PowerToys/Wox.Infrastructure/Image/ThumbnailReader.cs

using System;
using System.Runtime.InteropServices;
using System.IO;
using System.Windows.Interop;
using System.Windows.Media.Imaging;
using System.Windows;

namespace Wox.Infrastructure.Image
{
    [Flags]
    public enum ThumbnailOptions
    {
        None = 0x00,
        BiggerSizeOk = 0x01,
        InMemoryOnly = 0x02,
        IconOnly = 0x04,
        ThumbnailOnly = 0x08,
        InCacheOnly = 0x10,
    }

    public class WindowsThumbnailProvider
    {
        // Based on https://stackoverflow.com/questions/21751747/extract-thumbnail-for-any-file-in-windows

        private const string IShellItem2Guid = "7E9FB0D3-919F-4307-AB2E-9B1860310C93";

        [DllImport("shell32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern int SHCreateItemFromParsingName(
            [MarshalAs(UnmanagedType.LPWStr)] string path,
            IntPtr pbc,
            ref Guid riid,
            [MarshalAs(UnmanagedType.Interface)] out IShellItem shellItem);

        [DllImport("gdi32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool DeleteObject(IntPtr hObject);

        [ComImport]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        [Guid("43826d1e-e718-42ee-bc55-a1e261c37bfe")]
        internal interface IShellItem
        {
            void BindToHandler(IntPtr pbc,
                [MarshalAs(UnmanagedType.LPStruct)]Guid bhid,
                [MarshalAs(UnmanagedType.LPStruct)]Guid riid,
                out IntPtr ppv);

            void GetParent(out IShellItem ppsi);
            void GetDisplayName(SIGDN sigdnName, out IntPtr ppszName);
            void GetAttributes(uint sfgaoMask, out uint psfgaoAttribs);
            void Compare(IShellItem psi, uint hint, out int piOrder);
        };

        internal enum SIGDN : uint
        {
            NORMALDISPLAY = 0,
            PARENTRELATIVEPARSING = 0x80018001,
            PARENTRELATIVEFORADDRESSBAR = 0x8001c001,
            DESKTOPABSOLUTEPARSING = 0x80028000,
            PARENTRELATIVEEDITING = 0x80031001,
            DESKTOPABSOLUTEEDITING = 0x8004c000,
            FILESYSPATH = 0x80058000,
            URL = 0x80068000
        }

        internal enum HResult
        {
            Ok = 0x0000,
            False = 0x0001,
            InvalidArguments = unchecked((int)0x80070057),
            OutOfMemory = unchecked((int)0x8007000E),
            NoInterface = unchecked((int)0x80004002),
            Fail = unchecked((int)0x80004005),
            ExtractionFailed = unchecked((int)0x8004B200),
            ElementNotFound = unchecked((int)0x80070490),
            TypeElementNotFound = unchecked((int)0x8002802B),
            NoObject = unchecked((int)0x800401E5),
            Win32ErrorCanceled = 1223,
            Canceled = unchecked((int)0x800704C7),
            ResourceInUse = unchecked((int)0x800700AA),
            AccessDenied = unchecked((int)0x80030005)
        }

        [ComImportAttribute()]
        [GuidAttribute("bcc18b79-ba16-442f-80c4-8a59c30c463b")]
        [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
        internal interface IShellItemImageFactory
        {
            [PreserveSig]
            HResult GetImage(
            [In, MarshalAs(UnmanagedType.Struct)] NativeSize size,
            [In] ThumbnailOptions flags,
            [Out] out IntPtr phbm);
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct NativeSize
        {
            private int width;
            private int height;

            public int Width { set => width = value; }
            public int Height { set => height = value; }
        };


        public static BitmapSource GetThumbnail(string fileName, int width, int height, ThumbnailOptions options)
        {
            IntPtr hBitmap = GetHBitmap(Path.GetFullPath(fileName), width, height, options);

            try
            {

                return Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
            }
            finally
            {
                // delete HBitmap to avoid memory leaks
                DeleteObject(hBitmap);
            }
        }
        
        private static IntPtr GetHBitmap(string fileName, int width, int height, ThumbnailOptions options)
        {
            IShellItem nativeShellItem;
            Guid shellItem2Guid = new Guid(IShellItem2Guid);
            int retCode = SHCreateItemFromParsingName(fileName, IntPtr.Zero, ref shellItem2Guid, out nativeShellItem);

            if (retCode != 0)
                throw Marshal.GetExceptionForHR(retCode);

            NativeSize nativeSize = new NativeSize
            {
                Width = width,
                Height = height
            };

            IntPtr hBitmap;
            HResult hr = ((IShellItemImageFactory)nativeShellItem).GetImage(nativeSize, options, out hBitmap);

            // if extracting image thumbnail and failed, extract shell icon
            if (options == ThumbnailOptions.ThumbnailOnly && hr == HResult.ExtractionFailed)
            {
                hr = ((IShellItemImageFactory) nativeShellItem).GetImage(nativeSize, ThumbnailOptions.IconOnly, out hBitmap);
            }

            Marshal.ReleaseComObject(nativeShellItem);

            if (hr == HResult.Ok) return hBitmap;

            throw new COMException($"Error while extracting thumbnail for {fileName}", Marshal.GetExceptionForHR((int)hr));
        }
    }
}