gecko-dev/widget/cocoa/nsLookAndFeel.mm

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/widget/ThemeChangeKind.h"
#include "nsLookAndFeel.h"
#include "nsCocoaFeatures.h"
#include "nsNativeThemeColors.h"
#include "nsStyleConsts.h"
#include "nsIContent.h"
#include "gfxFont.h"
#include "gfxFontConstants.h"
#include "gfxPlatformMac.h"
#include "nsCSSColorUtils.h"
#include "mozilla/FontPropertyTypes.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/StaticPrefs_widget.h"
#include "mozilla/glean/GleanMetrics.h"
#include "mozilla/widget/WidgetMessageUtils.h"
#include "mozilla/MacStringHelpers.h"

#import <Cocoa/Cocoa.h>
#import <Carbon/Carbon.h>
#import <AppKit/NSColor.h>

// This must be included last:
#include "nsObjCExceptions.h"

using namespace mozilla;

@interface MOZLookAndFeelDynamicChangeObserver : NSObject
+ (void)startObserving;
@end

nsLookAndFeel::nsLookAndFeel() {
  [MOZLookAndFeelDynamicChangeObserver startObserving];
}

nsLookAndFeel::~nsLookAndFeel() = default;

void nsLookAndFeel::EnsureInit() {
  if (mInitialized) {
    return;
  }

  NS_OBJC_BEGIN_TRY_ABORT_BLOCK

  mInitialized = true;
  NSWindow* window =
      [[NSWindow alloc] initWithContentRect:NSZeroRect
                                  styleMask:NSWindowStyleMaskTitled
                                    backing:NSBackingStoreBuffered
                                      defer:NO];
  auto release = MakeScopeExit([&] { [window release]; });

  mRtl = window.windowTitlebarLayoutDirection ==
         NSUserInterfaceLayoutDirectionRightToLeft;
  mTitlebarHeight = std::ceil(window.frame.size.height);

  RecordTelemetry();

  NS_OBJC_END_TRY_ABORT_BLOCK
}

void nsLookAndFeel::RefreshImpl() {
  mInitialized = false;
  nsXPLookAndFeel::RefreshImpl();
}

static nscolor GetColorFromNSColor(NSColor* aColor) {
  NSColor* deviceColor =
      [aColor colorUsingColorSpace:NSColorSpace.deviceRGBColorSpace];
  return NS_RGBA((unsigned int)(deviceColor.redComponent * 255.0),
                 (unsigned int)(deviceColor.greenComponent * 255.0),
                 (unsigned int)(deviceColor.blueComponent * 255.0),
                 (unsigned int)(deviceColor.alphaComponent * 255.0));
}

static nscolor GetColorFromNSColorWithCustomAlpha(NSColor* aColor,
                                                  float alpha) {
  NSColor* deviceColor =
      [aColor colorUsingColorSpace:[NSColorSpace deviceRGBColorSpace]];
  return NS_RGBA((unsigned int)(deviceColor.redComponent * 255.0),
                 (unsigned int)(deviceColor.greenComponent * 255.0),
                 (unsigned int)(deviceColor.blueComponent * 255.0),
                 (unsigned int)(alpha * 255.0));
}

// Turns an opaque selection color into a partially transparent selection color,
// which usually leads to better contrast with the text color and which should
// look more visually appealing in most contexts.
// The idea is that the text and its regular, non-selected background are
// usually chosen in such a way that they contrast well. Making the selection
// color partially transparent causes the selection color to mix with the text's
// regular background, so the end result will often have better contrast with
// the text than an arbitrary opaque selection color.
// The motivating example for this is the light selection color on dark web
// pages: White text on a light blue selection color has very bad contrast,
// whereas white text on dark blue (which what you get if you mix
// partially-transparent light blue with the black textbox background) has much
// better contrast.
static nscolor ProcessSelectionBackground(nscolor aColor, ColorScheme aScheme) {
  if (aScheme == ColorScheme::Dark) {
    // When we use a dark selection color, we do not change alpha because we do
    // not use dark selection in content. The dark system color is appropriate
    // for Firefox UI without needing to adjust its alpha.
    return aColor;
  }
  uint16_t hue, sat, value;
  uint8_t alpha;
  nscolor resultColor = aColor;
  NS_RGB2HSV(resultColor, hue, sat, value, alpha);
  int factor = 2;
  alpha = alpha / factor;
  if (sat > 0) {
    // The color is not a shade of grey, restore the saturation taken away by
    // the transparency.
    sat = std::clamp(sat * factor, 0, 255);
  } else {
    // The color is a shade of grey, find the value that looks equivalent
    // on a white background with the given opacity.
    value = std::clamp(255 - (255 - value) * factor, 0, 255);
  }
  NS_HSV2RGB(resultColor, hue, sat, value, alpha);
  return resultColor;
}

nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
                                       nscolor& aColor) {
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK

