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transparent Widget

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  • C CodeFreaks
    6 Aug 2018, 16:04

    @mrjj
    Thanks,
    Set the window opacity is not the thing that I want because it influences whole contents not only the background.
    I want to make both main window and QTabWidget be transparent (in Windows).
    Something like this:
    MyWidget

    M Offline
    M Offline
    mrjj
    Lifetime Qt Champion
    wrote on 6 Aug 2018, 17:25 last edited by mrjj 8 Jun 2018, 17:26
    #5

    @CodeFreaks
    So the image one can see in your sample actually the Desktop image ?

    Well you can do
    setAttribute(Qt::WA_TranslucentBackground, true);
    setWindowFlags(Qt::FramelessWindowHint);

    and mainwindow will be completely transparent.
    (but also loses close buttons etc)

    C 1 Reply Last reply 6 Aug 2018, 20:12
    3
    • M mrjj
      6 Aug 2018, 17:25

      @CodeFreaks
      So the image one can see in your sample actually the Desktop image ?

      Well you can do
      setAttribute(Qt::WA_TranslucentBackground, true);
      setWindowFlags(Qt::FramelessWindowHint);

      and mainwindow will be completely transparent.
      (but also loses close buttons etc)

      C Offline
      C Offline
      CodeFreaks
      wrote on 6 Aug 2018, 20:12 last edited by CodeFreaks 8 Jul 2018, 14:01
      #6

      @mrjj
      Thanks for reply,
      @mrjj said in transparent Widget:

      So the image one can see in your sample actually the Desktop image ?

      Any thing behind my app can be seen.
      This method doesn't work for QTabWidget (as I tried),
      also for Main Window any content behind it, is accessible for all mouse/touch events (In Windows 8.1).

      1 Reply Last reply
      0
      • C Chris Kawa
        6 Aug 2018, 16:15

        Hi, the image you linked can't be seen by people that don't have account on qtcentre. I'm reuploding it, hope you don't mind.

        Aero window

        This effect is not opacity. It is called Aero Glass and it's a window frame style provided by the Windows DWM (Desktop Window Manager). It's done by extending the window frame into the client area. Qt has a wrapper for that API in the WinExtras module (as seen in the window title in that screenshot). The function you're looking for is extendFrameIntoClientArea().
        Note that this will only work on Windows Vista and 7. In Windows 8 and 10 the glass effect on the frame was replaced by a solid color so you still can extend the frame, but you won't get that blurred transparency.

        C Offline
        C Offline
        CodeFreaks
        wrote on 6 Aug 2018, 20:23 last edited by CodeFreaks 8 Jun 2018, 20:24
        #7

        @Chris-Kawa
        Thanks for reply,
        As I realized;
        It is possible to make a semi transparent widget (parent/child) in Linux but if I want to do the same in Windows I should use Winextras which windows 8 and later versions don't support it.
        Doesn't exist any way to make it possible for Windows 8 and 10?

        1 Reply Last reply
        0
        • C Online
          C Online
          Chris Kawa
          Lifetime Qt Champion
          wrote on 6 Aug 2018, 20:56 last edited by
          #8

          windows 8 and later versions don't support it

          Well it's not that they don't support it. They do and the APIs are exactly the same. It's just that the style has changed and aero windows are no longer transparent.

          I'm afraid I don't have good news. The closest thing to that effect in Windows 10 is the new Acrylic Material:

          The bad part is that it is available exclusively via XAML brushes, so while trivial to use with C# it might be very difficult or even impossible to make it work with native C++ (yeah, thanks Microsoft...). Combining it with Qt on top of that. Well... good luck ;)

          The only other alternative I know is to implement the whole thing yourself i.e. take a screenshot from under the window with native API and write your own DirectX shaders to add the glass effect. That would be just a very dirty hack though that would probably break easily. It is a lot of very low level work involving DirectComposition and expected performance is not gonna be too good. Combining it with Qt would also pose quite a challenge.

