Introduce basic support for Windows GDI resources

Signed-off-by: Simon Rozman <simon@rozman.si>

include/WinStd/GDI.h

@@ -0,0 +1,199 @@
+/*
+    Copyright © 1991-2021 Amebis
+
+    This file is part of WinStd.
+
+    Setup is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Setup is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Setup. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+///
+/// \defgroup WinStdGdiAPI GDI API
+/// Integrates WinStd classes with Microsoft Windows GDI
+///
+
+#include "Common.h"
+
+#include <Windows.h>
+
+namespace winstd
+{
+    template<class T> class gdi_handle;
+    class dc;
+    class window_dc;
+    class dc_selector;
+}
+
+
+#pragma once
+
+
+namespace winstd
+{
+    /// \addtogroup WinStdGdiAPI
+    /// @{
+
+    ///
+    /// Windows HGDIOBJ wrapper class
+    ///
+    template<class T>
+    class gdi_handle : public handle<T, NULL>
+    {
+        HANDLE_IMPL(gdi_handle, NULL)
+
+    public:
+        ///
+        /// Closes an open object handle.
+        ///
+        /// \sa [DeleteObject function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-deleteobject)
+        ///
+        virtual ~gdi_handle()
+        {
+            if (m_h != invalid)
+                DeleteObject(m_h);
+        }
+
+    protected:
+        ///
+        /// Closes an open object handle.
+        ///
+        /// \sa [DeleteObject function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-deleteobject)
+        ///
+        void free_internal() noexcept override
+        {
+            DeleteObject(m_h);
+        }
+    };
+
+
+    ///
+    /// Device context wrapper class
+    ///
+    class dc : public handle<HDC, NULL>
+    {
+        HANDLE_IMPL(dc, NULL)
+
+    public:
+        ///
+        /// Deletes the specified device context (DC).
+        ///
+        /// \sa [DeleteDC function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-deletedc)
+        ///
+        virtual ~dc();
+
+    protected:
+        ///
+        /// Deletes the specified device context (DC).
+        ///
+        /// \sa [DeleteDC function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-deletedc)
+        ///
+        void free_internal() noexcept override;
+    };
+
+
+    ///
+    /// Device context wrapper class
+    ///
+    class window_dc : public handle<HDC, NULL>
+    {
+    public:
+        inline window_dc() noexcept :
+            m_hwnd(NULL)
+        {}
+
+        inline window_dc(_In_opt_ handle_type h, _In_opt_ HWND hwnd) noexcept :
+            handle<handle_type, NULL>(h),
+            m_hwnd(hwnd)
+        {}
+
+        inline window_dc(_Inout_ window_dc &&h) noexcept :
+            handle<handle_type, NULL>(std::move(h)),
+            m_hwnd(h.m_hwnd)
+        {}
+
+        inline window_dc& operator=(_Inout_ window_dc &&h) noexcept
+        {
+            handle<handle_type, NULL>::operator=(std::move(h));
+            m_hwnd = h.m_hwnd;
+            return *this;
+        }
+
+        WINSTD_NONCOPYABLE(window_dc)
+
+    public:
+        ///
+        /// Releases a device context (DC), freeing it for use by other applications.
+        ///
+        /// \sa [ReleaseDC function](https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-releasedc)
+        ///
+        virtual ~window_dc();
+
+    protected:
+        ///
+        /// Releases a device context (DC), freeing it for use by other applications.
+        ///
+        /// \sa [ReleaseDC function](https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-releasedc)
+        ///
+        void free_internal() noexcept override;
+
+    protected:
+        HWND m_hwnd;    ///< Window handle
+    };
+
+
+    ///
+    /// Context scope DC object restorer
+    ///
+    class dc_selector
+    {
+        WINSTD_NONCOPYABLE(dc_selector)
+        WINSTD_NONMOVABLE(dc_selector)
+
+    public:
+        ///
+        /// Selects an object into the specified device context (DC). The new object replaces the previous object of the same type.
+        ///
+        /// \sa [SelectObject function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-selectobject)
+        ///
+        inline dc_selector(_In_ HDC hdc, _In_ HGDIOBJ h) noexcept :
+            m_hdc(hdc),
+            m_orig(SelectObject(hdc, h))
+        {
+        }
+
+
+        ///
+        /// Restores original object.
+        ///
+        /// \sa [SelectObject function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-selectobject)
+        ///
+        virtual ~dc_selector();
+
+
+        ///
+        /// Return result of `SelectObject()` call.
+        ///
+        /// \sa [SelectObject function](https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-selectobject)
+        ///
+        inline HGDIOBJ status() const noexcept
+        {
+            return m_orig;
+        }
+
+    protected:
+        HDC m_hdc;      ///< A handle to the device context
+        HGDIOBJ m_orig; ///< Original object handle
+    };
+
+    /// @}
+}