McNeel Wiki

[System.Runtime.InteropServices.Guid("9E940874-883B-4537-81C2-F001654DC497")]
public class ExtractThumbnailCommand : Command
{
  public override string EnglishName { get { return "csExtractThumbnail"; } }
 
  protected override Result RunCommand(RhinoDoc doc, RunMode mode)
  {
    var gf = RhinoGet.GetFileName(GetFileNameMode.OpenImage, "*.3dm", "select file", null);
    if (gf == string.Empty || !System.IO.File.Exists(gf))
      return Result.Cancel;
 
    var bitmap = Rhino.FileIO.File3dm.ReadPreviewImage(gf);
    // convert System.Drawing.Bitmap to BitmapSource
    var imageSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(), IntPtr.Zero,
      Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
 
    // show in WPF window
    var window = new Window();
    var image = new Image {Source = imageSource};
    window.Content = image;
    window.Show();
 
    return Result.Success;
  }
}

<System.Runtime.InteropServices.Guid("96F966CC-F8DA-4C09-A6B0-A4351BEC40FC")> _
Public Class ExtractThumbnailCommand
  Inherits Command
  Public Overrides ReadOnly Property EnglishName() As String
    Get
      Return "vbExtractThumbnail"
    End Get
  End Property
 
  Protected Overrides Function RunCommand(doc As RhinoDoc, mode As RunMode) As Result
    Dim gf = RhinoGet.GetFileName(GetFileNameMode.OpenImage, "*.3dm", "select file", Nothing)
    If gf = String.Empty OrElse Not System.IO.File.Exists(gf) Then
      Return Result.Cancel
    End If
 
    Dim bitmap = Rhino.FileIO.File3dm.ReadPreviewImage(gf)
    ' convert System.Drawing.Bitmap to BitmapSource
    Dim imageSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions())
 
    ' show in WPF window
    Dim window = New Window()
    Dim image = New Image()
    image.Source = imageSource
 
    window.Content = image
    window.Show()
 
    Return Result.Success
  End Function
End Class
d Namespace

import Rhino
import rhinoscriptsyntax as rs
from scriptcontext import doc
 
import clr
clr.AddReference("System.Windows.Forms")
import System.Windows.Forms
 
def RunCommand():
 
  fn = rs.OpenFileName(title="select file", filter="Rhino files|*.3dm||")
  if fn == None:
    return
 
  bitmap = doc.ExtractPreviewImage(fn)
 
  f = System.Windows.Forms.Form()
  f.Height = bitmap.Height
  f.Width = bitmap.Width
  pb = System.Windows.Forms.PictureBox()
  pb.Image = bitmap
  pb.Height = bitmap.Height  #SizeMode = System.Windows.Forms.PictueBoxSizeMode.AutoSize
  pb.Width = bitmap.Width
  f.Controls.Add(pb);
  f.Show();
 
if __name__ == "__main__":
  RunCommand()