          The sad state of the world is that Microsoft is heavily promoting XAML technology and has actively taken away all the easy ways to add the same effect to native c++ apps.

          1 Reply Last reply
          5
          • C Offline
            C Offline
            CodeFreaks
            wrote on 7 Aug 2018, 11:44 last edited by CodeFreaks 8 Jul 2018, 15:22
            #9
            This post is deleted!
            1 Reply Last reply
            0
            • C Offline
              C Offline
              CodeFreaks
              wrote on 7 Aug 2018, 15:23 last edited by CodeFreaks 8 Aug 2018, 06:58
              #10
              This post is deleted!
              1 Reply Last reply
              0
              • C Offline
                C Offline
                CodeFreaks
                wrote on 8 Aug 2018, 06:47 last edited by CodeFreaks 8 Aug 2018, 06:59
                #11

                I examined many ways,
                But I can't make a transparent tabwidget (In Linux) :
                0_1533655210141_trpr2.png

                1 Reply Last reply
                0
                • C Online
                  C Online
                  Chris Kawa
                  Lifetime Qt Champion
                  wrote on 8 Aug 2018, 09:46 last edited by Chris Kawa
                  #12

                  It's a 3 step process.

                  1. Make the window widget transparent using attribute Qt::WA_TranslucentBackground, which gives you something like in your picture:
                    Transparency step 1

                  2. Make the tab header transparent. You can do that with stylesheet QTabBar::tab { background: transparent; }
                    Note that this is styling QTabBar, not QTabWidget.
                    Transparency step 2
                    You can modify the stylesheet to add the borders of the tab back if you like.

                  3. Make the tab content transparent. Note that QTabWidget itself doesn't have a background. It's the background of the widget inside it that you need to make transparent. The easiest way to do this is to tell Qt that the paint event takes care of all the painting and it does not need to fill the background with default color i.e. use Qt::WA_OpaquePaintEvent attribute.
                    Transparency step 3

                  So the entire example looks like this:

                  int main(int argc, char *argv[])
                  {
                      QApplication a(argc, argv);
                  
                      QWidget* tab_content = new QWidget();
                      tab_content->setAttribute(Qt::WA_OpaquePaintEvent); //makes the widget transparent
                  
                      QTabWidget* tw = new QTabWidget();
                      tw->addTab(tab_content, "Example");
                      tw->setStyleSheet("QTabBar::tab { background: transparent; }"); //makes the header transparent
                  
                      QWidget w;
                      w.setAttribute(Qt::WA_TranslucentBackground); //makes the window transparent
                      w.setLayout(new QVBoxLayout());
                      w.layout()->addWidget(tw);
                      w.show();
                  
                      return a.exec();
                  }
                  
                  C 8Observer88 JoeCFDJ 3 Replies Last reply 20 Sept 2018, 06:54
                  10
                  • C Chris Kawa
                    8 Aug 2018, 09:46

                    It's a 3 step process.

                    1. Make the window widget transparent using attribute Qt::WA_TranslucentBackground, which gives you something like in your picture:
                      Transparency step 1

                    2. Make the tab header transparent. You can do that with stylesheet QTabBar::tab { background: transparent; }
                      Note that this is styling QTabBar, not QTabWidget.
                      Transparency step 2
                      You can modify the stylesheet to add the borders of the tab back if you like.

                    3. Make the tab content transparent. Note that QTabWidget itself doesn't have a background. It's the background of the widget inside it that you need to make transparent. The easiest way to do this is to tell Qt that the paint event takes care of all the painting and it does not need to fill the background with default color i.e. use Qt::WA_OpaquePaintEvent attribute.
                      Transparency step 3

                    So the entire example looks like this:

                    int main(int argc, char *argv[])
                    {
                        QApplication a(argc, argv);
                    
                        QWidget* tab_content = new QWidget();
                        tab_content->setAttribute(Qt::WA_OpaquePaintEvent); //makes the widget transparent
                    
