modules/desktop_capture/mac/window_list_utils.cc - src - Git at Google

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 #include "modules/desktop_capture/mac/window_list_utils.h"

 #include <ApplicationServices/ApplicationServices.h>

 #include <algorithm>
 #include <cmath>
 #include <iterator>
 #include <limits>
 #include <list>
 #include <map>
 #include <memory>
 #include <utility>

 #include "rtc_base/checks.h"

 static_assert(static_cast<webrtc::WindowId>(kCGNullWindowID) ==
                   webrtc::kNullWindowId,
               "kNullWindowId needs to equal to kCGNullWindowID.");

 namespace webrtc {

 namespace {

 // WindowName of the status indicator dot shown since Monterey in the taskbar.
 // Testing on 12.2.1 shows this is independent of system language setting.
 const CFStringRef kStatusIndicator = CFSTR("StatusIndicator");
 const CFStringRef kStatusIndicatorOwnerName = CFSTR("Window Server");

 bool ToUtf8(const CFStringRef str16, std::string* str8) {
   size_t maxlen = CFStringGetMaximumSizeForEncoding(CFStringGetLength(str16),
                                                     kCFStringEncodingUTF8) +
                   1;
   std::unique_ptr<char[]> buffer(new char[maxlen]);
   if (!buffer ||
       !CFStringGetCString(str16, buffer.get(), maxlen, kCFStringEncodingUTF8)) {
     return false;
   }
   str8->assign(buffer.get());
   return true;
 }

 // Get CFDictionaryRef from `id` and call `on_window` against it. This function
 // returns false if native APIs fail, typically it indicates that the `id` does
 // not represent a window. `on_window` will not be called if false is returned
 // from this function.
 bool GetWindowRef(CGWindowID id,
                   rtc::FunctionView<void(CFDictionaryRef)> on_window) {
   RTC_DCHECK(on_window);

   // TODO(zijiehe): `id` is a 32-bit integer, casting it to an array seems not
   // safe enough. Maybe we should create a new
   // const void* arr[] = {
   //   reinterpret_cast<void*>(id) }
   // };
   CFArrayRef window_id_array =
       CFArrayCreate(NULL, reinterpret_cast<const void**>(&id), 1, NULL);
   CFArrayRef window_array =
       CGWindowListCreateDescriptionFromArray(window_id_array);

   bool result = false;
   // TODO(zijiehe): CFArrayGetCount(window_array) should always return 1.
   // Otherwise, we should treat it as failure.
   if (window_array && CFArrayGetCount(window_array)) {
     on_window(reinterpret_cast<CFDictionaryRef>(
         CFArrayGetValueAtIndex(window_array, 0)));
     result = true;
   }

   if (window_array) {
     CFRelease(window_array);
   }
   CFRelease(window_id_array);
   return result;
 }

 }  // namespace

 bool GetWindowList(rtc::FunctionView<bool(CFDictionaryRef)> on_window,
                    bool ignore_minimized,
                    bool only_zero_layer) {
   RTC_DCHECK(on_window);

   // Only get on screen, non-desktop windows.
   // According to
   // https://developer.apple.com/documentation/coregraphics/cgwindowlistoption/1454105-optiononscreenonly
   // , when kCGWindowListOptionOnScreenOnly is used, the order of windows are in
   // decreasing z-order.
   CFArrayRef window_array = CGWindowListCopyWindowInfo(
       kCGWindowListOptionOnScreenOnly | kCGWindowListExcludeDesktopElements,
       kCGNullWindowID);
   if (!window_array)
     return false;

   MacDesktopConfiguration desktop_config = MacDesktopConfiguration::GetCurrent(
       MacDesktopConfiguration::TopLeftOrigin);

   // Check windows to make sure they have an id, title, and use window layer
   // other than 0.
   CFIndex count = CFArrayGetCount(window_array);
   for (CFIndex i = 0; i < count; i++) {
     CFDictionaryRef window = reinterpret_cast<CFDictionaryRef>(
         CFArrayGetValueAtIndex(window_array, i));
     if (!window) {
       continue;
     }

