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Minimizing Vertical Spacing in QGridLayout

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  • A Absurd

    But that's the thing; why is there remaining space in the first place, if I used QGridLayout.setSpacing(0)?

    J.HilkJ Offline
    J.HilkJ Offline
    J.Hilk
    Moderators
    wrote on last edited by
    #17

    @Absurd
    because you do set a fixed size to the content of the layout. If the content can not fill the layout, margins ans spacings are added, or what would you expect to happen?


    Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


    Q: What's that?
    A: It's blue light.
    Q: What does it do?
    A: It turns blue.

    1 Reply Last reply
    1
    • A Offline
      A Offline
      Absurd
      wrote on last edited by
      #18

      @J-Hilk see what I wrote above:

      @Absurd said in Minimizing Vertical Spacing in QGridLayout:

      I did nothing special on the QGridLayout nor on the QLineEdit...
      You can see the constructor for the main Widget above (PacketHeader), and even when commenting all size-related lines in the Bit constructor (which is actually a QLineEdit):

      Bit::Bit(QWidget* parent) : QLineEdit(parent) {
          QFont font("Courier New", 10, QFont::Bold);
          setFont(font);
          //setMaxLength(1);
          setFrame(false);
          //setFixedWidth(16);
          setAlignment(Qt::AlignCenter);
          setText("0");
      }
      

      I am still left with this:
      0_1544962979993_ca034ea7-e723-452e-acf2-013c272ace57-image.png

      Here's the main entry for the window, in case anyone kindly wants to try running:

      int main(int argc, char* argv[]) {
          QApplication app(argc, argv);
      
          PacketHeader element;
          element.show();
      
          return app.exec();
      }
      

      Thanks.

      edit
      My goal is to have 4 x 32 one-character boxes such that the boxes will be packed together with no space between them.

      edit 2
      mrjj, I am guessing that you are using some kind of Designer Tool, can you please share the code that's generated? Maybe I can take a look at it as a reference to understand what I am doing wrong...

      Specifically:

      and even when commenting all size-related lines in the Bit constructor

      J.HilkJ 1 Reply Last reply
      0
      • A Absurd

        @J-Hilk see what I wrote above:

        @Absurd said in Minimizing Vertical Spacing in QGridLayout:

        I did nothing special on the QGridLayout nor on the QLineEdit...
        You can see the constructor for the main Widget above (PacketHeader), and even when commenting all size-related lines in the Bit constructor (which is actually a QLineEdit):

        Bit::Bit(QWidget* parent) : QLineEdit(parent) {
            QFont font("Courier New", 10, QFont::Bold);
            setFont(font);
            //setMaxLength(1);
            setFrame(false);
            //setFixedWidth(16);
            setAlignment(Qt::AlignCenter);
            setText("0");
        }
        

        I am still left with this:
        0_1544962979993_ca034ea7-e723-452e-acf2-013c272ace57-image.png

        Here's the main entry for the window, in case anyone kindly wants to try running:

        int main(int argc, char* argv[]) {
            QApplication app(argc, argv);
        
            PacketHeader element;
            element.show();
        
            return app.exec();
        }
        

        Thanks.

        edit
        My goal is to have 4 x 32 one-character boxes such that the boxes will be packed together with no space between them.

        edit 2
        mrjj, I am guessing that you are using some kind of Designer Tool, can you please share the code that's generated? Maybe I can take a look at it as a reference to understand what I am doing wrong...

        Specifically:

        and even when commenting all size-related lines in the Bit constructor

        J.HilkJ Offline
        J.HilkJ Offline
        J.Hilk
        Moderators
        wrote on last edited by J.Hilk
        #19

        @Absurd

        #include <QGridLayout>
        #include <QLineEdit>
        #include <QSpacerItem>
        
        Widget::Widget(QWidget *parent)
            : QWidget(parent)
        {
            QGridLayout *gLay = new QGridLayout(this);
            gLay->setSpacing(0);
            gLay->setMargin(0);
        
            for(int i(0); i < 4; i++){
                for(int j(0); j < 32; j++) {
                    if( j == 0 || j == 31){
                        gLay->addItem(new QSpacerItem(0,0,QSizePolicy::Expanding, QSizePolicy::Minimum),i,j);
                    } else {
                        QLineEdit *le = new QLineEdit(this);
                        le->setMaxLength(1);
                        le->setFixedWidth(16);
                        le->setAlignment(Qt::AlignCenter);
                        le->setText("0");
                        gLay->addWidget(le,i,j,1,1, Qt::AlignCenter);
                    }
                }
            }
        }
        

        works fine for me:

        0_1545038347999_e912c7fe-8088-4e3a-a8ca-1fe85fca4538-image.png

        0_1545038365685_84906f62-49d6-4ce4-b3e2-f5bde4ebcaaf-image.png


        ups, j should run to 34 so that there are 32 QLineEdits.