                        QTabWidget* tw = new QTabWidget();
                        tw->addTab(tab_content, "Example");
                        tw->setStyleSheet("QTabBar::tab { background: transparent; }"); //makes the header transparent
                    
                        QWidget w;
                        w.setAttribute(Qt::WA_TranslucentBackground); //makes the window transparent
                        w.setLayout(new QVBoxLayout());
                        w.layout()->addWidget(tw);
                        w.show();
                    
                        return a.exec();
                    }
                    
                    C Offline
                    C Offline
                    CodeFreaks
                    wrote on 20 Sept 2018, 06:54 last edited by CodeFreaks
                    #13

                    @Chris-Kawa
                    Hi Dear Chris Kawa
                    The method that you mentioned in previous post helped me a lot.
                    Thanks a lot.
                    But I tried to make a semi-transparent canvas (of qwtplot) . The canvas inherit from QFrame. I tried many days but I still can't do that.
                    A black background will appear instead of parent widget behind it.
                    QwtPlotCanvas Class Reference

                    1 Reply Last reply
                    0
                    • C Chris Kawa
                      8 Aug 2018, 09:46

                      It's a 3 step process.

                      1. Make the window widget transparent using attribute Qt::WA_TranslucentBackground, which gives you something like in your picture:
                        Transparency step 1

                      2. Make the tab header transparent. You can do that with stylesheet QTabBar::tab { background: transparent; }
                        Note that this is styling QTabBar, not QTabWidget.
                        Transparency step 2
                        You can modify the stylesheet to add the borders of the tab back if you like.

                      3. Make the tab content transparent. Note that QTabWidget itself doesn't have a background. It's the background of the widget inside it that you need to make transparent. The easiest way to do this is to tell Qt that the paint event takes care of all the painting and it does not need to fill the background with default color i.e. use Qt::WA_OpaquePaintEvent attribute.
                        Transparency step 3

                      So the entire example looks like this:

                      int main(int argc, char *argv[])
                      {
                          QApplication a(argc, argv);
                      
                          QWidget* tab_content = new QWidget();
                          tab_content->setAttribute(Qt::WA_OpaquePaintEvent); //makes the widget transparent
                      
                          QTabWidget* tw = new QTabWidget();
                          tw->addTab(tab_content, "Example");
                          tw->setStyleSheet("QTabBar::tab { background: transparent; }"); //makes the header transparent
                      
                          QWidget w;
                          w.setAttribute(Qt::WA_TranslucentBackground); //makes the window transparent
                          w.setLayout(new QVBoxLayout());
                          w.layout()->addWidget(tw);
                          w.show();
                      
                          return a.exec();
                      }
                      
                      8Observer88 Offline
                      8Observer88 Offline
                      8Observer8
                      wrote on 24 Jun 2021, 10:46 last edited by 8Observer8
                      #14

                      @Chris-Kawa, I tried your code but it does not work on Windows 10 and Qt 5.15.2. Why? Maybe does somebody else know it?

                      75fed7ee-28f7-4f06-bc0e-964e810e3be0-image.png

                      T 1 Reply Last reply 8 May 2023, 15:31
                      1
                      • 8Observer88 8Observer8
                        24 Jun 2021, 10:46

                        @Chris-Kawa, I tried your code but it does not work on Windows 10 and Qt 5.15.2. Why? Maybe does somebody else know it?

                        75fed7ee-28f7-4f06-bc0e-964e810e3be0-image.png

                        T Offline
                        T Offline
                        Taytoo
                        wrote on 8 May 2023, 15:31 last edited by
                        #15

                        @8Observer8 Were you able to resolve this issue? I'm having weird behavior even though i'm following the instructions, so not sure what am I doing wrong?

                        8Observer88 1 Reply Last reply 30 May 2023, 10:39
                        0
                        • T Taytoo
                          8 May 2023, 15:31

                          @8Observer8 Were you able to resolve this issue? I'm having weird behavior even though i'm following the instructions, so not sure what am I doing wrong?

