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Forum Update on Monday, May 27th 2025

Create a matrix from a .csv file

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  • A Offline
    A Offline
    AliM93
    wrote on last edited by
    #119

    done! but i only see the grid, not the content

    mrjjM 1 Reply Last reply
    0
    • A AliM93

      done! but i only see the grid, not the content

      mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by
      #120

      @AliM93
      \o/
      Good work.
      I hope you learn a few Creator tricks.

      we didnt paint the values yet :)
      just all other stuff :=)

      But its 4 in the morning so rest must be tomorrow as its bed time for me :)

      A 1 Reply Last reply
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      • mrjjM mrjj

        @AliM93
        \o/
        Good work.
        I hope you learn a few Creator tricks.

        we didnt paint the values yet :)
        just all other stuff :=)

        But its 4 in the morning so rest must be tomorrow as its bed time for me :)

        A Offline
        A Offline
        AliM93
        wrote on last edited by
        #121

        @mrjj yes! but i don't even see the number

        mrjjM 1 Reply Last reply
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        • A Offline
          A Offline
          AliM93
          wrote on last edited by
          #122

          anyway, ok for tomorrow, you have been too much patient with me, thanks. and for the first time, i can say thay i better undestand how qt works! i start to appreciate it

          1 Reply Last reply
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          • A AliM93

            @mrjj yes! but i don't even see the number

            mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by
            #123

            @AliM93
            well do you have that version of paint ?

            
            void MatrixWidget::paintEvent(QPaintEvent *event)
            {
            
                QPainter p(this);
                // draw frame.
                p.drawRect(0, 0, width() - 1, height() - 1);
            
                // size of area we have. w = width , h = height , we take 2 pixles for border
                int w = width() - 2;
                int h = height() - 2;
            
                // now we find out how big each box should be which area we have  divided with how many on x and y
                bw = w / max_x;
                bh = h / max_y;
            
                // now we loop and drw the boxes
                for (int xi = 0; xi < max_x; ++xi) {
                    for (int yi = 0; yi < max_x; ++yi) {
                        p.drawRect( QRect( xi * bw, yi * bh, bw, bh  ) )  ;
                        p.drawText(QRect( xi * bw, yi * bh, bw, bh  ),
                                   QString::number(xi + 1) + "," + QString::number(yi+1) ); // the +1 aswe dont want to use first at 0,0
                    }
                }
            
            }
            
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            • A Offline
              A Offline
              AliM93
              wrote on last edited by
              #124

              yes i have

              mrjjM 1 Reply Last reply
              0
              • A AliM93

                yes i have

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #125

                @AliM93
                But it dont draw numbers ?
                That seems very odd.

                But you do see grid ?

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                • A Offline
                  A Offline
                  AliM93
                  wrote on last edited by
                  #126

                  sorry! now i have, i lost a part of that version of matrix, sorry!

                  mrjjM 1 Reply Last reply
                  0
                  • A AliM93

                    sorry! now i have, i lost a part of that version of matrix, sorry!

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #127

                    @AliM93
                    Ok that good news as it would be very impossible that numbers went missing :)

                    what is remaining is the click logic and to actual draw the 1.

                    how shall we draw 0 ones ?
                    just no value in cell and cant be selected or what is the goal?

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                    • A Offline
                      A Offline
                      AliM93
                      wrote on last edited by
                      #128

                      my idea was to color all the 1s in green and the 0s in gray. so the user know that can select only the green cells, is it possible?

                      1 Reply Last reply
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                      • A Offline
                        A Offline
                        AliM93
                        wrote on last edited by
                        #129

                        i don't want to disturb you anymore tonight, if you want and if you have time we can continue tomorrow

                        1 Reply Last reply
                        0
                        • mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by
                          #130

                          Yes its possible. we can paint it any way we like. teasers included.

                          Well im getting very tired as 4.20 in the morning is late for me even i do love programming at night.

                          Tomorrow we add the last part. It's not that much. Promise.
                          You did good. First custom widget is always a bit tuff.

                          alt text

                          alt text

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                          • A Offline
                            A Offline
                            AliM93
                            wrote on last edited by
                            #131

                            thank you so much! you help me a lot also in understand the ideas. thanks. night!

                            1 Reply Last reply
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                            • mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by mrjj
                              #132

                              Hi
                              The last remaining steps are to
                              +Add box width/height as members to use when clicking and a variable to keep track of the number of selected

                              class MatrixWidget : public QWidget
                              {....    
                                  int bw =0;
                                  int bh =0;
                                  int selCount=0; // to make sure we can only select 3
                              ,...
                              

                              +call loadData from construtor.

