Partial work on nullable for Gdi32

Core/InteropServices/SafeIDispatch.cs

@@ -27,7 +27,7 @@ namespace Vanara.InteropServices
 		/// <summary>Determines whether the specified <see cref="System.Object"/>, is equal to this instance.</summary>
 		/// <param name="obj">The <see cref="System.Object"/> to compare with this instance.</param>
 		/// <returns><see langword="true"/> if the specified <see cref="System.Object"/> is equal to this instance; otherwise, <see langword="false"/>.</returns>
-		public override bool Equals(object obj) => obj is ComReleaser<dynamic> o ? Equals(o) : base.Equals(obj);
+		public override bool Equals(object? obj) => obj is ComReleaser<dynamic> o ? Equals(o) : base.Equals(obj);
 
 		/// <summary>Returns a hash code for this instance.</summary>
 		/// <returns>A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table.</returns>

Core/InteropServices/time_t.cs

@@ -9,7 +9,7 @@ namespace Vanara.PInvoke;
 [StructLayout(LayoutKind.Sequential), Serializable]
 [TypeConverter(typeof(time_tTypeConverter))]
 #pragma warning disable IDE1006 // Naming Styles
-public struct time_t : IEquatable<time_t>, IComparable<time_t>, IEquatable<DateTime>, IComparable<DateTime>, IConvertible, IComparable
+public readonly struct time_t : IEquatable<time_t>, IComparable<time_t>, IEquatable<DateTime>, IComparable<DateTime>, IConvertible, IComparable
 #pragma warning restore IDE1006 // Naming Styles
 {
 	private static readonly DateTime epoch = new(1970, 1, 1, 0, 0, 0, DateTimeKind.Local);

PInvoke/ComCtl32/CommCtrl.Button.cs

@@ -8,7 +8,7 @@ namespace Vanara.PInvoke;
 public static partial class ComCtl32
 {
 	/// <summary>Used in the <see cref="BUTTON_IMAGELIST"/> structure himl member to indicate that no glyph should be displayed.</summary>
-	public static IntPtr BCCL_NOGLYPH = new IntPtr(-1);
+	public static IntPtr BCCL_NOGLYPH = new(-1);
 
 	/// <summary>Used by the <see cref="BUTTON_IMAGELIST.uAlign"/> member to specify alignment.</summary>
 	[PInvokeData("Commctrl.h", MSDNShortId = "bb775953")]

PInvoke/ComCtl32/CommCtrl.TreeView.cs

@@ -2294,16 +2294,16 @@ public static partial class ComCtl32
 
 	/// <summary>Provides a handle to a tree view item.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HTREEITEM
+	public readonly struct HTREEITEM
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HTREEITEM"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HTREEITEM(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HTREEITEM"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HTREEITEM NULL => new HTREEITEM(IntPtr.Zero);
+		public static HTREEITEM NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -2316,7 +2316,7 @@ public static partial class ComCtl32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HTREEITEM"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HTREEITEM(IntPtr h) => new HTREEITEM(h);
+		public static implicit operator HTREEITEM(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -2331,7 +2331,7 @@ public static partial class ComCtl32
 		public static bool operator ==(HTREEITEM h1, HTREEITEM h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HTREEITEM h && handle == h.handle;
+		public override bool Equals(object? obj) => obj is HTREEITEM h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/Gdi32/WinGdi.BITMAPINFO.cs

@@ -3,6 +3,7 @@ using System.Runtime.InteropServices;
 using Vanara.Extensions;
 using Vanara.InteropServices;
 
+#pragma warning disable IDE1006 // Naming Styles
 namespace Vanara.PInvoke;
 
 /// <summary>Functions and types from Gdi32.dll.</summary>
@@ -248,10 +249,10 @@ public static partial class Gdi32
 		/// </item>
 		/// <item>
 		/// <description>
-		/// An array of 16-bit unsigned integers that specifies indexes into the currently realized logical palette. This use of
+		/// An array of 16-bit unsigned integers that specifies indexes into the currently realized logical palette. This use of bmiColors is
-		/// bmiColors is allowed for functions that use DIBs. When bmiColors elements contain indexes to a realized logical palette,
+		/// allowed for functions that use DIBs. When bmiColors elements contain indexes to a realized logical palette, they must also call
-		/// they must also call the following bitmap
+		/// the following bitmap functions: CreateDIBitmap, CreateDIBPatternBrush, CreateDIBSection (The iUsage parameter of CreateDIBSection
-		/// functions: CreateDIBitmap, CreateDIBPatternBrush, CreateDIBSection (The iUsage parameter of CreateDIBSection must be set to DIB_PAL_COLORS.)
+		/// must be set to DIB_PAL_COLORS.)
 		/// </description>
 		/// </item>
 		/// </list>
@@ -271,6 +272,7 @@ public static partial class Gdi32
 			: this()
 		{
 			bmiHeader = new BITMAPINFOHEADER(width, height, bitCount);
+			bmiColors = new RGBQUAD[bitCount];
 		}
 
 		/// <summary>Creates a <see cref="BITMAPINFO"/> structure from the information in a bitmap handle.</summary>
@@ -1218,10 +1220,7 @@ public static partial class Gdi32
 		/// has a value greater than 8. Each color mask indicates the bits that are used to encode one of the three color channels (red,
 		/// green, and blue).
 		/// </summary>
-#pragma warning disable IDE1006 // Naming Styles
-
 		public uint[] dsBitFields
-#pragma warning restore IDE1006 // Naming Styles
 		{
 			get => new[] { dsBitField1, dsBitField2, dsBitField3 };
 			set { dsBitField1 = value[0]; dsBitField2 = value[1]; dsBitField3 = value[2]; }
@@ -1235,22 +1234,16 @@ public static partial class Gdi32
 	public class SafeBITMAPINFO : SafeCoTaskMemStruct<BITMAPINFO>
 	{
 		private const int RGBQUADSZ = 4;
+		private static readonly int hdrSize = Marshal.SizeOf(typeof(BITMAPINFOHEADER));
 
 		/// <summary>Initializes a new instance of the <see cref="SafeBITMAPINFO"/> class.</summary>
 		/// <param name="bmpInfo">The <see cref="BITMAPINFO"/> value.</param>
-		public SafeBITMAPINFO(in BITMAPINFO bmpInfo) : base(BaseStructSize + (bmpInfo.bmiColors?.Length ?? 0) * RGBQUADSZ)
+		public SafeBITMAPINFO(in BITMAPINFO bmpInfo) : this(bmpInfo.bmiHeader, bmpInfo.bmiColors.Length * RGBQUADSZ) => bmiColors = bmpInfo.bmiColors;
-		{
-			handle.Write(bmpInfo.bmiHeader, 0, Size);
-			bmiColors = bmpInfo.bmiColors;
-		}
 
 		/// <summary>Initializes a new instance of the <see cref="SafeBITMAPINFO"/> class.</summary>
-		/// <param name="hdr">The HDR.</param>
+		/// <param name="hdr">The <see cref="BITMAPINFOHEADER"/> to initialize.</param>
-		/// <param name="capacity">The capacity of the buffer, in bytes. If 0 or <see langword="default"/>, the capacity is calculated.</param>
+		/// <param name="capacity">The capacity of the buffer, in bytes.</param>
-		public SafeBITMAPINFO(in BITMAPINFOHEADER hdr, SizeT capacity = default) : base(Math.Max(capacity, BaseStructSize))
+		public SafeBITMAPINFO(in BITMAPINFOHEADER hdr, SizeT capacity = default) : base(hdrSize + capacity) => bmiHeader = hdr;
-		{
-			handle.Write(hdr, 0, Size);
-		}
 
 		/// <summary>Initializes a new instance of the <see cref="SafeBITMAPINFO"/> class.</summary>
 		/// <param name="ptr">Existing handle.</param>
@@ -1259,7 +1252,6 @@ public static partial class Gdi32
 		{
 		}
 
-#pragma warning disable IDE1006 // Naming Styles
 		/// <summary>
 		/// The bmiColors member contains one of the following:
 		/// <list type="bullet">
@@ -1280,17 +1272,15 @@ public static partial class Gdi32
 		/// </para>
 		/// <para>The colors in the bmiColors table appear in order of importance. For more information, see the Remarks section.</para>
 		/// </summary>
-		public byte[] bmiColorBytes
+		public ushort[] bmiColorBytes
 		{
-			get => handle.ToByteArray((Size - BaseStructSize), BaseStructSize, Size);
+			get => handle.ToArray<ushort>((Size - hdrSize) / 2, hdrSize, Size) ?? new ushort[0];
 			set
 			{
-				var reqSize = BaseStructSize + (value?.Length ?? 0);
+				var reqSize = hdrSize + value.Length;
 				if (Size < reqSize)
 					Size = reqSize;
-				else
+				handle.Write(value, hdrSize, Size);
-					handle.Offset(BaseStructSize).FillMemory(0, Size - BaseStructSize);
-				handle.Write(value, BaseStructSize, Size);
 			}
 		}
 
@@ -1316,15 +1306,13 @@ public static partial class Gdi32
 		/// </summary>
 		public RGBQUAD[] bmiColors
 		{
-			get => handle.ToArray<RGBQUAD>((Size - BaseStructSize) / RGBQUADSZ, BaseStructSize, Size);
+			get => handle.ToArray<RGBQUAD>((Size - hdrSize) / RGBQUADSZ, hdrSize, Size) ?? new RGBQUAD[0];
 			set
 			{
-				var reqSize = BaseStructSize + (value?.Length ?? 0) * RGBQUADSZ;
+				var reqSize = hdrSize + value.Length * RGBQUADSZ;
 				if (Size < reqSize)
 					Size = reqSize;
-				else
+				handle.Write(value, hdrSize, Size);
-					handle.Offset(BaseStructSize).FillMemory(0, Size - BaseStructSize);
-				handle.Write(value, BaseStructSize, Size);
 			}
 		}
 
