System/Drawing/Icon.Unix.cs

// Licensed to the .NET Foundation under one or more agreements.
// See the LICENSE file in the project root for more information.
//
// System.Drawing.Icon.cs
//
// Authors:
//   Gary Barnett (gary.barnett.mono@gmail.com)
//   Dennis Hayes (dennish@Raytek.com)
//   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
//   Sanjay Gupta (gsanjay@novell.com)
//   Peter Dennis Bartok (pbartok@novell.com)
//   Sebastien Pouliot  <sebastien@ximian.com>
//
// Copyright (C) 2002 Ximian, Inc. http://www.ximian.com
// Copyright (C) 2004-2008 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Collections;
using System.ComponentModel;
using System.Drawing.Imaging;
using System.IO;
using System.Reflection;
using System.Runtime.Serialization;
using System.Runtime.InteropServices;

namespace System.Drawing
{
#if !NETCORE
#if !MONOTOUCH
    [Editor ("System.Drawing.Design.IconEditor, " + Consts.AssemblySystem_Drawing_Design, typeof (System.Drawing.Design.UITypeEditor))]
#endif
    [TypeConverter(typeof(IconConverter))]
#endif
    public sealed partial class Icon : MarshalByRefObject, ISerializable, ICloneable, IDisposable
    {
        [StructLayout(LayoutKind.Sequential)]
        internal struct IconDirEntry
        {
            internal byte width;        // Width of icon
            internal byte height;       // Height of icon
            internal byte colorCount;   // colors in icon
            internal byte reserved; // Reserved
            internal ushort planes;         // Color Planes
            internal ushort bitCount;       // Bits per pixel
            internal uint bytesInRes;     // bytes in resource
            internal uint imageOffset;  // position in file
            internal bool ignore;       // for unsupported images (vista 256 png)
        };

        [StructLayout(LayoutKind.Sequential)]
        internal struct IconDir
        {
            internal ushort idReserved;   // Reserved
            internal ushort idType;       // resource type (1 for icons)
            internal ushort idCount;      // how many images?
            internal IconDirEntry[] idEntries;    // the entries for each image
        };

        [StructLayout(LayoutKind.Sequential)]
        internal struct BitmapInfoHeader
        {
            internal uint biSize;
            internal int biWidth;
            internal int biHeight;
            internal ushort biPlanes;
            internal ushort biBitCount;
            internal uint biCompression;
            internal uint biSizeImage;
            internal int biXPelsPerMeter;
            internal int biYPelsPerMeter;
            internal uint biClrUsed;
            internal uint biClrImportant;
        };

        [StructLayout(LayoutKind.Sequential)]   // added baseclass for non bmp image format support
        internal abstract class ImageData
        {
        };

        [StructLayout(LayoutKind.Sequential)]
        internal class IconImage : ImageData
        {
            internal BitmapInfoHeader iconHeader;   //image header
            internal uint[] iconColors; //colors table
            internal byte[] iconXOR;    // bits for XOR mask
            internal byte[] iconAND;    //bits for AND mask
        };

        [StructLayout(LayoutKind.Sequential)]
        internal class IconDump : ImageData
        {
            internal byte[] data;
        };

        private Size iconSize;
        private IntPtr handle = IntPtr.Zero;
        private IconDir iconDir;
        private ushort id;
        private ImageData[] imageData;
        private bool undisposable;
        private bool disposed;
        private Bitmap bitmap;

        private Icon()
        {
        }

#if !MONOTOUCH
        private Icon(IntPtr handle)
        {
            this.handle = handle;
            bitmap = Bitmap.FromHicon(handle);
            iconSize = new Size(bitmap.Width, bitmap.Height);
            bitmap = Bitmap.FromHicon(handle);
            iconSize = new Size(bitmap.Width, bitmap.Height);
            // FIXME: we need to convert the bitmap into an icon
            undisposable = true;
        }
#endif

