[Qgis-developer] rendering objects on canvas

[humarco]

Hi Nitin,

It is not clear to me what exactly you are programming. Are the objects you 
are creating vector features (in the gis sense with geometry/attributes)? If 
no, then i wouldn't create a renderer for it. Renderers symbolize features 
according to feature attributes. Using canvas items (as Martin described in 
his mail) would be the mechanism for your purpose. Martin, is there a way to 
group different items to something like a layer?

Marco 


Am Mittwoch 10 Mai 2006 12:42 schrieb nitin quick:
> Hello developers,
> I am currently trying to code a module which will put some primitives or
> object on qgis canvas irrespective of map. Lets  assume i have a algo
> generating some points  and now i want to plot these points on canvas with
> background of my map.Basic Operations like zooming , panning etc. should
> still work while algo may be generating hese points after some unknoown
> interval.
> Problem is these object directly relates to acetate layer so one way is to
> use acetate object hierarchy. But i couldn't found anyoone of renderer
> class supporting it in code.
> Other class relating to my problem is QgsSymbol which let me associate a
> picture to co-ordinate. But same thing here i couldn't find any renedere
> class supporting it directly.
> I am thinking of deriving one clss from one of rendere classes but i
> couldn't decide which one to use. I am not completely clear about
> QgsSiMaRendere, QgsGraduatedMarendere, QgsUValMaRenderer classes.
> Also say if i donot want a map in backgrond , just want to plot these
> points or objects and later i may add.. etc etc.
>
> Any help in this regard will be appreciabe and will save me good amount of
> time in prototyping.
> cya
> nitin quick