  NSAppearance.currentAppearance = NSAppearanceForColorScheme(aScheme);

  switch (aID) {
    case ColorID::Infobackground:
      aColor = aScheme == ColorScheme::Light
                   ? NS_RGB(0xdd, 0xdd, 0xdd)
                   : GetColorFromNSColor(NSColor.windowBackgroundColor);
      break;
    case ColorID::Highlight:
      aColor = ProcessSelectionBackground(
          GetColorFromNSColor(NSColor.selectedTextBackgroundColor), aScheme);
      break;
    // This is used to gray out the selection when it's not focused. Used with
    // nsISelectionController::SELECTION_DISABLED.
    case ColorID::TextSelectDisabledBackground:
      aColor = ProcessSelectionBackground(
          GetColorFromNSColor(NSColor.secondarySelectedControlColor), aScheme);
      break;
    case ColorID::MozMenuhoverdisabled:
      aColor = NS_TRANSPARENT;
      break;
    case ColorID::Accentcolor:
      aColor = GetColorFromNSColor(NSColor.controlAccentColor);
      break;
    case ColorID::MozMenuhover:
    case ColorID::Selecteditem:
      aColor = GetColorFromNSColor(NSColor.selectedContentBackgroundColor);
      if (aID == ColorID::MozMenuhover &&
          !LookAndFeel::GetInt(IntID::PrefersReducedTransparency)) {
        // Wash the color a little bit with semi-transparent white to match a
        // bit closer the native NSVisualEffectSelection on menus.
        aColor = NS_ComposeColors(
            aColor,
            NS_RGBA(255, 255, 255, aScheme == ColorScheme::Light ? 51 : 25));
      }
      break;
    case ColorID::Accentcolortext:
    case ColorID::MozMenuhovertext:
    case ColorID::Selecteditemtext:
      aColor = GetColorFromNSColor(NSColor.selectedMenuItemTextColor);
      break;
    case ColorID::IMESelectedRawTextBackground:
    case ColorID::IMESelectedConvertedTextBackground:
    case ColorID::IMERawInputBackground:
    case ColorID::IMEConvertedTextBackground:
      aColor = NS_TRANSPARENT;
      break;
    case ColorID::IMESelectedRawTextForeground:
    case ColorID::IMESelectedConvertedTextForeground:
    case ColorID::IMERawInputForeground:
    case ColorID::IMEConvertedTextForeground:
    case ColorID::Highlighttext:
      aColor = NS_SAME_AS_FOREGROUND_COLOR;
      break;
    case ColorID::IMERawInputUnderline:
    case ColorID::IMEConvertedTextUnderline:
      aColor = NS_40PERCENT_FOREGROUND_COLOR;
      break;
    case ColorID::IMESelectedRawTextUnderline:
    case ColorID::IMESelectedConvertedTextUnderline:
      aColor = NS_SAME_AS_FOREGROUND_COLOR;
      break;

