6 
      7 #include "ui/gfx/display.h"
      8 #include "ui/gfx/display_observer.h"
      9 
     10 namespace gfx {
     11 
     12 namespace {
     13 
     14 class DisplayComparator {
     15  public:
     16   explicit DisplayComparator(const Display& display)
     17     : display_id_(display.id())
     18   {}
     19 
     20   bool operator()(const Display& display) const {
     21     return display.id() == display_id_;
     22   }
     23 
     24  private:
     25   int64 display_id_;
     26 };
     27 
     28 } // anonymous namespace
     29 
     30 DisplayChangeNotifier::DisplayChangeNotifier() {
     31 }
     32 
     33 DisplayChangeNotifier::~DisplayChangeNotifier() {
     34 }
     35 
     36 void DisplayChangeNotifier::AddObserver(DisplayObserver* obs) {
     37   observer_list_.AddObserver(obs);
     38 }
     39 
     40 void DisplayChangeNotifier::RemoveObserver(DisplayObserver* obs) {
     41   observer_list_.RemoveObserver(obs);
     42 }
     43 
     44 void DisplayChangeNotifier::NotifyDisplaysChanged(
     45     const std::vector<Display>& old_displays,
     46     const std::vector<Display>& new_displays) {
     47   // Display present in old_displays but not in new_displays has been removed.
     48   std::vector<Display>::const_iterator old_it = old_displays.begin();
     49   for (; old_it != old_displays.end(); ++old_it) {
     50     if (std::find_if(new_displays.begin(), new_displays.end(),
     51                      DisplayComparator(*old_it)) == new_displays.end()) {
     52       FOR_EACH_OBSERVER(DisplayObserver, observer_list_,
     53                         OnDisplayRemoved(*old_it));
     54     }
     55   }
     56 
     57   // Display present in new_displays but not in old_displays has been added.
     58   // Display present in both might have been modified.
     59   for (std::vector<Display>::const_iterator new_it =
     60           new_displays.begin(); new_it != new_displays.end(); ++new_it) {
     61     std::vector<Display>::const_iterator old_it = std::find_if(
     62         old_displays.begin(), old_displays.end(), DisplayComparator(*new_it));
     63 
     64     if (old_it == old_displays.end()) {
     65       FOR_EACH_OBSERVER(DisplayObserver, observer_list_,
     66                         OnDisplayAdded(*new_it));
     67       continue;
     68     }
     69 
     70     uint32_t metrics = DisplayObserver::DISPLAY_METRIC_NONE;
     71 
     72     if (new_it->bounds() != old_it->bounds())
     73       metrics |= DisplayObserver::DISPLAY_METRIC_BOUNDS;
     74 
     75     if (new_it->rotation() != old_it->rotation())
     76       metrics |= DisplayObserver::DISPLAY_METRIC_ROTATION;
     77 
     78     if (new_it->work_area() != old_it->work_area())
     79       metrics |= DisplayObserver::DISPLAY_METRIC_WORK_AREA;
     80 
     81     if (new_it->device_scale_factor() != old_it->device_scale_factor())
     82       metrics |= DisplayObserver::DISPLAY_METRIC_DEVICE_SCALE_FACTOR;
     83 
     84     if (metrics != DisplayObserver::DISPLAY_METRIC_NONE) {
     85       FOR_EACH_OBSERVER(DisplayObserver,
     86                         observer_list_,
     87                         OnDisplayMetricsChanged(*new_it, metrics));
     88     }
     89   }
     90 }
     91 
     92 } // namespace gfx
     93