could you explain just a bit more what is a tile? Martin ______________________________________________ Verzicht und Vertraulichkeitanmerkung Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen.
> Date: Mon, 28 Sep 2009 21:27:15 +0200 > From: me...@mesw.de > To: users@tomcat.apache.org > Subject: Re: How to check if the client dropped the connection > > Jason Brittain schrieb: > > The first time you call flush, it will send the HTTP response > > headers to the client, so you would need to first set the headers before > > flushing. That sounds difficult for you to do because you're writing an > > image, and one of the headers would be Content-Length, which you probably > > don't know until your image is generated. > > Actually, Content-Length is optional as per the HTTP-1.1 spec: > > http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html > > However, my take on the OP is that a better optimization strategy in > this case would be to just cache a larger image on the server rather > than generating every image on-demand. That is, when the user is moving > around in the image, the server, on the first request, would calculate > the image for a much larger portion of the map than requested and stores > it on disk in temporary storage (or in some cache area in RAM, if > feasible, after all RAM is cheap these days and 64-bit machines can have > lots of RAM). Storage of the images would not be done all at once but in > tiles. When then user then moves around in the client, the requests just > reads the tiles of the created image from disk, puts them together and > clips the borders, then compresses the image and sends it to the client. > It is possible that PNG even has some support for compressing parts of > an image so the tiles itself could be already stored in compressed > format, but it's been a while since I read the PNG spec last time. The > same could be done for zooming by storing images in a pyramidal > structure, like it is done in pattern recognition. While the user is > moving, a background thread associated with the client could try to > anticipate where the user is likely to be moving to and calculate the > given tiles in advance. Actually, this sounds like an interesting > project for several Ph.D. theses... > > > Markus > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > _________________________________________________________________ Hotmail® has ever-growing storage! Don’t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutorial_Storage_062009