@@ -1335,7 +1323,6 @@ public static partial class Gdi32
 		/// <summary>A reference to the BITMAPINFOHEADER structure.</summary>
 		public ref BITMAPINFOHEADER bmiHeaderAsRef => ref AsRef().bmiHeader;
 #endif
-#pragma warning restore IDE1006 // Naming Styles
 
 		/// <summary>
 		/// Specifies the number of bytes required by the structure. This value does not include the size of the color table or the size
@@ -1357,6 +1344,6 @@ public static partial class Gdi32
 		public T GetHeader<T>() where T : struct => handle.ToStructure<T>(Size);
 
 		/// <summary>Zero out all allocated memory.</summary>
-		public override void Zero() { base.Zero(); HeaderSize = BaseStructSize; }
+		public override void Zero() { base.Zero(); HeaderSize = hdrSize; }
 	}
 }

PInvoke/Gdi32/WinGdi.Bitmap.cs

@@ -2609,16 +2609,16 @@ public static partial class Gdi32
 
 	/// <summary>Provides a handle to a DIB section.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HSECTION : IHandle
+	public readonly struct HSECTION : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HSECTION"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HSECTION(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HSECTION"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HSECTION NULL => new HSECTION(IntPtr.Zero);
+		public static HSECTION NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -2631,7 +2631,7 @@ public static partial class Gdi32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HSECTION"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HSECTION(IntPtr h) => new HSECTION(h);
+		public static implicit operator HSECTION(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -2646,7 +2646,7 @@ public static partial class Gdi32
 		public static bool operator ==(HSECTION h1, HSECTION h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HSECTION h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HSECTION h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/Gdi32/WinGdi.Brush.cs

@@ -482,6 +482,64 @@ public static partial class Gdi32
 	[return: MarshalAs(UnmanagedType.Bool)]
 	public static extern bool SetBrushOrgEx(HDC hdc, int x, int y, in POINT lppt);
 
+	/// <summary>
+	/// <para>
+	/// The <c>SetBrushOrgEx</c> function sets the brush origin that GDI assigns to the next brush an application selects into the
+	/// specified device context.
+	/// </para>
+	/// </summary>
+	/// <param name="hdc">
+	/// <para>A handle to the device context.</para>
+	/// </param>
+	/// <param name="x">
+	/// <para>
+	/// The x-coordinate, in device units, of the new brush origin. If this value is greater than the brush width, its value is reduced
+	/// using the modulus operator (nXOrg <c>mod</c> brush width).
+	/// </para>
+	/// </param>
+	/// <param name="y">
+	/// <para>
+	/// The y-coordinate, in device units, of the new brush origin. If this value is greater than the brush height, its value is reduced
+	/// using the modulus operator (nYOrg <c>mod</c> brush height).
+	/// </para>
+	/// </param>
+	/// <param name="lppt">
+	/// <para>A pointer to a POINT structure that receives the previous brush origin.</para>
+	/// <para>This parameter can be <c>NULL</c> if the previous brush origin is not required.</para>
+	/// </param>
+	/// <returns>
+	/// <para>If the function succeeds, the return value is nonzero.</para>
+	/// <para>If the function fails, the return value is zero.</para>
+	/// </returns>
+	/// <remarks>
+	/// <para>A brush is a bitmap that the system uses to paint the interiors of filled shapes.</para>
+	/// <para>
+	/// The brush origin is a pair of coordinates specifying the location of one pixel in the bitmap. The default brush origin
+	/// coordinates are (0,0). For horizontal coordinates, the value 0 corresponds to the leftmost column of pixels; the width
+	/// corresponds to the rightmost column. For vertical coordinates, the value 0 corresponds to the uppermost row of pixels; the height
+	/// corresponds to the lowermost row.
+	/// </para>
+	/// <para>
+	/// The system automatically tracks the origin of all window-managed device contexts and adjusts their brushes as necessary to
+	/// maintain an alignment of patterns on the surface. The brush origin that is set with this call is relative to the upper-left
+	/// corner of the client area.
+	/// </para>
+	/// <para>
+	/// An application should call <c>SetBrushOrgEx</c> after setting the bitmap stretching mode to HALFTONE by using SetStretchBltMode.
+	/// This must be done to avoid brush misalignment.
+	/// </para>
+	/// <para>
+	/// The system automatically tracks the origin of all window-managed device contexts and adjusts their brushes as necessary to
+	/// maintain an alignment of patterns on the surface.
+	/// </para>
+	/// </remarks>
+	// https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/nf-wingdi-setbrushorgex BOOL SetBrushOrgEx( HDC hdc, int x, int y,
+	// LPPOINT lppt );
+	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
+	[PInvokeData("wingdi.h", MSDNShortId = "dcc7575a-49fd-4306-8baa-57e9e0d5ed1f")]
+	[return: MarshalAs(UnmanagedType.Bool)]
+	public static extern bool SetBrushOrgEx(HDC hdc, int x, int y, [In, Optional] IntPtr lppt);
+
 	/// <summary>
 	/// <c>SetDCBrushColor</c> function sets the current device context (DC) brush color to the specified color value. If the device
 	/// cannot represent the specified color value, the color is set to the nearest physical color.

PInvoke/Gdi32/WinGdi.Clipping.cs

@@ -171,7 +171,7 @@ public static partial class Gdi32
 	// mode );
 	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "d222defe-2ef9-4622-b2e1-462a91cb1b0a")]
-	public static extern RegionFlags ExtSelectClipRgn(HDC hdc, HRGN hrgn, RegionOp mode);
+	public static extern RegionFlags ExtSelectClipRgn(HDC hdc, [In, Optional] HRGN hrgn, RegionOp mode);
 
 	/// <summary>
 	/// The <c>GetClipBox</c> function retrieves the dimensions of the tightest bounding rectangle that can be drawn around the current
@@ -286,7 +286,7 @@ public static partial class Gdi32
 	// https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getrandomrgn int GetRandomRgn( HDC hdc, HRGN hrgn, INT i );
 	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "a7527d7a-7b5e-4dd5-9270-94bc92b5a4a0")]
-	public static extern int GetRandomRgn(HDC hdc, [In, Out] HRGN hrgn, int i = 4 /* SYSRGN */);
+	public static extern int GetRandomRgn(HDC hdc, [In, Out, Optional] HRGN hrgn, int i = 4 /* SYSRGN */);
 
 	/// <summary>
 	/// The <c>IntersectClipRect</c> function creates a new clipping region from the intersection of the current clipping region and the
@@ -503,7 +503,7 @@ public static partial class Gdi32
 	// https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-selectcliprgn int SelectClipRgn( HDC hdc, HRGN hrgn );
 	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "7a4f0b9c-8588-4da8-a030-ed9d8b4ee08d")]
-	public static extern RegionFlags SelectClipRgn(HDC hdc, HRGN hrgn);
+	public static extern RegionFlags SelectClipRgn(HDC hdc, [In, Optional] HRGN hrgn);
 
 	/// <summary>
 	/// The <c>SetMetaRgn</c> function intersects the current clipping region for the specified device context with the current

PInvoke/Gdi32/WinGdi.Color.cs

@@ -513,7 +513,7 @@ public static partial class Gdi32
 	[DllImport(Lib.Gdi32, SetLastError = true, CharSet = CharSet.Auto)]
 	[PInvokeData("wingdi.h", MSDNShortId = "1e16771a-80c5-47bb-9c98-14169d4dd773")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool GetICMProfile(HDC hdc, ref uint pBufSize, StringBuilder pszFilename);
+	public static extern bool GetICMProfile(HDC hdc, ref uint pBufSize, StringBuilder? pszFilename);
 
 	/// <summary>The <c>GetLogColorSpace</c> function retrieves the color space definition identified by a specified handle.</summary>
 	/// <param name="hColorSpace">Specifies the handle to a color space.</param>
@@ -603,7 +603,7 @@ public static partial class Gdi32
 	// UINT iStart, UINT cEntries, LPPALETTEENTRY pPalEntries );
 	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "5e72e881-32e1-458e-a09e-91fa13abe178")]
-	public static extern uint GetPaletteEntries(HPALETTE hpal, uint iStart, uint cEntries, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] PALETTEENTRY[] pPalEntries);
+	public static extern uint GetPaletteEntries([Optional] HPALETTE hpal, uint iStart, uint cEntries, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] PALETTEENTRY[] pPalEntries);
 
 	/// <summary>
 	/// The <c>GetSystemPaletteEntries</c> function retrieves a range of palette entries from the system palette that is associated with
@@ -629,7 +629,7 @@ public static partial class Gdi32
 	// hdc, UINT iStart, UINT cEntries, LPPALETTEENTRY pPalEntries );
 	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "67bb0adf-ae7f-48d5-bc62-82ece45aeee6")]
-	public static extern uint GetSystemPaletteEntries(HDC hdc, uint iStart, uint cEntries, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] PALETTEENTRY[] pPalEntries);
+	public static extern uint GetSystemPaletteEntries(HDC hdc, uint iStart, uint cEntries, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] PALETTEENTRY[]? pPalEntries);
 
 	/// <summary>
 	/// The <c>GetSystemPaletteUse</c> function retrieves the current state of the system (physical) palette for the specified device
@@ -1447,7 +1447,7 @@ public static partial class Gdi32
 		public string lcsFilename;
 
 		/// <summary>The default structure with size and default fields preset.</summary>
-		public static readonly LOGCOLORSPACE Default = new LOGCOLORSPACE { lcsSignature = LCS_SIGNATURE, lcsVersion = 0x400, lcsSize = (uint)Marshal.SizeOf(typeof(LOGCOLORSPACE)) };
+		public static readonly LOGCOLORSPACE Default = new() { lcsSignature = LCS_SIGNATURE, lcsVersion = 0x400, lcsSize = (uint)Marshal.SizeOf(typeof(LOGCOLORSPACE)) };
 	}
 
