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How to get position or mouse click event in QLabel

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  • M ManiRon28

    @JonB no I dont get any values from the X and Y , only the DataVal string gets printed

    9a0e6f10-3ebe-46f8-a61c-44a78dfcc0f5-image.png

    This is how mu print is coming

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #10

    @ManiRon28 Please use qDebug properly:

    void MainWindow::points(QPoint &pos)
    {
        qDebug() << "DataVal" << pos.x() << pos.y();
    }
    

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
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    • M ManiRon28

      @JonB no I dont get any values from the X and Y , only the DataVal string gets printed

      9a0e6f10-3ebe-46f8-a61c-44a78dfcc0f5-image.png

      This is how mu print is coming

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #11

      @ManiRon28
      That is because your call to qDebug() is incorrect.

      qDebug() << "DataVal" << pos.x() << pos.y());
      
      M 1 Reply Last reply
      0
      • JonBJ JonB

        @ManiRon28
        That is because your call to qDebug() is incorrect.

        qDebug() << "DataVal" << pos.x() << pos.y());
        
        M Offline
        M Offline
        ManiRon28
        wrote on last edited by ManiRon28
        #12

        @JonB, @jsulm oh sorry thanks for correcting me,

        I have one more doubt

        Is there any way to differentiate between left and right mouse click

        jsulmJ 1 Reply Last reply
        0
        • M ManiRon28

          @JonB, @jsulm oh sorry thanks for correcting me,

          I have one more doubt

          Is there any way to differentiate between left and right mouse click

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #13

          @ManiRon28 It's all in the documentation:

          • https://doc.qt.io/qt-6/qsinglepointevent.html#button
          • https://doc.qt.io/qt-6/qsinglepointevent.html#buttons

          https://forum.qt.io/topic/113070/qt-code-of-conduct

          M 1 Reply Last reply
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          • jsulmJ jsulm

            @ManiRon28 It's all in the documentation:

            • https://doc.qt.io/qt-6/qsinglepointevent.html#button
            • https://doc.qt.io/qt-6/qsinglepointevent.html#buttons
            M Offline
            M Offline
            ManiRon28
            wrote on last edited by ManiRon28
            #14

            @jsulm, @JonB Thanks for providing me the necessary details

            I have a qlabel and now I am able to detect the click/press event in label, but I want to capture the coordinates based on image size

            For example
            The image size is 100x100 and the qlabel size is 200x200, I should get coordinates when I press on the image and not on the other part of qlabel which doesnt have image or empty

            JonBJ 1 Reply Last reply
            0
            • M ManiRon28

              @jsulm, @JonB Thanks for providing me the necessary details

              I have a qlabel and now I am able to detect the click/press event in label, but I want to capture the coordinates based on image size

              For example
              The image size is 100x100 and the qlabel size is 200x200, I should get coordinates when I press on the image and not on the other part of qlabel which doesnt have image or empty

              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by
              #15

              @ManiRon28
              I assume by "image" you mean QLabel::pixmap()? So you need to find where that is within the label. I don't know, but if you start with qDebug() << this->pixmap()->rect() what does that tell you, can you get from that where the pixmap is positioned within the label?

              M 1 Reply Last reply
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              • JonBJ JonB

                @ManiRon28
                I assume by "image" you mean QLabel::pixmap()? So you need to find where that is within the label. I don't know, but if you start with qDebug() << this->pixmap()->rect() what does that tell you, can you get from that where the pixmap is positioned within the label?

                M Offline
                M Offline
                ManiRon28
                wrote on last edited by
                #16

                @JonB Yes the image is loaded using pixmap

                JonBJ 1 Reply Last reply
                0
                • M ManiRon28

                  @JonB Yes the image is loaded using pixmap

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #17

                  @ManiRon28 Good.

                  M 1 Reply Last reply
                  0
                  • JonBJ JonB

                    @ManiRon28 Good.

                    M Offline
                    M Offline
                    ManiRon28
                    wrote on last edited by ManiRon28
                    #18

                    @JonB

                    I get the ouput like this

                    x = pos.x();
                    y=pos.y();
                    
                        int XVal = ui->labelImage->pixmap().rect().x();
                        int YVal = ui->labelImage->pixmap().rect().y();
                        int widthVal = ui->labelImage->pixmap().rect().width();
                        int heightVal = ui->labelImage->pixmap().rect().height();
                    
                    
                        QString qsVal = "x = " + QString::number(XVal) + ", y = " + QString::number(YVal) + ", Width = " + QString::number(widthVal) + ", height = " + QString::number(heightVal);
                    
                    x = 522, y =78, Button = LEFT, 
                    Rect - x = 0, y = 0, Width = 1379, height = 516
                    
                    jsulmJ 1 Reply Last reply
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                    • M ManiRon28

                      @JonB

                      I get the ouput like this

                      x = pos.x();
                      y=pos.y();
                      
                          int XVal = ui->labelImage->pixmap().rect().x();
                          int YVal = ui->labelImage->pixmap().rect().y();
                          int widthVal = ui->labelImage->pixmap().rect().width();
                          int heightVal = ui->labelImage->pixmap().rect().height();
                      
