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  4. cropping image on QLabel using mouseEvent

cropping image on QLabel using mouseEvent

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  • D Dimple

    @mjjj as u said i hv changed
    copyImage=newImage.copy(myRect);

    but here wat happens after dragged image,, its showing QLabel is completely black

    mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by
    #5

    @Dimple
    you mean when you drag the image to be cropped to the label ?

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    • D Offline
      D Offline
      Dimple
      wrote on last edited by
      #6

      yeah ,,after dragged the image ,,its showing QLabel is completely black (not shows image after cropped the image)

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      • D Offline
        D Offline
        Dimple
        wrote on last edited by Dimple
        #7

        0_1545661635737_img2.PNG

        0_1545661348348_img.PNG

        mrjjM 1 Reply Last reply
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        • D Dimple

          0_1545661635737_img2.PNG

          0_1545661348348_img.PNG

          mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by
          #8

          @Dimple
          I think the mapping of the coordinates are a bit off so the rect copied is outside
          the coordinates for label holding image.

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          • D Offline
            D Offline
            Dimple
            wrote on last edited by
            #9

            can u please send me correct code ,,,im not getting

            mrjjM 1 Reply Last reply
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            • D Dimple

              can u please send me correct code ,,,im not getting

              mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #10

              @Dimple
              the calculations for the actual rect to copy

              a = ui->label->mapFromGlobal(a);
              b = ui->label->mapFromGlobal(b);
              
              double sx = ui->label->rect().width();
              double sy = ui->label->rect().height();
              
              sx = OriginalPix.width() / sx;
              sy = OriginalPix.height() / sy;
              
              a.setX(int(a.x() * sx));
              b.setX(int(b.x() * sx));
              a.setX(int(a.x() * sy));
              b.setX(int(b.x() * sy));
              
              QRect myRect(a, b); // im not sure this rect is as intended.
              

              try use qDebug to write it out and inspect the values.
              like
              qDebug() << " crop rect" << myRect;

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              • mrjjM mrjj

                @Dimple
                the calculations for the actual rect to copy

                a = ui->label->mapFromGlobal(a);
                b = ui->label->mapFromGlobal(b);
                
                double sx = ui->label->rect().width();
                double sy = ui->label->rect().height();
                
                sx = OriginalPix.width() / sx;
                sy = OriginalPix.height() / sy;
                
                a.setX(int(a.x() * sx));
                b.setX(int(b.x() * sx));
                a.setX(int(a.x() * sy));
                b.setX(int(b.x() * sy));
                
                QRect myRect(a, b); // im not sure this rect is as intended.
                

                try use qDebug to write it out and inspect the values.
                like
                qDebug() << " crop rect" << myRect;

                F Offline
                F Offline
                fouad2130
                Banned
                wrote on last edited by fouad2130
                #11
                This post is deleted!
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                • D Offline
                  D Offline
                  Dimple
                  wrote on last edited by
                  #12

                  @mrjj

                  a.setX(int(a.x() * sx));
                  b.setX(int(b.x() * sx));
                  a.setY(int(a.y() * sy));
                  b.setY(int(b.y() * sy));

                  QRect myRect(a,b);

                  QImage newImage;
                  newImage = OriginalPix.toImage();
                  QImage copyImage;
                  copyImage=newImage.copy(myRect);
                  ui->label->setPixmap(QPixmap::fromImage(copyImage));
                  ui->label->setScaledContents(true);
                  ui->label->repaint();

                  now its working ,,i can crop the image but after cropped the image ,,,if i click on cropped image ,,image is disappearing?

                  mrjjM 1 Reply Last reply
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                  • D Dimple

                    @mrjj

                    a.setX(int(a.x() * sx));
                    b.setX(int(b.x() * sx));
                    a.setY(int(a.y() * sy));
                    b.setY(int(b.y() * sy));

                    QRect myRect(a,b);

                    QImage newImage;
                    newImage = OriginalPix.toImage();
                    QImage copyImage;
                    copyImage=newImage.copy(myRect);
                    ui->label->setPixmap(QPixmap::fromImage(copyImage));
                    ui->label->setScaledContents(true);
                    ui->label->repaint();

                    now its working ,,i can crop the image but after cropped the image ,,,if i click on cropped image ,,image is disappearing?

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by mrjj
                    #13

                    @Dimple
                    Hi
                    clicking the label triggers mousePressEvent and mouseReleaseEvent
                    so you will grab a very small /invalid area. ( thats my guess )

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                    • D Offline
                      D Offline
                      Dimple
                      wrote on last edited by
                      #14

                      @mrjj said in cropping image on QLabel using mouseEvent:

                      triggers

                      ok i ll change some functionality ,,Thanks for ur help

                      mrjjM 1 Reply Last reply
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                      • D Dimple

                        @mrjj said in cropping image on QLabel using mouseEvent:

                        triggers

                        ok i ll change some functionality ,,Thanks for ur help

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #15

                        @Dimple
                        Hi
                        i imagine a bool flag to tell it its in crop mode , else it will just ignore the mosuePress code etc.

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                        • D Offline
                          D Offline
                          Dimple
                          wrote on last edited by
                          #16

                          @mrjj

                          ok i ll check it out,,,thanks

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