      //
      // css2 system colors http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
      //
      // It's really hard to effectively map these to the Appearance Manager
      // properly, since they are modeled word for word after the win32 system
      // colors and don't have any real counterparts in the Mac world. I'm sure
      // we'll be tweaking these for years to come.
      //
      // Thanks to mpt26@student.canterbury.ac.nz for the hardcoded values that
      // form the defaults
      //  if querying the Appearance Manager fails ;)
      //
    case ColorID::MozMacDefaultbuttontext:
      aColor = NS_RGB(0xFF, 0xFF, 0xFF);
      break;
    case ColorID::MozSidebar:
      aColor = aScheme == ColorScheme::Light ? NS_RGB(0xff, 0xff, 0xff)
                                             : NS_RGB(0x2d, 0x2d, 0x2d);
      break;
    case ColorID::MozSidebarborder:
      // hsla(240, 5%, 5%, .1)
      aColor = NS_RGBA(12, 12, 13, 26);
      break;
    case ColorID::MozButtonactivetext:
      // Pre-macOS 12, pressed buttons were filled with the highlight color and
      // the text was white. Starting with macOS 12, pressed (non-default)
      // buttons are filled with medium gray and the text color is the same as
      // in the non-pressed state.
      aColor = nsCocoaFeatures::OnMontereyOrLater()
                   ? GetColorFromNSColor(NSColor.controlTextColor)
                   : NS_RGB(0xFF, 0xFF, 0xFF);
      break;
    case ColorID::Appworkspace:
      aColor = NS_RGB(0xFF, 0xFF, 0xFF);
      break;
    case ColorID::Background:
      aColor = NS_RGB(0x63, 0x63, 0xCE);
      break;
    case ColorID::Buttonface:
    case ColorID::MozButtonhoverface:
    case ColorID::MozButtonactiveface:
    case ColorID::MozButtondisabledface:
      aColor = GetColorFromNSColor(NSColor.controlColor);
      if (!NS_GET_A(aColor)) {
        aColor = GetColorFromNSColor(NSColor.controlBackgroundColor);
      }
      break;
    case ColorID::Buttonhighlight:
      aColor = GetColorFromNSColor(NSColor.selectedControlColor);
      break;
    case ColorID::Scrollbar:
      aColor = GetColorFromNSColor(NSColor.scrollBarColor);
      break;
    case ColorID::Threedhighlight:
      aColor = GetColorFromNSColor(NSColor.highlightColor);
      break;
    case ColorID::Buttonshadow:
    case ColorID::Threeddarkshadow:
      aColor = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
                                            : NS_RGB(0xDC, 0xDC, 0xDC);
      break;
    case ColorID::Threedshadow:
      aColor = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
                                            : NS_RGB(0xE0, 0xE0, 0xE0);
      break;
    case ColorID::Threedface:
      aColor = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
                                            : NS_RGB(0xF0, 0xF0, 0xF0);
      break;
    case ColorID::Threedlightshadow:
    case ColorID::Buttonborder:
    case ColorID::MozDisabledfield:
      aColor = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
                                            : NS_RGB(0xDA, 0xDA, 0xDA);
      break;
    case ColorID::Menu:
      // Hand-picked from Sonoma because there doesn't seem to be any
      // appropriate menu system color.
      aColor = aScheme == ColorScheme::Dark ? NS_RGB(0x36, 0x36, 0x39)
                                            : NS_RGB(0xeb, 0xeb, 0xeb);
      break;
