Improve PInvoke WinApi and add DPI Support

SkinFramWorkCore.sln

@@ -1,11 +1,14 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.32929.386
+# Visual Studio Version 17
+VisualStudioVersion = 17.4.33103.184
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SkinFramWorkCore", "SkinFramWorkCore\SkinFramWorkCore.csproj", "{2D1532E1-CB47-467C-AB40-3C910A0100AE}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SkinFramWorkCore", "SkinFramWorkCore\SkinFramWorkCore.csproj", "{2D1532E1-CB47-467C-AB40-3C910A0100AE}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestApp", "TestApp\TestApp.csproj", "{28D26C77-C889-4603-9F5C-8234A8C0690E}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestApp1", "TestApp1\TestApp1.csproj", "{12A05D1D-6EFC-49D0-9C58-28DBE9EE743B}"
+	ProjectSection(ProjectDependencies) = postProject
+		{2D1532E1-CB47-467C-AB40-3C910A0100AE} = {2D1532E1-CB47-467C-AB40-3C910A0100AE}
+	EndProjectSection
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -17,10 +20,10 @@ Global
 		{2D1532E1-CB47-467C-AB40-3C910A0100AE}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{2D1532E1-CB47-467C-AB40-3C910A0100AE}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{2D1532E1-CB47-467C-AB40-3C910A0100AE}.Release|Any CPU.Build.0 = Release|Any CPU
-		{28D26C77-C889-4603-9F5C-8234A8C0690E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{28D26C77-C889-4603-9F5C-8234A8C0690E}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{28D26C77-C889-4603-9F5C-8234A8C0690E}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{28D26C77-C889-4603-9F5C-8234A8C0690E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{12A05D1D-6EFC-49D0-9C58-28DBE9EE743B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{12A05D1D-6EFC-49D0-9C58-28DBE9EE743B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{12A05D1D-6EFC-49D0-9C58-28DBE9EE743B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{12A05D1D-6EFC-49D0-9C58-28DBE9EE743B}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

SkinFramWorkCore/DebugConsole.cs

@@ -5,7 +5,7 @@
 using System.Runtime.InteropServices;
 namespace SkinFramWorkCore
 {
-    public class DebugConsole
+    internal class DebugConsole
     {
         #region Methods
         /// <summary>

SkinFramWorkCore/Interop/Dwmapi/Inetrop.DwmExtendFrameIntoClientArea.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Runtime.InteropServices;
+internal static partial class Interop
+{
+    internal static partial class Dwmapi
+    {
+        [DllImport(Libraries.Dwmapi, CharSet = CharSet.Auto, ExactSpelling = false)]
+        public static extern HRESULT DwmExtendFrameIntoClientArea(IntPtr hWnd, ref UxTheme.MARGINS pMarInset);
+        public static HRESULT DwmExtendFrameIntoClientArea(IHandle hWnd, ref UxTheme.MARGINS pMarInset)
+        {
+            var result = DwmExtendFrameIntoClientArea(hWnd.Handle, ref pMarInset);
+            GC.KeepAlive(hWnd);
+            return result;
+        }
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.CreateRoundRectRgn.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        [DllImport(Libraries.Gdi32)]
+        public static extern HRGN CreateRoundRectRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect, int nWidthEllipse, int nHeightEllipse);
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.CreateSolidBrush.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        [DllImport(Libraries.Gdi32, ExactSpelling = true, SetLastError = true)]
+        public static extern HBRUSH CreateSolidBrush(int crColor);
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.DeleteObject.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+using System;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        [DllImport(Libraries.Gdi32, ExactSpelling = true)]
+        public static extern BOOL DeleteObject(IntPtr hObject);
+
+        public static BOOL DeleteObject(HGDIOBJ hObject) => DeleteObject(hObject.Handle);
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.ExcludeClipRect.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        [DllImport(Libraries.Gdi32)]
+        public static extern int ExcludeClipRect(HDC hdc, int left, int top, int right, int bottom);
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.GetObjectType.cs

@@ -0,0 +1,23 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        // This does set last error but *only* in one error case that doesn't add any real value.
+        [DllImport(Libraries.Gdi32, ExactSpelling = true)]
+        public static extern OBJ GetObjectType(HGDIOBJ h);
+
+        public static OBJ GetObjectType(HandleRef h)
+        {
+            OBJ result = GetObjectType((HGDIOBJ)h.Handle);
+            GC.KeepAlive(h.Wrapper);
+            return result;
+        }
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.GetRegionData.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+using System;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        [DllImport(Libraries.Gdi32, ExactSpelling = true)]
+        public static extern uint GetRegionData(IntPtr hRgn, uint nCount, IntPtr lpRgnData);
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.HBRUSH.cs