 	/// <summary>

PInvoke/Gdi32/WinGdi.CoordSpaceTxfm.cs

@@ -386,6 +386,46 @@ public static partial class Gdi32
 	[return: MarshalAs(UnmanagedType.Bool)]
 	public static extern bool LPtoDP(HDC hdc, [In, Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] POINT[] lppt, int c);
 
+	/// <summary>
+	/// <para>
+	/// The <c>LPtoDP</c> function converts logical coordinates into device coordinates. The conversion depends on the mapping mode of
+	/// the device context, the settings of the origins and extents for the window and viewport, and the world transformation.
+	/// </para>
+	/// </summary>
+	/// <param name="hdc">
+	/// <para>A handle to the device context.</para>
+	/// </param>
+	/// <param name="lppt">
+	/// <para>
+	/// A pointer to an array of POINT structures. The x-coordinates and y-coordinates contained in each of the <c>POINT</c> structures
+	/// will be transformed.
+	/// </para>
+	/// </param>
+	/// <param name="c">
+	/// <para>The number of points in the array.</para>
+	/// </param>
+	/// <returns>
+	/// <para>If the function succeeds, the return value is nonzero.</para>
+	/// <para>If the function fails, the return value is zero.</para>
+	/// </returns>
+	/// <remarks>
+	/// <para>
+	/// The <c>LPtoDP</c> function fails if the logical coordinates exceed 32 bits, or if the converted device coordinates exceed 27
+	/// bits. In the case of such an overflow, the results for all the points are undefined.
+	/// </para>
+	/// <para>
+	/// <c>LPtoDP</c> calculates complex floating-point arithmetic, and it has a caching system for efficiency. Therefore, the conversion
+	/// result of an initial call to <c>LPtoDP</c> might not exactly match the conversion result of a later call to <c>LPtoDP</c>. We
+	/// recommend not to write code that relies on the exact match of the conversion results from multiple calls to <c>LPtoDP</c> even if
+	/// the parameters that are passed to each call are identical.
+	/// </para>
+	/// </remarks>
+	// https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/nf-wingdi-lptodp BOOL LPtoDP( HDC hdc, LPPOINT lppt, int c );
+	[DllImport(Lib.Gdi32, SetLastError = false, ExactSpelling = true)]
+	[PInvokeData("wingdi.h", MSDNShortId = "670a16fb-842e-4250-9ad7-dc08e849c2ba")]
+	[return: MarshalAs(UnmanagedType.Bool)]
+	public static extern bool LPtoDP(HDC hdc, ref POINT lppt, int c = 1);
+
 	/// <summary>
 	/// The <c>ModifyWorldTransform</c> function changes the world transformation for a device context using the specified mode.
 	/// </summary>

PInvoke/Gdi32/WinGdi.FontText.cs

@@ -2007,7 +2007,7 @@ public static partial class Gdi32
 		[Optional] int cWeight, [Optional, MarshalAs(UnmanagedType.Bool)] bool bItalic, [Optional, MarshalAs(UnmanagedType.Bool)] bool bUnderline,
 		[Optional, MarshalAs(UnmanagedType.Bool)] bool bStrikeOut, CharacterSet iCharSet = CharacterSet.DEFAULT_CHARSET,
 		OutputPrecision iOutPrecision = OutputPrecision.OUT_DEFAULT_PRECIS, ClippingPrecision iClipPrecision = ClippingPrecision.CLIP_DEFAULT_PRECIS,
-		OutputQuality iQuality = OutputQuality.DEFAULT_QUALITY, PitchAndFamily iPitchAndFamily = PitchAndFamily.FF_DONTCARE, string pszFaceName = null);
+		OutputQuality iQuality = OutputQuality.DEFAULT_QUALITY, PitchAndFamily iPitchAndFamily = PitchAndFamily.FF_DONTCARE, string? pszFaceName = null);
 
 	/// <summary>
 	/// The <c>CreateFontIndirect</c> function creates a logical font that has the specified characteristics. The font can subsequently
@@ -4569,7 +4569,7 @@ public static partial class Gdi32
 		/// <summary>Performs an implicit conversion from <see cref="System.Decimal"/> to <see cref="Vanara.PInvoke.Gdi32.FIXED"/>.</summary>
 		/// <param name="d">The decimal value.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator FIXED(decimal d) => new FIXED { value = (short)Math.Truncate(d), fract = ushort.Parse(d.ToString(NumberFormatInfo.InvariantInfo).Split(new[] { NumberFormatInfo.InvariantInfo.NumberDecimalSeparator }, StringSplitOptions.None)[1], NumberFormatInfo.InvariantInfo) };
+		public static implicit operator FIXED(decimal d) => new() { value = (short)Math.Truncate(d), fract = ushort.Parse(d.ToString(NumberFormatInfo.InvariantInfo).Split(new[] { NumberFormatInfo.InvariantInfo.NumberDecimalSeparator }, StringSplitOptions.None)[1], NumberFormatInfo.InvariantInfo) };
 
 		/// <summary>Converts to string.</summary>
 		/// <returns>A <see cref="string"/> that represents this instance.</returns>
@@ -4838,7 +4838,7 @@ public static partial class Gdi32
 		public int nMaxFit;
 
 		/// <summary>The default instance of this structure with the structure size value set.</summary>
-		public static GCP_RESULTS Default = new GCP_RESULTS { lStructSize = (uint)Marshal.SizeOf(typeof(GCP_RESULTS)) };
+		public static GCP_RESULTS Default = new() { lStructSize = (uint)Marshal.SizeOf(typeof(GCP_RESULTS)) };
 	}
 
 	/// <summary>
@@ -4950,7 +4950,7 @@ public static partial class Gdi32
 		public FIXED eM22;
 
 		/// <summary>The identity matrix value.</summary>
-		public static readonly MAT2 IdentityMatrix = new MAT2 { eM11 = new FIXED { fract = 1 }, eM22 = new FIXED { fract = 1 } };
+		public static readonly MAT2 IdentityMatrix = new() { eM11 = new FIXED { fract = 1 }, eM22 = new FIXED { fract = 1 } };
 	}
 
 	/// <summary>The <c>NEWTEXTMETRIC</c> structure contains data that describes a physical font.</summary>

PInvoke/Gdi32/WinGdi.Metafile.cs

@@ -1654,7 +1654,7 @@ public static partial class Gdi32
 		public SIZE szlMicrometers;
 
 		/// <summary>A default instance of the structure with the size field preset.</summary>
-		public static readonly ENHMETAHEADER Default = new ENHMETAHEADER { nSize = (uint)Marshal.SizeOf(typeof(ENHMETAHEADER)) };
+		public static readonly ENHMETAHEADER Default = new() { nSize = (uint)Marshal.SizeOf(typeof(ENHMETAHEADER)) };
 	}
 
 	/// <summary>
@@ -1742,7 +1742,7 @@ public static partial class Gdi32
 		}
 
 		/// <summary>An array of parameters passed to the GDI function identified by the record.</summary>
-		public uint[] dParm => base.Elements;
+		public uint[] dParm => base.Elements ?? new uint[0];
 
 		/// <summary>The record type.</summary>
 		public RecordType iType => handle.ToStructure<RecordType>();
@@ -1753,7 +1753,7 @@ public static partial class Gdi32
 		/// <summary>Performs an explicit conversion from <see cref="IntPtr"/> to <see cref="ENHMETARECORD"/>.</summary>
 		/// <param name="ptr">The pointer to an instance.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static explicit operator ENHMETARECORD(IntPtr ptr) => new ENHMETARECORD(ptr);
+		public static explicit operator ENHMETARECORD(IntPtr ptr) => new(ptr);
 	}
 
 	/// <summary>The <c>METARECORD</c> structure contains a Windows-format metafile record.</summary>
@@ -1782,7 +1782,7 @@ public static partial class Gdi32
 		public ushort rdFunction => handle.ToStructure<ushort>(Size, 4);
 
 		/// <summary>An array of words containing the function parameters, in reverse of the order they are passed to the function.</summary>
-		public ushort[] rdParm => base.Elements;
+		public ushort[] rdParm => base.Elements ?? new ushort[0];
 
 		/// <summary>The size, in words, of the record.</summary>
 		public uint rdSize => Size / 2U;
@@ -1790,7 +1790,7 @@ public static partial class Gdi32
 		/// <summary>Performs an explicit conversion from <see cref="IntPtr"/> to <see cref="METARECORD"/>.</summary>
 		/// <param name="ptr">The pointer to an instance.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static explicit operator METARECORD(IntPtr ptr) => new METARECORD(ptr);
+		public static explicit operator METARECORD(IntPtr ptr) => new(ptr);
 	}
 
 	/// <summary>Provides a <see cref="SafeHandle"/> for <see cref="HENHMETAFILE"/> that is disposed using <see cref="DeleteEnhMetaFile"/>.</summary>

PInvoke/Gdi32/WinGdi.Region.cs

@@ -690,7 +690,7 @@ public static partial class Gdi32
 		/// <summary>Specifies an arbitrary-size buffer that contains the RECT structures that make up the region.</summary>
 		public RECT[] Buffer
 		{
-			get => _Buffer.ToArray<RECT>((int)rdh.nCount);
+			get => _Buffer.ToArray<RECT>((int)rdh.nCount) ?? new RECT[0];
 			set
 			{
 				((IDisposable)this).Dispose();

PInvoke/Gdi32/WinGdi.SafeDCHandles.cs

@@ -139,7 +139,7 @@ public static partial class Gdi32
 		/// <summary>Creates a context into which a graphics object is selected.</summary>
 		/// <param name="hObject">The graphics object to select.</param>
 		/// <returns>A selection context for the graphics object.</returns>
-		public GdiObjectContext SelectObject(HGDIOBJ hObject) => new GdiObjectContext(handle, hObject);
+		public GdiObjectContext SelectObject(HGDIOBJ hObject) => new(handle, hObject);
 
 		/// <inheritdoc/>
 		protected override bool InternalReleaseHandle()