        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


        Q: What's that?
        A: It's blue light.
        Q: What does it do?
        A: It turns blue.

        1 Reply Last reply
        2
        • A Offline
          A Offline
          Absurd
          wrote on last edited by
          #20

          Thanks for the help. Appreciate it!

          Ok, running the exact same code as yours, I get different results...

          main.cpp:

          #include <QApplication>
          #include "Widget.h"
          
          
          
          int main(int argc, char* argv[]) {
              QApplication app(argc, argv);
          
              Widget widget;
              widget.show();
          
              return app.exec();
          }
          

          Widget.h:

          #ifndef WIDGET_H_
          #define WIDGET_H_
          
          #include <QWidget>
          
          class Widget : public QWidget {
              Q_OBJECT
          
          public:
              Widget(QWidget* parent = 0);
          };
          
          #endif
          

          Widget.cpp:

          #include "Widget.h"
          #include <QGridLayout>
          #include <QLineEdit>
          #include <QSpacerItem>
          
          Widget::Widget(QWidget *parent)
              : QWidget(parent)
          {
              QGridLayout *gLay = new QGridLayout(this);
              gLay->setSpacing(0);
              gLay->setMargin(0);
          
              for(int i(0); i < 4; i++){
                  for(int j(0); j < 32; j++) {
                      if( j == 0 || j == 31){
                          gLay->addItem(new QSpacerItem(0,0,QSizePolicy::Expanding, QSizePolicy::Minimum),i,j);
                      } else {
                          QLineEdit *le = new QLineEdit(this);
                          le->setMaxLength(1);
                          le->setFixedWidth(16);
                          le->setAlignment(Qt::AlignCenter);
                          le->setText("0");
                          gLay->addWidget(le,i,j,1,1, Qt::AlignCenter);
                      }
                  }
              }
          }
          

          And then:

          $> qmake-qt4 -project
          $> qmake-qt4 testing.pro
          $> make
          $> ./testing
          

          and the result:
          0_1545131067077_61efcb2e-9c97-48ec-8d01-eaaaa3fac713-image.png


          Maybe I am using different qt version?
          Maybe it's an environment issue?
          What else could it be?

          1 Reply Last reply
          0
          • A Offline
            A Offline
            Absurd
            wrote on last edited by Absurd
            #21

            Important update
            I tried to compile & run the same code on another machine, and guess what...

            0_1545142446417_9270b473-9f2b-43a9-b213-846dae79abd5-image.png

            $> uname -a
            Linux 4.15.0-42-generic #45-Ubuntu SMP Thu Nov 15 19:32:57 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
            

            Does anyone has an idea on why would different machine render the GUI differently?

            mrjjM 1 Reply Last reply
            0
            • A Absurd

              Important update
              I tried to compile & run the same code on another machine, and guess what...

              0_1545142446417_9270b473-9f2b-43a9-b213-846dae79abd5-image.png

              $> uname -a
              Linux 4.15.0-42-generic #45-Ubuntu SMP Thu Nov 15 19:32:57 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
              

              Does anyone has an idea on why would different machine render the GUI differently?

              mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by mrjj
              #22

              @Absurd
              Are the both linuxes ? ( with GNOME)

              A 1 Reply Last reply
              0
              • mrjjM mrjj

                @Absurd
                Are the both linuxes ? ( with GNOME)

                A Offline
                A Offline
                Absurd
                wrote on last edited by Absurd
                #23

                @mrjj
                Yes, they are both Linux-based, but not both are GNOME:

                The bad:

                $> uname -a 
                Linux 3.10.0-327.el7.x86_64 #1 SMP Thu Oct 29 17:29:29 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux
                $> ls /usr/bin/*session
                /usr/bin/gnome-session*  /usr/bin/gnome-session-custom-session*
                $> qmake-qt4 --version
                QMake version 2.01a
                Using Qt version 4.8.5 in /usr/lib64
                

                The good:

                $> uname -a
                Linux 4.15.0-42-generic #45-Ubuntu SMP Thu Nov 15 19:32:57 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
                $> ls /usr/bin/*session
                /usr/bin/byobu-select-session*  /usr/bin/dbus-run-session*
                $> qmake-qt4 --version
                QMake version 2.01a
                Using Qt version 4.8.7 in /usr/lib/x86_64-linux-gnu
                
                mrjjM 1 Reply Last reply
                0
                • A Absurd

                  @mrjj
                  Yes, they are both Linux-based, but not both are GNOME:

                  The bad:

