-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Markus,
On 9/28/2009 6:03 PM, Markus Meyer wrote: > Martin Gainty schrieb: >> could you explain just a bit more what is a tile? > > If you have a very large image, say 1 million x 1 million pixels or > something like that, it is more efficient to split the image into tiles, > that is small images of, say, 256 x 256 pixels. If a certain portion of > the big image is requested, you can then load these tiles individually > from disk and put them together to form the portion of the image that > was requested. Oddly enough, this is much more efficient to do on the client side if, say, javascript is available. Google appears to do this with their maps: if you pan around your home on maps.google.com, you can see the individual tiles loading and being rendered on the screen to create a larger image. If you pan "off the screen" no loading has to occur until you cross one of the tile boundaries that has already been sent. It's like looking through a small window at a large painting: you are only seeing a small portion of the painting (the sum total of all previously-fetched tiles) because of the size of the window (the view port on the screen). The OP seems to be using tiles on the backend for convenience, but then using complex server-side methods to assemble the /exact/ image that the client requested. That requires things like image decoding followed by lots of memory allocation, and then a heavy re-compression before streaming the result back to the client. If the client has some measure of power, the server can take advantage of that by converting all complex requests into individual, simple requests. A request for a single 1000x1000 image could be converted into 16 requests for 256x256 static tile images, then re-assembled on the client. No image manipulation occurs on the server, which is a /huge/ win for your service. Unfortunately, it requires something like javascript to be present on the client. If your service cannot tolerate such a requirement, then you need to make arrangements for those clients who /don't/ have javascript available. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkrCKdcACgkQ9CaO5/Lv0PCh3QCeIWWVAQ7+ynyC9IaxfAQJ6bb5 hzcAnAqgYsWDPbKki8Yjsn/Tiuvh4T+a =BzDn -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