        public Icon(Icon original, int width, int height)
            : this(original, new Size(width, height))
        {
        }

        public Icon(Icon original, Size size)
        {
            if (original == null)
                throw new ArgumentNullException(nameof(original));

            iconSize = size;
            iconDir = original.iconDir;

            int count = iconDir.idCount;
            if (count > 0)
            {
                imageData = original.imageData;
                id = UInt16.MaxValue;

                for (ushort i = 0; i < count; i++)
                {
                    IconDirEntry ide = iconDir.idEntries[i];
                    if (((ide.height == size.Height) || (ide.width == size.Width)) && !ide.ignore)
                    {
                        id = i;
                        break;
                    }
                }

                // if a perfect match isn't found we look for the biggest icon *smaller* than specified
                if (id == UInt16.MaxValue)
                {
                    int requested = Math.Min(size.Height, size.Width);
                    // previously best set to 1st image, as this might not be smallest changed loop to check all
                    IconDirEntry? best = null;
                    for (ushort i = 0; i < count; i++)
                    {
                        IconDirEntry ide = iconDir.idEntries[i];
                        if (((ide.height < requested) || (ide.width < requested)) && !ide.ignore)
                        {
                            if (best == null)
                            {
                                best = ide;
                                id = i;
                            }
                            else if ((ide.height > best.Value.height) || (ide.width > best.Value.width))
                            {
                                best = ide;
                                id = i;
                            }
                        }
                    }
                }

                // last one, if nothing better can be found
                if (id == UInt16.MaxValue)
                {
                    int i = count;
                    while (id == UInt16.MaxValue && i > 0)
                    {
                        i--;
                        if (!iconDir.idEntries[i].ignore)
                            id = (ushort)i;
                    }
                }

                if (id == UInt16.MaxValue)
                    throw new ArgumentException("Icon", "No valid icon image found");

                iconSize.Height = iconDir.idEntries[id].height;
                iconSize.Width = iconDir.idEntries[id].width;
            }
            else
            {
                iconSize.Height = size.Height;
                iconSize.Width = size.Width;
            }

            if (original.bitmap != null)
                bitmap = (Bitmap)original.bitmap.Clone();
        }

        public Icon(Stream stream) : this(stream, 32, 32)
        {
        }

        public Icon(Stream stream, int width, int height)
        {
            InitFromStreamWithSize(stream, width, height);
        }

        public Icon(string fileName)
        {
            using (FileStream fs = File.OpenRead(fileName))
            {
                InitFromStreamWithSize(fs, 32, 32);
            }
        }

        public Icon(Type type, string resource)
        {
            if (resource == null)
                throw new ArgumentException("resource");

            // For compatibility with the .NET Framework
            if (type == null)
                throw new NullReferenceException();

            using (Stream s = type.GetTypeInfo().Assembly.GetManifestResourceStream(type, resource))
            {
                if (s == null)
                {
                    throw new ArgumentException(null);
                }
                InitFromStreamWithSize(s, 32, 32);      // 32x32 is default
            }
        }


        internal Icon(string resourceName, bool undisposable)
        {
            using (Stream s = typeof(Icon).GetTypeInfo().Assembly.GetManifestResourceStream(resourceName))
            {
                if (s == null)
                {
                    string msg = string.Format("Resource '{0}' was not found.", resourceName);
                    throw new FileNotFoundException(msg);
                }
                InitFromStreamWithSize(s, 32, 32);      // 32x32 is default
            }
            this.undisposable = true;
        }

        public Icon(Stream stream, Size size) :
            this(stream, size.Width, size.Height)
        {
        }

        public Icon(string fileName, int width, int height)
        {
            using (FileStream fs = File.OpenRead(fileName))
            {
                InitFromStreamWithSize(fs, width, height);
            }
        }

        public Icon(string fileName, Size size)
        {
            using (FileStream fs = File.OpenRead(fileName))
            {
                InitFromStreamWithSize(fs, size.Width, size.Height);
            }
        }

