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transparent Widget

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  • CodeFreaksC Offline
    CodeFreaksC Offline
    CodeFreaks
    wrote on last edited by CodeFreaks
    #1

    Hi everyone,
    I want to make a semi-transparent/transparent window like:
    Transparent
    I want to make something like a semi transparent QTabWidget object which whole the background be semi transparent (even the icons) but the text of the icons and also whole the contents don't be.

    1 Reply Last reply
    0
    • mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by mrjj
      #2

      Hi and welcome to the forums.
      (we cant see your links to www.qtcentre.org for some reason)

      For window type of widgets , you can use
      http://doc.qt.io/qt-5/qwidget.html#windowOpacity-prop

      alt text

      1 Reply Last reply
      2
      • CodeFreaksC Offline
        CodeFreaksC Offline
        CodeFreaks
        wrote on last edited by CodeFreaks
        #3

        @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

        mrjjM 1 Reply Last reply
        0
        • Chris KawaC Offline
          Chris KawaC Offline
          Chris Kawa
          Lifetime Qt Champion
          wrote on last edited by Chris Kawa
          #4

          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.

          CodeFreaksC 1 Reply Last reply
          2
          • CodeFreaksC CodeFreaks

            @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

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

            CodeFreaksC 1 Reply Last reply
            3
            • mrjjM mrjj

              @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)

              CodeFreaksC Offline
              CodeFreaksC Offline
              CodeFreaks
              wrote on last edited by CodeFreaks
              #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
              • Chris KawaC Chris Kawa

                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.

                CodeFreaksC Offline
                CodeFreaksC Offline
                CodeFreaks
                wrote on last edited by CodeFreaks
                #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
                • Chris KawaC Offline
                  Chris KawaC Offline
                  Chris Kawa
                  Lifetime Qt Champion
                  wrote on 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
                  • CodeFreaksC Offline
                    CodeFreaksC Offline
                    CodeFreaks
                    wrote on last edited by CodeFreaks
                    #9
                    This post is deleted!
                    1 Reply Last reply
                    0
                    • CodeFreaksC Offline
                      CodeFreaksC Offline
                      CodeFreaks
                      wrote on last edited by CodeFreaks
                      #10
                      This post is deleted!
                      1 Reply Last reply
                      0
                      • CodeFreaksC Offline
                        CodeFreaksC Offline
                        CodeFreaks
                        wrote on last edited by CodeFreaks
                        #11

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

                        1 Reply Last reply
                        0
                        • Chris KawaC Offline
                          Chris KawaC Offline
                          Chris Kawa
                          Lifetime Qt Champion
                          wrote on 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();
                          }
                          
                          CodeFreaksC 8Observer88 JoeCFDJ 3 Replies Last reply
                          10
                          • Chris KawaC Chris Kawa

                            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();
                            }
                            
                            CodeFreaksC Offline
                            CodeFreaksC Offline
                            CodeFreaks
                            wrote on 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
                            • Chris KawaC Chris Kawa

                              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 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
                              1
                              • 8Observer88 8Observer8

                                @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 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
                                0
                                • T Taytoo

                                  @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 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
                                  • Chris KawaC Chris Kawa

                                    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 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
                                    0
                                    • JoeCFDJ JoeCFD

                                      @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 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
                                      0
                                      • JoeCFDJ JoeCFD

                                        @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 last edited by
                                        #19

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

                                        JoeCFDJ 1 Reply Last reply
                                        0
                                        • Ronel_qtmasterR Ronel_qtmaster

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

                                          JoeCFDJ Offline
                                          JoeCFDJ Offline
                                          JoeCFD
                                          wrote on 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
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