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PyQt QImage cna't copy, crash without error code

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  • JonBJ JonB

    @darrenleeleelee1
    Then OOI how does

    qimage = qimage.copy(QtCore.QRect(0, 0, 2235, 3408))
    

    behave?

    D Offline
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    darrenleeleelee1
    wrote on last edited by darrenleeleelee1
    #12

    @JonB It won't crash!But when I change to

    qimage.copy(0, 0, qimage.width(), qimage.height()) 
    

    then it crash.Even I give to other variable first it still not work

    wt = qimage.width()
    ht = qimage.height()
    qimage = qimage.copy(0, 0, wt, ht)
    
    J.HilkJ KroMignonK JonBJ 3 Replies Last reply
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    • D darrenleeleelee1

      @JonB It won't crash!But when I change to

      qimage.copy(0, 0, qimage.width(), qimage.height()) 
      

      then it crash.Even I give to other variable first it still not work

      wt = qimage.width()
      ht = qimage.height()
      qimage = qimage.copy(0, 0, wt, ht)
      
      J.HilkJ Online
      J.HilkJ Online
      J.Hilk
      Moderators
      wrote on last edited by
      #13

      @darrenleeleelee1 what about
      qimage = qimage.copy(QtCore.QRect())


      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.

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      • J.HilkJ J.Hilk

        @darrenleeleelee1 what about
        qimage = qimage.copy(QtCore.QRect())

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        darrenleeleelee1
        wrote on last edited by
        #14

        @J-Hilk I try it.But also crash.

        1 Reply Last reply
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        • D darrenleeleelee1

          @JonB It won't crash!But when I change to

          qimage.copy(0, 0, qimage.width(), qimage.height()) 
          

          then it crash.Even I give to other variable first it still not work

          wt = qimage.width()
          ht = qimage.height()
          qimage = qimage.copy(0, 0, wt, ht)
          
          KroMignonK Offline
          KroMignonK Offline
          KroMignon
          wrote on last edited by KroMignon
          #15

          @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

          qimage.copy(0, 0, qimage.width(), qimage.height())

          then it crash

          It looks very strange to me, because when looking for QImage::copy(int x, int y, int w, int h), I found:

             inline QImage copy(int x, int y, int w, int h) const
                  { return copy(QRect(x, y, w, h)); }
          
          

          What if when you change your code to:

          qimage = QtGui.QImage(arr, arr.shape[1], arr.shape[0], QtGui.QImage.Format_Grayscale16)
          qimageCopy = qimage.copy()
          

          Does this also crash?

          It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

          1 Reply Last reply
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          • D darrenleeleelee1

            @JonB It won't crash!But when I change to

            qimage.copy(0, 0, qimage.width(), qimage.height()) 
            

            then it crash.Even I give to other variable first it still not work

            wt = qimage.width()
            ht = qimage.height()
            qimage = qimage.copy(0, 0, wt, ht)
            
            JonBJ Offline
            JonBJ Offline
            JonB
            wrote on last edited by JonB
            #16

            @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

            @JonB It won't crash!But when I change to
            qimage.copy(0, 0, qimage.width(), qimage.height())

            then it crash.Even I give to other variable first it still not work
            wt = qimage.width()
            ht = qimage.height()
            qimage = qimage.copy(0, 0, wt, ht)

            This all implies that the source qimage you start with is the issue.

            Start by looking at exactly what your arr = ds.pixel_array holds/returns. The QImage() constructor you use states "it must remain valid". That looks to me like the danger area. I think when you copy a portion of the image Qt takes a copy of its own. But probably not when you copy the whole thing. For example, are you able to do a Python copy() on it so you have your own separate copy, which you then use for the image? And btw, if you have any threading involved anywhere, please say so......

            D 1 Reply Last reply
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            • JonBJ JonB

              @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

              @JonB It won't crash!But when I change to
              qimage.copy(0, 0, qimage.width(), qimage.height())

              then it crash.Even I give to other variable first it still not work
              wt = qimage.width()
              ht = qimage.height()
              qimage = qimage.copy(0, 0, wt, ht)

              This all implies that the source qimage you start with is the issue.