                              +Set some colors in void MatrixWidget::LoadData()
                              for 0 cells and 1 cells (see code)

                              +Add selection logic to mousePress

                              void MatrixWidget::mousePressEvent(QMouseEvent *event)
                              {
                                  QPoint p = event->pos(); // where we clicked
                              
                                  int xindex =  p.x() / bw;
                                  int yindex =  p.y() / bh;
                              
                                  qDebug() << xindex << " " << yindex;
                                  // get the data point ( we should check index is not outside array...)
                                  DataPoint &dp = Data[xindex + 1 ][yindex + 1]; 
                              
                                  // value zero cannot be selected
                                  if ( dp.value == 0 ) return;
                              
                                  // selection logic. If not already selected, select it and set color. Else deselect and reset color
                                  if ( dp.isSelected == false) {
                              
                                      // no more than 3 selected ( 0,1,2 )
                                      if ( selCount > 2 ) return;
                              
                                      dp.DrawColor = Qt::blue;
                                      dp.isSelected = true;
                                      selCount++; // extra selected
                                  } else {
                                      dp.DrawColor =  Qt::green;
                                      dp.isSelected = false;
                                      selCount--; // less selected
                                  }
                                  update(); // tell it to redraw grid
                              
                              }
                              
                              

                              +Adjust draw to skip 0,0 as we don't use it but the array must start at zero.

                              void MatrixWidget::paintEvent(QPaintEvent *event)
                              {
                              
                                  QPainter p(this);
                                  // draw frame.
                                  p.drawRect(0, 0, width() - 1, height() - 1);
                              
                                  // size of area we have. w = width , h = height , we take 2 pixles for border
                                  int w = width() - 2;
                                  int h = height() - 2;
                              
                                  // now we find out how big each box should be which area we have  divided with how many on x and y
                                  bw = w / max_x;
                                  bh = h / max_y;
                              
                                  // now we loop and draw the boxes. we dont use the boxes from 0,0 as data starts with 1,1
                                  for (int xi = 0; xi < max_x - 1; ++xi) {
                                      for (int yi = 0; yi < max_x - 1; ++yi) {
                                          p.setBrush(QBrush( Data[xi + 1][yi + 1].DrawColor )); // +1 as we dont want to use from 0,0
                                          QRect cellRect( xi * bw, yi * bh, bw, bh  );
                                          p.drawRect( cellRect );
                                          // show x,y . just for debug
                                          p.drawText( cellRect ,
                                                     QString::number(xi + 1) + "," +
                                                     QString::number(yi +1) );
                              
                                      }
                                  }
                              }
                              
                              
                              

                              Then we have a working version.

                              alt text

                              project
                              https://www.dropbox.com/s/z4nllgag1tjy4j3/GridWidgetApp.zip?dl=0

                              Things to improve/add
                              The limit of how many points user can select,
                              should be a parameter to the class so it can be set to anything and not a fixed value.

                              The colors could also be parameters ( for not selectable, selectable and selected)

                              Add a function to return the selected data pointsby looping the Data list and check isSelected.

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                              • A Offline
                                A Offline
                                AliM93
                                wrote on last edited by AliM93
                                #133

                                thanks! i'll do it step by step, i quite understand it, but when i run i got a black grid, and the error floating point exeption (core dumped) No more error, (i also see the coordinates in the debug), but black grid.

                                mrjjM 1 Reply Last reply
                                0
                                • A AliM93

                                  thanks! i'll do it step by step, i quite understand it, but when i run i got a black grid, and the error floating point exeption (core dumped) No more error, (i also see the coordinates in the debug), but black grid.

                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #134

                                  @AliM93 said in Create a matrix from a .csv file:

                                  it, but when i run i got a black grid, and the error floating point exeption (core dumped)

                                  In my project or yours ?

                                  A 1 Reply Last reply
                                  0
                                  • mrjjM mrjj

                                    @AliM93 said in Create a matrix from a .csv file:

                                    it, but when i run i got a black grid, and the error floating point exeption (core dumped)

                                    In my project or yours ?

                                    A Offline
                                    A Offline
                                    AliM93
                                    wrote on last edited by
                                    #135

                                    @mrjj in mine

                                    mrjjM 1 Reply Last reply
                                    0
                                    • A AliM93

                                      @mrjj in mine

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #136

                                      @AliM93

                                      Ok, i would guess that you forgot something from the maxtric class to put in yours.
                                      But if the grid is drawn ( you see it) and then when you click error comes ?

                                      1 Reply Last reply
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                                      • A Offline
                                        A Offline
                                        AliM93
                                        wrote on last edited by
                                        #137
                                        This post is deleted!
                                        mrjjM 1 Reply Last reply
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                                        • A AliM93

                                          This post is deleted!

                                          mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by mrjj
                                          #138

                                          @AliM93
                                          If it compiles then all includes are fine.

                                          Do you load data ?

                                          Did you change LoadData function to set colors ?
                                          (or use mine, just change the path to the data file)

                                          I think all is just black :)
                                          (default zero)

                                          A 1 Reply Last reply
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