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  1. Qt
  2. QTBUG-28214

Cannot make transparent (translucent) background for QQuickView

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Details

    • Bug
    • Resolution: Done
    • P2: Important
    • None
    • 5.0.0 Beta 2
    • GUI: OpenGL, GUI: Painting, Quick: Core Declarative QML
    • Windows 7 x86 32 bit, NVIDIA GeForce GTX 460 with vendor's native latest DirectX and OpenGL drivers, Qt 5.0 beta2 (tested with "ANGLE" and "desktop OpenGL" configurations)
      Linux: works
    • a79e42b8f40317f7275b26637e6735754b21727f

    Description

      I have seen that this bug was already reported by somebody, but i decided to report it once more, because i tried everything and there are not any working solutions about it and it seems to be wrongly forgotten. And in that report it was Linux testing, here i tested it on Windows platform.

      I understand that QQuickView is not QWidget and that it's different from QDeclarativeView component. But when i was using Qt 4.8.x it was greatly usefull feature that allowed to make transparent backroud. It allowed to make QML widget hovering over the screen, splash-screens, and make impressive GUI designs with semi-transparent parts. Now it has been unfortunately regressed in Qt 5.0 and i believe that it can be improved. And i can't back to Qt 4.8 only because of this bug...

      I tested it on Windows 7 x86 32 bit platform with two configurations:
      1. Qt 5.0 beta 2 downloaded from official qt-project.org link (seems to be configured with ANGLE graphics backend).
      2. Qt 5.0 beta 2 downloaded from git on 22/Nov/12, configured with "configure -debug-and-release -opensource -confirm-license -nomake examples -nomake tests -no-icu -opengl desktop -platform win32-msvc2010" (desktop OpenGL backend) and successfully built by myself. And i have latest DirectX and OpenGL vendor's drivers on my NVidia GeForce GTX 460. Also tried all the same on other computer with AMD/ATI videocard.

      There is code below that i used to test it.

      main.cpp :

      QQuickView viewer;
viewer.setResizeMode(QQuickView::SizeRootObjectToView);
QSurfaceFormat format;
format.setAlphaBufferSize(8);
viewer.setFormat(format);
viewer.setClearBeforeRendering(true);
viewer.setColor(QColor(Qt::transparent));
viewer.setWindowFlags(Qt::FramelessWindowHint);
viewer.setMainQmlFile(QStringLiteral("qml/Qt5_TEST/main.qml"));
viewer.show();

      main.qml :

      Rectangle {
  width: 360
  height: 360
  color: "transparent"
  Rectangle {
    x: 50
    y: 50
    width: 100
    height: 100
    color: "blue"
  }
}

      result is:

      Important notes:
      1. I see the same visual result if i change "Rectangle" to "Item" type in root node and remove "color" property.
      2. If i set there "color" property to "#00000000" or "#FF000000" in root rectangle result is also the same
      3. If i set "opacity" property to 0.0 in root "Rectangle" visual result is the same
      4. But if i set "opacity" property to 1.0 i see result below:

      Related bug reports (not resolved and forgotten):
      1. https://bugreports.qt-project.org/browse/QTBUG-20768
      2. https://bugreports.qt-project.org/browse/QTBUG-24707

      Attachments

        1. bug_qml.png
          bug_qml.png
          14 kB
        2. bug_qml2.png
          bug_qml2.png
          13 kB
        3. qtbug28214.zip
          3 kB

        Issue Links

          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-43114 QtQuick Window color with alpha doesn't work in Windows 8.1

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-55169 [Windows]: When starting the application in Windows 7 Basic theme or switching to/from this theme then it the corners of the widget are visible

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Reported

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-37322 Windows: TextField's placeholder text is blurry and almost transparent when you set transparent color on QQuickWindow

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-20768 [Regression] With QtQuick 2.0 it is not possible anymore to get a top level translucent item.

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-53116 QQuickWidget loses translucent background when switching user on Windows

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-71951 add QML API for window mask

          • P4: Low - Would be nice to fix, but it's not very important.
          • Reported

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-33919 Windows/Desktop OpenGL: QGLWidget has transparent background instead of a full opaque one as in 5.1.1 if configured with QGL::AlphaChannel

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-34844 [Win] qtbase/examples/opengl/2dpainting broken with TranslucentBackground

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-36896 Transparent QQuickView doesn't clear graphics buffer when moved

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-72693 Windows MenuBar rendering with artefacts on HiDPI screens when QQuickWindow::setDefaultAlphaBuffer(true) is set.

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-34376 Windows/Desktop OpenGL: QGLWidget based main window is invisible if configured with format QGL::AlphaChannel and Qt::FramelessWindowHint

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-54734 Windows: Frameless translucent window with QOpenGLWidget in QTabWidget is not being repainted after opening another tab

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-55955 Windows: Transparent background in a GL window with frames is not cleared while moving

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
          resulted in

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-36739 QWindow with OpenGL alpha blending becomes translucent

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-52494 QML SplashScreen not transparent On Windows 7

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
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          Activity

            People

              kleint Friedemann Kleint
              avassen Vasily Shchukin
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              22 Vote for this issue
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              39 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:

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