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QTableView and Image

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  • M MokJ

    Here's the widget class

    MyWidget::MyWidget(QWidget *parent) : QWidget(parent)
    {
            QTableView *view=new QTableView(this);
            view->setShowGrid(false);
            view->setFocus();
            QStandardItemModel *model=new QStandardItemModel(3,2);
            myDelegate *delegate=new myDelegate;
    
            
            view->columnWidth(500);// no matter what I put in here, it remains of the same size
            view->rowHeight(500); //same as mentioned above, I tried to take the height and width
              //of the image for column width and column height but nothing happened.
    
            view->setModel(model);
            view->setItemDelegate(delegate);
            QStringList SL={"Column 1","Column 2"};
            model->setHorizontalHeaderLabels(SL);
            QStandardItem *item=new QStandardItem;
            model->setItem(0,0,item);
    }
           
    

    And the QItemDelegate class, paint method

    void myDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const{
        const QStandardItemModel *model=static_cast<const QStandardItemModel*>(index.model());
    
         painter->drawImage(option.rect.x(),option.rect.y(),m_image);
    
    }
    
    JonBJ Online
    JonBJ Online
    JonB
    wrote on last edited by JonB
    #4

    @MokJ said in QTableView and Image:

        view->columnWidth(500);// no matter what I put in here, it remains of the same size
        view->rowHeight(500); //same as mentioned above, I tried to take the height and width
          //of the image for column width and column height but nothing happened.
    

    I'm not saying this is the right way to do it, but these lines do nothing. Look carefully at the documentation: columnWidth/rowHeight are getters, you want the setters here! In general, Qt uses methods named set... for every property you can set.

    M 1 Reply Last reply
    2
    • JonBJ JonB

      @MokJ said in QTableView and Image:

          view->columnWidth(500);// no matter what I put in here, it remains of the same size
          view->rowHeight(500); //same as mentioned above, I tried to take the height and width
            //of the image for column width and column height but nothing happened.
      

      I'm not saying this is the right way to do it, but these lines do nothing. Look carefully at the documentation: columnWidth/rowHeight are getters, you want the setters here! In general, Qt uses methods named set... for every property you can set.

      M Offline
      M Offline
      MokJ
      wrote on last edited by MokJ
      #5

      @JonB thanks , I've got it, that problem has just been solved.
      Now I'm trying to display a new image to that particular block by selecting it ,is there a way ? I mean the point is ....the rest of the Table must not get affected .

      bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index) ;
      

      can it be used or should I go for

      void updateEditorGeometry(QWidget*editor,const QStyleOptionViewItem &option,const QModelIndex &index)const;
      
      1 Reply Last reply
      0
      • VRoninV Offline
        VRoninV Offline
        VRonin
        wrote on last edited by VRonin
        #6
        • Where does m_image come from?
        • Are you subclassing QItemDelegate or QStyledItemDelegate?
        • Are you implementing myDelegate::sizeHint?

        LEAKFEST!

        The view does not own either the model or the delegate. You need to pass a parent to them or they are leaked

        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
        ~Napoleon Bonaparte

        On a crusade to banish setIndexWidget() from the holy land of Qt

        M 1 Reply Last reply
        1
        • VRoninV VRonin
          • Where does m_image come from?
          • Are you subclassing QItemDelegate or QStyledItemDelegate?
          • Are you implementing myDelegate::sizeHint?

          LEAKFEST!

          The view does not own either the model or the delegate. You need to pass a parent to them or they are leaked

          M Offline
          M Offline
          MokJ
          wrote on last edited by MokJ
          #7

          thank you @VRonin , It was a mistake of mine ,that I didn't provide the complete information.
          I'm subclassing QItemDelegate....on this note how its different from subclassing QStyledItemDelegate?? I mean Qt document says that

          QStyledItemDelegate uses the current style to paint its items

          whats the current style here !!

          QSize myDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const{
                    return  QSize newSize(70,30);
          }
          
          QImage m_image(":/new/prefix1/d.jpg");
          

          m_image is in private of myDelegate.

          1 Reply Last reply
          0
          • VRoninV Offline
            VRoninV Offline
            VRonin
            wrote on last edited by VRonin
            #8

            So m_image does not depend at all on what's in the model?

            @MokJ said in QTableView and Image:

            whats the current style here !!

            http://doc.qt.io/qt-5/style-reference.html

            Let's go step by step. The below should be an improvement already, correct?

            void myDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const{
            (option.widget ? option.widget.style() : QApplication::style())->drawItemPixmap(painter,option.rect(),QPixmap::fromImage(m_image.scaled(option.rect().size())));
            }
            

            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
            ~Napoleon Bonaparte

            On a crusade to banish setIndexWidget() from the holy land of Qt

            M 1 Reply Last reply
            2
            • VRoninV VRonin

              So m_image does not depend at all on what's in the model?

              @MokJ said in QTableView and Image:

              whats the current style here !!

              http://doc.qt.io/qt-5/style-reference.html

              Let's go step by step. The below should be an improvement already, correct?

              void myDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const{
              (option.widget ? option.widget.style() : QApplication::style())->drawItemPixmap(painter,option.rect(),QPixmap::fromImage(m_image.scaled(option.rect().size())));
              }
              
              M Offline
              M Offline
              MokJ
              wrote on last edited by
              #9

              @VRonin Thanks
              yes, m_image doesn't depend on model at all.
              I'm clear about current style now.