     CFNumberRef window_id = reinterpret_cast<CFNumberRef>(
         CFDictionaryGetValue(window, kCGWindowNumber));
     if (!window_id) {
       continue;
     }

     CFNumberRef window_layer = reinterpret_cast<CFNumberRef>(
         CFDictionaryGetValue(window, kCGWindowLayer));
     if (!window_layer) {
       continue;
     }

     // Skip windows with layer!=0 (menu, dock).
     int layer;
     if (!CFNumberGetValue(window_layer, kCFNumberIntType, &layer)) {
       continue;
     }
     if (only_zero_layer && layer != 0) {
       continue;
     }

     // Skip windows that are minimized and not full screen.
     if (ignore_minimized && !IsWindowOnScreen(window) &&
         !IsWindowFullScreen(desktop_config, window)) {
       continue;
     }

     // If window title is empty, only consider it if it is either on screen or
     // fullscreen.
     CFStringRef window_title = reinterpret_cast<CFStringRef>(
         CFDictionaryGetValue(window, kCGWindowName));
     if (!window_title && !IsWindowOnScreen(window) &&
         !IsWindowFullScreen(desktop_config, window)) {
       continue;
     }

     CFStringRef window_owner_name = reinterpret_cast<CFStringRef>(
         CFDictionaryGetValue(window, kCGWindowOwnerName));
     // Ignore the red dot status indicator shown in the stats bar. Unlike the
     // rest of the system UI it has a window_layer of 0, so was otherwise
     // included. See crbug.com/1297731.
     if (window_title && CFEqual(window_title, kStatusIndicator) &&
         window_owner_name &&
         CFEqual(window_owner_name, kStatusIndicatorOwnerName)) {
       continue;
     }

     if (!on_window(window)) {
       break;
     }
   }

   CFRelease(window_array);
   return true;
 }

 bool GetWindowList(DesktopCapturer::SourceList* windows,
                    bool ignore_minimized,
                    bool only_zero_layer) {
   // Use a std::list so that iterators are preversed upon insertion and
   // deletion.
   std::list<DesktopCapturer::Source> sources;
   std::map<int, std::list<DesktopCapturer::Source>::const_iterator> pid_itr_map;
   const bool ret = GetWindowList(
       [&sources, &pid_itr_map](CFDictionaryRef window) {
         WindowId window_id = GetWindowId(window);
         if (window_id != kNullWindowId) {
           const std::string title = GetWindowTitle(window);
           const int pid = GetWindowOwnerPid(window);
           // Check if window for the same pid have been already inserted.
           std::map<int,
                    std::list<DesktopCapturer::Source>::const_iterator>::iterator
               itr = pid_itr_map.find(pid);

           // Only consider empty titles if the app has no other window with a
           // proper title.
           if (title.empty()) {
             std::string owner_name = GetWindowOwnerName(window);

             // At this time we do not know if there will be other windows
             // for the same pid unless they have been already inserted, hence
             // the check in the map. Also skip the window if owner name is
             // empty too.
             if (!owner_name.empty() && (itr == pid_itr_map.end())) {
               sources.push_back(DesktopCapturer::Source{window_id, owner_name});
               RTC_DCHECK(!sources.empty());
               // Get an iterator on the last valid element in the source list.
               std::list<DesktopCapturer::Source>::const_iterator last_source =
                   --sources.end();
               pid_itr_map.insert(
                   std::pair<int,
                             std::list<DesktopCapturer::Source>::const_iterator>(
                       pid, last_source));
             }
           } else {
             sources.push_back(DesktopCapturer::Source{window_id, title});
             // Once the window with empty title has been removed no other empty
             // windows are allowed for the same pid.
             if (itr != pid_itr_map.end() && (itr->second != sources.end())) {
               sources.erase(itr->second);
               // sdt::list::end() never changes during the lifetime of that
               // list.
               itr->second = sources.end();
             }
           }
         }
         return true;
       },
       ignore_minimized, only_zero_layer);

   if (!ret)
     return false;