              Start by looking at exactly what your arr = ds.pixel_array holds/returns. The QImage() constructor you use states "it must remain valid". That looks to me like the danger area. I think when you copy a portion of the image Qt takes a copy of its own. But probably not when you copy the whole thing. For example, are you able to do a Python copy() on it so you have your own separate copy, which you then use for the image? And btw, if you have any threading involved anywhere, please say so......

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              darrenleeleelee1
              wrote on last edited by
              #17

              @JonB Sorry I am not really get what did you mean.And I think I don't have any threading.(I think..)

              JonBJ 1 Reply Last reply
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              • D darrenleeleelee1

                @JonB Sorry I am not really get what did you mean.And I think I don't have any threading.(I think..)

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #18

                @darrenleeleelee1
                I have no idea what is behind your

                        ds = dcmread('./5F329172_20170623_CR_2_1_1')
                        arr = ds.pixel_array
                

                It's some external library stuff. (And btw I have no idea whether arr.shape[1], arr.shape[0] is the right thing to use. Don't bother to explain, just make sure it's correct for whatever this ds stuff is.)

                Try this:

                import copy
                ...
                        arr = copy.copy(ds.pixel_array)
                # or even:
                #        arr = copy.deepcopy(ds.pixel_array)
                

                before you proceed to qimage = QtGui.QImage(arr, ...). Any better, crash-wise?

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                • JonBJ JonB

                  @darrenleeleelee1
                  I have no idea what is behind your

                          ds = dcmread('./5F329172_20170623_CR_2_1_1')
                          arr = ds.pixel_array
                  

                  It's some external library stuff. (And btw I have no idea whether arr.shape[1], arr.shape[0] is the right thing to use. Don't bother to explain, just make sure it's correct for whatever this ds stuff is.)

                  Try this:

                  import copy
                  ...
                          arr = copy.copy(ds.pixel_array)
                  # or even:
                  #        arr = copy.deepcopy(ds.pixel_array)
                  

                  before you proceed to qimage = QtGui.QImage(arr, ...). Any better, crash-wise?

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                  darrenleeleelee1
                  wrote on last edited by
                  #19

                  @JonB 72c6dea2-3187-4f9b-b755-d7939e474ce1-image.png
                  I add deepcopy,and it also crash. I add some arr attribute for you.
                  ed678234-91b9-475e-b889-0117c72ec04c-image.png

                  KroMignonK 1 Reply Last reply
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                  • D darrenleeleelee1

                    @JonB 72c6dea2-3187-4f9b-b755-d7939e474ce1-image.png
                    I add deepcopy,and it also crash. I add some arr attribute for you.
                    ed678234-91b9-475e-b889-0117c72ec04c-image.png

                    KroMignonK Offline
                    KroMignonK Offline
                    KroMignon
                    wrote on last edited by KroMignon
                    #20

                    @darrenleeleelee1 I think you should change your code to:

                    qimage = QtGui.QImage(arr.data, arr.shape[1], arr.shape[0], QtGui.QImage.Format_Grayscale16)
                    

                    It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

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                    • KroMignonK KroMignon

                      @darrenleeleelee1 I think you should change your code to:

                      qimage = QtGui.QImage(arr.data, arr.shape[1], arr.shape[0], QtGui.QImage.Format_Grayscale16)
                      
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                      darrenleeleelee1
                      wrote on last edited by
                      #21

                      @KroMignon I change but still crash...What is the different between arr and arr.data?

                      KroMignonK 1 Reply Last reply
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                      • D darrenleeleelee1

                        @KroMignon I change but still crash...What is the different between arr and arr.data?

                        KroMignonK Offline
                        KroMignonK Offline
                        KroMignon
                        wrote on last edited by
                        #22

                        @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                        What is the different between arr and arr.data?

                        arr is an instance of numpy.ndarray type, according to your code!
                        And arr.data is the data buffer according to numpy documentation ==> https://numpy.org/doc/stable/reference/generated/numpy.ndarray.html

                        I think it would be great if you first explain what you want to do.
                        Perhaps you should take a look at this python script which converts numpy.ndatarray to QImage and vice versa:
                        https://kogs-www.informatik.uni-hamburg.de/~meine/software/vigraqt/qimage2ndarray.py

                        It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                        D 1 Reply Last reply
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                        • KroMignonK KroMignon

                          @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                          What is the different between arr and arr.data?