    case ColorID::Windowframe:
      aColor = GetColorFromNSColor(NSColor.windowFrameColor);
      break;
    case ColorID::MozDialog:
    case ColorID::Window:
      aColor = GetColorFromNSColor(aScheme == ColorScheme::Light
                                       ? NSColor.windowBackgroundColor
                                       : NSColor.underPageBackgroundColor);
      break;
    case ColorID::Field:
    case ColorID::MozCombobox:
      aColor = GetColorFromNSColor(NSColor.controlBackgroundColor);
      break;
    case ColorID::Fieldtext:
    case ColorID::MozComboboxtext:
    case ColorID::Buttontext:
    case ColorID::MozButtonhovertext:
    case ColorID::Menutext:
    case ColorID::Infotext:
    case ColorID::MozCellhighlighttext:
    case ColorID::MozSidebartext:
      aColor = GetColorFromNSColor(NSColor.controlTextColor);
      break;
    case ColorID::MozMacFocusring:
      aColor = GetColorFromNSColorWithCustomAlpha(
          NSColor.keyboardFocusIndicatorColor, 0.48);
      break;
    case ColorID::MozMacDisabledtoolbartext:
    case ColorID::Graytext:
      aColor = GetColorFromNSColor(NSColor.disabledControlTextColor);
      break;
    case ColorID::MozCellhighlight:
      // For inactive list selection
      aColor = GetColorFromNSColor(NSColor.secondarySelectedControlColor);
      break;
    case ColorID::MozColheadertext:
    case ColorID::MozColheaderhovertext:
    case ColorID::MozColheaderactivetext:
      aColor = GetColorFromNSColor(NSColor.headerTextColor);
      break;
    case ColorID::MozColheaderactive:
      aColor = GetColorFromNSColor(
          NSColor.unemphasizedSelectedContentBackgroundColor);
      break;
    case ColorID::MozColheader:
    case ColorID::MozColheaderhover:
    case ColorID::MozEventreerow:
      // Background color of even list rows.
      aColor =
          GetColorFromNSColor(NSColor.controlAlternatingRowBackgroundColors[0]);
      break;
    case ColorID::MozOddtreerow:
      // Background color of odd list rows.
      aColor =
          GetColorFromNSColor(NSColor.controlAlternatingRowBackgroundColors[1]);
      break;
    case ColorID::MozNativehyperlinktext:
      aColor = GetColorFromNSColor(NSColor.linkColor);
      break;
    case ColorID::MozNativevisitedhyperlinktext:
      aColor = GetColorFromNSColor(NSColor.systemPurpleColor);
      break;
    case ColorID::MozHeaderbartext:
    case ColorID::MozHeaderbarinactivetext:
    case ColorID::Inactivecaptiontext:
    case ColorID::Captiontext:
    case ColorID::Windowtext:
    case ColorID::MozDialogtext:
      aColor = GetColorFromNSColor(NSColor.labelColor);
      return NS_OK;
    case ColorID::MozHeaderbar:
    case ColorID::MozHeaderbarinactive:
    case ColorID::Inactivecaption:
    case ColorID::Activecaption:
      // This has better contrast than the stand-in colors.
      aColor = GetColorFromNSColor(NSColor.windowBackgroundColor);
      return NS_OK;
    case ColorID::Marktext:
    case ColorID::Mark:
    case ColorID::SpellCheckerUnderline:
    case ColorID::Activeborder:
    case ColorID::Inactiveborder:
    case ColorID::MozAutofillBackground:
    case ColorID::TargetTextBackground:
    case ColorID::TargetTextForeground:
      aColor = GetStandinForNativeColor(aID, aScheme);
      return NS_OK;
    default:
      aColor = NS_RGB(0xff, 0xff, 0xff);
      return NS_ERROR_FAILURE;
  }
  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK
}