PInvoke/Gdi32/WinGdi.cs

@@ -318,7 +318,7 @@ public static partial class Gdi32
 	[DllImport(Lib.Gdi32, SetLastError = true, ExactSpelling = true)]
 	[PInvokeData("wingdi.h", MSDNShortId = "0e6e81f1-ec7b-42ba-8706-a352349fa6ab")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool TranslateCharsetInfo(ref uint lpSrc, out CHARSETINFO lpCs, TCI dwFlags);
+	public static extern bool TranslateCharsetInfo([In, MarshalAs(UnmanagedType.LPArray, SizeConst = 2)] uint[] lpSrc, out CHARSETINFO lpCs, TCI dwFlags);
 
 	/// <summary>Translates character set information and sets all members of a destination structure to appropriate values.</summary>
 	/// <param name="lpSrc">
@@ -377,9 +377,9 @@ public static partial class Gdi32
 	public struct CHARSETINFO
 	{
 		/// <summary>Character set value.</summary>
-		public uint ciCharset;
+		public CharacterSetUint ciCharset;
 
-		/// <summary>Windows ANSI code page identifier. For a list of identifiers, see Code Page Identifiers.</summary>
+		/// <summary>Windows ANSI code page identifier. For a list of identifiers, see Code Page Identifiers constants in <c>Vanara.PInvoke.Kernel32</c>.</summary>
 		public uint ciACP;
 
 		/// <summary>
@@ -473,6 +473,6 @@ public static partial class Gdi32
 		public string DeviceKey;
 
 		/// <summary>Gets an empty structure with the <see cref="cb"/> set to the size of the structure.</summary>
-		public static readonly DISPLAY_DEVICE Default = new DISPLAY_DEVICE { cb = (uint)Marshal.SizeOf(typeof(DISPLAY_DEVICE)) };
+		public static readonly DISPLAY_DEVICE Default = new() { cb = (uint)Marshal.SizeOf(typeof(DISPLAY_DEVICE)) };
 	}
 }

PInvoke/Gdi32/Winppi.cs

@@ -419,16 +419,16 @@ public static partial class Gdi32
 
 	/// <summary>Provides a handle to a spool file.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HSPOOLFILE : IHandle
+	public readonly struct HSPOOLFILE : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HSPOOLFILE"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HSPOOLFILE(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HSPOOLFILE"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HSPOOLFILE NULL => new HSPOOLFILE(IntPtr.Zero);
+		public static HSPOOLFILE NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -441,7 +441,7 @@ public static partial class Gdi32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HSPOOLFILE"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HSPOOLFILE(IntPtr h) => new HSPOOLFILE(h);
+		public static implicit operator HSPOOLFILE(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -456,7 +456,7 @@ public static partial class Gdi32
 		public static bool operator ==(HSPOOLFILE h1, HSPOOLFILE h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HSPOOLFILE h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HSPOOLFILE h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/Imm32/Imm.cs

@@ -2522,7 +2522,7 @@ lpImeMenu is null ? 0 : Marshal.SizeOf(typeof(IMEMENUITEMINFO)) * lpImeMenu.Leng
 
 	/// <summary>Provides a handle to an input context.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HIMC : IHandle
+	public readonly struct HIMC : IHandle
 	{
 		private readonly IntPtr handle;
 
@@ -2574,7 +2574,7 @@ lpImeMenu is null ? 0 : Marshal.SizeOf(typeof(IMEMENUITEMINFO)) * lpImeMenu.Leng
 		}
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj)
+		public override bool Equals(object? obj)
 		{
 			return (obj is IHandle h && handle == h.DangerousGetHandle()) || (obj is IntPtr p && handle == p);
 		}

PInvoke/Security/AdvApi32/Evntrace.cs

@@ -5985,7 +5985,7 @@ public static partial class AdvApi32
 		/// <param name="providerName">Name of the provider.</param>
 		/// <returns>An initialized instance of <see cref="EVENT_TRACE_PROPERTIES"/>.</returns>
 		public static EVENT_TRACE_PROPERTIES Create(string? logFileName = null, string? providerName = null) =>
-			new EVENT_TRACE_PROPERTIES
+			new()
 			{
 				Wnode = new WNODE_HEADER
 				{

PInvoke/Shared/Handles/HANDLE.cs

@@ -7,7 +7,7 @@ namespace Vanara.PInvoke;
 
 /// <summary>Provides a handle to an accelerator table.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HACCEL : IUserHandle
+public readonly struct HACCEL : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -60,7 +60,7 @@ public struct HACCEL : IUserHandle
 
 /// <summary>Provides a generic handle.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HANDLE : IHandle
+public readonly struct HANDLE : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -118,7 +118,7 @@ public struct HANDLE : IHandle
 
 /// <summary>Provides a handle to a bitmap.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HBITMAP : IGraphicsObjectHandle
+public readonly struct HBITMAP : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -176,7 +176,7 @@ public struct HBITMAP : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to drawing brush.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HBRUSH : IGraphicsObjectHandle
+public readonly struct HBRUSH : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -239,7 +239,7 @@ public struct HBRUSH : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a color space.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HCOLORSPACE : IGraphicsObjectHandle
+public readonly struct HCOLORSPACE : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -297,7 +297,7 @@ public struct HCOLORSPACE : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to cursor.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HCURSOR : IGraphicsObjectHandle
+public readonly struct HCURSOR : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -355,7 +355,7 @@ public struct HCURSOR : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a graphic device context.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDC : IHandle
+public readonly struct HDC : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -408,7 +408,7 @@ public struct HDC : IHandle
 
 /// <summary>Provides a handle to a desktop.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDESK : IKernelHandle
+public readonly struct HDESK : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -461,7 +461,7 @@ public struct HDESK : IKernelHandle
 
 /// <summary>Provides a handle to a DPA.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDPA : IKernelHandle
+public readonly struct HDPA : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -514,7 +514,7 @@ public struct HDPA : IKernelHandle
 
 /// <summary>Provides a handle to a Windows drop operation.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDROP : IShellHandle
+public readonly struct HDROP : IShellHandle
 {
 	private readonly IntPtr handle;
 
@@ -567,7 +567,7 @@ public struct HDROP : IShellHandle
 
 /// <summary>Provides a handle to a DSA.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDSA : IKernelHandle
+public readonly struct HDSA : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -620,7 +620,7 @@ public struct HDSA : IKernelHandle
 
 /// <summary>Provides a handle to a deferred windows position.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HDWP : IUserHandle
+public readonly struct HDWP : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -673,7 +673,7 @@ public struct HDWP : IUserHandle
 
 /// <summary>Provides a handle to an enhanced metafile.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HENHMETAFILE : IHandle
+public readonly struct HENHMETAFILE : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -726,7 +726,7 @@ public struct HENHMETAFILE : IHandle
 
 /// <summary>Provides a handle to a sync event.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HEVENT : ISyncHandle
+public readonly struct HEVENT : ISyncHandle
 {
 	private readonly IntPtr handle;
 
@@ -779,7 +779,7 @@ public struct HEVENT : ISyncHandle
 
 /// <summary>Provides a handle to a file.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HFILE : ISyncHandle
+public readonly struct HFILE : ISyncHandle
 {
 	private readonly IntPtr handle;
 
@@ -843,7 +843,7 @@ public struct HFILE : ISyncHandle
 
 /// <summary>Provides a handle to a font.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HFONT : IGraphicsObjectHandle
+public readonly struct HFONT : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -901,7 +901,7 @@ public struct HFONT : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a graphic device object.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HGDIOBJ : IGraphicsObjectHandle
+public readonly struct HGDIOBJ : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -994,7 +994,7 @@ public struct HGDIOBJ : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to an icon.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HICON : IUserHandle
+public readonly struct HICON : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -1047,7 +1047,7 @@ public struct HICON : IUserHandle
 
 /// <summary>Provides a handle to a Windows image list.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HIMAGELIST : IShellHandle
+public readonly struct HIMAGELIST : IShellHandle
 {
 	private readonly IntPtr handle;
 
@@ -1100,7 +1100,7 @@ public struct HIMAGELIST : IShellHandle
 
 /// <summary>Provides a handle to a module or library instance.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HINSTANCE : IKernelHandle
+public readonly struct HINSTANCE : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -1153,7 +1153,7 @@ public struct HINSTANCE : IKernelHandle
 
 /// <summary>Provides a handle to a Windows registry key.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HKEY : IKernelHandle
+public readonly struct HKEY : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -1258,7 +1258,7 @@ public struct HKEY : IKernelHandle
 
 /// <summary>Provides a handle to a menu.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HMENU : IUserHandle
+public readonly struct HMENU : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -1311,7 +1311,7 @@ public struct HMENU : IUserHandle
 
 /// <summary>Provides a handle to a metafile.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HMETAFILE : IHandle
+public readonly struct HMETAFILE : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -1364,7 +1364,7 @@ public struct HMETAFILE : IHandle
 
 /// <summary>Provides a handle to a monitor.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HMONITOR : IKernelHandle
+public readonly struct HMONITOR : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -1417,7 +1417,7 @@ public struct HMONITOR : IKernelHandle
 
 /// <summary>Provides a handle to a palette.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HPALETTE : IGraphicsObjectHandle
+public readonly struct HPALETTE : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -1475,7 +1475,7 @@ public struct HPALETTE : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a drawing pen.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HPEN : IGraphicsObjectHandle
+public readonly struct HPEN : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -1533,7 +1533,7 @@ public struct HPEN : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a process.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HPROCESS : ISyncHandle
+public readonly struct HPROCESS : ISyncHandle
 {
 	private readonly IntPtr handle;
 
@@ -1591,7 +1591,7 @@ public struct HPROCESS : ISyncHandle
 
 /// <summary>Provides a handle to a Windows property sheet.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HPROPSHEET : IUserHandle
+public readonly struct HPROPSHEET : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -1644,7 +1644,7 @@ public struct HPROPSHEET : IUserHandle
 
 /// <summary>Provides a handle to a property sheet page.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HPROPSHEETPAGE : IUserHandle
+public readonly struct HPROPSHEETPAGE : IUserHandle
 {
 	private readonly IntPtr handle;
 
