You are correct this technique would only show the maximum size; and use it to query. The style data structure is available so you can perform the calculations yourself (to see if which rules have been used).
There are a couple different approaches to selection in an interactive map; I mentioned one hack with respect to checking the pixels; a more involved technique involves rendering as a zbuffer; you would need to rewrite the renderer (or supply a hint) asking it to write down an integer for each feature drawn; and then check the raster at the end of the day to see what feature was "on top" in order to be clicked on. Not very much fun which is why I have not done it yet. Jody On Sun, Apr 26, 2009 at 11:01 PM, yako yako <[email protected]> wrote: > > Thank you Jody, > > But each Feature on a Layer can be drawn in various ways depending on the > applied styling rules. > Is it possible to determine which rules has been applied by the renderer for > a given Feature? > > Yako Bak > >> Date: Sat, 25 Apr 2009 18:24:09 +1000 >> Subject: Re: [Geotools-gt2-users] Selecting a feature represented by a >> symbol >> From: [email protected] >> To: [email protected] >> CC: [email protected] >> >> Have a look at the StyleVisitor interface; you can use that to visit >> all the symbolizer elements used to rendering your features (and >> figure out what the target size is; and then use that size rather than >> 3x3 to determine your selection bounds). >> >> Note: In uDig we render each layer individual; allowing me to >> experimented in the past with just checking the pixels to see if >> anything is hit before trying to do a feature based query; this is >> only useful if you are rendering content onto individual rasters and >> then merging them. >> >> Jody >> >> On Sat, Apr 25, 2009 at 1:56 AM, yako yako <[email protected]> wrote: >> > Hello, >> > >> > I am making an application where the user can retrieve information from >> > a >> > feature by clicking on it. >> > >> > To do this, I make a filter to get all features located on the area >> > defined >> > by the projection on the map >> > of a 3x3 pixels square centered on the position of the click. >> > >> > I encouter a problem with Feature represented by a symbol because this >> > symbol can be bigger than >> > the real geometry of the feature. So we can not click anywhere on it to >> > retrieve its information. >> > >> > Is it possible to get the bounds of the symbol used to represent a >> > feature >> > in order to compute its projection >> > on the map and check if it intersects the 'click area'? >> > >> > Is there an other way to assign a feature to a pixel on the map whatever >> > its >> > type of representation is ? >> > >> > I hope I've been clear enough. >> > >> > Thank you, >> > >> > Yako Bak. >> > >> > ________________________________ >> > Découvrez toutes les possibilités de communication avec vos proches >> > >> > ------------------------------------------------------------------------------ >> > Crystal Reports - New Free Runtime and 30 Day Trial >> > Check out the new simplified licensign option that enables unlimited >> > royalty-free distribution of the report engine for externally facing >> > server and web deployment. >> > http://p.sf.net/sfu/businessobjects >> > _______________________________________________ >> > Geotools-gt2-users mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users >> > >> > > > ________________________________ > Votre correspondant a choisi Hotmail et profite d'un stockage quasiment > illimité. Créez un compte Hotmail gratuitement ! ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensign option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
