GdiplusPInvoke.cs

using System;
using System.Runtime.InteropServices;
using Unmanaged;

namespace Gdiplus
{
    [StructLayout(LayoutKind.Sequential)]
    public struct Point
    {
        public int x;
        public int y;

        public Point(int x, int y) { this.x = x; this.y = y; }
    }


    [StructLayout(LayoutKind.Sequential)]
    public struct Size
    {
        public int cx;
        public int cy;

        public Size(int cx, int cy) { this.cx = cx; this.cy = cy; }
    }


    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    struct ARGB
    {
        public byte Blue;
        public byte Green;
        public byte Red;
        public byte Alpha;
    }


    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct BLENDFUNCTION
    {
        public byte BlendOp;
        public byte BlendFlags;
        public byte SourceConstantAlpha;
        public byte AlphaFormat;
    }

    public static class GdiplusPInvoke
    {
        public const int ULW_COLORKEY = 0x00000001;
        public const int ULW_ALPHA = 0x00000002;
        public const int ULW_OPAQUE = 0x00000004;

        public const byte AC_SRC_OVER = 0x00;
        public const byte AC_SRC_ALPHA = 0x01;

        [DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
        public static extern Bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);

        [DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
        public static extern IntPtr GetDC(IntPtr hWnd);

        [DllImport("user32.dll", ExactSpelling = true)]
        public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);

        [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
        public static extern IntPtr CreateCompatibleDC(IntPtr hDC);

        [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
        public static extern Bool DeleteDC(IntPtr hdc);

        [DllImport("gdi32.dll", ExactSpelling = true)]
        public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);

        [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
        public static extern Bool DeleteObject(IntPtr hObject);
    }
}