mapObj.zoomRectangle from Java Mapscript.

[Umberto Nicoletti]

I found the bugzilla issue (eventually!):

http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1817

Umberto

On 12/12/06, Umberto Nicoletti <umberto.nicoletti at gmail.com> wrote:
> Howard's version is the right one, only the error message is still
> wrong, it should say:
>
> msSetError(MS_MISCERR, "image rectangle maxy >= miny",
>
> and this confuses both users and developers...
>
> There is an issue in bugzilla, but unfortunately I can't view it
> because bugzilla is slow/down at the moment.
>
> Umberto
>
> On 12/11/06, Tamas Szekeres <szekerest at gmail.com> wrote:
> > Hi All,
> >
> > Going through the CVS History of mapzoom.i I can see that umberto has
> > addressed this issue in ver1.3 (2006 05 30) but hobu has reverted the
> > changes in ver1.4 (2006 07 04)
> >
> > So the developers should agree with the desired action.
> >
> > I would vote +1 to correct this issue as logical, that is:
> >
> > mapzoom.i (282)
> >
> >   if (poPixRect->miny >= poPixRect->maxy)
> >         {
> >             msSetError(MS_MISCERR, "image rectangle miny >= maxy",
> >                        "mapscript::mapObj::zoomRectangle()");
> >             return MS_FAILURE;
> >         }
> >
> > However it will break the existing code and should be noted as a
> > backward incompatible change.
> >
> > Best Regards,
> >
> > Tamas Szekeres
> >
> >
> >
> >
> >
> > 2006/12/11, Rodrigo Del C. Andrade <rodrigo.andrade at digitro.com.br>:
> > >
> > >
> > >      Hello Javier, thanks for the info.
> > >
> > >      We have been struggling for some time now with the zoomRectangle and
> > > every piece of info is appreciated.
> > >      Concerning the swap of MinY with MaxY in your code, I gotta say this
> > > caught me off guard.
> > >       I couldn't get past a "miny >= maxy" error while trying to  use
> > > zoomRectangle before and went as far as changing and recompiling mapzoom.i
> > > where there is a consistency check that looks like:
> > >  if (poPixRect->maxy >= poPixRect->miny) { -- insert nasty error here -- }
> > >
> > >
> > >      thinking I found a bug. I got past the error after that change, however
> > > the zoom behavior was what could best be described as "all over the place".
> > > Like zooming to the wrong hemisphere and the like.
> > >      So I changed mapzoom.i back to the original code and swapped the order
> > > of arguments on my code following your example, and it worked better than
> > > the last behavior, however the zoom isn't still quite working in a
> > > predictable manner.
> > >      Sometimes when zooming the map will remain at the same zoom factor, and
> > > just pan a little to the sides or actually zooming out instead of going
> > > zooming to the passed coordinates. I am running out of ideas as to what
> > > could be causing this behavior.
> > >      Here is what I am doing:
> > >
> > >        //Current map geo extent
> > >        String[] extents = ((String) params.get("extent")).split(" ");
> > >         rectObj extent = new rectObj(Double.parseDouble(extents[0]),
> > > Double.parseDouble(extents[1]),
> > >                                       Double.parseDouble(extents[2]),
> > > Double.parseDouble(extents[3]), mapscript.MS_FALSE);
> > >         mapa.setExtent(extent);
> > >
> > >          //rectangle Pic coords
> > >          String[] pxCoordZoom = ((String) params.get("coordenadas")).split("
> > > ");
> > >          Double minx = Double.parseDouble(pxCoordZoom[0]);
> > >          Double miny = Double.parseDouble(pxCoordZoom[1]);
> > >          Double maxy = Double.parseDouble(pxCoordZoom[2]);
> > >          Double maxx = Double.parseDouble(pxCoordZoom[3]);
> > >
> > >         /*We are using a cropper javascript class and the order the
> > > rectangle coordinates where being passed was kind of unpredictable and
> > > causing errors                while trying to create the rectangle with the
> > > eventual minX > maxX /*
> > >          double transport;
> > >          if(minx > maxx){
> > >              transport = minx;
> > >              minx = maxx;
> > >              maxx = transport;
> > >          }
> > >          if(miny > maxy){
> > >              transport = miny;
> > >              miny = maxy;
> > >              maxy = transport;
> > >          }
> > >
> > >          rectObj zoomArea = new rectObj(minx, maxy, maxx, miny,
> > > mapscript.MS_TRUE);   //with MaxY and MinY swapped
> > >          mapa.zoomRectangle(zoomArea, mapa.getWidth(), mapa.getHeight(),
> > > extent, getMaxGeorefExtent(mapa));
> > >
> > >      Do you see any glaring mistakes that could cause the zoom to behave
> > > wrongly?
> > >      What confuses me is the fact that you mentioned that the rectangle
> > > should be constructed with bottom-left and top-right defined, but isn't the
> > > MinX and MaxY pair actually top-left?
> > >
> > >      Thanks in advance, any scrap of information helps immensely.
> > >
> > >      Rod.
> > >
> > >  --
> > >
> > >
> > >  Rodrigo Del C. Andrade
> > >  Estagiário Nível Superior
> > >  SIC - SSE - Soluções Segurança Pública
> > >
> > >  DÍGITRO TECNOLOGIA
> > >  E-mail: rodrigo.andrade at digitro.com.br
> > >  Fone: +55 48 3281- / +55 48 3281-7000
> > >  Fax: +55 48 3281-7299
> > >  Site: www.digitro.com
> > >
> > >
> > >  Javier Caicedo wrote:
> > >  According to the Mapscript API mapObj.zoomRectangle first parameter must
> > > be in image coordinates, so you should set the last parameter of the
> > > rectObj constructor to TRUE. Here goes an example from my current project:
> > >
> > >  //vMap is an instance of mapObj
> > >  rectObj rect = vMap.getExtent(); //map coordinates
> > >  String [] box =
> > > getCurrentRequest().getParameter("box").split(" ");
> > >  //box is something like this: 10 10 200 200
> > >  //0,0 is at top left, so box defines top left and bottom right corners
> > >  double mx = Double.parseDouble(box[0]);
> > >  double my = Double.parseDouble(box[1]);
> > >  double mxx = Double.parseDouble(box[2]);
> > >  double mxy = Double.parseDouble(box[3]);
> > >
> > >  //bunch of validation code ommitted
> > >
> > >  rectObj rbox = new rectObj(mx,mxy,mxx,my,mapscriptConstants.MS_TRUE);
> > >  //notice the switch of mxy and my
> > >  //rectObj constructor requires you define bottom left and top right
> > >  //corners. rbox is in image coordinates
> > >  vMap.zoomRectangle(rbox,w,h,rect,null);
> > >
> > > Hopefully this will help you out a little.
> > >
> > > Regards,
> > > Javier Caicedo Espinoza
> > > CTI - ESPOL
> > > Guayaquil, Ecuador
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
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