Hi Holger, Andreas, and all In fact, I allready use MapServer to produce the map which is displayed using SVG (as background of a map with some vector layers send using XMLHTTP and a simplified GML-like format parsed in javascript). The raster layer is used to display thematic products and my goal is to move a client side cursor on legend when I move the mouse over the image. For this reason, I can't send a request to the server at each mouse move. Images should have a size of 600x600 pixels. I can't use the method described by Holger because of the size of data to transfert. Another solution should be to vectorize the image before send to SVG. But images are too complex and the XML (using GML or SVG format) of the image may be too big to download. This solution requires also too server-side ressources. So... I think there is no way using javascript... Perhaps using an ActiveX control (I'm on IE), but I'm also in a wide Extranet and I can't force the installation of it. Thanks a lot for your response.
_____ De : [email protected] [mailto:[EMAIL PROTECTED] De la part de Andreas Neumann Envoyé : mardi 21 juin 2005 18:30 À : [email protected] Objet : [svg-developers] Re: Value of a pixel Currently, until SVG 1.2 (or 2.0?) provides this function I would use a webserver for that purpose. For geo/carto data there is the UMN mapserver who can send back pixel values. The requests can be sent through a URL. (see http://mapserver.gis.umn.edu/doc44/raster- howto.html#query) - mapserver can also do more complex raster queries than just simple pixel values. The idea that Holger proposes might be possible, but likely to be complicated to implement and slow, because javascript is not very fast for things like image-processing. Andreas --- In [email protected], "Nicolas BOUTET" <[EMAIL PROTECTED]> wrote: > Hi, > > does someone know if it's possible (and how), using ECMAScript, to get the > RGB value (or LookUpTable index) of a pixel (using X,Y coordinates) of an > image item. > > Thanks > > Nicolas > > > [Non-text portions of this message have been removed] ----- To unsubscribe send a message to: [EMAIL PROTECTED] -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ---- _____ Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/svg-developers/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed] ----- To unsubscribe send a message to: [EMAIL PROTECTED] -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ---- Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/svg-developers/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