                          8Observer88 Offline
                          8Observer88 Offline
                          8Observer8
                          wrote on 30 May 2023, 10:39 last edited by 8Observer8
                          #16

                          @Taytoo I am also waiting for a solution. Maybe someone knows what is the problem in the above example?

                          How to implement the same behavior as in ScreenToGif to take a screenshot inside a window?

                          a0b7471f-1d25-4498-8039-89ebd6a432ca-image.png

                          1 Reply Last reply
                          0
                          • C Chris Kawa
                            8 Aug 2018, 09:46

                            It's a 3 step process.

                            1. Make the window widget transparent using attribute Qt::WA_TranslucentBackground, which gives you something like in your picture:
                              Transparency step 1

                            2. Make the tab header transparent. You can do that with stylesheet QTabBar::tab { background: transparent; }
                              Note that this is styling QTabBar, not QTabWidget.
                              Transparency step 2
                              You can modify the stylesheet to add the borders of the tab back if you like.

                            3. Make the tab content transparent. Note that QTabWidget itself doesn't have a background. It's the background of the widget inside it that you need to make transparent. The easiest way to do this is to tell Qt that the paint event takes care of all the painting and it does not need to fill the background with default color i.e. use Qt::WA_OpaquePaintEvent attribute.
                              Transparency step 3

                            So the entire example looks like this:

                            int main(int argc, char *argv[])
                            {
                                QApplication a(argc, argv);
                            
                                QWidget* tab_content = new QWidget();
                                tab_content->setAttribute(Qt::WA_OpaquePaintEvent); //makes the widget transparent
                            
                                QTabWidget* tw = new QTabWidget();
                                tw->addTab(tab_content, "Example");
                                tw->setStyleSheet("QTabBar::tab { background: transparent; }"); //makes the header transparent
                            
                                QWidget w;
                                w.setAttribute(Qt::WA_TranslucentBackground); //makes the window transparent
                                w.setLayout(new QVBoxLayout());
                                w.layout()->addWidget(tw);
                                w.show();
                            
                                return a.exec();
                            }
                            
                            JoeCFDJ Offline
                            JoeCFDJ Offline
                            JoeCFD
                            wrote on 22 Apr 2024, 22:56 last edited by JoeCFD
                            #17

                            @Chris-Kawa Your code works nicely on my local computer. But the transparent feature is gone after I copy the executable from my machine to another computer. Any thoughts?

                            same OS: Ubuntu 22.04
                            same Qt version: 5.15.3

                            JoeCFDJ 1 Reply Last reply 23 Apr 2024, 04:19
                            0
                            • JoeCFDJ JoeCFD
                              22 Apr 2024, 22:56

                              @Chris-Kawa Your code works nicely on my local computer. But the transparent feature is gone after I copy the executable from my machine to another computer. Any thoughts?

                              same OS: Ubuntu 22.04
                              same Qt version: 5.15.3

                              JoeCFDJ Offline
                              JoeCFDJ Offline
                              JoeCFD
                              wrote on 23 Apr 2024, 04:19 last edited by JoeCFD
                              #18

                              @JoeCFD I lied. The desktop is different. One is gnome and another one is lxqt. It could be a qt bug.

                              Ronel_qtmasterR 1 Reply Last reply 23 Apr 2024, 06:16
                              0
                              • JoeCFDJ JoeCFD
                                23 Apr 2024, 04:19

                                @JoeCFD I lied. The desktop is different. One is gnome and another one is lxqt. It could be a qt bug.