        [MonoLimitation("The same icon, SystemIcons.WinLogo, is returned for all file types.")]
        public static Icon ExtractAssociatedIcon(string filePath)
        {
            if (filePath == null)
                throw new ArgumentNullException(nameof(filePath));
            if (String.IsNullOrEmpty(filePath))
                throw new ArgumentException("Null or empty path.", "path");
            if (!File.Exists(filePath))
                throw new FileNotFoundException("Couldn't find specified file.", filePath);

            return SystemIcons.WinLogo;
        }

        public void Dispose()
        {
            // SystemIcons requires this
            if (undisposable)
                return;

            if (!disposed)
            {
                if (bitmap != null)
                {
                    bitmap.Dispose();
                    bitmap = null;
                }
                GC.SuppressFinalize(this);
            }
            disposed = true;
        }

        public object Clone()
        {
            return new Icon(this, Size);
        }

#if !MONOTOUCH
        public static Icon FromHandle(IntPtr handle)
        {
            if (handle == IntPtr.Zero)
                throw new ArgumentException("handle");

            return new Icon(handle);
        }
#endif
        private void SaveIconImage(BinaryWriter writer, IconImage ii)
        {
            BitmapInfoHeader bih = ii.iconHeader;
            writer.Write(bih.biSize);
            writer.Write(bih.biWidth);
            writer.Write(bih.biHeight);
            writer.Write(bih.biPlanes);
            writer.Write(bih.biBitCount);
            writer.Write(bih.biCompression);
            writer.Write(bih.biSizeImage);
            writer.Write(bih.biXPelsPerMeter);
            writer.Write(bih.biYPelsPerMeter);
            writer.Write(bih.biClrUsed);
            writer.Write(bih.biClrImportant);

            //now write color table
            int colCount = ii.iconColors.Length;
            for (int j = 0; j < colCount; j++)
                writer.Write(ii.iconColors[j]);

            //now write XOR Mask
            writer.Write(ii.iconXOR);

            //now write AND Mask
            writer.Write(ii.iconAND);
        }

        private void SaveIconDump(BinaryWriter writer, IconDump id)
        {
            writer.Write(id.data);
        }

        private void SaveIconDirEntry(BinaryWriter writer, IconDirEntry ide, uint offset)
        {
            writer.Write(ide.width);
            writer.Write(ide.height);
            writer.Write(ide.colorCount);
            writer.Write(ide.reserved);
            writer.Write(ide.planes);
            writer.Write(ide.bitCount);
            writer.Write(ide.bytesInRes);
            writer.Write((offset == UInt32.MaxValue) ? ide.imageOffset : offset);
        }

        private void SaveAll(BinaryWriter writer)
        {
            writer.Write(iconDir.idReserved);
            writer.Write(iconDir.idType);
            ushort count = iconDir.idCount;
            writer.Write(count);

            for (int i = 0; i < (int)count; i++)
            {
                SaveIconDirEntry(writer, iconDir.idEntries[i], UInt32.MaxValue);
            }

            for (int i = 0; i < (int)count; i++)
            {

                //FIXME: HACK: 1 (out of the 8) vista type icons had additional bytes (value:0)
                //between images. This fixes the issue, but perhaps shouldnt include in production?
                while (writer.BaseStream.Length < iconDir.idEntries[i].imageOffset)
                    writer.Write((byte)0);

                if (imageData[i] is IconDump)
                    SaveIconDump(writer, (IconDump)imageData[i]);
                else
                    SaveIconImage(writer, (IconImage)imageData[i]);
            }
        }
        // TODO: check image not ignored (presently this method doesnt seem to be called unless width/height
        // refer to image)
        private void SaveBestSingleIcon(BinaryWriter writer, int width, int height)
        {
            writer.Write(iconDir.idReserved);
            writer.Write(iconDir.idType);
            writer.Write((ushort)1);

