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Dummy Thumbnails

Posted: Fri Oct 23, 2015 3:09 pm
by philip.y

I'm experiencing some performance issues when adding thumbnails to the thumbnail control which are very large (15mb+). Most pages are sub 100K so I'd like to load dummy thumbnails instead of real images if the filesize is greater than say 250K.

Is there a way to do this whilst still retaining the link between image viewer (masterviewer property)?

Are there any other performance tweaks I could try?



ps. Unfortunately, its a deployed app using so cant easily upgrade just now.

Re: Dummy Thumbnails

Posted: Fri Oct 23, 2015 3:19 pm
by Alex
Hi Phil,

Unfortunately, thumbnail viewer does not allow to use dummy thumbnails instead of real thumbnails.

Thumbnail viewer will render only visible thumbnails if you set the ThumbnailViewer.GenerateOnlyVisibleThumbnails property to True and this may increase performance of your application.

Also I suggest you to use the latest version (8.2) of SDK because it is the most stable and fast version.

Best regards, Alexander

Re: Dummy Thumbnails

Posted: Sat Oct 24, 2015 2:13 pm
by philip.y
Hi Alexander,

Ok thanks for the confirmation - I thought as much.

I'm already using GenerateOnlyVisibleThumbnails property.

The reason I have this problem is that the scanners don't seem to support JPG image compression properly (colours are off) so they are having to use LZW hence the big files and as a consequence slow thumbnail loading. I'm not entirely sure if its the version of the vinta twain (8.0.31) or the driver. Going to get them to try having .aquiredimages.tiffcompression set to jpeg and see if colours are OK. If works and image quality is ok, this problem will be less of an issue.