@@ -1697,7 +1697,7 @@ public struct HPROPSHEETPAGE : IUserHandle
 
 /// <summary>Provides a handle to a drawing region.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HRGN : IGraphicsObjectHandle
+public readonly struct HRGN : IGraphicsObjectHandle
 {
 	private readonly IntPtr handle;
 
@@ -1755,7 +1755,7 @@ public struct HRGN : IGraphicsObjectHandle
 
 /// <summary>Provides a handle to a file mapping object.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HSECTION : IHandle
+public readonly struct HSECTION : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -1808,7 +1808,7 @@ public struct HSECTION : IHandle
 
 /// <summary>Provides a handle to a blocking task.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HTASK : IHandle
+public readonly struct HTASK : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -1861,7 +1861,7 @@ public struct HTASK : IHandle
 
 /// <summary>Provides a handle to a Windows theme.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HTHEME : IHandle
+public readonly struct HTHEME : IHandle
 {
 	private readonly IntPtr handle;
 
@@ -1914,7 +1914,7 @@ public struct HTHEME : IHandle
 
 /// <summary>Provides a handle to a thread.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HTHREAD : ISyncHandle
+public readonly struct HTHREAD : ISyncHandle
 {
 	private readonly IntPtr handle;
 
@@ -1967,7 +1967,7 @@ public struct HTHREAD : ISyncHandle
 
 /// <summary>Provides a handle to a Windows thumbnail.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HTHUMBNAIL : IShellHandle
+public readonly struct HTHUMBNAIL : IShellHandle
 {
 	private readonly IntPtr handle;
 
@@ -2020,7 +2020,7 @@ public struct HTHUMBNAIL : IShellHandle
 
 /// <summary>Provides a handle to an access token.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HTOKEN : IKernelHandle
+public readonly struct HTOKEN : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -2073,7 +2073,7 @@ public struct HTOKEN : IKernelHandle
 
 /// <summary>Provides a handle to a windows station.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct HWINSTA : IKernelHandle
+public readonly struct HWINSTA : IKernelHandle
 {
 	private readonly IntPtr handle;
 
@@ -2206,7 +2206,7 @@ public struct HWND : IUserHandle
 
 /// <summary>Provides a pointer to an access control entry.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct PACE : ISecurityObject
+public readonly struct PACE : ISecurityObject
 {
 	private readonly IntPtr handle;
 
@@ -2259,7 +2259,7 @@ public struct PACE : ISecurityObject
 
 /// <summary>Provides a handle to an access control list.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct PACL : ISecurityObject
+public readonly struct PACL : ISecurityObject
 {
 	private readonly IntPtr handle;
 
@@ -2312,7 +2312,7 @@ public struct PACL : ISecurityObject
 
 /// <summary>Provides a handle to a security descriptor.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct PSECURITY_DESCRIPTOR : ISecurityObject
+public readonly struct PSECURITY_DESCRIPTOR : ISecurityObject
 {
 	private readonly IntPtr handle;
 
@@ -2365,7 +2365,7 @@ public struct PSECURITY_DESCRIPTOR : ISecurityObject
 
 /// <summary>Provides a handle to a security identifier.</summary>
 [StructLayout(LayoutKind.Sequential), DebuggerDisplay("{handle}")]
-public struct PSID : ISecurityObject
+public readonly struct PSID : ISecurityObject
 {
 	private readonly IntPtr handle;
 

PInvoke/Shared/WinGdi/WinGdi.RGBQUAD.cs

@@ -32,6 +32,13 @@ public struct RGBQUAD : IEquatable<RGBQUAD>
 		rgbReserved = 0;
 	}
 
+	/// <summary>Initializes a new instance of the <see cref="RGBQUAD"/> struct from a DWORD (<see cref="uint"/>) value.</summary>
+	/// <param name="dword">The 32-bit value with R, G and B values packed in the first 3 bytes.</param>
+	public RGBQUAD(uint dword)
+	{
+		unsafe { this = *(RGBQUAD*)&dword; }
+	}
+
 	/// <summary>Gets a value indicating whether any transparency is defined.</summary>
 	/// <value><see langword="true"/> if this value is transparent; otherwise, <see langword="false"/>.</value>
 	public bool IsTransparent => rgbReserved == 0;

PInvoke/Shared/WinUser/CLIPFORMAT.cs

@@ -19,7 +19,7 @@ namespace Vanara.PInvoke;
 /// <seealso cref="System.IEquatable{CLIPFORMAT}"/>
 [StructLayout(LayoutKind.Sequential)]
 [PInvokeData("wtypes.h", MSDNShortId = "fe42baec-6b00-4816-b379-7f335da8a197")]
-public partial struct CLIPFORMAT : IComparable, IComparable<CLIPFORMAT>, IEquatable<CLIPFORMAT>
+public readonly partial struct CLIPFORMAT : IComparable, IComparable<CLIPFORMAT>, IEquatable<CLIPFORMAT>
 {
 	internal readonly ushort _value;
 

PInvoke/User32/BasicMessageWindow.cs

@@ -26,13 +26,13 @@ public delegate bool BasicMessageWindowFilter(HWND hwnd, uint msg, IntPtr wParam
 public class BasicMessageWindow : MarshalByRefObject, IDisposable, IHandle
 {
 	private readonly WeakReference weakSelfRef;
-	private SafeHWND hwnd;
+	private SafeHWND? hwnd;
 	private bool isDisposed;
-	private WindowClass wCls;
+	private WindowClass? wCls;
 
 	/// <summary>Initializes a new instance of the <see cref="BasicMessageWindow"/> class.</summary>
 	/// <param name="callback">Specifies the callback method to use to process messages.</param>
-	public BasicMessageWindow(BasicMessageWindowFilter callback = null)
+	public BasicMessageWindow(BasicMessageWindowFilter? callback = null)
 	{
 		MessageFilter = callback;
 		weakSelfRef = new WeakReference(this);
@@ -48,11 +48,11 @@ public class BasicMessageWindow : MarshalByRefObject, IDisposable, IHandle
 
 	/// <summary>Gets or sets the callback method used to filter window messages.</summary>
 	/// <value>The callback method.</value>
-	public BasicMessageWindowFilter MessageFilter { get; set; }
+	public BasicMessageWindowFilter? MessageFilter { get; set; }
 
 	/// <summary>Gets the name of the class.</summary>
 	/// <value>The name of the class.</value>
-	public string ClassName => wCls?.ClassName;
+	public string? ClassName => wCls?.ClassName;
 
 	/// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
 	public void Dispose()

PInvoke/User32/MessagePump.cs

@@ -22,7 +22,7 @@ public interface IMessagePump
 	/// <returns>
 	/// The result of <see cref="PeekMessage(out MSG, HWND, uint, uint, PM)"/> or <see cref="GetMessage(out MSG, HWND, uint, uint)"/>.
 	/// </returns>
-	int Run(IWindowInstance mainWindow = null);
+	int Run(IWindowInstance? mainWindow = null);
 }
 
 /// <summary>An interface that represents a Win32 window with created and destroyed events.</summary>
@@ -48,7 +48,7 @@ public class MessagePump : IMessagePump
 	protected const ushort quitMsg = (ushort)WindowMessage.WM_QUIT;
 
 	/// <inhertdoc/>
-	public int Run(IWindowInstance mainWindow = null)
+	public int Run(IWindowInstance? mainWindow = null)
 	{
 		if (mainWindow is not null and not WindowBase)
 			mainWindow.Destroyed += onDestroy;
@@ -88,15 +88,15 @@ public class MessagePump : IMessagePump
 public class ExaminedMessagePump : MessagePump
 {
 	/// <summary>Occurs after <see cref="DispatchMessage(in MSG)"/>.</summary>
-	public event MsgPumpDelegate PostProcess;
+	public event MsgPumpDelegate? PostProcess;
 
 	/// <summary>Occurs after <see cref="TranslateMessage(in MSG)"/> and determines if message should be dispatched.</summary>
-	public event MsgPumpPredicateDelegate PostTranslate;
+	public event MsgPumpPredicateDelegate? PostTranslate;
 
 	/// <summary>
 	/// Occurs after <see cref="PeekMessage(out MSG, HWND, uint, uint, PM)"/> and determines if message should be translated or dispatched.
 	/// </summary>
-	public event MsgPumpPredicateDelegate PreProcess;
+	public event MsgPumpPredicateDelegate? PreProcess;
 
 	/// <inhertdoc/>
 	protected override int RunLoop()

PInvoke/User32/SystemEventHandler.cs

@@ -23,12 +23,12 @@ namespace Vanara.PInvoke;
 /// <seealso cref="System.IDisposable"/>
 public abstract class SystemEventHandler : IDisposable
 {
-	private static ManualResetEvent eventWindowReady;
+	private static ManualResetEvent? eventWindowReady;
-	private static Thread windowThread;
+	private static Thread? windowThread;
-	private readonly Dictionary<Guid, Delegate> eventHandles = new Dictionary<Guid, Delegate>();
+	private readonly Dictionary<Guid, Delegate> eventHandles = new();
-	private readonly object lockObj = new object();
+	private readonly object lockObj = new();
 	private bool disposedValue;
-	private BasicMessageWindow msgWindow;
+	private BasicMessageWindow? msgWindow;
 
 	/// <summary>Initializes a new instance of the <see cref="SystemEventHandler"/> class.</summary>
 	/// <param name="forceThread">
@@ -61,7 +61,7 @@ public abstract class SystemEventHandler : IDisposable
 	}
 
 	/// <summary>Occurs when the message window handle has been created.</summary>
-	public event EventHandler MessageWindowHandleCreated;
+	public event EventHandler? MessageWindowHandleCreated;
 
 	/// <summary>Gets a value indicating whether this instance is running in a thread.</summary>
 	/// <value><see langword="true"/> if this instance is running in a thread; otherwise, <see langword="false"/>.</value>
@@ -71,7 +71,7 @@ public abstract class SystemEventHandler : IDisposable
 	/// <value>The message window handle.</value>
 	public HWND MessageWindowHandle => msgWindow?.Handle ?? HWND.NULL;
 
