Silverlight / Deepzoom weird flashing rectangle bug

Question

I just launched my website - blackspike.com - under the 3D tab on the homepage I've put a deepzoom collection in there. A friend has noticed that if you pan down and to the right there's a weird psycadelic flashing rectangle.

I've tried recreating the collection, and reuploaded and there is nothing in the composer project to suggest anything out of the ordinary.

Has anyone seen a bug like this before, or have any ideas how to fix?

Thanks in advance!

Answer 1

I can see inside your Deem Zoom XML file (http://www.blackspike.com/site/wp-content/themes/blackspike09/sl/uberHeader/ClientBin/GeneratedImages/dzc_output.xml) that there are 23 images in the collection, but only 6 are visible on the page. Thumbnails of all the images used to compose the collection are visible here:

http://www.blackspike.com/site/wp-content/themes/blackspike09/sl/uberHeader/ClientBin/GeneratedImages/dzc_output_files/5/0_0.jpg

I think you added more images into Deep Zoom composer than needed, and theese extra images are placed outside the immediate visible area causing this rectangle to appear. You can fix that by recreating collection using only 6 images or you can just delete the entries with IDs from 6 to 22 from XML at http://www.blackspike.com/site/wp-content/themes/blackspike09/sl/uberHeader/ClientBin/GeneratedImages/dzc_output.xml

Answer 2

Did you use the deep zoom composer to create the image?

It looks like the kind of thing you get when floating point calculated results are rounded to integers for pixel placement. To avoid such artefacts the deep zoom composer sets the tile overlap to 1 which minimises this effect, although doesn't necessarily eliminate it.