@@ -0,0 +1,23 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+using System;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        public readonly struct HBRUSH
+        {
+            public IntPtr Handle { get; }
+
+            public HBRUSH(IntPtr handle) => Handle = handle;
+
+            public bool IsNull => Handle == IntPtr.Zero;
+
+            public static explicit operator IntPtr(HBRUSH hbrush) => hbrush.Handle;
+            public static explicit operator HBRUSH(IntPtr hbrush) => new HBRUSH(hbrush);
+            public static implicit operator HGDIOBJ(HBRUSH hbrush) => new HGDIOBJ(hbrush.Handle);
+            public static explicit operator HBRUSH(HGDIOBJ hbrush) => new HBRUSH(hbrush.Handle);
+        }
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.HDC.cs

@@ -0,0 +1,29 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        public readonly struct HDC
+        {
+            public IntPtr Handle { get; }
+
+            public HDC(IntPtr handle) => Handle = handle;
+
+            public bool IsNull => Handle == IntPtr.Zero;
+
+            public static explicit operator IntPtr(HDC hdc) => hdc.Handle;
+            public static explicit operator HDC(IntPtr hdc) => new HDC(hdc);
+            public static implicit operator HGDIOBJ(HDC hdc) => new HGDIOBJ(hdc.Handle);
+
+            public static bool operator ==(HDC value1, HDC value2) => value1.Handle == value2.Handle;
+            public static bool operator !=(HDC value1, HDC value2) => value1.Handle != value2.Handle;
+            public override bool Equals(object? obj) => obj is HDC hdc && hdc.Handle == Handle;
+            public override int GetHashCode() => Handle.GetHashCode();
+        }
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.HGDIOBJ.cs

@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        public struct HGDIOBJ
+        {
+            public IntPtr Handle { get; }
+
+            public HGDIOBJ(IntPtr handle) => Handle = handle;
+
+            public bool IsNull => Handle == IntPtr.Zero;
+
+            public static explicit operator IntPtr(HGDIOBJ hgdiobj) => hgdiobj.Handle;
+            public static explicit operator HGDIOBJ(IntPtr hgdiobj) => new HGDIOBJ(hgdiobj);
+
+            public static bool operator ==(HGDIOBJ value1, HGDIOBJ value2) => value1.Handle == value2.Handle;
+            public static bool operator !=(HGDIOBJ value1, HGDIOBJ value2) => value1.Handle != value2.Handle;
+            public override bool Equals(object? obj) => obj is HGDIOBJ hgdiobj && hgdiobj.Handle == Handle;
+            public override int GetHashCode() => Handle.GetHashCode();
+
+            public OBJ ObjectType => GetObjectType(this);
+        }
+    }
+}

SkinFramWorkCore/Interop/Gdi32/Interop.HRGN.cs

@@ -0,0 +1,47 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Buffers;
+using System;
+internal static partial class Interop
+{
+    internal static partial class Gdi32
+    {
+        public readonly struct HRGN
+        {
+            public IntPtr Handle { get; }
+
+            public HRGN(IntPtr handle) => Handle = handle;
+
+            public bool IsNull => Handle == IntPtr.Zero;
+
+            public static implicit operator HGDIOBJ(HRGN hrgn) => new HGDIOBJ(hrgn.Handle);
+            public static explicit operator IntPtr(HRGN hrgn) => hrgn.Handle;
+            public static explicit operator HRGN(IntPtr hrgn) => new HRGN(hrgn);
+
+            public unsafe RECT[] GetRegionRects()
+            {
+                uint regionDataSize = GetRegionData(Handle, 0, IntPtr.Zero);
+                if (regionDataSize == 0)
+                {
+                    return Array.Empty<RECT>();
+                }
+
+                byte[] buffer = ArrayPool<byte>.Shared.Rent((int)regionDataSize);
+
+                fixed (byte* b = buffer)
+                {
+                    if (GetRegionData(Handle, regionDataSize, (IntPtr)b) != regionDataSize)
+                    {
+                        return Array.Empty<RECT>();
+                    }
+
+                    RECT[] result = RGNDATAHEADER.GetRegionRects((RGNDATAHEADER*)b);
+                    ArrayPool<byte>.Shared.Return(buffer);
+                    return result;
+                }
+            }
+        }
+    }
+}