-	private ManualResetEvent ThreadRunning { get; set; }
+	private ManualResetEvent? ThreadRunning { get; set; }
 
 	/// <summary>Adds a delegate and its associated key to the handler list.</summary>
 	/// <param name="key">The key.</param>
@@ -80,7 +80,7 @@ public abstract class SystemEventHandler : IDisposable
 	{
 		lock (lockObj)
 		{
-			if (!eventHandles.TryGetValue(key, out Delegate h))
+			if (!eventHandles.TryGetValue(key, out Delegate? h))
 			{
 				eventHandles.Add(key, value);
 				OnEventAdd(key);
@@ -99,7 +99,7 @@ public abstract class SystemEventHandler : IDisposable
 	{
 		lock (lockObj)
 		{
-			if (eventHandles.TryGetValue(key, out Delegate h))
+			if (eventHandles.TryGetValue(key, out Delegate? h))
 			{
 				h = Delegate.Remove(h, value);
 				if (h is null || h.GetInvocationList().Length == 0)
@@ -144,7 +144,7 @@ public abstract class SystemEventHandler : IDisposable
 				}
 			}
 
-			msgWindow.Dispose();
+			msgWindow?.Dispose();
 
 			disposedValue = true;
 		}
@@ -202,24 +202,25 @@ public abstract class SystemEventHandler : IDisposable
 	/// <param name="args">The arguments.</param>
 	/// <returns>The value returned by the call to the delegate list.</returns>
 	/// <exception cref="InvalidOperationException">Event for {key} is not registered.</exception>
-	protected object RaiseEvent(Guid key, params object[] args)
+	protected object? RaiseEvent(Guid key, params object?[] args)
 	{
-		Delegate h;
+		Delegate? h;
 		lock (lockObj)
 		{
 			if (!eventHandles.TryGetValue(key, out h))
 				throw new InvalidOperationException($"Event for {key} is not registered.");
 		}
-		return h.DynamicInvoke(args);
+		return h?.DynamicInvoke(args);
 	}
 
-	private static void MTAThreadProc(object param)
+	private static void MTAThreadProc(object? param)
 	{
-		var handler = (SystemEventHandler)param;
+		if (param is not SystemEventHandler handler)
+			throw new InvalidOperationException("Invalid parameter type.");
 		try
 		{
 			handler.Init();
-			eventWindowReady.Set();
+			eventWindowReady?.Set();
 			if (!handler.MessageWindowHandle.IsNull)
 			{
 				var keepRunning = true;
@@ -251,12 +252,12 @@ public abstract class SystemEventHandler : IDisposable
 		}
 		catch (Exception e)
 		{
-			eventWindowReady.Set();
+			eventWindowReady?.Set();
 			if (e is not (ThreadInterruptedException or ThreadAbortException))
 				System.Diagnostics.Debug.Fail("Unexpected thread exception in SystemEventHandler thread.", e.ToString());
 		}
 
-		handler.ThreadRunning.Set();
+		handler.ThreadRunning?.Set();
 	}
 
 	private void Init()

PInvoke/User32/User32_NMHDR.cs

@@ -25,7 +25,7 @@ public static partial class User32
 		/// <summary>Creates a <see cref="NMHDR"/> structure from an LPARAM value.</summary>
 		/// <param name="lParam">The LPARAM value.</param>
 		/// <returns>A <see cref="NMHDR"/> structure.</returns>
-		public static NMHDR FromLParam(IntPtr lParam) => (NMHDR)Marshal.PtrToStructure(lParam, typeof(NMHDR));
+		public static NMHDR FromLParam(IntPtr lParam) => lParam.ToStructure<NMHDR>();
 
 #if ALLOWSPAN
 		/// <summary>Creates a reference to an <see cref="NMHDR"/> structure from an LPARAM value.</summary>

PInvoke/User32/WinUser.Dbt.cs

@@ -720,16 +720,16 @@ public static partial class User32
 	/// <summary>Provides a handle to a device notification.</summary>
 	[PInvokeData("dbt.h")]
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HDEVNOTIFY : IHandle
+	public readonly struct HDEVNOTIFY : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HDEVNOTIFY"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HDEVNOTIFY(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HDEVNOTIFY"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HDEVNOTIFY NULL => new HDEVNOTIFY(IntPtr.Zero);
+		public static HDEVNOTIFY NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -742,7 +742,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HDEVNOTIFY"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HDEVNOTIFY(IntPtr h) => new HDEVNOTIFY(h);
+		public static implicit operator HDEVNOTIFY(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -757,7 +757,7 @@ public static partial class User32
 		public static bool operator ==(HDEVNOTIFY h1, HDEVNOTIFY h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HDEVNOTIFY h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HDEVNOTIFY h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.HighDpi2.cs

@@ -695,16 +695,16 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a DPI awareness context.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct DPI_AWARENESS_CONTEXT : IHandle
+	public readonly struct DPI_AWARENESS_CONTEXT : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="DPI_AWARENESS_CONTEXT"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public DPI_AWARENESS_CONTEXT(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="DPI_AWARENESS_CONTEXT"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static DPI_AWARENESS_CONTEXT NULL => new DPI_AWARENESS_CONTEXT(IntPtr.Zero);
+		public static DPI_AWARENESS_CONTEXT NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -717,7 +717,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="DPI_AWARENESS_CONTEXT"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator DPI_AWARENESS_CONTEXT(IntPtr h) => new DPI_AWARENESS_CONTEXT(h);
+		public static implicit operator DPI_AWARENESS_CONTEXT(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -732,7 +732,7 @@ public static partial class User32
 		public static bool operator ==(DPI_AWARENESS_CONTEXT h1, DPI_AWARENESS_CONTEXT h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is DPI_AWARENESS_CONTEXT h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is DPI_AWARENESS_CONTEXT h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Hook.cs

@@ -1135,16 +1135,16 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a hook.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HHOOK : IUserHandle
+	public readonly struct HHOOK : IUserHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HHOOK"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HHOOK(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HHOOK"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HHOOK NULL => new HHOOK(IntPtr.Zero);
+		public static HHOOK NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -1157,7 +1157,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HHOOK"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HHOOK(IntPtr h) => new HHOOK(h);
+		public static implicit operator HHOOK(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -1172,7 +1172,7 @@ public static partial class User32
 		public static bool operator ==(HHOOK h1, HHOOK h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HHOOK h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HHOOK h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -1183,16 +1183,16 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a Windows Event Hook.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HWINEVENTHOOK : IHandle
+	public readonly struct HWINEVENTHOOK : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HWINEVENTHOOK"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HWINEVENTHOOK(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HWINEVENTHOOK"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HWINEVENTHOOK NULL => new HWINEVENTHOOK(IntPtr.Zero);
+		public static HWINEVENTHOOK NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -1205,7 +1205,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HWINEVENTHOOK"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HWINEVENTHOOK(IntPtr h) => new HWINEVENTHOOK(h);
+		public static implicit operator HWINEVENTHOOK(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -1220,7 +1220,7 @@ public static partial class User32
 		public static bool operator ==(HWINEVENTHOOK h1, HWINEVENTHOOK h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HWINEVENTHOOK h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HWINEVENTHOOK h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Input.cs

@@ -690,7 +690,7 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a RAWINPUT structure.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HRAWINPUT : IHandle
+	public readonly struct HRAWINPUT : IHandle
 	{
 		private readonly IntPtr handle;
 
@@ -727,7 +727,7 @@ public static partial class User32
 		public static bool operator ==(HRAWINPUT h1, HRAWINPUT h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HRAWINPUT h && handle == h.handle;
+		public override bool Equals(object? obj) => obj is HRAWINPUT h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Keyboard.cs

@@ -2841,7 +2841,7 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a .</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HKL : IHandle
+	public readonly struct HKL : IHandle
 	{
 		private readonly IntPtr handle;
 
@@ -2878,7 +2878,7 @@ public static partial class User32
 		public static bool operator ==(HKL h1, HKL h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HKL h && handle == h.handle;
+		public override bool Equals(object? obj) => obj is HKL h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Message.cs

@@ -1248,7 +1248,7 @@ public static partial class User32
 	// DWORD nCount, const HANDLE *pHandles, BOOL fWaitAll, DWORD dwMilliseconds, DWORD dwWakeMask );
 	[DllImport(Lib.User32, SetLastError = true, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "0629f1b3-6805-43a7-9aeb-4f80939ec62c")]
-	public static extern uint MsgWaitForMultipleObjects(uint nCount, HANDLE[] pHandles, [MarshalAs(UnmanagedType.Bool)] bool fWaitAll, uint dwMilliseconds,
+	public static extern uint MsgWaitForMultipleObjects(uint nCount, HANDLE[]? pHandles, [MarshalAs(UnmanagedType.Bool)] bool fWaitAll, uint dwMilliseconds,
 		QS dwWakeMask);
 
 	/// <summary>
@@ -1511,7 +1511,7 @@ public static partial class User32
 	// MsgWaitForMultipleObjectsEx( DWORD nCount, const HANDLE *pHandles, DWORD dwMilliseconds, DWORD dwWakeMask, DWORD dwFlags );
 	[DllImport(Lib.User32, SetLastError = true, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "1774b721-3ad4-492e-96af-b71de9066f0c")]
-	public static extern uint MsgWaitForMultipleObjectsEx(uint nCount, HANDLE[] pHandles, uint dwMilliseconds, QS dwWakeMask, MWMO dwFlags);
+	public static extern uint MsgWaitForMultipleObjectsEx(uint nCount, HANDLE[]? pHandles, uint dwMilliseconds, QS dwWakeMask, MWMO dwFlags);
 
 	/// <summary>Packs a Dynamic Data Exchange (DDE) lParam value into an internal structure used for sharing DDE data between processes.</summary>
 	/// <param name="msg">

