Hi!
I’ve a problem with a remote filesystem that has thumbnails. When the explorer opens up a directory without thumbnails, it goes through the whole process of looking in the registry to determine those file system types with an explorer extension dll that handles thumbnails, and makes the appropriate calls (via IExtractImage) to generate the requested thumbnails. This process means that for some file types upwards of 5 MB must be read and processed. What I’d like to be able to do is to disable thumbnail generation just for the directories found in my mapped drive. I’ve tried marking the files as offline, but then I get into problems where copy operations fail using explorer. I’ve tried replacing the thumbnail registrations with my own thumbnail dll that just returns some simple graphic, but I’m not sure if I can read the current registry, temporarily replace the registered DLLs with my own, and then if when called my thumbnail DLL determines that the file in question isn’t my mapped drive, go ahead and call the real thumbnail DLL to generate an appropriate thumbnail. What I’d really love to do is to just be able to programmatically say (preferrably from the file system driver) that either thumbnails are not available for this directory, or we have a dummy thumbnail database that I can just return simple images to the default thumbnail handlers.
This must be a common problem-any thoughts on how to solve it?
Thanks for your time!
Steve Harris
Hi-
Can one simply select the “Do not cache thumbnails” folder option and then delete all thumbs.db subdirectories to stop the creation and usage of thumbnails? Can one do this programatically somehow for the user for specific directory trees? This option must be kept in the file system somewhere as one of the attributes-anyone know which one? Will this eliminate the more egregious cases, unless one chooses to view the directory by thumbnails? I’m interested in your thoughts on this! Thanks!
Steve Harris again…
Try hooking IExtractImage:GetLocation to call your own function and
return the location of a simple thumbnail.
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Sent: 23 January 2008 14:49
To: Windows File Systems Devs Interest List
Subject: [ntfsd] New thoughts on optimizing thumbnail performance?
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Hi!
I’ve a problem with a remote filesystem that has thumbnails. When the
explorer opens up a directory without thumbnails, it goes through the
whole process of looking in the registry to determine those file system
types with an explorer extension dll that handles thumbnails, and makes
the appropriate calls (via IExtractImage) to generate the requested
thumbnails. This process means that for some file types upwards of 5 MB
must be read and processed. What I’d like to be able to do is to
disable thumbnail generation just for the directories found in my mapped
drive. I’ve tried marking the files as offline, but then I get into
problems where copy operations fail using explorer. I’ve tried
replacing the thumbnail registrations with my own thumbnail dll that
just returns some simple graphic, but I’m not sure if I can read the
current registry, temporarily replace the registered DLLs with my own,
and then if when called my thumbnail DLL determines that the file in
question isn’t my mapped drive, go ahead and call the real thumbnail DLL
to generate an appropriate thumbnail. What I’d really love to do is to
just be able to programmatically say (preferrably from the file system
driver) that either thumbnails are not available for this directory, or
we have a dummy thumbnail database that I can just return simple images
to the default thumbnail handlers.
This must be a common problem-any thoughts on how to solve it?
Thanks for your time!
Steve Harris
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