Thumbnails in explorer.

[Elias Montoya]

Hello guys, i have a question. Many applications can display thumbnails
in the explorer, for example image editors, M$ Office, Etc...

Would it be too hard to add this functionality to my application?

Im guessing i would have to create a COM Server app of some sort...
anyone has done that?

[Egbert Zijlema]

Should not the user decide?

As far as I can interprete this, you want to force the user to see thumbnails instead of, for instance, details (filename, filedate etc). Imo it's the user who should decide how he wants to open his explorer views. The View-menu is the standard tool for this kind of user action.

[Michael Mattias]

Assuming you are using a listview control (which is what Explorer uses), you can specify the icon for each row of the control; and you can get the icon from any executable program which has one.

(I forget which WinApi call that is, but I think it's one of the "SHxxxx" fucntions in SHLWAPI.DLL).

[Elias Montoya]

As far as I can interprete this, you want to force the user to see thumbnails instead of, for instance, details (filename, filedate etc). Imo it's the user who should decide how he wants to open his explorer views. The View-menu is the standard tool for this kind of user action.

No, no, no...

I dont want to force anyone, i just want the user to be able to see the thumbnails IF he selects to view thumnails.

No files can display thumbnails if user uses details view.

Michael... i dont understand your suggestion, perhaps you didnt understand the question... IDK... ill re read it many times. I dont have any access to any code and i will not have any programs running, all i have is a File with my own extension, and i would like to display a thumbnail in the explorer when user selects Thumbnail view.

[Adam J. Drake]

Elias,

Are you talking about different display modes you can select in one of the common dialogs, or displaying thumbnails in a custom created listview?

[Roger Garstang]

I think he means he has his own file type and when the user selects thumbnail view he wants his file type to have a thumbnail. So, he will need to create something that gives Explorer the needed data to display a thumbnail of his file.

Sounds kind of interesting if I'm correct in what he wants. There must be some way of telling explorer how to handle your files. I remember back before XP and such to get thumbnails you used to have to do things like setting the registry key for HKEY_CLASSES_ROOT\Paint.Picture\DefaultIcon to be %1, etc. Back then the name may have been bmpfile or something since Paint changed names so much, but something told Explorer that %1 opened the file and returned contents to display as an icon.

[Roger Garstang]

A quick Google gave me:

http://www.codeproject.com/KB/shell/thumbextract.aspx

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=125283&SiteID=1

http://www.rw-designer.com/thumbnails.php

http://www.vbaccelerator.com/home/net/code/libraries/shell_projects/Thumbnail_Extraction/article.asp

http://www.vbaccelerator.com/home/Resources/Links/IBrowse/Thumbnail_Extractor_feature/article.asp

Some of those could be useful. This would be a cool edition for 3rd Party Developers to display thumbs of their project files and such.

[Mike Doty]

Josa Roca's web browser allows this and I also believe Semen has posted some COM code. May not be exactly what you are looking for, but it
is easy to size images to look like thumbnails on a web page.

[Patrice Terrier]

I don't know if this is what your are looking for, but you could try my freeware "ZAP Media Lite" there it can do much things with pictures "on the fly" and also create thumbnail contact sheets.

Now if you just want to embed a thumbnail in common dialog save/load then you must hook it (there is an example in the GDImage load/save built-in dialog). And there is also a Borje's example in Poff showing how to hook a common dialog.

...

[Kev Peel]

It requires a COM server extension...

If the file is an image or video, you need to register the extension as such and Windows will handle the thumbnail. Otherwise I believe you need to create an "extension" DLL, which are COM only. Windows queries this extension DLL for the required display data (thumbnail, icon, etc).

IExtractImage Interface () (Windows 2000/ME+)
IThumbnailProvider Interface () (Vista)

[Elias Montoya]

Roger, you are right, thats what i want... I dont notice it... but from the
comments, i think im somewhat hard to understand...

Here is what i want in simple terms:

Windows Explorer + My own file type + User selecting Thumbnail view = A preview of the documents as thumbnails in the WIndows explorer.

Mike im going to look for that code for a good start, thanx!