            // find best entry and save it
            int best = 0;
            int bitCount = 0;
            for (int i = 0; i < iconDir.idCount; i++)
            {
                IconDirEntry ide = iconDir.idEntries[i];
                if ((width == ide.width) && (height == ide.height))
                {
                    if (ide.bitCount >= bitCount)
                    {
                        bitCount = ide.bitCount;
                        best = i;
                    }
                }
            }

            SaveIconDirEntry(writer, iconDir.idEntries[best], 22);
            SaveIconImage(writer, (IconImage)imageData[best]);
        }

        private void SaveBitmapAsIcon(BinaryWriter writer)
        {
            writer.Write((ushort)0);    // idReserved must be 0
            writer.Write((ushort)1);    // idType must be 1
            writer.Write((ushort)1);    // only one icon

            // when transformed into a bitmap only a single image exists
            IconDirEntry ide = new IconDirEntry();
            ide.width = (byte)bitmap.Width;
            ide.height = (byte)bitmap.Height;
            ide.colorCount = 0; // 32 bbp == 0, for palette size
            ide.reserved = 0;   // always 0
            ide.planes = 0;
            ide.bitCount = 32;
            ide.imageOffset = 22;   // 22 is the first icon position (for single icon files)

            BitmapInfoHeader bih = new BitmapInfoHeader();
            bih.biSize = (uint)Marshal.SizeOf(typeof(BitmapInfoHeader));
            bih.biWidth = bitmap.Width;
            bih.biHeight = 2 * bitmap.Height; // include both XOR and AND images
            bih.biPlanes = 1;
            bih.biBitCount = 32;
            bih.biCompression = 0;
            bih.biSizeImage = 0;
            bih.biXPelsPerMeter = 0;
            bih.biYPelsPerMeter = 0;
            bih.biClrUsed = 0;
            bih.biClrImportant = 0;

            IconImage ii = new IconImage();
            ii.iconHeader = bih;
            ii.iconColors = new uint[0];    // no palette
            int xor_size = (((bih.biBitCount * bitmap.Width + 31) & ~31) >> 3) * bitmap.Height;
            ii.iconXOR = new byte[xor_size];
            int p = 0;
            for (int y = bitmap.Height - 1; y >= 0; y--)
            {
                for (int x = 0; x < bitmap.Width; x++)
                {
                    Color c = bitmap.GetPixel(x, y);
                    ii.iconXOR[p++] = c.B;
                    ii.iconXOR[p++] = c.G;
                    ii.iconXOR[p++] = c.R;
                    ii.iconXOR[p++] = c.A;
                }
            }
            int and_line_size = (((Width + 31) & ~31) >> 3);    // must be a multiple of 4 bytes
            int and_size = and_line_size * bitmap.Height;
            ii.iconAND = new byte[and_size];

            ide.bytesInRes = (uint)(bih.biSize + xor_size + and_size);

            SaveIconDirEntry(writer, ide, UInt32.MaxValue);
            SaveIconImage(writer, ii);
        }

        private void Save(Stream outputStream, int width, int height)
        {
            BinaryWriter writer = new BinaryWriter(outputStream);
            // if we have the icon information then save from this
            if (iconDir.idEntries != null)
            {
                if ((width == -1) && (height == -1))
                    SaveAll(writer);
                else
                    SaveBestSingleIcon(writer, width, height);
            }
            else if (bitmap != null)
            {
                // if the icon was created from a bitmap then convert it
                SaveBitmapAsIcon(writer);
            }
            writer.Flush();
        }

        public void Save(Stream outputStream)
        {
            if (outputStream == null)
                throw new NullReferenceException("outputStream");

            // save every icons available
            Save(outputStream, -1, -1);
        }
#if !MONOTOUCH
        internal Bitmap BuildBitmapOnWin32()
        {
            Bitmap bmp;

            if (imageData == null)
                return new Bitmap(32, 32);