   RTC_DCHECK(windows);
   windows->reserve(windows->size() + sources.size());
   std::copy(std::begin(sources), std::end(sources),
             std::back_inserter(*windows));

   return true;
 }

 // Returns true if the window is occupying a full screen.
 bool IsWindowFullScreen(const MacDesktopConfiguration& desktop_config,
                         CFDictionaryRef window) {
   bool fullscreen = false;
   CFDictionaryRef bounds_ref = reinterpret_cast<CFDictionaryRef>(
       CFDictionaryGetValue(window, kCGWindowBounds));

   CGRect bounds;
   if (bounds_ref &&
       CGRectMakeWithDictionaryRepresentation(bounds_ref, &bounds)) {
     for (MacDisplayConfigurations::const_iterator it =
              desktop_config.displays.begin();
          it != desktop_config.displays.end(); it++) {
       if (it->bounds.equals(
               DesktopRect::MakeXYWH(bounds.origin.x, bounds.origin.y,
                                     bounds.size.width, bounds.size.height))) {
         fullscreen = true;
         break;
       }
     }
   }

   return fullscreen;
 }

 bool IsWindowFullScreen(const MacDesktopConfiguration& desktop_config,
                         CGWindowID id) {
   bool fullscreen = false;
   GetWindowRef(id, [&](CFDictionaryRef window) {
     fullscreen = IsWindowFullScreen(desktop_config, window);
   });
   return fullscreen;
 }

 bool IsWindowOnScreen(CFDictionaryRef window) {
   CFBooleanRef on_screen = reinterpret_cast<CFBooleanRef>(
       CFDictionaryGetValue(window, kCGWindowIsOnscreen));
   return on_screen != NULL && CFBooleanGetValue(on_screen);
 }

 bool IsWindowOnScreen(CGWindowID id) {
   bool on_screen;
   if (GetWindowRef(id, [&on_screen](CFDictionaryRef window) {
         on_screen = IsWindowOnScreen(window);
       })) {
     return on_screen;
   }
   return false;
 }

 std::string GetWindowTitle(CFDictionaryRef window) {
   CFStringRef title = reinterpret_cast<CFStringRef>(
       CFDictionaryGetValue(window, kCGWindowName));
   std::string result;
   if (title && ToUtf8(title, &result)) {
     return result;
   }

   return std::string();
 }

 std::string GetWindowTitle(CGWindowID id) {
   std::string title;
   if (GetWindowRef(id, [&title](CFDictionaryRef window) {
         title = GetWindowTitle(window);
       })) {
     return title;
   }
   return std::string();
 }

 std::string GetWindowOwnerName(CFDictionaryRef window) {
   CFStringRef owner_name = reinterpret_cast<CFStringRef>(
       CFDictionaryGetValue(window, kCGWindowOwnerName));
   std::string result;
   if (owner_name && ToUtf8(owner_name, &result)) {
     return result;
   }
   return std::string();
 }

 std::string GetWindowOwnerName(CGWindowID id) {
   std::string owner_name;
   if (GetWindowRef(id, [&owner_name](CFDictionaryRef window) {
         owner_name = GetWindowOwnerName(window);
       })) {
     return owner_name;
   }
   return std::string();
 }

 WindowId GetWindowId(CFDictionaryRef window) {
   CFNumberRef window_id = reinterpret_cast<CFNumberRef>(
       CFDictionaryGetValue(window, kCGWindowNumber));
   if (!window_id) {
     return kNullWindowId;
   }

   // Note: WindowId is 64-bit on 64-bit system, but CGWindowID is always 32-bit.
   // CFNumberGetValue() fills only top 32 bits, so we should use CGWindowID to
   // receive the window id.
   CGWindowID id;
   if (!CFNumberGetValue(window_id, kCFNumberIntType, &id)) {
     return kNullWindowId;
   }

   return id;
 }

 int GetWindowOwnerPid(CFDictionaryRef window) {
   CFNumberRef window_pid = reinterpret_cast<CFNumberRef>(
       CFDictionaryGetValue(window, kCGWindowOwnerPID));
   if (!window_pid) {
     return 0;
   }

   int pid;
   if (!CFNumberGetValue(window_pid, kCFNumberIntType, &pid)) {
     return 0;
   }

   return pid;
 }

 int GetWindowOwnerPid(CGWindowID id) {
   int pid;
   if (GetWindowRef(id, [&pid](CFDictionaryRef window) {
         pid = GetWindowOwnerPid(window);
       })) {
     return pid;
   }
   return 0;
 }

