1997.05.09 17:01 "Re: compression", by Randy Prakken

i convert tiffs from the proprietary canofile interface to get the index file along with the corresponding tiffs. then i display these tiffs to an internet browser.

how do i go about making sure the tiffs are compressed during storage and decompressed when they are called by the browser? in other words, are these CCIT G4 tiffs compressed already or is there anything i can do to compress them for storage? i'd appreaciate direction towards proper literature/websites.

The only Canofile TIFF we ever got was uncompressed but standard and completely readable by standard TIFF viewers (like our SwiftView). I would do this:

See if the Canofile can be induced to create G4 TIFF and other formats you may want - like multipage.

If it cannot, then I would put a piece of software in series with "storage" to your web site which compressed the file(s) and potentially turned multiple, single page TIFF files into single multi-page files. You can get "free stuff" to do this as talked about on this list or you can buy commercial programs like our SwiftView which don't cost very mucb.

Once you have 100% standard TIFF G4 on your web site, linked with standard URL's, you can view with any TIFF G4 capable viewer configured as a helper. If you want a plug-in, I would look at both TMS at http://www.tmsinc.com and our products at http://www.ndg.com. Our plug-in is in beta now. Just email if you would like to try it out.

If you have any number of pages in your documents, our client/server approach provides _much_ faster performance using standard multipage TIFF files - those properly using Tag 297. This enables you to make each document into a single file. Then instead of sending the entire file before viewing (the most common web approach), you use some trivial CGI (provided on our web site) and our SwiftServe product (eval on our web site). The result is that SwiftView, either as a plug-in or as as helper in a separate window, starts immediately, gets the first few scan lines of the first page and displays them immediately. You get _much_ more interactive and fast TIFF file viewing from your web site.

Feel free to ask any questions. Good luck.

Randy

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Randy Prakken
randy@ndg.com http://www.ndg.com
Northern Development Group, Inc.
Phone:(503)620-0196 x11, Fax:(503)639-8466