TheSwamp

Code Red => .NET => Topic started by: latour_g on November 02, 2020, 04:45:01 PM

Title: Block preview icon
Post by: latour_g on November 02, 2020, 04:45:01 PM

Hi,

I have a command that extract each block of a drawing into a folder.  I use previewicon to see a preview in Windows Explorer.
It's working fine except for certain block.  It says previewicon null but in Autocad I see the preview for those blocks.
Does it mean that the preview that I am seeing in Autocad is stock elsewhere ?
Thank you

Title: Re: Block preview icon
Post by: Atook on November 02, 2020, 10:00:56 PM

Hey latour_g, perhaps this will help:

Code - C#: [Select]

1. using Autodesk.AutoCAD.Windows.Data;
2.  
3. public static Bitmap BlockPreview(string blockName)
4. {
5.   Bitmap result = new Bitmap(1,1);
6.   if (Active.Document == null) return result;
7.   using (Transaction acTr = Active.TransactionManager.StartTransaction())
8.   {
9.     BlockTable bt = (BlockTable)acTr.GetObject(Active.Database.BlockTableId, OpenMode.ForRead);
10.     if (!bt.Has(blockName)) return result;
11.     BlockTableRecord btr = acTr.GetObject(bt[blockName], OpenMode.ForRead) as BlockTableRecord;
12.     if (btr == null) return result;
13.     if (btr.HasPreviewIcon)
14.     {
15.       result = btr.PreviewIcon;
16.     }
17.     else
18.     {
19.       // generate the preview icon
20.       result = new Bitmap(ImageSourceToGDI(CMLContentSearchPreviews.GetBlockTRThumbnail(btr) as BitmapSource));
21.     }
22.     acTr.Commit();
23.   }
24.   return result;
25. }

Title: Re: Block preview icon
Post by: latour_g on November 09, 2020, 11:21:20 AM

Thanks Atook, it look great but I wasn't able to test it so far.  I'm struggling finding ImageSourceToGDI.

Could you tell me in which library to find it ?

I was looking at AcMgd version 21.0 in Autodesk.Windows.Data but it's not there. 

Thank you

Title: Re: Block preview icon
Post by: Atook on November 09, 2020, 04:03:20 PM

Hey latour, sorry I left that out, it's just a static function in the same class:

Code - C#: [Select]

1. private static System.Drawing.Image ImageSourceToGDI(System.Windows.Media.Imaging.BitmapSource src)
2. {
3.   var ms = new MemoryStream();
4.   var encoder =
5.     new System.Windows.Media.Imaging.BmpBitmapEncoder();
6.   encoder.Frames.Add(
7.     System.Windows.Media.Imaging.BitmapFrame.Create(src)
8.   );
9.   encoder.Save(ms);
10.   ms.Flush();
11.   return System.Drawing.Image.FromStream(ms);
12. }

But the real work horse here is:

Code - C#: [Select]

1. CMLContentSearchPreviews.GetBlockTRThumbnail(btr);

It's included in Autodesk.AutoCAD.Windows.Data

Kean has more on it here. (https://www.keanw.com/2013/11/generating-larger-preview-images-for-all-blocks-in-an-autocad-drawing-using-net.html)