PInvoke/User32/WinUser.Paint.cs

@@ -1478,7 +1478,7 @@ public static partial class User32
 	[DllImport(Lib.User32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "5a823d36-d08b-41c9-8857-540576f54b55")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool InvalidateRect(HWND hWnd, [In] PRECT lpRect, [MarshalAs(UnmanagedType.Bool)] bool bErase);
+	public static extern bool InvalidateRect(HWND hWnd, [In, Optional] PRECT? lpRect, [MarshalAs(UnmanagedType.Bool)] bool bErase);
 
 	/// <summary>
 	/// The <c>InvalidateRgn</c> function invalidates the client area within the specified region by adding it to the current update
@@ -1516,7 +1516,7 @@ public static partial class User32
 	[DllImport(Lib.User32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "b5b44efe-8045-4e54-89f9-1766689a053d")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool InvalidateRgn(HWND hWnd, HRGN hRgn, [MarshalAs(UnmanagedType.Bool)] bool bErase);
+	public static extern bool InvalidateRgn(HWND hWnd, [In, Optional] HRGN hRgn, [MarshalAs(UnmanagedType.Bool)] bool bErase);
 
 	/// <summary>
 	/// The <c>LockWindowUpdate</c> function disables or enables drawing in the specified window. Only one window can be locked at a time.
@@ -1747,7 +1747,7 @@ public static partial class User32
 	// bRedraw );
 	[DllImport(Lib.User32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "06209d0c-14f9-45ec-ae2c-9cc596b5bbaa")]
-	public static extern int SetWindowRgn(HWND hWnd, HRGN hRgn, [MarshalAs(UnmanagedType.Bool)] bool bRedraw);
+	public static extern int SetWindowRgn(HWND hWnd, [In, Optional] HRGN hRgn, [MarshalAs(UnmanagedType.Bool)] bool bRedraw);
 
 	/// <summary>
 	/// The <c>UpdateWindow</c> function updates the client area of the specified window by sending a WM_PAINT message to the window if
@@ -1793,7 +1793,7 @@ public static partial class User32
 	[DllImport(Lib.User32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "961dd768-1849-44df-bc7f-480881ed6477")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool ValidateRect(HWND hWnd, [In] PRECT lpRect);
+	public static extern bool ValidateRect(HWND hWnd, [In, Optional] PRECT? lpRect);
 
 	/// <summary>
 	/// The <c>ValidateRgn</c> function validates the client area within a region by removing the region from the current update region
@@ -1819,7 +1819,7 @@ public static partial class User32
 	[DllImport(Lib.User32, SetLastError = false, ExactSpelling = true)]
 	[PInvokeData("winuser.h", MSDNShortId = "80fb1d4a-d9b1-4e67-b585-eee81893ed34")]
 	[return: MarshalAs(UnmanagedType.Bool)]
-	public static extern bool ValidateRgn(HWND hWnd, HRGN hRgn);
+	public static extern bool ValidateRgn(HWND hWnd, [In, Optional] HRGN hRgn);
 
 	/// <summary>
 	/// <para>

PInvoke/User32/WinUser.Pointer.cs

@@ -1748,16 +1748,16 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a synthetic pointer device.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HSYNTHETICPOINTERDEVICE : IHandle
+	public readonly struct HSYNTHETICPOINTERDEVICE : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HSYNTHETICPOINTERDEVICE"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HSYNTHETICPOINTERDEVICE(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HSYNTHETICPOINTERDEVICE"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HSYNTHETICPOINTERDEVICE NULL => new HSYNTHETICPOINTERDEVICE(IntPtr.Zero);
+		public static HSYNTHETICPOINTERDEVICE NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -1770,7 +1770,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HSYNTHETICPOINTERDEVICE"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HSYNTHETICPOINTERDEVICE(IntPtr h) => new HSYNTHETICPOINTERDEVICE(h);
+		public static implicit operator HSYNTHETICPOINTERDEVICE(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -1785,7 +1785,7 @@ public static partial class User32
 		public static bool operator ==(HSYNTHETICPOINTERDEVICE h1, HSYNTHETICPOINTERDEVICE h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HSYNTHETICPOINTERDEVICE h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HSYNTHETICPOINTERDEVICE h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Res.cs

@@ -225,7 +225,7 @@ public static partial class User32
 	/// NULL.To get extended error information, call GetLastError.
 	/// </returns>
 	public static SafeHBITMAP LoadImage_Bitmap(HINSTANCE hinst, SafeResourceId lpszName, int cxDesired, int cyDesired, LoadImageOptions fuLoad) =>
-		new SafeHBITMAP(LoadImage(hinst, lpszName, LoadImageType.IMAGE_BITMAP, cxDesired, cyDesired, fuLoad), true);
+		new(LoadImage(hinst, lpszName, LoadImageType.IMAGE_BITMAP, cxDesired, cyDesired, fuLoad), true);
 
 	/// <summary>Loads a cursor or animated cursor.</summary>
 	/// <param name="hinst">
@@ -270,7 +270,7 @@ public static partial class User32
 	/// NULL.To get extended error information, call GetLastError.
 	/// </returns>
 	public static SafeHCURSOR LoadImage_Cursor(HINSTANCE hinst, SafeResourceId lpszName, int cxDesired, int cyDesired, LoadImageOptions fuLoad) =>
-		new SafeHCURSOR(LoadImage(hinst, lpszName, LoadImageType.IMAGE_CURSOR, cxDesired, cyDesired, fuLoad), true);
+		new(LoadImage(hinst, lpszName, LoadImageType.IMAGE_CURSOR, cxDesired, cyDesired, fuLoad), true);
 
 	/// <summary>Loads an enhanced metafile.</summary>
 	/// <param name="hinst">
@@ -315,7 +315,7 @@ public static partial class User32
 	/// NULL.To get extended error information, call GetLastError.
 	/// </returns>
 	public static SafeHENHMETAFILE LoadImage_EnhMetaFile(HINSTANCE hinst, SafeResourceId lpszName, int cxDesired, int cyDesired, LoadImageOptions fuLoad) =>
-		new SafeHENHMETAFILE(LoadImage(hinst, lpszName, LoadImageType.IMAGE_ENHMETAFILE, cxDesired, cyDesired, fuLoad), true);
+		new(LoadImage(hinst, lpszName, LoadImageType.IMAGE_ENHMETAFILE, cxDesired, cyDesired, fuLoad), true);
 
 	/// <summary>Loads an icon.</summary>
 	/// <param name="hinst">
@@ -360,7 +360,7 @@ public static partial class User32
 	/// NULL.To get extended error information, call GetLastError.
 	/// </returns>
 	public static SafeHICON LoadImage_Icon(HINSTANCE hinst, SafeResourceId lpszName, int cxDesired, int cyDesired, LoadImageOptions fuLoad) =>
-		new SafeHICON(LoadImage(hinst, lpszName, LoadImageType.IMAGE_ICON, cxDesired, cyDesired, fuLoad), true);
+		new(LoadImage(hinst, lpszName, LoadImageType.IMAGE_ICON, cxDesired, cyDesired, fuLoad), true);
 
 	/// <summary>
 	/// Loads a string resource from the executable file associated with a specified module, copies the string into a buffer, and appends

PInvoke/User32/WinUser.Touch.cs

@@ -1297,7 +1297,7 @@ public static partial class User32
 		public uint cbExtraArgs;
 
 		/// <summary>A default value for <see cref="GESTUREINFO"/> with the <see cref="cbSize"/> field value set correctly.</summary>
-		public static readonly GESTUREINFO Default = new GESTUREINFO { cbSize = (uint)Marshal.SizeOf(typeof(GESTUREINFO)) };
+		public static readonly GESTUREINFO Default = new() { cbSize = (uint)Marshal.SizeOf(typeof(GESTUREINFO)) };
 	}
 
 	/// <summary>When transmitted with WM_GESTURENOTIFY messages, passes information about a gesture.</summary>
@@ -1324,21 +1324,21 @@ public static partial class User32
 		public uint dwInstanceID;
 
 		/// <summary>A default value for <see cref="GESTURENOTIFYSTRUCT"/> with the <see cref="cbSize"/> field value set correctly.</summary>
-		public static readonly GESTURENOTIFYSTRUCT Default = new GESTURENOTIFYSTRUCT { cbSize = (uint)Marshal.SizeOf(typeof(GESTURENOTIFYSTRUCT)) };
+		public static readonly GESTURENOTIFYSTRUCT Default = new() { cbSize = (uint)Marshal.SizeOf(typeof(GESTURENOTIFYSTRUCT)) };
 	}
 
 	/// <summary>Provides a handle to a gesture info.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HGESTUREINFO : IHandle
+	public readonly struct HGESTUREINFO : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HGESTUREINFO"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HGESTUREINFO(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HGESTUREINFO"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HGESTUREINFO NULL => new HGESTUREINFO(IntPtr.Zero);
+		public static HGESTUREINFO NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -1351,7 +1351,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HGESTUREINFO"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HGESTUREINFO(IntPtr h) => new HGESTUREINFO(h);
+		public static implicit operator HGESTUREINFO(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -1366,7 +1366,7 @@ public static partial class User32
 		public static bool operator ==(HGESTUREINFO h1, HGESTUREINFO h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HGESTUREINFO h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HGESTUREINFO h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();
@@ -1377,16 +1377,16 @@ public static partial class User32
 
 	/// <summary>Provides a handle to a touch input.</summary>
 	[StructLayout(LayoutKind.Sequential)]
-	public struct HTOUCHINPUT : IHandle
+	public readonly struct HTOUCHINPUT : IHandle
 	{
-		private IntPtr handle;
+		private readonly IntPtr handle;
 
 		/// <summary>Initializes a new instance of the <see cref="HTOUCHINPUT"/> struct.</summary>
 		/// <param name="preexistingHandle">An <see cref="IntPtr"/> object that represents the pre-existing handle to use.</param>
 		public HTOUCHINPUT(IntPtr preexistingHandle) => handle = preexistingHandle;
 
