SkyCopy/ThumbnailExtractor.cs at developer · zeusmx/SkyCopy · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace SkyCopy
{
    public static class ThumbnailExtractor
    {
        [DllImport("shell32.dll", CharSet = CharSet.Unicode, PreserveSig = false)]
        private static extern void SHCreateItemFromParsingName(
            [MarshalAs(UnmanagedType.LPWStr)] string pszPath,
            IntPtr pbc,
            ref Guid riid,
            [MarshalAs(UnmanagedType.Interface)] out IShellItemImageFactory ppv);

        [ComImport]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        [Guid("bcc18b79-ba16-442f-80c4-8a59c30c463b")]
        private interface IShellItemImageFactory
        {
            void GetImage([In] SIZE size, [In] SIIGBF flags, out IntPtr phbm);
        }

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

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

        [Flags]
        private enum SIIGBF
        {
            SIIGBF_RESIZETOFIT = 0x00,
            SIIGBF_THUMBNAILONLY = 0x02,
        }

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

        /// <summary>
        /// Extracts a thumbnail for the given file path using the Windows Shell.
        /// Returns null if thumbnail extraction fails.
        /// </summary>
        public static ImageSource? GetThumbnail(string filePath, int size = 64)
        {
            IntPtr hBitmap = IntPtr.Zero;
            try
            {
                var iidFactory = new Guid("bcc18b79-ba16-442f-80c4-8a59c30c463b");
                SHCreateItemFromParsingName(filePath, IntPtr.Zero, ref iidFactory, out var factory);

                factory.GetImage(new SIZE(size, size), SIIGBF.SIIGBF_RESIZETOFIT, out hBitmap);

                var source = Imaging.CreateBitmapSourceFromHBitmap(
                    hBitmap, IntPtr.Zero, Int32Rect.Empty,
                    BitmapSizeOptions.FromEmptyOptions());
                source.Freeze();
                return source;
            }
            catch
            {
                return null;
            }
            finally
            {
                if (hBitmap != IntPtr.Zero)
                    DeleteObject(hBitmap);
            }
        }
    }
}