 float GetScaleFactorAtPosition(const MacDesktopConfiguration& desktop_config,
                                DesktopVector position) {
   // Find the dpi to physical pixel scale for the screen where the mouse cursor
   // is.
   for (auto it = desktop_config.displays.begin();
        it != desktop_config.displays.end(); ++it) {
     if (it->bounds.Contains(position)) {
       return it->dip_to_pixel_scale;
     }
   }
   return 1;
 }

 float GetWindowScaleFactor(CGWindowID id, DesktopSize size) {
   DesktopRect window_bounds = GetWindowBounds(id);
   float scale = 1.0f;

   if (!window_bounds.is_empty() && !size.is_empty()) {
     float scale_x = size.width() / window_bounds.width();
     float scale_y = size.height() / window_bounds.height();
     // Currently the scale in X and Y directions must be same.
     if ((std::fabs(scale_x - scale_y) <=
          std::numeric_limits<float>::epsilon() * std::max(scale_x, scale_y)) &&
         scale_x > 0.0f) {
       scale = scale_x;
     }
   }

   return scale;
 }

 DesktopRect GetWindowBounds(CFDictionaryRef window) {
   CFDictionaryRef window_bounds = reinterpret_cast<CFDictionaryRef>(
       CFDictionaryGetValue(window, kCGWindowBounds));
   if (!window_bounds) {
     return DesktopRect();
   }

   CGRect gc_window_rect;
   if (!CGRectMakeWithDictionaryRepresentation(window_bounds, &gc_window_rect)) {
     return DesktopRect();
   }

   return DesktopRect::MakeXYWH(gc_window_rect.origin.x, gc_window_rect.origin.y,
                                gc_window_rect.size.width,
                                gc_window_rect.size.height);
 }

 DesktopRect GetWindowBounds(CGWindowID id) {
   DesktopRect result;
   if (GetWindowRef(id, [&result](CFDictionaryRef window) {
         result = GetWindowBounds(window);
       })) {
     return result;
   }
   return DesktopRect();
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	#include "modules/desktop_capture/mac/window_list_utils.h"

	#include <ApplicationServices/ApplicationServices.h>

	#include <algorithm>
	#include <cmath>
	#include <iterator>
	#include <limits>
	#include <list>
	#include <map>
	#include <memory>
	#include <utility>

	#include "rtc_base/checks.h"

	static_assert(static_cast<webrtc::WindowId>(kCGNullWindowID) ==
	webrtc::kNullWindowId,
	"kNullWindowId needs to equal to kCGNullWindowID.");

	namespace webrtc {

	namespace {

	// WindowName of the status indicator dot shown since Monterey in the taskbar.
	// Testing on 12.2.1 shows this is independent of system language setting.
	const CFStringRef kStatusIndicator = CFSTR("StatusIndicator");
	const CFStringRef kStatusIndicatorOwnerName = CFSTR("Window Server");

	bool ToUtf8(const CFStringRef str16, std::string* str8) {
	size_t maxlen = CFStringGetMaximumSizeForEncoding(CFStringGetLength(str16),
	kCFStringEncodingUTF8) +
	1;
	std::unique_ptr<char[]> buffer(new char[maxlen]);
	if (!buffer \|\|
	!CFStringGetCString(str16, buffer.get(), maxlen, kCFStringEncodingUTF8)) {
	return false;
	}
	str8->assign(buffer.get());
	return true;
	}

	// Get CFDictionaryRef from `id` and call `on_window` against it. This function
	// returns false if native APIs fail, typically it indicates that the `id` does
	// not represent a window. `on_window` will not be called if false is returned
	// from this function.
	bool GetWindowRef(CGWindowID id,
	rtc::FunctionView<void(CFDictionaryRef)> on_window) {
	RTC_DCHECK(on_window);

