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author | Laszlo Agocs <laszlo.agocs@qt.io> | 2021-01-13 16:45:47 +0100 |
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committer | Laszlo Agocs <laszlo.agocs@qt.io> | 2021-01-15 15:21:28 +0100 |
commit | b5ce973b29875d8cea6302de8ccfaa06d0b7c870 (patch) | |
tree | b6bfe2c1e6dbd9ca877a49bd0c927bf0bcbb1197 /src/openglwidgets | |
parent | 2aa7ad5e6716ac01b2b43fa68e4b5d50aaf00944 (diff) |
Document QOpenGLWidget limitations without an alpha channel
Pick-to: 6.0 5.15
Task-number: QTBUG-85869
Change-Id: I20fb70a451fc1ed93089ed699539fa12ac38fe73
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
Diffstat (limited to 'src/openglwidgets')
-rw-r--r-- | src/openglwidgets/qopenglwidget.cpp | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/openglwidgets/qopenglwidget.cpp b/src/openglwidgets/qopenglwidget.cpp index a596416471..2ae1a7f215 100644 --- a/src/openglwidgets/qopenglwidget.cpp +++ b/src/openglwidgets/qopenglwidget.cpp @@ -401,6 +401,19 @@ QT_BEGIN_NAMESPACE each frame. To restore the preserved behavior, call setUpdateBehavior() with \c PartialUpdate. + \note Displaying a QOpenGLWidget requires an alpha channel in the associated + top-level window's backing store due to the way composition with other + QWidget-based content works. If there is no alpha channel, the content + rendered by the QOpenGLWidget will not be visible. This can become + particularly relevant on Linux/X11 in remote display setups (such as, with + Xvnc), when using a color depth lower than 24. For example, a color depth of + 16 will typically map to using a backing store image with the format + QImage::Format_RGB16 (RGB565), leaving no room for an alpha + channel. Therefore, if experiencing problems with getting the contents of a + QOpenGLWidget composited correctly with other the widgets in the window, make + sure the server (such as, vncserver) is configured with a 24 or 32 bit depth + instead of 16. + \section1 Alternatives Adding a QOpenGLWidget into a window turns on OpenGL-based |