EasyProgressBarPacket

using System;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using EasyProgressBarPacket.Components;
using EasyProgressBarPacket.Win32;

namespace EasyProgressBarPacket
{
    public class EasyProgressBarSplashForm : Form
    {
        #region Event
        
        /// <summary>
        /// Represents an event which occurs when the index of the active frame changed.
        /// </summary>
        [Description("Represents an event which occurs when the index of the active frame changed")]
        public event EventHandler<ReportTaskProgressEventArgs> FrameChanged;

        #endregion

        #region Instance Members

        private Image newFrameImage = null;
        private AniEasyProgressTaskManager easyProgressTaskManager = null;

        #endregion

        #region Constructor

        public EasyProgressBarSplashForm()
        {
            this.SetStyle(ControlStyles.Selectable, false);
            this.SetStyle(ControlStyles.ResizeRedraw, false);
            this.SetStyle(ControlStyles.FixedWidth | ControlStyles.FixedHeight, true);
            this.DoubleBuffered = true;

            this.ShowIcon = false;
            this.ControlBox = false;
            this.MaximizeBox = false;
            this.ShowInTaskbar = false;
            this.StartPosition = FormStartPosition.Manual;
            this.FormBorderStyle = FormBorderStyle.None;
        }

        #endregion

        #region Destructor

        ~EasyProgressBarSplashForm()
        {
            GC.SuppressFinalize(this);
        }

        #endregion

        #region Property

        /// <summary>
        /// Gets or Sets the task manager for painting this control.
        /// </summary>
        [Description("Gets or Sets the task manager for painting this control")]
        public AniEasyProgressTaskManager EasyProgressTaskManager
        {
            get { return easyProgressTaskManager; }
            set
            {
                try
                {
                    if (!value.Equals(easyProgressTaskManager))
                    {
                        if (easyProgressTaskManager != null)
                            easyProgressTaskManager.TaskProgress -= OnFrameChanged;

                        easyProgressTaskManager = value;
                        easyProgressTaskManager.TaskProgress += new EventHandler<ReportTaskProgressEventArgs>(OnFrameChanged);
                    }
                }
                catch (NullReferenceException)
                {
                    if (easyProgressTaskManager != null)
                        easyProgressTaskManager.TaskProgress -= OnFrameChanged;

                    easyProgressTaskManager = null;
                }
            }
        }

        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;

                // This form has to have the WS_EX_LAYERED extended style.
                cp.ExStyle |= (int)User32.WindowExStyles.WS_EX_LAYERED;
                // Hide from ALT+Tab menu, Turn on WS_EX_TOOLWINDOW style.
                cp.ExStyle |= (int)User32.WindowExStyles.WS_EX_TOOLWINDOW;
                return cp;
            }
        }

        protected override bool ShowWithoutActivation
        {
            // True if the window will not be activated when it is shown; otherwise, false.
            get { return true; }
        }

        #endregion

        #region Virtual Methods

        protected virtual void OnFrameChanged(object sender, ReportTaskProgressEventArgs e)
        {
            if (FrameChanged != null)
                FrameChanged(this, e);

            newFrameImage = e.GetActiveFrameImage;
            if (newFrameImage != null)
                GDIWindow((Bitmap)newFrameImage);
        }

        #endregion

        #region Override Methods

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                EasyProgressTaskManager = null;
            }
            
            base.Dispose(disposing);
        }
        
        #endregion

        #region Helper Methods

        private void GDIWindow(Bitmap bmp)
        {
            IntPtr hDC = User32.GetDC(IntPtr.Zero);
            try
            {
                IntPtr hMemDC = User32.CreateCompatibleDC(hDC);
                try
                {
                    IntPtr hBmp = bmp.GetHbitmap(Color.FromArgb(0));
                    try
                    {
                        IntPtr previousBmp = User32.SelectObject(hMemDC, hBmp);
                        try
                        {
                            Point ptDst = new Point(Left, Top);
                            Size size = new Size(bmp.Width, bmp.Height);
                            Point ptSrc = new Point(0, 0);

                            User32.BLENDFUNCTION blend = new User32.BLENDFUNCTION();
                            blend.BlendOp = User32._AC_SRC_OVER;
                            blend.BlendFlags = 0;
                            blend.SourceConstantAlpha = 255;
                            blend.AlphaFormat = User32._AC_SRC_ALPHA;

                            User32.UpdateLayeredWindow(
                                Handle,
                                hDC,
                                ref ptDst,
                                ref size,
                                hMemDC,
                                ref ptSrc,
                                0,
                                ref blend,
                                User32._LWA_ALPHA);
                        }
                        finally
                        {
                            User32.SelectObject(hDC, previousBmp);
                        }
                    }
                    finally
                    {
                        User32.DeleteObject(hBmp);
                    }
                }
                finally
                {
                    User32.DeleteDC(hMemDC);
                }
            }
            finally
            {
                User32.ReleaseDC(IntPtr.Zero, hDC);
            }
        }

        #endregion
    }
}