[Qgis-developer] rendering objects on canvas

[Martin Dobias]

On 5/10/06, humarco <marco.hugentobler at karto.baug.ethz.ch> wrote:
> 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?

Grouping map canvas items is left to the developer... I don't know if
it makes sense to create such functionality as it's not really a big
great deal to store the items in any kind of container...

Martin

>
> 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
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