	// TODO(zijiehe): `id` is a 32-bit integer, casting it to an array seems not
	// safe enough. Maybe we should create a new
	// const void* arr[] = {
	// reinterpret_cast<void*>(id) }
	// };
	CFArrayRef window_id_array =
	CFArrayCreate(NULL, reinterpret_cast<const void**>(&id), 1, NULL);
	CFArrayRef window_array =
	CGWindowListCreateDescriptionFromArray(window_id_array);

	bool result = false;
	// TODO(zijiehe): CFArrayGetCount(window_array) should always return 1.
	// Otherwise, we should treat it as failure.
	if (window_array && CFArrayGetCount(window_array)) {
	on_window(reinterpret_cast<CFDictionaryRef>(
	CFArrayGetValueAtIndex(window_array, 0)));
	result = true;
	}

	if (window_array) {
	CFRelease(window_array);
	}
	CFRelease(window_id_array);
	return result;
	}

	} // namespace

	bool GetWindowList(rtc::FunctionView<bool(CFDictionaryRef)> on_window,
	bool ignore_minimized,
	bool only_zero_layer) {
	RTC_DCHECK(on_window);

	// Only get on screen, non-desktop windows.
	// According to
	// https://developer.apple.com/documentation/coregraphics/cgwindowlistoption/1454105-optiononscreenonly
	// , when kCGWindowListOptionOnScreenOnly is used, the order of windows are in
	// decreasing z-order.
	CFArrayRef window_array = CGWindowListCopyWindowInfo(
	kCGWindowListOptionOnScreenOnly \| kCGWindowListExcludeDesktopElements,
	kCGNullWindowID);
	if (!window_array)
	return false;

	MacDesktopConfiguration desktop_config = MacDesktopConfiguration::GetCurrent(
	MacDesktopConfiguration::TopLeftOrigin);

	// Check windows to make sure they have an id, title, and use window layer
	// other than 0.
	CFIndex count = CFArrayGetCount(window_array);
	for (CFIndex i = 0; i < count; i++) {
	CFDictionaryRef window = reinterpret_cast<CFDictionaryRef>(
	CFArrayGetValueAtIndex(window_array, i));
	if (!window) {
	continue;
	}

	CFNumberRef window_id = reinterpret_cast<CFNumberRef>(
	CFDictionaryGetValue(window, kCGWindowNumber));
	if (!window_id) {
	continue;
	}

	CFNumberRef window_layer = reinterpret_cast<CFNumberRef>(
	CFDictionaryGetValue(window, kCGWindowLayer));
	if (!window_layer) {
	continue;
	}

	// Skip windows with layer!=0 (menu, dock).
	int layer;
	if (!CFNumberGetValue(window_layer, kCFNumberIntType, &layer)) {
	continue;
	}
	if (only_zero_layer && layer != 0) {
	continue;
	}

	// Skip windows that are minimized and not full screen.
	if (ignore_minimized && !IsWindowOnScreen(window) &&
	!IsWindowFullScreen(desktop_config, window)) {
	continue;
	}

	// If window title is empty, only consider it if it is either on screen or
	// fullscreen.
	CFStringRef window_title = reinterpret_cast<CFStringRef>(
	CFDictionaryGetValue(window, kCGWindowName));
	if (!window_title && !IsWindowOnScreen(window) &&
	!IsWindowFullScreen(desktop_config, window)) {
	continue;
	}

	CFStringRef window_owner_name = reinterpret_cast<CFStringRef>(
	CFDictionaryGetValue(window, kCGWindowOwnerName));
	// Ignore the red dot status indicator shown in the stats bar. Unlike the
	// rest of the system UI it has a window_layer of 0, so was otherwise
	// included. See crbug.com/1297731.
	if (window_title && CFEqual(window_title, kStatusIndicator) &&
	window_owner_name &&
	CFEqual(window_owner_name, kStatusIndicatorOwnerName)) {
	continue;
	}

	if (!on_window(window)) {
	break;
	}
	}

	CFRelease(window_array);
	return true;
	}

	bool GetWindowList(DesktopCapturer::SourceList* windows,
	bool ignore_minimized,
	bool only_zero_layer) {
	// Use a std::list so that iterators are preversed upon insertion and
	// deletion.
	std::list<DesktopCapturer::Source> sources;
	std::map<int, std::list<DesktopCapturer::Source>::const_iterator> pid_itr_map;
	const bool ret = GetWindowList(
	[&sources, &pid_itr_map](CFDictionaryRef window) {
	WindowId window_id = GetWindowId(window);
	if (window_id != kNullWindowId) {
	const std::string title = GetWindowTitle(window);
	const int pid = GetWindowOwnerPid(window);
	// Check if window for the same pid have been already inserted.
	std::map<int,
	std::list<DesktopCapturer::Source>::const_iterator>::iterator
	itr = pid_itr_map.find(pid);