            IconImage ii = (IconImage)imageData[id];
            BitmapInfoHeader bih = ii.iconHeader;
            int biHeight = bih.biHeight / 2;

            int ncolors = (int)bih.biClrUsed;
            if ((ncolors == 0) && (bih.biBitCount < 24))
                ncolors = (int)(1 << bih.biBitCount);

            switch (bih.biBitCount)
            {
                case 1:
                    bmp = new Bitmap(bih.biWidth, biHeight, PixelFormat.Format1bppIndexed);
                    break;
                case 4:
                    bmp = new Bitmap(bih.biWidth, biHeight, PixelFormat.Format4bppIndexed);
                    break;
                case 8:
                    bmp = new Bitmap(bih.biWidth, biHeight, PixelFormat.Format8bppIndexed);
                    break;
                case 24:
                    bmp = new Bitmap(bih.biWidth, biHeight, PixelFormat.Format24bppRgb);
                    break;
                case 32:
                    bmp = new Bitmap(bih.biWidth, biHeight, PixelFormat.Format32bppArgb);
                    break;
                default:
                    string msg = string.Format("Unexpected number of bits: {0}", bih.biBitCount);
                    throw new Exception(msg);
            }

            if (bih.biBitCount < 24)
            {
                ColorPalette pal = bmp.Palette; // Managed palette

                for (int i = 0; i < ii.iconColors.Length; i++)
                {
                    pal.Entries[i] = Color.FromArgb((int)ii.iconColors[i] | unchecked((int)0xff000000));
                }
                bmp.Palette = pal;
            }

            int bytesPerLine = (int)((((bih.biWidth * bih.biBitCount) + 31) & ~31) >> 3);
            BitmapData bits = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.WriteOnly, bmp.PixelFormat);

            for (int y = 0; y < biHeight; y++)
            {
                Marshal.Copy(ii.iconXOR, bytesPerLine * y,
                    (IntPtr)(bits.Scan0.ToInt64() + bits.Stride * (biHeight - 1 - y)), bytesPerLine);
            }

            bmp.UnlockBits(bits);

            bmp = new Bitmap(bmp); // This makes a 32bpp image out of an indexed one

            // Apply the mask to make properly transparent
            bytesPerLine = (int)((((bih.biWidth) + 31) & ~31) >> 3);
            for (int y = 0; y < biHeight; y++)
            {
                for (int x = 0; x < bih.biWidth / 8; x++)
                {
                    for (int bit = 7; bit >= 0; bit--)
                    {
                        if (((ii.iconAND[y * bytesPerLine + x] >> bit) & 1) != 0)
                        {
                            bmp.SetPixel(x * 8 + 7 - bit, biHeight - y - 1, Color.Transparent);
                        }
                    }
                }
            }

            return bmp;
        }

        internal Bitmap GetInternalBitmap()
        {
            if (bitmap == null)
            {
                // Mono's libgdiplus doesn't require to keep the stream alive when loading images
                using (MemoryStream ms = new MemoryStream())
                {
                    // save the current icon
                    Save(ms, Width, Height);
                    ms.Position = 0;

                    // libgdiplus can now decode icons
                    bitmap = (Bitmap)Image.LoadFromStream(ms, false);
                }
            }
            return bitmap;
        }

        // note: all bitmaps are 32bits ARGB - no matter what the icon format (bitcount) was
        public Bitmap ToBitmap()
        {
            if (disposed)
                throw new ObjectDisposedException("Icon instance was disposed.");

            // note: we can't return the original image because
            // (a) we have no control over the bitmap instance we return (i.e. it could be disposed)
            // (b) the palette, flags won't match MS results. See MonoTests.System.Drawing.Imaging.IconCodecTest.
            //     Image16 for the differences
            return new Bitmap(GetInternalBitmap());
        }
#endif
        public override string ToString()
        {
            //is this correct, this is what returned by .Net
            return "<Icon>";
        }