              Let's go step by step. The below should be an improvement already, correct?

              yes , after a small change It has improved.
              So whats the next step !
              What method should be used to get desired output !

              @MokJ said in QTableView and Image:

              Another thing is , is it possible to create something like, whenever a block from QTableView is selected ,the image on that particular block should get changed?

              VRoninV 1 Reply Last reply
              0
              • M MokJ

                @VRonin Thanks
                yes, m_image doesn't depend on model at all.
                I'm clear about current style now.

                Let's go step by step. The below should be an improvement already, correct?

                yes , after a small change It has improved.
                So whats the next step !
                What method should be used to get desired output !

                @MokJ said in QTableView and Image:

                Another thing is , is it possible to create something like, whenever a block from QTableView is selected ,the image on that particular block should get changed?

                VRoninV Offline
                VRoninV Offline
                VRonin
                wrote on last edited by VRonin
                #10

                @MokJ said in QTableView and Image:

                So whats the next step !

                We make the image depend on the model.
                In the constructor add:

                connect(view->selectionModel(),&QItemSelectionModel::selectionChanged,[view](const QItemSelection &selected, const QItemSelection &deselected)->void{
                QModelIndexList indexList = selected.indexes();
                for(auto& index : qAsConst(indexList))
                view->model()->setData(index,true,Qt::UserRole);
                indexList = deselected.indexes();
                for(auto& index : qAsConst(indexList))
                view->model()->setData(index,QVariant(),Qt::UserRole);
                });
                

                now in myDelegate::paint you can add if(index.data(Qt::UserRole).toBool()) to check if an item is selected or not

                "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                ~Napoleon Bonaparte

                On a crusade to banish setIndexWidget() from the holy land of Qt

                M 1 Reply Last reply
                3
                • VRoninV VRonin

                  @MokJ said in QTableView and Image:

                  So whats the next step !

                  We make the image depend on the model.
                  In the constructor add:

                  connect(view->selectionModel(),&QItemSelectionModel::selectionChanged,[view](const QItemSelection &selected, const QItemSelection &deselected)->void{
                  QModelIndexList indexList = selected.indexes();
                  for(auto& index : qAsConst(indexList))
                  view->model()->setData(index,true,Qt::UserRole);
                  indexList = deselected.indexes();
                  for(auto& index : qAsConst(indexList))
                  view->model()->setData(index,QVariant(),Qt::UserRole);
                  });
                  

                  now in myDelegate::paint you can add if(index.data(Qt::UserRole).toBool()) to check if an item is selected or not

                  M Offline
                  M Offline
                  MokJ
                  wrote on last edited by
                  #11

                  @VRonin Thank you
                  I have added that snippet too, now question is , How is it making m_image depend on model ?

                  VRoninV 1 Reply Last reply
                  0
                  • M MokJ

                    @VRonin Thank you
                    I have added that snippet too, now question is , How is it making m_image depend on model ?

                    VRoninV Offline
                    VRoninV Offline
                    VRonin
                    wrote on last edited by VRonin
                    #12

                    @MokJ I made a mistake, if(index.data().toBool()) should have been if(index.data(Qt::UserRole).toBool()) fixed above now

                    P.S.
                    if(index.data(Qt::UserRole).isValid()) does the same and it's probably more efficient

                    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                    ~Napoleon Bonaparte

                    On a crusade to banish setIndexWidget() from the holy land of Qt

                    M H 3 Replies Last reply
                    3
                    • VRoninV VRonin

                      @MokJ I made a mistake, if(index.data().toBool()) should have been if(index.data(Qt::UserRole).toBool()) fixed above now

                      P.S.
                      if(index.data(Qt::UserRole).isValid()) does the same and it's probably more efficient

                      M Offline
                      M Offline
                      MokJ
                      wrote on last edited by MokJ
                      #13

                      @VRonin
                      I'm a bit confused about how its supposed to work. I mean once I select an Index it goes inside

                      if(index.data(Qt::UserRole).isValid()) {}
                      

                      What should get implemented in If?

                      I appreciate your help greatly.

                      1 Reply Last reply
                      0
                      • VRoninV VRonin

                        @MokJ I made a mistake, if(index.data().toBool()) should have been if(index.data(Qt::UserRole).toBool()) fixed above now

                        P.S.
                        if(index.data(Qt::UserRole).isValid()) does the same and it's probably more efficient

                        H Offline
                        H Offline
                        hjohn
                        wrote on last edited by hjohn
                        #14

                        @VRonin
                        can we take the Image as string ?

                        M 1 Reply Last reply
                        0
                        • VRoninV VRonin

                          @MokJ I made a mistake, if(index.data().toBool()) should have been if(index.data(Qt::UserRole).toBool()) fixed above now

                          P.S.
                          if(index.data(Qt::UserRole).isValid()) does the same and it's probably more efficient

                          M Offline
                          M Offline
                          MokJ
                          wrote on last edited by
                          #15

                          @VRonin
                          I got it,
                          in If , I'm drawing the new Image.
                          Thanks very much @VRonin.
                          Now If we want to keep that image in model should we implement

                          void setModelData(QWidget*editor,QAbstractItemModel *model,const QModelIndex &index)const
                          

                          again thanks @VRonin .

                          1 Reply Last reply
                          0
                          • H hjohn

                            @VRonin
                            can we take the Image as string ?

                            M Offline
                            M Offline
                            MokJ
                            wrote on last edited by
                            #16

                            @hjohn
                            I came across this , maybe it could be helpful.

                            1 Reply Last reply
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