	// Only consider empty titles if the app has no other window with a
	// proper title.
	if (title.empty()) {
	std::string owner_name = GetWindowOwnerName(window);

	// At this time we do not know if there will be other windows
	// for the same pid unless they have been already inserted, hence
	// the check in the map. Also skip the window if owner name is
	// empty too.
	if (!owner_name.empty() && (itr == pid_itr_map.end())) {
	sources.push_back(DesktopCapturer::Source{window_id, owner_name});
	RTC_DCHECK(!sources.empty());
	// Get an iterator on the last valid element in the source list.
	std::list<DesktopCapturer::Source>::const_iterator last_source =
	--sources.end();
	pid_itr_map.insert(
	std::pair<int,
	std::list<DesktopCapturer::Source>::const_iterator>(
	pid, last_source));
	}
	} else {
	sources.push_back(DesktopCapturer::Source{window_id, title});
	// Once the window with empty title has been removed no other empty
	// windows are allowed for the same pid.
	if (itr != pid_itr_map.end() && (itr->second != sources.end())) {
	sources.erase(itr->second);
	// sdt::list::end() never changes during the lifetime of that
	// list.
	itr->second = sources.end();
	}
	}
	}
	return true;
	},
	ignore_minimized, only_zero_layer);

	if (!ret)
	return false;

	RTC_DCHECK(windows);
	windows->reserve(windows->size() + sources.size());
	std::copy(std::begin(sources), std::end(sources),
	std::back_inserter(*windows));

	return true;
	}

	// Returns true if the window is occupying a full screen.
	bool IsWindowFullScreen(const MacDesktopConfiguration& desktop_config,
	CFDictionaryRef window) {
	bool fullscreen = false;
	CFDictionaryRef bounds_ref = reinterpret_cast<CFDictionaryRef>(
	CFDictionaryGetValue(window, kCGWindowBounds));

	CGRect bounds;
	if (bounds_ref &&
	CGRectMakeWithDictionaryRepresentation(bounds_ref, &bounds)) {
	for (MacDisplayConfigurations::const_iterator it =
	desktop_config.displays.begin();
	it != desktop_config.displays.end(); it++) {
	if (it->bounds.equals(
	DesktopRect::MakeXYWH(bounds.origin.x, bounds.origin.y,
	bounds.size.width, bounds.size.height))) {
	fullscreen = true;
	break;
	}
	}
	}

	return fullscreen;
	}

	bool IsWindowFullScreen(const MacDesktopConfiguration& desktop_config,
	CGWindowID id) {
	bool fullscreen = false;
	GetWindowRef(id, [&](CFDictionaryRef window) {
	fullscreen = IsWindowFullScreen(desktop_config, window);
	});
	return fullscreen;
	}

	bool IsWindowOnScreen(CFDictionaryRef window) {
	CFBooleanRef on_screen = reinterpret_cast<CFBooleanRef>(
	CFDictionaryGetValue(window, kCGWindowIsOnscreen));
	return on_screen != NULL && CFBooleanGetValue(on_screen);
	}

	bool IsWindowOnScreen(CGWindowID id) {
	bool on_screen;
	if (GetWindowRef(id, [&on_screen](CFDictionaryRef window) {
	on_screen = IsWindowOnScreen(window);
	})) {
	return on_screen;
	}
	return false;
	}

	std::string GetWindowTitle(CFDictionaryRef window) {
	CFStringRef title = reinterpret_cast<CFStringRef>(
	CFDictionaryGetValue(window, kCGWindowName));
	std::string result;
	if (title && ToUtf8(title, &result)) {
	return result;
	}