                  $> uname -a 
                  Linux 3.10.0-327.el7.x86_64 #1 SMP Thu Oct 29 17:29:29 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux
                  $> ls /usr/bin/*session
                  /usr/bin/gnome-session*  /usr/bin/gnome-session-custom-session*
                  $> qmake-qt4 --version
                  QMake version 2.01a
                  Using Qt version 4.8.5 in /usr/lib64
                  

                  The good:

                  $> uname -a
                  Linux 4.15.0-42-generic #45-Ubuntu SMP Thu Nov 15 19:32:57 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
                  $> ls /usr/bin/*session
                  /usr/bin/byobu-select-session*  /usr/bin/dbus-run-session*
                  $> qmake-qt4 --version
                  QMake version 2.01a
                  Using Qt version 4.8.7 in /usr/lib/x86_64-linux-gnu
                  
                  mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #24

                  @Absurd
                  Hi
                  Could yo try to do

                  #include <QDebug>
                  #include <QStyle>
                  
                  int main(int argc, char *argv[])
                  {
                      QApplication a(argc, argv);
                      qDebug() << QApplication::style()->objectName();
                  ...normal code...
                  

                  and see if they list different styles ?

                  1 Reply Last reply
                  1
                  • A Offline
                    A Offline
                    Absurd
                    wrote on last edited by Absurd
                    #25

                    Adding the code you suggested;
                    The Bad prints out "oxygen",
                    The Good prints out "windows".

                    What does that mean?

                    Thanks.

                    mrjjM 1 Reply Last reply
                    0
                    • A Absurd

                      Adding the code you suggested;
                      The Bad prints out "oxygen",
                      The Good prints out "windows".

                      What does that mean?

                      Thanks.

                      mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by mrjj
                      #26

                      @Absurd
                      It means that it uses different QStyles for the look and apparently
                      the oxygen draws the LineEdit with little border or something like that.

                      on the good, could you try

                       QStyle *style = QStyleFactory::create("oxygen");
                          if(style)
                          {
                              qDebug("Oxygen loaded!");        
                              QApplication::setStyle(style);
                          }
                      

                      and see if it then get a space like the bad one ?

                      1 Reply Last reply
                      2
                      • A Offline
                        A Offline
                        Absurd
                        wrote on last edited by Absurd
                        #27

                        You nailed it!
                        I added this code on the 'Good', but QStyleFactory::create("oxygen"); returned NULL for some reason (do you happen to know how can I inspect why? is there something like 'errno' I can print out?), so instead I tried this on the 'Bad':

                        QStyle *style = QStyleFactory::create("windows");
                           if(style)
                           {
                               qDebug("windows loaded!");        
                               QApplication::setStyle(style);
                           }
                        

                        and voilĂ :
                        0_1545145924547_6f35a3ef-60b0-4f07-b136-60657b3ef691-image.png

                        Now, I guess I can use it as a WA, but I'm curious:
                        How is the QStyle determined inside a QApplication?
                        Could it be related to the qt4 versions? (in the 'Bad' machine I didn't have to install qt4 - it was there when I got it, but on the 'Good' I had to install it with sudo apt install qt4-default)

                        Thanks again!

                        mrjjM 1 Reply Last reply
                        0
                        • A Absurd

                          You nailed it!
                          I added this code on the 'Good', but QStyleFactory::create("oxygen"); returned NULL for some reason (do you happen to know how can I inspect why? is there something like 'errno' I can print out?), so instead I tried this on the 'Bad':

                          QStyle *style = QStyleFactory::create("windows");
                             if(style)
                             {
                                 qDebug("windows loaded!");        
                                 QApplication::setStyle(style);
                             }
                          

                          and voilĂ :
                          0_1545145924547_6f35a3ef-60b0-4f07-b136-60657b3ef691-image.png

                          Now, I guess I can use it as a WA, but I'm curious:
                          How is the QStyle determined inside a QApplication?
                          Could it be related to the qt4 versions? (in the 'Bad' machine I didn't have to install qt4 - it was there when I got it, but on the 'Good' I had to install it with sudo apt install qt4-default)

                          Thanks again!

                          mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by mrjj
                          #28

                          @Absurd said in Minimizing Vertical Spacing in QGridLayout:
                          Hi
                          As far as i know QStyleFactory cannot tell you why. only list available styles.

                          • How is the QStyle determined inside a QApplication?
                            Never saw the actual for that detection. so cant tell. sorry.

                          Im wondering if 4.8.5 had a small bug where even disable the border would not
                          reduce the space used. And that was fixed in 4.8.7. Or it simply is a QStyle drawing difference.

                          1 Reply Last reply
                          0
                          • A Offline
                            A Offline
                            Absurd
                            wrote on last edited by
                            #29

                            I will try installing 4.8.7 and will update if the behavior is different there...

                            1 Reply Last reply
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