Undefined Reference error!!!

[Kapil]

Hi...

what exactly the problem i am facing is that i am not able to intiate the mouse events.. my functions are not emitting any errors but mouse clicks or mouse moves are not being captured.. where to exactly intitiate them in the code so that the mouse movement gets recognized..

[Kapil]

hi,

i have re-implemented the mouseMoveEvent(QMouseEvent *event), mousePressEvent(QMouseEvent *event), mouseReleaseEvent(QMouseEvent *event)
and am just trying to pop-up a message box whenever the mouse moves over the widget but there is no response.. i went thru quite a few docs and also examples and all have done something similar to what i have done but there is still no response...

why is it so????

thanking you,
Kapil

[zlatko]

Have you declare this events handler in protected section ?

[Kapil]

Have you declare this events handler in protected section ?

yes,

they are declared in the protected section...

[zlatko]

So if i have undestand you we talk about ImageZoomer class?
Who is his parent?

[Kapil]

So if i have undestand you we talk about ImageZoomer class?
Who is his parent?

This class inherits the QMainWindow class and the header file for the class is :
ImageZoomer.h

class ImageZoomer : public QMainWindow
{
      Q_OBJECT
 
      public:
             ImageZoomer(Ui::MainWindow *_mw);
             ~ImageZoomer();
             void scaleImage(double factor);
             void adjustScrollBar(QScrollBar *sbar, double factor);
 
      protected:
             void contentsMousePressEvent(QMouseEvent*);
 
      public slots:
 
             void open();
             void zoomIn();
             void zoomOut();
             void zoomNormal();
             void fitToWindow();
 
      private:
 
              QFrame *frame;
              QScrollArea *sarea;
              Q3ScrollView *sview;
              double scalefactor;
              Ui_MainWindow *mwin;
              QPixmap fromImage;
              Q3Canvas *canvas;
              Q3CanvasView *canview;
              QMouseEvent *mEvent;
              Q3CanvasItem* moving;
              QPoint moving_start;
              QImage image;
};

class ImageZoomer : public QMainWindow
{
      Q_OBJECT
      
      public:
             ImageZoomer(Ui::MainWindow *_mw);
             ~ImageZoomer();
             void scaleImage(double factor);
             void adjustScrollBar(QScrollBar *sbar, double factor);
                   
      protected:
             void contentsMousePressEvent(QMouseEvent*);
                             
      public slots:
             
             void open();
             void zoomIn();
             void zoomOut();
             void zoomNormal();
             void fitToWindow();
     
      private:
              
              QFrame *frame;
              QScrollArea *sarea;
              Q3ScrollView *sview;
              double scalefactor;
              Ui_MainWindow *mwin;
              QPixmap fromImage;
              Q3Canvas *canvas;
              Q3CanvasView *canview;
              QMouseEvent *mEvent;
              Q3CanvasItem* moving;
              QPoint moving_start;
              QImage image;
};

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[zlatko]

QMainWindow doesnt have slot void contentsMousePressEvent(QMouseEvent*);

[Kapil]

QMainWindow doesnt have slot void contentsMousePressEvent(QMouseEvent*);

Hi,

Okay.. This means that i will have to also inherit the class QCanvasView 'coz it contains the method contentsMousePressEvents(QMouseEvent *)...

Is it so?????

[incubator]

no, you just dont capture mouse events on a main window.

If you want to capture them in your canvas, make a class that extends QCanvas and override its mouse events.

[Kapil]

no, you just dont capture mouse events on a main window.

If you want to capture them in your canvas, make a class that extends QCanvas and override its mouse events.

Hi,

It means that i would make another class and its structure would look like this..
[HTML]
#include "imagezoomer.h"
class Sample : public QCanvas
{
public:
Sample();
protected:
void contentsMousePressEvent(QMouseEvent *);
private:
ImageZoomer *zoom;
};
Sample::Sample()
{
ImageZoomer zoom = new ImageZoomer;
}
void Sample::contentsMousePressEvent(QMouseEvent *event)
{
code
}
[/HTML]

Is it so??????????????

[incubator]

sort of, but your ImageZoomer extends a main window, so that class should have a private member MyCanvas that extends a QCanvas (if you use Qt4 its Q3Canvas I think)

and in that MyCanvas class you override your mouse events.

[Kapil]

Hi...

The new class which i have created is CanvasMouse..

Now in my ImageZoomer i have created a CanvasMouse *canmouse variable which would call the CanvasMouse which inherits the Q3CanvasView....

In imageZoomer i have created a Q3CanvasView and have passed in the constructor of the CanvasMouse which reads this
CanvasMouse(Q3CanvasView *canview): canvasview(canview)

Now class CanvasMouse contains all the canvas related functionalities...

is this approach correct ?????