static bool SystemWantsDarkTheme() {
  // This returns true if the macOS system appearance is set to dark mode,
  // false otherwise.
  NSAppearanceName aquaOrDarkAqua =
      [NSApp.effectiveAppearance bestMatchFromAppearancesWithNames:@[
        NSAppearanceNameAqua, NSAppearanceNameDarkAqua
      ]];
  return [aquaOrDarkAqua isEqualToString:NSAppearanceNameDarkAqua];
}

nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  nsresult res = NS_OK;

  switch (aID) {
    case IntID::ScrollButtonLeftMouseButtonAction:
      aResult = 0;
      break;
    case IntID::ScrollButtonMiddleMouseButtonAction:
    case IntID::ScrollButtonRightMouseButtonAction:
      aResult = 3;
      break;
    case IntID::CaretBlinkTime:
      aResult = 567;
      break;
    case IntID::CaretWidth:
      aResult = 1;
      break;
    case IntID::SelectTextfieldsOnKeyFocus:
      // Select textfield content when focused by kbd
      // used by EventStateManager::sTextfieldSelectModel
      aResult = 1;
      break;
    case IntID::SubmenuDelay:
      aResult = 200;
      break;
    case IntID::MenusCanOverlapOSBar:
      // xul popups are not allowed to overlap the menubar.
      aResult = 0;
      break;
    case IntID::SkipNavigatingDisabledMenuItem:
      aResult = 1;
      break;
    case IntID::DragThresholdX:
    case IntID::DragThresholdY:
      aResult = 4;
      break;
    case IntID::ScrollArrowStyle:
      aResult = eScrollArrow_None;
      break;
    case IntID::UseOverlayScrollbars:
    case IntID::AllowOverlayScrollbarsOverlap:
      aResult = NSScroller.preferredScrollerStyle == NSScrollerStyleOverlay;
      break;
    case IntID::ScrollbarDisplayOnMouseMove:
      aResult = 0;
      break;
    case IntID::ScrollbarFadeBeginDelay:
      aResult = 450;
      break;
    case IntID::ScrollbarFadeDuration:
      aResult = 200;
      break;
    case IntID::TreeOpenDelay:
      aResult = 1000;
      break;
    case IntID::TreeCloseDelay:
      aResult = 1000;
      break;
    case IntID::TreeLazyScrollDelay:
      aResult = 150;
      break;
    case IntID::TreeScrollDelay:
      aResult = 100;
      break;
    case IntID::TreeScrollLinesMax:
      aResult = 3;
      break;
    case IntID::MacBigSurTheme:
      aResult = nsCocoaFeatures::OnBigSurOrLater();
      break;
    case IntID::MacRTL:
      EnsureInit();
      aResult = mRtl;
      break;
    case IntID::MacTitlebarHeight:
      EnsureInit();
      aResult = mTitlebarHeight;
      break;
    case IntID::AlertNotificationOrigin:
      aResult = NS_ALERT_TOP;
      break;
    case IntID::ScrollToClick: {
      aResult = [[NSUserDefaults standardUserDefaults]
          boolForKey:@"AppleScrollerPagingBehavior"];
    } break;
    case IntID::ChosenMenuItemsShouldBlink:
      aResult = 1;
      break;
    case IntID::IMERawInputUnderlineStyle:
    case IntID::IMEConvertedTextUnderlineStyle:
    case IntID::IMESelectedRawTextUnderlineStyle:
    case IntID::IMESelectedConvertedTextUnderline:
      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Solid);
      break;
    case IntID::SpellCheckerUnderlineStyle:
      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Dotted);
      break;
    case IntID::ScrollbarButtonAutoRepeatBehavior:
      aResult = 0;
      break;
    case IntID::SwipeAnimationEnabled:
      aResult = NSEvent.isSwipeTrackingFromScrollEventsEnabled;
      break;
    case IntID::ContextMenuOffsetVertical:
      aResult = -6;
      break;
    case IntID::ContextMenuOffsetHorizontal:
      aResult = 1;
      break;
    case IntID::SystemUsesDarkTheme:
      aResult = SystemWantsDarkTheme();
      break;
    case IntID::PrefersReducedMotion:
      aResult =
          NSWorkspace.sharedWorkspace.accessibilityDisplayShouldReduceMotion;
      break;
    case IntID::PrefersReducedTransparency:
      aResult = NSWorkspace.sharedWorkspace
                    .accessibilityDisplayShouldReduceTransparency;
      break;
    case IntID::InvertedColors:
      aResult =
          NSWorkspace.sharedWorkspace.accessibilityDisplayShouldInvertColors;
      break;
    case IntID::UseAccessibilityTheme:
      aResult = NSWorkspace.sharedWorkspace
                    .accessibilityDisplayShouldIncreaseContrast;
      break;
    case IntID::PanelAnimations:
      aResult = 1;
      break;
    case IntID::FullKeyboardAccess:
      aResult = NSApp.isFullKeyboardAccessEnabled;
      break;
    default:
      aResult = 0;
      res = NS_ERROR_FAILURE;
  }
  return res;

  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
}

nsresult nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  nsresult res = NS_OK;

  switch (aID) {
    case FloatID::IMEUnderlineRelativeSize:
      aResult = 2.0f;
      break;
    case FloatID::SpellCheckerUnderlineRelativeSize:
      aResult = 2.0f;
      break;
    case FloatID::CursorScale: {
      id uaDefaults = [[NSUserDefaults alloc]
          initWithSuiteName:@"com.apple.universalaccess"];
      float f = [uaDefaults floatForKey:@"mouseDriverCursorSize"];
      [uaDefaults release];
      aResult = f > 0.0 ? f : 1.0;  // default to 1.0 if value not available
      break;
    }
    default:
      aResult = -1.0;
      res = NS_ERROR_FAILURE;
  }

  return res;

  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
}

bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
                                  gfxFontStyle& aFontStyle) {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  nsAutoCString name;
  gfxPlatformMac::LookupSystemFont(aID, name, aFontStyle);
  aFontName.Append(NS_ConvertUTF8toUTF16(name));

  return true;