	return std::string();
	}

	std::string GetWindowTitle(CGWindowID id) {
	std::string title;
	if (GetWindowRef(id, [&title](CFDictionaryRef window) {
	title = GetWindowTitle(window);
	})) {
	return title;
	}
	return std::string();
	}

	std::string GetWindowOwnerName(CFDictionaryRef window) {
	CFStringRef owner_name = reinterpret_cast<CFStringRef>(
	CFDictionaryGetValue(window, kCGWindowOwnerName));
	std::string result;
	if (owner_name && ToUtf8(owner_name, &result)) {
	return result;
	}
	return std::string();
	}

	std::string GetWindowOwnerName(CGWindowID id) {
	std::string owner_name;
	if (GetWindowRef(id, [&owner_name](CFDictionaryRef window) {
	owner_name = GetWindowOwnerName(window);
	})) {
	return owner_name;
	}
	return std::string();
	}

	WindowId GetWindowId(CFDictionaryRef window) {
	CFNumberRef window_id = reinterpret_cast<CFNumberRef>(
	CFDictionaryGetValue(window, kCGWindowNumber));
	if (!window_id) {
	return kNullWindowId;
	}

	// Note: WindowId is 64-bit on 64-bit system, but CGWindowID is always 32-bit.
	// CFNumberGetValue() fills only top 32 bits, so we should use CGWindowID to
	// receive the window id.
	CGWindowID id;
	if (!CFNumberGetValue(window_id, kCFNumberIntType, &id)) {
	return kNullWindowId;
	}

	return id;
	}

	int GetWindowOwnerPid(CFDictionaryRef window) {
	CFNumberRef window_pid = reinterpret_cast<CFNumberRef>(
	CFDictionaryGetValue(window, kCGWindowOwnerPID));
	if (!window_pid) {
	return 0;
	}

	int pid;
	if (!CFNumberGetValue(window_pid, kCFNumberIntType, &pid)) {
	return 0;
	}

	return pid;
	}

	int GetWindowOwnerPid(CGWindowID id) {
	int pid;
	if (GetWindowRef(id, [&pid](CFDictionaryRef window) {
	pid = GetWindowOwnerPid(window);
	})) {
	return pid;
	}
	return 0;
	}

	float GetScaleFactorAtPosition(const MacDesktopConfiguration& desktop_config,
	DesktopVector position) {
	// Find the dpi to physical pixel scale for the screen where the mouse cursor
	// is.
	for (auto it = desktop_config.displays.begin();
	it != desktop_config.displays.end(); ++it) {
	if (it->bounds.Contains(position)) {
	return it->dip_to_pixel_scale;
	}
	}
	return 1;
	}

	float GetWindowScaleFactor(CGWindowID id, DesktopSize size) {
	DesktopRect window_bounds = GetWindowBounds(id);
	float scale = 1.0f;

	if (!window_bounds.is_empty() && !size.is_empty()) {
	float scale_x = size.width() / window_bounds.width();
	float scale_y = size.height() / window_bounds.height();
	// Currently the scale in X and Y directions must be same.
	if ((std::fabs(scale_x - scale_y) <=
	std::numeric_limits<float>::epsilon() * std::max(scale_x, scale_y)) &&
	scale_x > 0.0f) {
	scale = scale_x;
	}
	}

	return scale;
	}

	DesktopRect GetWindowBounds(CFDictionaryRef window) {
	CFDictionaryRef window_bounds = reinterpret_cast<CFDictionaryRef>(
	CFDictionaryGetValue(window, kCGWindowBounds));
	if (!window_bounds) {
	return DesktopRect();
	}

	CGRect gc_window_rect;
	if (!CGRectMakeWithDictionaryRepresentation(window_bounds, &gc_window_rect)) {
	return DesktopRect();
	}

	return DesktopRect::MakeXYWH(gc_window_rect.origin.x, gc_window_rect.origin.y,
	gc_window_rect.size.width,
	gc_window_rect.size.height);
	}

	DesktopRect GetWindowBounds(CGWindowID id) {
	DesktopRect result;
	if (GetWindowRef(id, [&result](CFDictionaryRef window) {
	result = GetWindowBounds(window);
	})) {
	return result;
	}
	return DesktopRect();
	}

	} // namespace webrtc