                          arr is an instance of numpy.ndarray type, according to your code!
                          And arr.data is the data buffer according to numpy documentation ==> https://numpy.org/doc/stable/reference/generated/numpy.ndarray.html

                          I think it would be great if you first explain what you want to do.
                          Perhaps you should take a look at this python script which converts numpy.ndatarray to QImage and vice versa:
                          https://kogs-www.informatik.uni-hamburg.de/~meine/software/vigraqt/qimage2ndarray.py

                          D Offline
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                          darrenleeleelee1
                          wrote on last edited by
                          #23

                          @KroMignon I saw this before, but I don't know how to apply to uint16.

                          KroMignonK 1 Reply Last reply
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                          • D darrenleeleelee1

                            @KroMignon I saw this before, but I don't know how to apply to uint16.

                            KroMignonK Offline
                            KroMignonK Offline
                            KroMignon
                            wrote on last edited by
                            #24

                            @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                            I saw this before, but I don't know how to apply to uint16.

                            Which version of Qt-Libs are you using?
                            Format_Grayscale16 is only support starting from Qt 5.13 (cf. QImage.Format)

                            Because of this note from documentation:

                            Constructs an image with the given width , height and format , that uses an existing memory buffer, data . The width and height must be specified in pixels, data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned.

                            Perhaps you should specify the number of bytes per line, like this:

                            qimage = QtGui.QImage(arr.data, arr.shape[1], arr.shape[0], arr.shape[1]*2, QtGui.QImage.Format_Grayscale16)
                            

                            It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                            D 1 Reply Last reply
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                            • KroMignonK KroMignon

                              @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                              I saw this before, but I don't know how to apply to uint16.

                              Which version of Qt-Libs are you using?
                              Format_Grayscale16 is only support starting from Qt 5.13 (cf. QImage.Format)

                              Because of this note from documentation:

                              Constructs an image with the given width , height and format , that uses an existing memory buffer, data . The width and height must be specified in pixels, data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned.

                              Perhaps you should specify the number of bytes per line, like this:

                              qimage = QtGui.QImage(arr.data, arr.shape[1], arr.shape[0], arr.shape[1]*2, QtGui.QImage.Format_Grayscale16)
                              
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                              darrenleeleelee1
                              wrote on last edited by darrenleeleelee1
                              #25

                              @KroMignon said in PyQt QImage cna't copy, crash without error code:

                              arr.shape[1]*2

                              sorry, I read through the QImage API, but I don;t get why I need to add this.
                              After I add this it seems can work.

                              KroMignonK 1 Reply Last reply
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                              • D darrenleeleelee1

                                @KroMignon said in PyQt QImage cna't copy, crash without error code:

                                arr.shape[1]*2

                                sorry, I read through the QImage API, but I don;t get why I need to add this.
                                After I add this it seems can work.

                                KroMignonK Offline
                                KroMignonK Offline
                                KroMignon
                                wrote on last edited by KroMignon
                                #26

                                @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                                sorry, I read through the QImage API, but I don;t get why I need to add this.

                                Then you don't read carefully ;)
                                The point is when you only specify width and height: The width and height must be specified in pixels, data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned.

                                To avoid this, you can use width, height and scanline length in bytes, which is pixel_per_line x pixel_size:

                                • pixel_per_line is arr.shape[1]
                                • pixel_size is uint16 which are 2 bytes

                                ==> scanline_size = arr.shape[1]*2

                                After I add this it seems can work.

                                Great

                                It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                                D 1 Reply Last reply
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                                • KroMignonK KroMignon

                                  @darrenleeleelee1 said in PyQt QImage cna't copy, crash without error code:

                                  sorry, I read through the QImage API, but I don;t get why I need to add this.

                                  Then you don't read carefully ;)
                                  The point is when you only specify width and height: The width and height must be specified in pixels, data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned.

                                  To avoid this, you can use width, height and scanline length in bytes, which is pixel_per_line x pixel_size:

                                  • pixel_per_line is arr.shape[1]
                                  • pixel_size is uint16 which are 2 bytes

                                  ==> scanline_size = arr.shape[1]*2

                                  After I add this it seems can work.

                                  Great

                                  D Offline
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                                  darrenleeleelee1
                                  wrote on last edited by
                                  #27

                                  @KroMignon @J-Hilk @JonB @jsulm thanks all u guys!

                                  1 Reply Last reply
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