Hi!

I am experiencing some crazy issues with graphics view.
I am trying to create an image viewer.

What I am experiencing is mixing of pointers.

The code goes like this:

Qt Code: 
  1. //when loading an image
  2. imagePix = new QPixmap(fileName);
  3. scene->clear();
  4. image = new QGraphicsPixmapItem( *imagePix );
  5. scene->addItem( image );
  6.  
  7. ...
  8.  
  9. //when displaying the image (and processing it)
  10.     if(imagePix == NULL)
  11.         return;
  12.  
  13.     //if(mask1 != NULL){
  14.             qDebug()<<"here0";
  15.         scene->removeItem(mask1);
  16.  
  17.         //delete mask1;
  18.     //}
  19. qDebug()<<"here1";
  20.     int w = imagePix->width();
  21.     int h = imagePix->height();
  22.  
  23.     QPixmap *temp = new QPixmap( w,h );
  24.     QPainter painter(temp);
  25.         painter.setPen( Qt::black );
  26.         painter.setBrush( Qt::black );
  27.         painter.drawRect(imagePix->rect());
  28.     painter.end();
  29.  
  30.     mask1Pix = new QImage(w,h, QImage::Format_RGB888);
  31.     mask1Pix->fill(qRgb(255,255,255));
  32.  
  33.     ui->bar->setVisible(true);
  34.     ui->bar->setValue(0);
  35.  
  36.     int pix = w*h;
  37.     QImage src = imagePix->toImage();
  38.  
  39.     //here paint what areas to reveal--------------------------------------------------
  40.         for(int i=0; i<w; i++){
  41.             for(int j=0; j<h; j++){
  42.                 QRgb p = src.pixel(i,j);
  43.                 if( qRed(p) - qBlue(p) - qGreen(p) >= 10){
  44.                     mask1Pix->setPixel( i,j, qRgb(0,0,0) ); //where red - will be transparent
  45.                 }
  46.             }
  47.             ui->bar->setValue(((i+1)*h*100)/pix);
  48.         }
  49.     //--------------------------------------------------------------------------------
  50.     ui->bar->setValue(0);
  51.     ui->bar->setVisible(false);
  52.  
  53.  
  54.     temp->setAlphaChannel( QPixmap::fromImage( *mask1Pix ) );
  55.  
  56.     mask1 = new QGraphicsPixmapItem( *temp );
  57.     mask1->setZValue(2);
  58.     mask1->setOpacity(0.9f);
  59.  
  60.     scene->addItem(mask1);
  61.  
  62.     qDebug() << imagePix << mask1Pix << "\n"<< image << mask1;
  63.  
  64.     delete temp;
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Please ignore the large ammount of comments - I was trying to check everything before posting here.

The app creates a second item (mask1), based on the red channel of the original pic.

The issue is as follows:
- first time I load a pic - works great
- second time i load a pic (i.e. the same one) - it all mixes up - the "picture" is being replaced with the mask (check the qDebug() output - pointer values). Instead of seeing the Pic WITH a second semi-transparent layer, i see only the second layer. Why?

I tried deleting whatever i allocate, no effect. My very temporary solution is allocating everything multiple times, the pointers differ then.

What am I missing?

Regards,
Rav