  NS_OBJC_END_TRY_BLOCK_RETURN(false);
}

void nsLookAndFeel::RecordAccessibilityTelemetry() {
  if ([[NSWorkspace sharedWorkspace]
          respondsToSelector:@selector
          (accessibilityDisplayShouldInvertColors)]) {
    bool val =
        [[NSWorkspace sharedWorkspace] accessibilityDisplayShouldInvertColors];
    glean::a11y::invert_colors.Set(val);
  }
}

nsresult nsLookAndFeel::GetKeyboardLayoutImpl(nsACString& aLayout) {
  TISInputSourceRef source = ::TISCopyCurrentKeyboardInputSource();
  nsAutoString layout;

  CFStringRef layoutName = static_cast<CFStringRef>(
      ::TISGetInputSourceProperty(source, kTISPropertyLocalizedName));
  CopyNSStringToXPCOMString((const NSString*)layoutName, layout);
  aLayout.Assign(NS_ConvertUTF16toUTF8(layout));

  ::CFRelease(source);
  return NS_OK;
}

@implementation MOZLookAndFeelDynamicChangeObserver

+ (void)startObserving {
  static MOZLookAndFeelDynamicChangeObserver* gInstance = nil;
  if (!gInstance) {
    gInstance = [[MOZLookAndFeelDynamicChangeObserver alloc] init];  // leaked
  }
}

- (instancetype)init {
  self = [super init];

  [NSNotificationCenter.defaultCenter
      addObserver:self
         selector:@selector(colorsChanged)
             name:NSControlTintDidChangeNotification
           object:nil];
  [NSNotificationCenter.defaultCenter
      addObserver:self
         selector:@selector(colorsChanged)
             name:NSSystemColorsDidChangeNotification
           object:nil];

  [NSWorkspace.sharedWorkspace.notificationCenter
      addObserver:self
         selector:@selector(mediaQueriesChanged)
             name:NSWorkspaceAccessibilityDisplayOptionsDidChangeNotification
           object:nil];

  [NSNotificationCenter.defaultCenter
      addObserver:self
         selector:@selector(scrollbarsChanged)
             name:NSPreferredScrollerStyleDidChangeNotification
           object:nil];
  [NSDistributedNotificationCenter.defaultCenter
             addObserver:self
                selector:@selector(scrollbarsChanged)
                    name:@"AppleAquaScrollBarVariantChanged"
                  object:nil
      suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];
  [NSDistributedNotificationCenter.defaultCenter
             addObserver:self
                selector:@selector(cachedValuesChanged)
                    name:@"AppleNoRedisplayAppearancePreferenceChanged"
                  object:nil
      suspensionBehavior:NSNotificationSuspensionBehaviorCoalesce];
  [NSDistributedNotificationCenter.defaultCenter
             addObserver:self
                selector:@selector(cachedValuesChanged)
                    name:@"com.apple.KeyboardUIModeDidChange"
                  object:nil
      suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];

  [NSApp addObserver:self
          forKeyPath:@"effectiveAppearance"
             options:0
             context:nil];

  return self;
}

- (void)observeValueForKeyPath:(NSString*)keyPath
                      ofObject:(id)object
                        change:(NSDictionary<NSKeyValueChangeKey, id>*)change
                       context:(void*)context {
  if ([keyPath isEqualToString:@"effectiveAppearance"]) {
    [self entireThemeChanged];
  } else {
    [super observeValueForKeyPath:keyPath
                         ofObject:object
                           change:change
                          context:context];
  }
}

- (void)entireThemeChanged {
  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::StyleAndLayout);
}

- (void)scrollbarsChanged {
  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::StyleAndLayout);
}

- (void)mediaQueriesChanged {
  // Changing`Invert Colors` sends
  // AccessibilityDisplayOptionsDidChangeNotifications. We monitor that setting
  // via telemetry, so call into that recording method here.
  nsLookAndFeel::RecordAccessibilityTelemetry();
  LookAndFeel::NotifyChangedAllWindows(
      widget::ThemeChangeKind::MediaQueriesOnly);
}

- (void)colorsChanged {
  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::Style);
}

- (void)cachedValuesChanged {
  // We only need to re-cache (and broadcast) updated LookAndFeel values, so
  // that they're up-to-date the next time they're queried. No further change
  // handling is needed.
  // TODO: Add a change hint for this which avoids the unnecessary media query
  // invalidation.
  LookAndFeel::NotifyChangedAllWindows(
      widget::ThemeChangeKind::MediaQueriesOnly);
}
@end