Problem with QPixmap using framebuffer with omapfb. Works with qt 4.x, but dosn't work using qt 5.x



  • Hello

    The subject describes the Problem.

    Platform is a Debian armel Linux. Using omapfb as display driver to the framebuffer.
    Hardware is an AM3517.

    This code:
    -------------------- 8< --------------------------
    QPixmap image = QPixmap("resources/images/foo.png");
    ui->label->setPixmap(image); // label is of type QLabel
    -------------------- 8< --------------------------

    works without any problems with qt 4.8.4 [1]. No matter if i use
    ./app -qws (for using linuxfb)
    or
    ./app -qws -display directfb (for using directfb [3])

    The same code dosen' t work with qt 5.1.1[2] nor qt 5.2.0 using directfb.

    A call to
    ./app -platform directfb
    doesn't show the picture.

    A call to
    ./app -platform linuxfb
    shows the picture, but has really bad Performance.

    I tried to break it down in the qt's directfb code. As far as i can see, directfb is used to render the png using directfb's plugin 'libidirectfbimageprovider_png.so'. But then there is no call to display it on the screen...

    As a side node: If i use a css file like this
    -------------------- 8< --------------------------
    QRadioButton::indicator::unchecked {
    image: url(resources/images/radiobutton_unchecked.png);
    }
    -------------------- 8< --------------------------
    the image is rendered using directfb and displayed on the widget.

    Does anyone has any hints how to solve this problem?

    Bye
    Georg

    [1]
    ./configure -v -release -embedded arm -confirm-license -prefix /opt/qt-embedded-4.8.4-arm -opensource -shared -no-fast -no-qt3support -plugin-sql-sqlite -no-audio-backend -no-javascript-jit -platform linux-g++ -xplatform qws/linux-arm-gnueabi-g++ -qt-zlib -qt-libtiff -qt-libpng -qt-libmng -qt-libjpeg -no-cups -separate-debug-info -no-dbus -little-endian -qt-gfx-directfb -force-pkg-config -openssl -nomake examples
    [2]
    ./configure -separate-debug-info -opensource -confirm-license -prefix /opt/qt-embedded-5.1.1-arm -no-javascript-jit -no-qml-debug -qt-zlib -qt-libpng -qt-libjpeg -qt-xkbcommon -no-cups -no-dbus -xplatform linux-arm-gnueabi-g++ -force-pkg-config -directfb -qt-xcb
    [3]
    system=fbdev
    mode=800x600
    depth=32
    disable-module=ps2mouse
    disable-module=keyboard
    disable-module=linux_input
    graphics-vt
    no-vt
    no-vt-switching


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Since it's getting in the lower levels of Qt, I would advise you to bring this on the interest mailings list. You'll find there Qt's developers/maintainers (this forum is more user oriented)

    In between, you should also checkout the "bug report system":http://bugreports.qt-project.org to see if it's something known



  • Hello George,

    I stumbled over the same problem using BMP images with Qt 5.1.1 under DirectFB on the same way. Have you found a solution or a workaround about this issue already?

    Bye
    Thomas


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