DarkModeHelper.h

// sktoolslib - common files for SK tools

// Copyright (C) 2019-2021 - Stefan Kueng

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
#pragma once

/// helper class for the Windows 10 dark mode
/// note: we use undocumented APIs here, so be careful!
class DarkModeHelper
{
public:
    static DarkModeHelper& Instance();

    // ReSharper disable CppInconsistentNaming
    enum IMMERSIVE_HC_CACHE_MODE
    {
        IHCM_USE_CACHED_VALUE,
        IHCM_REFRESH
    };
    enum PreferredAppMode
    {
        Default,
        AllowDark,
        ForceDark,
        ForceLight,
        Max
    };
    enum WINDOWCOMPOSITIONATTRIB
    {
        WCA_UNDEFINED                     = 0,
        WCA_NCRENDERING_ENABLED           = 1,
        WCA_NCRENDERING_POLICY            = 2,
        WCA_TRANSITIONS_FORCEDISABLED     = 3,
        WCA_ALLOW_NCPAINT                 = 4,
        WCA_CAPTION_BUTTON_BOUNDS         = 5,
        WCA_NONCLIENT_RTL_LAYOUT          = 6,
        WCA_FORCE_ICONIC_REPRESENTATION   = 7,
        WCA_EXTENDED_FRAME_BOUNDS         = 8,
        WCA_HAS_ICONIC_BITMAP             = 9,
        WCA_THEME_ATTRIBUTES              = 10,
        WCA_NCRENDERING_EXILED            = 11,
        WCA_NCADORNMENTINFO               = 12,
        WCA_EXCLUDED_FROM_LIVEPREVIEW     = 13,
        WCA_VIDEO_OVERLAY_ACTIVE          = 14,
        WCA_FORCE_ACTIVEWINDOW_APPEARANCE = 15,
        WCA_DISALLOW_PEEK                 = 16,
        WCA_CLOAK                         = 17,
        WCA_CLOAKED                       = 18,
        WCA_ACCENT_POLICY                 = 19,
        WCA_FREEZE_REPRESENTATION         = 20,
        WCA_EVER_UNCLOAKED                = 21,
        WCA_VISUAL_OWNER                  = 22,
        WCA_HOLOGRAPHIC                   = 23,
        WCA_EXCLUDED_FROM_DDA             = 24,
        WCA_PASSIVEUPDATEMODE             = 25,
        WCA_USEDARKMODECOLORS             = 26,
        WCA_LAST                          = 27
    };

    struct WINDOWCOMPOSITIONATTRIBDATA
    {
        WINDOWCOMPOSITIONATTRIB Attrib;
        PVOID                   pvData;
        SIZE_T                  cbData;
    };
    // ReSharper restore CppInconsistentNaming

    bool CanHaveDarkMode() const;
    void AllowDarkModeForApp(BOOL allow) const;
    void AllowDarkModeForWindow(HWND hwnd, BOOL allow) const;
    BOOL ShouldAppsUseDarkMode() const;
    BOOL IsDarkModeAllowedForWindow(HWND hwnd) const;
    BOOL IsDarkModeAllowedForApp() const;
    BOOL ShouldSystemUseDarkMode() const;
    void RefreshImmersiveColorPolicyState() const;
    BOOL GetIsImmersiveColorUsingHighContrast(IMMERSIVE_HC_CACHE_MODE mode) const;
    void FlushMenuThemes() const;
    BOOL SetWindowCompositionAttribute(HWND hWnd, WINDOWCOMPOSITIONATTRIBDATA* data) const;
    void RefreshTitleBarThemeColor(HWND hWnd, BOOL dark) const;

private:
    DarkModeHelper();
    ~DarkModeHelper();

    using AllowDarkModeForAppFpn = void(WINAPI* )(BOOL allow);
    using SetPreferredAppModeFpn = PreferredAppMode(WINAPI* )(PreferredAppMode appMode);
    using AllowDarkModeForWindowFpn = void(WINAPI* )(HWND hwnd, BOOL allow);
    using ShouldAppsUseDarkModeFpn = BOOL(WINAPI* )();
    using IsDarkModeAllowedForWindowFpn = BOOL(WINAPI* )(HWND hwnd);
    using IsDarkModeAllowedForAppFpn = BOOL(WINAPI* )();
    using ShouldSystemUseDarkModeFpn = BOOL(WINAPI* )();
    using RefreshImmersiveColorPolicyStateFn = void(WINAPI* )();
    using GetIsImmersiveColorUsingHighContrastFn = BOOL(WINAPI* )(IMMERSIVE_HC_CACHE_MODE mode);
    using FlushMenuThemesFn = void(WINAPI* )();
    using SetWindowCompositionAttributeFpn = BOOL(WINAPI* )(HWND hwnd, WINDOWCOMPOSITIONATTRIBDATA* data);

    AllowDarkModeForAppFpn                 m_pAllowDarkModeForApp                  = nullptr;
    SetPreferredAppModeFpn                 m_pSetPreferredAppMode                  = nullptr;
    AllowDarkModeForWindowFpn              m_pAllowDarkModeForWindow               = nullptr;
    ShouldAppsUseDarkModeFpn               m_pShouldAppsUseDarkMode                = nullptr;
    IsDarkModeAllowedForWindowFpn          m_pIsDarkModeAllowedForWindow           = nullptr;
    IsDarkModeAllowedForAppFpn             m_pIsDarkModeAllowedForApp              = nullptr;
    ShouldSystemUseDarkModeFpn             m_pShouldSystemUseDarkMode              = nullptr;
    RefreshImmersiveColorPolicyStateFn     m_pRefreshImmersiveColorPolicyState     = nullptr;
    GetIsImmersiveColorUsingHighContrastFn m_pGetIsImmersiveColorUsingHighContrast = nullptr;
    FlushMenuThemesFn                      m_pFlushMenuThemes                      = nullptr;
    SetWindowCompositionAttributeFpn       m_pSetWindowCompositionAttribute        = nullptr;
    HMODULE                                m_hUxthemeLib                           = nullptr;
    bool                                   m_bCanHaveDarkMode                      = false;
};