#if !MONOTOUCH
        [Browsable(false)]
        public IntPtr Handle
        {
            get
            {
                if (disposed)
                {
                    throw new ObjectDisposedException(GetType().Name);
                }

                // note: this handle doesn't survive the lifespan of the icon instance
                if (handle == IntPtr.Zero)
                {
                    handle = GetInternalBitmap().nativeImage;
                }
                return handle;
            }
        }
#endif
        [Browsable(false)]
        public int Height
        {
            get
            {
                if (disposed)
                {
                    throw new ObjectDisposedException(GetType().Name);
                }

                return iconSize.Height;
            }
        }

        public Size Size
        {
            get
            {
                if (disposed)
                {
                    throw new ObjectDisposedException(GetType().Name);
                }

                return iconSize;
            }
        }

        [Browsable(false)]
        public int Width
        {
            get
            {
                if (disposed)
                {
                    throw new ObjectDisposedException(GetType().Name);
                }

                return iconSize.Width;
            }
        }

        ~Icon()
        {
            Dispose();
        }

        private void InitFromStreamWithSize(Stream stream, int width, int height)
        {
            if (stream == null)
                throw new ArgumentNullException(nameof(stream));

            if (stream.Length == 0)
                throw new System.ArgumentException("The argument 'stream' must be a picture that can be used as a Icon", "stream");

            //read the icon header
            BinaryReader reader = new BinaryReader(stream);

            //iconDir = new IconDir ();
            iconDir.idReserved = reader.ReadUInt16();
            if (iconDir.idReserved != 0) //must be 0
                throw new System.ArgumentException("Invalid Argument", "stream");

            iconDir.idType = reader.ReadUInt16();
            if (iconDir.idType != 1) //must be 1
                throw new System.ArgumentException("Invalid Argument", "stream");

            ushort dirEntryCount = reader.ReadUInt16();
            imageData = new ImageData[dirEntryCount];
            iconDir.idCount = dirEntryCount;
            iconDir.idEntries = new IconDirEntry[dirEntryCount];
            bool sizeObtained = false;
            // now read in the IconDirEntry structures
            for (int i = 0; i < dirEntryCount; i++)
            {
                IconDirEntry ide;
                ide.width = reader.ReadByte();
                ide.height = reader.ReadByte();
                ide.colorCount = reader.ReadByte();
                ide.reserved = reader.ReadByte();
                ide.planes = reader.ReadUInt16();
                ide.bitCount = reader.ReadUInt16();
                ide.bytesInRes = reader.ReadUInt32();
                ide.imageOffset = reader.ReadUInt32();

                // Vista 256x256 icons points directly to a PNG bitmap
                // 256x256 icons are decoded as 0x0 (width and height are encoded as BYTE)
                // and we ignore them just like MS does (at least up to fx 2.0)
                // Added: storing data so it can be saved back
                if ((ide.width == 0) && (ide.height == 0))
                    ide.ignore = true;
                else
                    ide.ignore = false;

                iconDir.idEntries[i] = ide;

                //is this is the best fit??
                if (!sizeObtained)
                {
                    if (((ide.height == height) || (ide.width == width)) && !ide.ignore)
                    {
                        this.id = (ushort)i;
                        sizeObtained = true;
                        this.iconSize.Height = ide.height;
                        this.iconSize.Width = ide.width;
                    }
                }
            }

            // throw error if no valid entries found
            int valid = 0;
            for (int i = 0; i < dirEntryCount; i++)
            {
                if (!(iconDir.idEntries[i].ignore))
                    valid++;
            }

            if (valid == 0)
                throw new Win32Exception(0, "No valid icon entry were found.");

            // if we havent found the best match, return the one with the
            // largest size. Is this approach correct??
            if (!sizeObtained)
            {
                uint largestSize = 0;
                for (int j = 0; j < dirEntryCount; j++)
                {
                    if (iconDir.idEntries[j].bytesInRes >= largestSize && !iconDir.idEntries[j].ignore)
                    {
                        largestSize = iconDir.idEntries[j].bytesInRes;
                        this.id = (ushort)j;
                        this.iconSize.Height = iconDir.idEntries[j].height;
                        this.iconSize.Width = iconDir.idEntries[j].width;
                    }
                }
            }

