ShrlAlgoToolkit/WPFluent/Interop/UxTheme.cs




/* This Source Code is partially based on reverse engineering of the Windows Operating System,
   and is intended for use on Windows systems only.
   This Source Code is partially based on the source code provided by the .NET Foundation.

   NOTE:
   I split unmanaged code stuff into the NativeMethods library.
   If you have suggestions for the code below, please submit your changes there.
   https://github.com/lepoco/nativemethods */

using System.Runtime.InteropServices;
using System.Text;

namespace WPFluent.Interop;

// ReSharper disable IdentifierTypo
// ReSharper disable InconsistentNaming
#pragma warning disable SA1307 // Accessible fields should begin with upper-case letter
#pragma warning disable CA1060 // Move pinvokes to native methods class

internal static class UxTheme
{
    /// <summary>
    /// Retrieves the name of the current visual style, and optionally retrieves the color scheme name and size name.
    /// </summary>
    /// <param name="pszThemeFileName">Pointer to a string that receives the theme path and file name.</param>
    /// <param name="dwMaxNameChars">Value of type int that contains the maximum number of characters allowed in the theme file name.</param>
    /// <param name="pszColorBuff">Pointer to a string that receives the color scheme name. This parameter may be set to NULL.</param>
    /// <param name="cchMaxColorChars">Value of type int that contains the maximum number of characters allowed in the color scheme name.</param>
    /// <param name="pszSizeBuff">Pointer to a string that receives the size name. This parameter may be set to NULL.</param>
    /// <param name="cchMaxSizeChars">Value of type int that contains the maximum number of characters allowed in the size name.</param>
    /// <returns>HRESULT</returns>
    [DllImport(Libraries.UxTheme, CharSet = CharSet.Unicode)]
    public static extern int GetCurrentThemeName(
        [Out] StringBuilder pszThemeFileName,
        [In] int dwMaxNameChars,
        [Out] StringBuilder pszColorBuff,
        [In] int cchMaxColorChars,
        [Out] StringBuilder pszSizeBuff,
        [In] int cchMaxSizeChars);
    [DllImport("uxtheme.dll", EntryPoint = "#132", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool ShouldAppsUseDarkMode();
    [DllImport("uxtheme.dll", EntryPoint = "#136", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern void FlushMenuThemes();

    [DllImport("uxtheme.dll", EntryPoint = "#138", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool ShouldSystemUseDarkMode();

    public enum PreferredAppMode : int { Default, AllowDark, ForceDark, ForceLight, Max };
    /// <summary>
    /// Windows 10 1903, aka 18362, broke the API.
    ///  - Before 18362, the #135 is AllowDarkModeForApp(BOOL)
    ///  - After 18362, the #135 is SetPreferredAppMode(PreferredAppMode)
    /// Since the support for AllowDarkModeForApp is uncertain, it will not be considered for use.
    /// </summary>
    [DllImport("uxtheme.dll", EntryPoint = "#135", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern int SetPreferredAppMode(PreferredAppMode preferredAppMode);

    /// <summary>
    /// Tests if a visual style for the current application is active.
    /// </summary>
    /// <returns>
    /// <see langword="true"/> if a visual style is enabled, and windows with visual styles applied should call
    /// OpenThemeData to start using theme drawing services.
    /// </returns>
    [DllImport(Libraries.UxTheme)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool IsThemeActive();

    /// <summary>
    /// Sets attributes to control how visual styles are applied to a specified window.
    /// </summary>
    /// <param name="hWnd">
    /// Handle to a window to apply changes to.
    /// </param>
    /// <param name="eAttribute">
    /// Value of type WINDOWTHEMEATTRIBUTETYPE that specifies the type of attribute to set. The value of this parameter
    /// determines the type of data that should be passed in the pvAttribute parameter. Can be the following value:
    /// <list>WTA_NONCLIENT (Specifies non-client related attributes).</list> pvAttribute must be a pointer of type
    /// WTA_OPTIONS.
    /// </param>
    /// <param name="pvAttribute">
    /// A pointer that specifies attributes to set. Type is determined by the value of the eAttribute value.
    /// </param>
    /// <param name="cbAttribute">
    /// Specifies the size, in bytes, of the data pointed to by pvAttribute.
    /// </param>
    [DllImport(Libraries.UxTheme, PreserveSig = false)]
    public static extern void SetWindowThemeAttribute(
        [In] IntPtr hWnd,
        [In] WINDOWTHEMEATTRIBUTETYPE eAttribute,
        [In] ref WTA_OPTIONS pvAttribute,
        [In] uint cbAttribute);

    /// <summary>
    /// Returned by the GetThemeMargins function to define the margins of windows that have visual styles applied.
    /// </summary>
    public struct MARGINS
    {
        /// <summary>
        /// Width of left border that retains its size.
        /// </summary>
        public int cxLeftWidth;

        /// <summary>
        /// Width of right border that retains its size.
        /// </summary>
        public int cxRightWidth;

        /// <summary>
        /// Height of top border that retains its size.
        /// </summary>
        public int cyTopHeight;

        /// <summary>
        /// Height of bottom border that retains its size.
        /// </summary>
        public int cyBottomHeight;
    }

    /// <summary>
    /// Specifies the type of visual style attribute to set on a window.
    /// </summary>
    public enum WINDOWTHEMEATTRIBUTETYPE : uint
    {
        /// <summary>
        /// Non-client area window attributes will be set.
        /// </summary>
        WTA_NONCLIENT = 1,
    }

    /// <summary>
    /// WindowThemeNonClientAttributes
    /// </summary>
    [Flags]
    public enum WTNCA : uint
    {
        /// <summary>
        /// Prevents the window caption from being drawn.
        /// </summary>
        NODRAWCAPTION = 0x00000001,

        /// <summary>
        /// Prevents the system icon from being drawn.
        /// </summary>
        NODRAWICON = 0x00000002,

        /// <summary>
        /// Prevents the system icon menu from appearing.
        /// </summary>
        NOSYSMENU = 0x00000004,

        /// <summary>
        /// Prevents mirroring of the question mark, even in right-to-left (RTL) layout.
        /// </summary>
        NOMIRRORHELP = 0x00000008,

        /// <summary>
        /// A mask that contains all the valid bits.
        /// </summary>
        VALIDBITS = NODRAWCAPTION | NODRAWICON | NOMIRRORHELP | NOSYSMENU,
    }

    /// <summary>
    /// Defines options that are used to set window visual style attributes.
    /// </summary>
    [StructLayout(LayoutKind.Explicit)]
    public struct WTA_OPTIONS
    {
        /// <summary>
        /// A combination of flags that modify window visual style attributes. Can be a combination of the WTNCA
        /// constants.
        /// </summary>
        [FieldOffset(0)]
        public WTNCA dwFlags;

        /// <summary>
        /// A bitmask that describes how the values specified in dwFlags should be applied. If the bit corresponding to
        /// a value in dwFlags is 0, that flag will be removed. If the bit is 1, the flag will be added.
        /// </summary>
        [FieldOffset(4)]
        public WTNCA dwMask;

        // public static readonly uint Size = (uint)Marshal.SizeOf(typeof(WTA_OPTIONS));
        public const uint Size = 8;
    }
}

#pragma warning restore SA1307 // Accessible fields should begin with upper-case letter
#pragma warning restore CA1060 // Move pinvokes to native methods class