[Qgis-developer] Re: creating a new vector layer supporting all line, point n polygon

[nitin quick]

i found what wrong i was doing. i was calling updateCanvas( ) inside
drawShape() function which in turn was resulting in call to drawShape().
Second, slot defining visibility rectangle was not connnected.

On 8/24/06, nitin quick <quick.nitin at gmail.com> wrote:
>
> Hello everybody,
> As against my previous approach, i followed a newer one.
> Let user put/mark on canvas as QgsMapCanvasItem  and mouse interactivity
> using QgsMapCanvasTool.
> But i have some issue which i couldn't sort out.
> a. When i click on canvas ,after loading plugin , point symbol donot
> apears until i refesh.
> Header file look like this:-
> /*----------vp.h-------------*/
> class vP:public QgsMapCanvasItem, public QgsMapTool, public QgisPlugin
> {
>   Q_OBJECT;
>   public:
>   vP(QgisApp * theApplication, QgisIface * theInterface);
>   //! Destructor
>   virtual ~vP();
>     //! Mouse move event for overriding
>     virtual void canvasMoveEvent(QMouseEvent * e) { }
>
>     //! Mouse press event for overriding
>     virtual void canvasPressEvent(QMouseEvent * e) { }
>
>     //! Mouse release event for overriding
>     virtual void canvasReleaseEvent(QMouseEvent * e);
>
>      void drawShape(QPainter & p);
>
>      void updatePixmap();
>
> public slots:
>   //! init the gui
>   virtual void initGui();
>   //! Show the dialog box
>   void run();
>   //! unload the plugin
>   void unload();
>   //! show the help document
>   void help();
>
>   //!draw a raster layer in the qui
>   void drawRasterLayer(QString);
>   //! Add a vector layer given vectorLayerPath, baseName, providerKey
> ("ogr" or "postgres");
>   void drawVectorLayer(QString,QString,QString);
>   //!will receive signal pbnOk clicked
>     void recvOkClicked();
> private:
>   int mPluginType;
>   //! Pointer to our toolbar
>   QToolBar *mToolBarPointer;
>   //! Pionter to QGIS main application object
>   QgisApp *mQGisApp;
>   //! Pointer to the QGIS interface object
>   QgisIface *mQGisIface;
>   //!pointer to the qaction for this plugin
>   QAction * mQActionPointer;
>     //! container for storing location of elements, later will be made of
> appropriate struct
>     QList<float > elementList;
>
> };
>
> here is code for drawShape()
>     [CODE]
>   //!This will draw the elements on to canvas
> void vP::drawShape(QPainter &p)
> {
>     double temp_x, temp_y;
>     QgsPoint qPoint(0.0,0.0);
>     QPoint cPoint(0,0);
>     //loading image to pixmap which will be displayed on points
>     QString myFileNameQString= "/home1/qgis/images/vP/hit.png";
>     QPixmap myQPixmap;
>     myQPixmap.load(myFileNameQString);
>
>     //displaying it at position where the points are marked
>     //currently drwing all points which are is in list but only point
> which is added latest should be drawn
>     QListIterator<float> listIterator(elementList);
>     cout<<"\n";
>     while(listIterator.hasNext())
>     {    temp_x=listIterator.next();
>         //cout<<"\t"<<temp_x<<" ";
>         if(listIterator.hasNext())
>         {    temp_y=listIterator.next(); //cout<<temp_y;
>             qPoint.setX(temp_x);
>             qPoint.setY(temp_y);
>             cPoint=QgsMapCanvasItem::toCanvasCoords(qPoint);
>             p.drawPixmap(cPoint.x(),cPoint.y(),myQPixmap);
>             show();
>
>         }
>         cout<<"vp.cpp-205\t";
>     }
>     updateCanvas();
>
>     //update();
>     cout<<"vp.cpp-210\n";
>  }
> [/CODE]
>
> I had observer that this function drawShape() is continuously being
> called. I myself has not made any connection to it.
>
> Code for canvasReleaseEvent() is :-
> void vP::canvasReleaseEvent(QMouseEvent * e)
> {
>   QgsPoint point =
> mQGisIface->getMapCanvas()->getCoordinateTransform()->toMapCoordinates(e->x(),
> e->y());
> if (e->button() == Qt::LeftButton)
>   {
>     show();//why here-find out priority at 5
>     //!make data available for storage
>     cout<<"\nelement bein added "<<point.x()<<" "<<point.y()<<"vp.cpp-171";
>     elementList.append(point.x());
>     elementList.append(point.y());
>   }
> }
>
> All advices are welcome. Also i keep stucking at such situations where i i
> have to display on canvas through interactivity with user. Will anyone guide
> me in improving here?
> regards
> quickNitin
>
>
> On 8/21/06, nitin quick <quick.nitin at gmail.com> wrote:
> >
> > hello everybody,
> > Currently i am trying to create a application which let me overlay(
> > creation of some  objects using mouse like marking something on map) some
> > shapes over current map.
> > For this purpose i am thinking of few steps:
> > 1. Creating a new vector layer:
> >                   Issue: here issue is layer supports only either lineor
> > point or polygon but usually i want to have all of these available to me.
> > How i can sort out this issue?
> > 2. Add projection information ( if this is independent of underlying
> > map's projection information)
> > 3. Displaying it and editing it.
> >
> > Any advices on how i can carry out this task more effectively is
> > welcome.
> >
> > regards
> > quickNitin
> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/qgis-developer/attachments/20060824/4382eff8/attachment.html