 		/// <summary>Returns an invalid handle by instantiating a <see cref="HTOUCHINPUT"/> object with <see cref="IntPtr.Zero"/>.</summary>
-		public static HTOUCHINPUT NULL => new HTOUCHINPUT(IntPtr.Zero);
+		public static HTOUCHINPUT NULL => new(IntPtr.Zero);
 
 		/// <summary>Gets a value indicating whether this instance is a null handle.</summary>
 		public bool IsNull => handle == IntPtr.Zero;
@@ -1399,7 +1399,7 @@ public static partial class User32
 		/// <summary>Performs an implicit conversion from <see cref="IntPtr"/> to <see cref="HTOUCHINPUT"/>.</summary>
 		/// <param name="h">The pointer to a handle.</param>
 		/// <returns>The result of the conversion.</returns>
-		public static implicit operator HTOUCHINPUT(IntPtr h) => new HTOUCHINPUT(h);
+		public static implicit operator HTOUCHINPUT(IntPtr h) => new(h);
 
 		/// <summary>Implements the operator !=.</summary>
 		/// <param name="h1">The first handle.</param>
@@ -1414,7 +1414,7 @@ public static partial class User32
 		public static bool operator ==(HTOUCHINPUT h1, HTOUCHINPUT h2) => h1.Equals(h2);
 
 		/// <inheritdoc/>
-		public override bool Equals(object obj) => obj is HTOUCHINPUT h ? handle == h.handle : false;
+		public override bool Equals(object? obj) => obj is HTOUCHINPUT h && handle == h.handle;
 
 		/// <inheritdoc/>
 		public override int GetHashCode() => handle.GetHashCode();

PInvoke/User32/WinUser.Window.cs

@@ -8710,7 +8710,7 @@ public static partial class User32
 		public MessageFilterInformation ExtStatus;
 
 		/// <summary>The default value for this structure with the size field set appropriately.</summary>
-		public static CHANGEFILTERSTRUCT Default = new CHANGEFILTERSTRUCT() { cbSize = (uint)Marshal.SizeOf(typeof(CHANGEFILTERSTRUCT)) };
+		public static CHANGEFILTERSTRUCT Default = new() { cbSize = (uint)Marshal.SizeOf(typeof(CHANGEFILTERSTRUCT)) };
 	}
 
 	/// <summary>
@@ -9767,7 +9767,7 @@ public static partial class User32
 		/// </para>
 		/// </summary>
 		[MarshalAs(UnmanagedType.LPTStr)]
-		public string lpszMenuName;
+		public string? lpszMenuName;
 
 		/// <summary>
 		/// <para>Type: <c>LPCTSTR</c></para>

PInvoke/Usp10/Usp10.cs

@@ -341,7 +341,7 @@ public static partial class Usp10
 		/// <returns>
 		/// <see langword="true"/> if the specified <see cref="System.Object"/> is equal to this instance; otherwise, <see langword="false"/>.
 		/// </returns>
-		public override bool Equals(object obj) => obj is OPENTYPE_TAG tAG && Equals(tAG);
+		public override bool Equals(object? obj) => obj is OPENTYPE_TAG tAG && Equals(tAG);
 
 		/// <summary>Determines whether the specified <see cref="OPENTYPE_TAG"/>, is equal to this instance.</summary>
 		/// <param name="other">The <see cref="OPENTYPE_TAG"/> to compare with this instance.</param>

UnitTests/CSharpRunner/GenericTester.cs

@@ -7,7 +7,7 @@ namespace Vanara.PInvoke;
 
 public class GenericComTester<TInt> where TInt : class
 {
-	protected Stack<object> objects = new Stack<object>();
+	protected Stack<object> objects = new();
 
 	public virtual TInt Instance => (TInt)objects.Peek();
 

UnitTests/CSharpRunner/SuccessfulConstraint.cs

@@ -5,13 +5,13 @@ namespace Vanara.PInvoke.Tests;
 
 public abstract class ResultIs // : NUnit.Framework.Is
 {
-	public static FailureConstraint Failure => new FailureConstraint();
+	public static FailureConstraint Failure => new();
 	public static MyConstraintExpression Not => MyConstraintExpression.Not;
-	public static SuccessfulConstraint Successful => new SuccessfulConstraint();
+	public static SuccessfulConstraint Successful => new();
-	public static ValidHandleConstraint ValidHandle => new ValidHandleConstraint();
+	public static ValidHandleConstraint ValidHandle => new();
 
-	public static FailureConstraint FailureCode(object expectedError) => new FailureConstraint(expectedError);
+	public static FailureConstraint FailureCode(object expectedError) => new(expectedError);
-	public static ValueConstraint Value(object value) => new ValueConstraint(value);
+	public static ValueConstraint Value(object value) => new(value);
 }
 
 public class MyConstraintExpression
@@ -20,11 +20,11 @@ public class MyConstraintExpression
 
 	private MyConstraintExpression(OpConstraint.Op _op) => op = _op;
 
-	public static MyConstraintExpression Not => new MyConstraintExpression(OpConstraint.Op.Not);
+	public static MyConstraintExpression Not => new(OpConstraint.Op.Not);
 
-	public ValidHandleConstraint ValidHandle => new ValidHandleConstraint(op);
+	public ValidHandleConstraint ValidHandle => new(op);
 
-	public ValueConstraint Value(object value) => new ValueConstraint(value, op);
+	public ValueConstraint Value(object value) => new(value, op);
 }
 
 public class FailureConstraint : Constraint

UnitTests/CSharpRunner/TestCaseSources.cs

@@ -192,7 +192,7 @@ public static class TestCaseSources
 
 			public DEnum(StrArrDict parent) => p = parent;
 
-			public KeyValuePair<string, string> Current => new KeyValuePair<string, string>(p.keys[c], p.values[c]);
+			public KeyValuePair<string, string> Current => new(p.keys[c], p.values[c]);
 
 			object IEnumerator.Current => Current;
 

UnitTests/PInvoke/Gdi32/BitmapTests.cs

@@ -117,7 +117,7 @@ public class BitmapTests
 		ajBits[0] = 0xff; ajBits[2] = 0xc; ajBits[3] = 0xf0; ajBits[4] = 0x0f;
 
 		var bisize = Marshal.SizeOf(typeof(BITMAPINFOHEADER)) + 256 * Marshal.SizeOf(typeof(uint));
-		using SafeBITMAPINFO pbi = new SafeBITMAPINFO(default, bisize);
+		using SafeBITMAPINFO pbi = new(default, bisize);
 
 		using var hdcScreen = GetDC();
 		Assert.That(hdcScreen, ResultIs.ValidHandle);

UnitTests/PInvoke/Gdi32/Gdi32Tests.cs

@@ -143,6 +143,35 @@ public class Gdi32Tests
 		}
 	}
 
+	[Test]
+	public void GetTextCharsetInfoTest()
+	{
+		using var hdc = SafeHDC.ScreenCompatibleDCHandle;
+		var cs = GetTextCharsetInfo(hdc, out var fs);
+		Assert.AreNotEqual(cs, CharacterSetUint.DEFAULT_CHARSET);
+		fs.WriteValues();
+	}
+
+	[Test]
+	public void TranslateCharsetInfoTest()
+	{
+		var acp = Kernel32.GetACP();
+		Assert.That(TranslateCharsetInfo((IntPtr)acp, out var csi, TCI.TCI_SRCCODEPAGE), ResultIs.Successful);
+		csi.WriteValues();
+
+		Assert.That(TranslateCharsetInfo((IntPtr)csi.ciCharset, out csi, TCI.TCI_SRCCHARSET), ResultIs.Successful);
+		csi.WriteValues();
+
+		Assert.That(TranslateCharsetInfo((IntPtr)(int)(uint)Kernel32.GetThreadLocale(), out csi, TCI.TCI_SRCLOCALE), ResultIs.Successful);
+		csi.WriteValues();
+
+		FONTSIGNATURE fs = default;
+		using (var hdc = SafeHDC.ScreenCompatibleDCHandle)
+			GetTextCharsetInfo(hdc, out fs);
+		Assert.That(TranslateCharsetInfo(fs.fsCsb, out csi, TCI.TCI_SRCFONTSIG), ResultIs.Successful);
+		csi.WriteValues();
+	}
+
 	// TODO: [Test]
 	public void SelectObjectTest()
 	{

Windows.Extensions/GdiObjExtensions.cs

@@ -102,12 +102,12 @@ public static class GdiObjExtensions2
 				break;
 
 			case BrushStyle.BS_HATCHED:
-				HatchBrush hbr = new HatchBrush((System.Drawing.Drawing2D.HatchStyle)lpen.elpHatch.ToInt32(), lpen.elpColor);
+				HatchBrush hbr = new((System.Drawing.Drawing2D.HatchStyle)lpen.elpHatch.ToInt32(), lpen.elpColor);
 				pen = new Pen(hbr);
 				break;
 
 			case BrushStyle.BS_PATTERN:
-				TextureBrush pbr = new TextureBrush(Image.FromHbitmap(lpen.elpHatch));
+				TextureBrush pbr = new(Image.FromHbitmap(lpen.elpHatch));
 				pen = new Pen(pbr);
 				break;
 

Windows.Extensions/GraphicsExtension.cs

@@ -155,7 +155,7 @@ public static partial class GdiExtension
 			throw new ArgumentException("Bitmaps must be of the same size and their pixel format must be Format32bppArgb.");
 
 		var bmp = new Bitmap(whiteBmp.Width, whiteBmp.Height, whiteBmp.PixelFormat);
-		using (SmartBitmapLock oVals = new SmartBitmapLock(bmp), wVals = new SmartBitmapLock(whiteBmp), bVals = new SmartBitmapLock(blackBmp))
+		using (SmartBitmapLock oVals = new(bmp), wVals = new(whiteBmp), bVals = new(blackBmp))
 		{
 			for (var i = 0; i < oVals.Length; i++)
 			{