1 // Copyright 2022 The Chromium Authors
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 "base/win/dark_mode_support.h"
6
7 #include <windows.h>
8
9 #include "base/check.h"
10 #include "base/native_library.h"
11 #include "base/win/win_util.h"
12 #include "base/win/windows_version.h"
13
14 namespace {
15
16 // APIs for controlling how an app and window respond to system-level
17 // dark/light modes.
18
19 // Available on Wwindows build base::win::Version::WIN10_19H1 and up.
20 enum class PreferredAppMode {
21 kDefault,
22 kAllowDark,
23 kForceDark,
24 kForceLight,
25 kMax
26 };
27
28 // The following APIs and code was based on information from here:
29 // https://github.com/ysc3839/win32-darkmode
30
31 // Only available on Windows build base::win::Version::WIN10_RS5.
32 // NOLINTNEXTLINE(readability/casting)
33 using UxThemeAllowDarkModeForAppFunc = bool(WINAPI*)(bool allow);
34
35 // Available on Windows build base::win::Version::WIN10_19H1 and up.
36 using UxThemeSetPreferredAppModeFunc =
37 // NOLINTNEXTLINE(readability/casting)
38 PreferredAppMode(WINAPI*)(PreferredAppMode app_mode);
39
40 // Available on Windows build base::win::Version::WIN10_RS5 and up.
41 // NOLINTNEXTLINE(readability/casting)
42 using UxThemeAllowDarkModeForWindowFunc = bool(WINAPI*)(HWND hwnd, bool allow);
43
44 // The following two ordinals are mutually exclusive and represent a difference
45 // between base::win::Version::WIN10_RS5 and base::win::Version::WIN10_19H1.
46 constexpr WORD kUxThemeAllowDarkModeForAppOrdinal = 135;
47 constexpr WORD kUxThemeSetPreferredAppModeOrdinal = 135;
48 constexpr WORD kUxThemeAllowDarkModeForWindowOrdinal = 133;
49
50 struct DarkModeSupport {
51 UxThemeAllowDarkModeForAppFunc allow_dark_mode_for_app = nullptr;
52 UxThemeSetPreferredAppModeFunc set_preferred_app_mode = nullptr;
53 UxThemeAllowDarkModeForWindowFunc allow_dark_mode_for_window = nullptr;
54 };
55
GetDarkModeSupport()56 const DarkModeSupport& GetDarkModeSupport() {
57 static const DarkModeSupport dark_mode_support =
58 [] {
59 DarkModeSupport dark_mode_support;
60 auto* os_info = base::win::OSInfo::GetInstance();
61 // Dark mode only works on WIN10_RS5 and up. uxtheme.dll depends on
62 // GDI32.dll which is not available under win32k lockdown sandbox.
63 if (os_info->version() >= base::win::Version::WIN10_RS5 &&
64 base::win::IsUser32AndGdi32Available()) {
65 base::NativeLibraryLoadError error;
66 HMODULE ux_theme_lib = base::PinSystemLibrary(L"uxtheme.dll", &error);
67 DCHECK(!error.code);
68 if (os_info->version() >= base::win::Version::WIN10_19H1) {
69 dark_mode_support.set_preferred_app_mode =
70 reinterpret_cast<UxThemeSetPreferredAppModeFunc>(
71 ::GetProcAddress(
72 ux_theme_lib,
73 MAKEINTRESOURCEA(kUxThemeSetPreferredAppModeOrdinal)));
74 } else {
75 dark_mode_support.allow_dark_mode_for_app =
76 reinterpret_cast<UxThemeAllowDarkModeForAppFunc>(
77 ::GetProcAddress(
78 ux_theme_lib,
79 MAKEINTRESOURCEA(kUxThemeAllowDarkModeForAppOrdinal)));
80 }
81 dark_mode_support.allow_dark_mode_for_window =
82 reinterpret_cast<UxThemeAllowDarkModeForWindowFunc>(
83 ::GetProcAddress(
84 ux_theme_lib,
85 MAKEINTRESOURCEA(kUxThemeAllowDarkModeForWindowOrdinal)));
86 }
87 return dark_mode_support;
88 }();
89 return dark_mode_support;
90 }
91
92 } // namespace
93
94 namespace base::win {
95
IsDarkModeAvailable()96 bool IsDarkModeAvailable() {
97 auto& dark_mode_support = GetDarkModeSupport();
98 return (dark_mode_support.allow_dark_mode_for_app ||
99 dark_mode_support.set_preferred_app_mode) &&
100 dark_mode_support.allow_dark_mode_for_window;
101 }
102
AllowDarkModeForApp(bool allow)103 void AllowDarkModeForApp(bool allow) {
104 if (!IsDarkModeAvailable())
105 return;
106 auto& dark_mode_support = GetDarkModeSupport();
107 if (dark_mode_support.set_preferred_app_mode) {
108 dark_mode_support.set_preferred_app_mode(
109 allow ? PreferredAppMode::kAllowDark : PreferredAppMode::kDefault);
110 } else {
111 dark_mode_support.allow_dark_mode_for_app(allow);
112 }
113 }
114
AllowDarkModeForWindow(HWND hwnd,bool allow)115 bool AllowDarkModeForWindow(HWND hwnd, bool allow) {
116 if (!IsDarkModeAvailable())
117 return false;
118 return GetDarkModeSupport().allow_dark_mode_for_window(hwnd, allow);
119 }
120
121 } // namespace base::win
122