            //now read in the icon data
            for (int j = 0; j < dirEntryCount; j++)
            {
                // process ignored into IconDump
                if (iconDir.idEntries[j].ignore)
                {
                    IconDump id = new IconDump();
                    stream.Seek(iconDir.idEntries[j].imageOffset, SeekOrigin.Begin);
                    id.data = new byte[iconDir.idEntries[j].bytesInRes];
                    stream.Read(id.data, 0, id.data.Length);
                    imageData[j] = id;
                    continue;
                }
                // standard image
                IconImage iidata = new IconImage();
                BitmapInfoHeader bih = new BitmapInfoHeader();
                stream.Seek(iconDir.idEntries[j].imageOffset, SeekOrigin.Begin);
                byte[] buffer = new byte[iconDir.idEntries[j].bytesInRes];
                stream.Read(buffer, 0, buffer.Length);
                BinaryReader bihReader = new BinaryReader(new MemoryStream(buffer));
                bih.biSize = bihReader.ReadUInt32();
                bih.biWidth = bihReader.ReadInt32();
                bih.biHeight = bihReader.ReadInt32();
                bih.biPlanes = bihReader.ReadUInt16();
                bih.biBitCount = bihReader.ReadUInt16();
                bih.biCompression = bihReader.ReadUInt32();
                bih.biSizeImage = bihReader.ReadUInt32();
                bih.biXPelsPerMeter = bihReader.ReadInt32();
                bih.biYPelsPerMeter = bihReader.ReadInt32();
                bih.biClrUsed = bihReader.ReadUInt32();
                bih.biClrImportant = bihReader.ReadUInt32();
                iidata.iconHeader = bih;
                //Read the number of colors used and corresponding memory occupied by
                //color table. Fill this memory chunk into rgbquad[]
                int numColors;
                switch (bih.biBitCount)
                {
                    case 1:
                        numColors = 2;
                        break;
                    case 4:
                        numColors = 16;
                        break;
                    case 8:
                        numColors = 256;
                        break;
                    default:
                        numColors = 0;
                        break;
                }

                iidata.iconColors = new uint[numColors];
                for (int i = 0; i < numColors; i++)
                    iidata.iconColors[i] = bihReader.ReadUInt32();

                //XOR mask is immediately after ColorTable and its size is
                //icon height* no. of bytes per line

                //icon height is half of BITMAPINFOHEADER.biHeight, since it contains
                //both XOR as well as AND mask bytes
                int iconHeight = bih.biHeight / 2;

                //bytes per line should should be uint aligned
                int numBytesPerLine = ((((bih.biWidth * bih.biPlanes * bih.biBitCount) + 31) >> 5) << 2);

                //Determine the XOR array Size
                int xorSize = numBytesPerLine * iconHeight;
                iidata.iconXOR = new byte[xorSize];
                int nread = bihReader.Read(iidata.iconXOR, 0, xorSize);
                if (nread != xorSize)
                {
                    string msg = string.Format("{0} data length expected {1}, read {2}", "XOR", xorSize, nread);
                    throw new ArgumentException(msg, "stream");
                }

                //Determine the AND array size
                numBytesPerLine = (int)((((bih.biWidth) + 31) & ~31) >> 3);
                int andSize = numBytesPerLine * iconHeight;
                iidata.iconAND = new byte[andSize];
                nread = bihReader.Read(iidata.iconAND, 0, andSize);
                if (nread != andSize)
                {
                    string msg = string.Format("{0} data length expected {1}, read {2}", "AND", andSize, nread);
                    throw new ArgumentException(msg, "stream");
                }

                imageData[j] = iidata;
                bihReader.Dispose();
            }

            reader.Dispose();
        }
    }
}