                      
                          QString qsVal = "x = " + QString::number(XVal) + ", y = " + QString::number(YVal) + ", Width = " + QString::number(widthVal) + ", height = " + QString::number(heightVal);
                      
                      x = 522, y =78, Button = LEFT, 
                      Rect - x = 0, y = 0, Width = 1379, height = 516
                      
                      jsulmJ Offline
                      jsulmJ Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on last edited by
                      #19

                      @ManiRon28 If you know where the pixmap is located inside the QLabel and you get the mouse coordinates inside the QLabel then it is simple math to get the coordinates inside the pixmap, right?

                      https://forum.qt.io/topic/113070/qt-code-of-conduct

                      M 1 Reply Last reply
                      1
                      • jsulmJ jsulm

                        @ManiRon28 If you know where the pixmap is located inside the QLabel and you get the mouse coordinates inside the QLabel then it is simple math to get the coordinates inside the pixmap, right?

                        M Offline
                        M Offline
                        ManiRon28
                        wrote on last edited by ManiRon28
                        #20

                        @jsulm
                        Can you please specify the procedure which would be helpful

                        jsulmJ 1 Reply Last reply
                        0
                        • M ManiRon28

                          @jsulm
                          Can you please specify the procedure which would be helpful

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #21

                          @ManiRon28 Come on, this is really basic.
                          Let's say xPixmap is the x coordinate of the pixmap inside the QLabel and xMouse is the x coordinate where the use clicked inside the QLabel. Then the x coordinate inside the pixmap is: xMouse - xPixmap.

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                          M 1 Reply Last reply
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                          • jsulmJ jsulm

                            @ManiRon28 Come on, this is really basic.
                            Let's say xPixmap is the x coordinate of the pixmap inside the QLabel and xMouse is the x coordinate where the use clicked inside the QLabel. Then the x coordinate inside the pixmap is: xMouse - xPixmap.

                            M Offline
                            M Offline
                            ManiRon28
                            wrote on last edited by ManiRon28
                            #22

                            @jsulm

                            Hi When I try to get the X and Y coordinate of pixmap I get the values as Zero

                            ui->label->pixmap().rect().x();
                            ui->label->pixmap().rect().y();
                            

                            and I found out that the width and height of QLabel is 950400 and the pixmap width is 948398

                            kindly help me with it

                            jsulmJ Pl45m4P 2 Replies Last reply
                            0
                            • M ManiRon28

                              @jsulm

                              Hi When I try to get the X and Y coordinate of pixmap I get the values as Zero

                              ui->label->pixmap().rect().x();
                              ui->label->pixmap().rect().y();
                              

                              and I found out that the width and height of QLabel is 950400 and the pixmap width is 948398

                              kindly help me with it

                              jsulmJ Offline
                              jsulmJ Offline
                              jsulm
                              Lifetime Qt Champion
                              wrote on last edited by
                              #23

                              @ManiRon28 said in How to get position or mouse click event in QLabel:

                              When I try to get the X and Y coordinate of pixmap I get the values as Zero

                              This simply means that the pixmap is located at 0,0 inside the label, so what is the problem?

                              https://forum.qt.io/topic/113070/qt-code-of-conduct

                              1 Reply Last reply
                              0
                              • M ManiRon28

                                @jsulm

                                Hi When I try to get the X and Y coordinate of pixmap I get the values as Zero

                                ui->label->pixmap().rect().x();
                                ui->label->pixmap().rect().y();
                                

                                and I found out that the width and height of QLabel is 950400 and the pixmap width is 948398

                                kindly help me with it

                                Pl45m4P Offline
                                Pl45m4P Offline
                                Pl45m4
                                wrote on last edited by Pl45m4
                                #24

                                @ManiRon28 said in How to get position or mouse click event in QLabel:

                                and I found out that the width and height of QLabel is 950400 and the pixmap width is 948398

                                I think you mean 900x400 (948x398)?!
                                The 2px difference could be a frame of QLabel.

                                I should get coordinates when I press on the image and not on the other part of qlabel which doesnt have image or empty

                                Simply math / geometry.

                                You have the image rectangle and you have your mouseClick coordinates.

                                • https://www.geeksforgeeks.org/check-if-a-point-lies-on-or-inside-a-rectangle-set-2/

                                Edit:
                                You dont even have to calculate it yourself. There is QRect::contains(QPoint)

                                • https://doc.qt.io/qt-6/qrect.html#contains

                                So pass your point you get from clickedLabel(QPoint) to that check function and do whatever you want to do, if it's inside the image rect (function will return true then).
                                And how to get the equivalent point on your pixmap, if you want to do something with your image data, @jsulm has explained here:

                                @jsulm said in How to get position or mouse click event in QLabel:

                                Let's say xPixmap is the x coordinate of the pixmap inside the QLabel and xMouse is the x coordinate where the use clicked inside the QLabel. Then the x coordinate inside the pixmap is: xMouse - xPixmap.

                                same for y of course


                                If debugging is the process of removing software bugs, then programming must be the process of putting them in.

                                ~E. W. Dijkstra

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