                                Ronel_qtmasterR Offline
                                Ronel_qtmasterR Offline
                                Ronel_qtmaster
                                wrote on 23 Apr 2024, 06:16 last edited by
                                #19

                                @JoeCFD you people may find this helpfull
                                https://github.com/jordanprog86/QtTransparentWindow.git
                                tw.PNG

                                JoeCFDJ 1 Reply Last reply 23 Apr 2024, 22:56
                                0
                                • Ronel_qtmasterR Ronel_qtmaster
                                  23 Apr 2024, 06:16

                                  @JoeCFD you people may find this helpfull
                                  https://github.com/jordanprog86/QtTransparentWindow.git
                                  tw.PNG

                                  JoeCFDJ Offline
                                  JoeCFDJ Offline
                                  JoeCFD
                                  wrote on 23 Apr 2024, 22:56 last edited by JoeCFD
                                  #20

                                  @Ronel_qtmaster thanks for your post. Your code is not working on Lubuntu with LXQt desktop as well for Qt5/6. Chris Kawa's test code has the same issue.

                                  The following example works
                                  https://doc.qt.io/qt-5/qtwidgets-widgets-shapedclock-example.html

                                  JoeCFDJ Ronel_qtmasterR 2 Replies Last reply 24 Apr 2024, 15:33
                                  0
                                  • JoeCFDJ JoeCFD
                                    23 Apr 2024, 22:56

                                    @Ronel_qtmaster thanks for your post. Your code is not working on Lubuntu with LXQt desktop as well for Qt5/6. Chris Kawa's test code has the same issue.

                                    The following example works
                                    https://doc.qt.io/qt-5/qtwidgets-widgets-shapedclock-example.html

                                    JoeCFDJ Offline
                                    JoeCFDJ Offline
                                    JoeCFD
                                    wrote on 24 Apr 2024, 15:33 last edited by JoeCFD
                                    #21

                                    @JoeCFD solved the transparency issue in my code with mask. but kind of awkward and unnecessary. Submit a bug report with Chris Kawa's test code here
                                    https://bugreports.qt.io/browse/QTBUG-124722

                                    JoeCFDJ 2 Replies Last reply 25 Apr 2024, 14:44
                                    0
                                    • JoeCFDJ JoeCFD
                                      23 Apr 2024, 22:56

                                      @Ronel_qtmaster thanks for your post. Your code is not working on Lubuntu with LXQt desktop as well for Qt5/6. Chris Kawa's test code has the same issue.

                                      The following example works
                                      https://doc.qt.io/qt-5/qtwidgets-widgets-shapedclock-example.html

                                      Ronel_qtmasterR Offline
                                      Ronel_qtmasterR Offline
                                      Ronel_qtmaster
                                      wrote on 24 Apr 2024, 15:58 last edited by
                                      #22

                                      @JoeCFD i think on ubuntu it might depend on the windows manager

                                      1 Reply Last reply
                                      0
                                      • JoeCFDJ JoeCFD
                                        24 Apr 2024, 15:33

                                        @JoeCFD solved the transparency issue in my code with mask. but kind of awkward and unnecessary. Submit a bug report with Chris Kawa's test code here
                                        https://bugreports.qt.io/browse/QTBUG-124722

                                        JoeCFDJ Offline
                                        JoeCFDJ Offline
                                        JoeCFD
                                        wrote on 25 Apr 2024, 14:44 last edited by
                                        #23

                                        @JoeCFD The ticket is set to Important.

                                        1 Reply Last reply
                                        0
                                        • JoeCFDJ JoeCFD
                                          24 Apr 2024, 15:33

                                          @JoeCFD solved the transparency issue in my code with mask. but kind of awkward and unnecessary. Submit a bug report with Chris Kawa's test code here
                                          https://bugreports.qt.io/browse/QTBUG-124722

                                          JoeCFDJ Offline
                                          JoeCFDJ Offline
                                          JoeCFD
                                          wrote on 3 May 2024, 15:09 last edited by JoeCFD 5 Mar 2024, 15:17
                                          #24

                                          @JoeCFD My solution with mask for transparency works for LXQt desktop, but not for Gnome Desktop of Ubuntu. Reset of mask regions is wrong sometimes. Added this issue to the bug report.

                                          1 Reply Last reply
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