QT embedded simulate (up,down,left,right,enter) navigation



  • Hello,

    I am new to the QT embedded development and I have few problems:

    I am currently developing on a different target display which has a resolution of 640x480 pixels and 96 dpi using /dev/fb0.
    But the new target display has a color depth of 1 (black/white) and 240x128 dots per inch.
    Now my question is how can I simulate the new target display size on the the old one with the higher resolution? Is there any way of scale or zooming to fit the size, it later will have (real physical Millimeters), including Buttons etc?

    Here is a example how it Looks now:
    http://www.bilder-upload.eu/show.php?file=5e32bf-1430483434.png
    and this way i would have it (zoomed/scaled to full width)
    http://www.bilder-upload.eu/show.php?file=980a99-1430483686.jpg

    Is it possible to set color depth to black white for the LinuxFB
    for e.g.

    ./my_app -qws -display LinuxFb:/dev/fb0:depth=1 ?

    Can QT handle a membrane button touches? For example a 5 keys keypad, to handle the menu and input navigations?

    Many Thanks in advance

    Regards


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Since you are working with Qt 4, you could use QVFB to develop the GUI at the right size on your desktop machine. As for the the depth, IIRC, you must build Qt with support for it.

    Is your keypad seen like a keyboard from a device point of view ?

    Hope it helps



  • Hi,

    thank you for your response ;) and first help

    • Okay for the depth I could try to cross compile it again with the depth 1 flag, maybe it shows up correct after that.
    • Is there no direct way to scale it direct on the current embedded dev/fbo screen?
      I have read with qvfb there is a flag -zoom, is this also available for /dev/fbo ?
      Would be nice for demonstrating and get a feeling of the size.
    • The Keyboard will be seen as normal device, as far as I know at the moment.

    Many Thanks for upcoming further help.


  • Lifetime Qt Champion

    • You can set several depth IIRC
    • I don't remember of such an option
    • Then unless it gets a special name, you should see its input in your software


  • Hi,

    thanks again for your response.

    I have done a sample application with a OnScreen Navigation (up, down, left,right,enter).
    But now I having problems to navigate on the Window.
    I tried to use for each button a different Event in the regarding slot :

    Mainwindow:

    QKeyEvent *event = new QKeyEvent( QEvent::KeyPress, Qt::Key_Right, Qt::NoModifier);
    QCoreApplication::postEvent (this, event);

    Am I thinking wrong? or how can i use the virtual onscreen mini keypad to navigate on the Windows, Dialogs etc?

    Many Thanks


  • Lifetime Qt Champion

    Why are you generating key events ? You should receive them from your keyboard in your application and then in your application handle them.



  • HI,

    I am using a Touchpanel for demonstration purpose, but in fact later it will not have touch functionality.

    So i have added 5 Buttons (touchable left,right etc.) and if i press on one of these buttons the GUI (seperate widget) should then for example scroll down, mark a button click a button if i use the virtual keys.

    I handle the touch events to see which one was pressed (left right etc.) and then executing the regarding Key Event.

    But nothing happens in the widget. I thought qt can handle that easily if i trigger the KeyEvent, but it seems not to do it like I hoped.

    So how can i achieve a navigation with my tocuhbuttons which are simulating the final embedded config?


  • Lifetime Qt Champion

    You should rather make a virtual input panel like described in the "Input panel example". That would be more accurate with the final setup of your device



  • Is it possible with that input panel to navigate through the windows and pages ?

    Because I need to handle all input's navigation s with a 5 keys pad.

    Many thanks



  • Hi,

    i found in the net some hint using the configure switch -D QT_KEYPAD_NAVIGATION and set the nav mode QApplication::setNavigationMode.

    But if i try that approach I get setNavigationMode is not a member if QApplication.
    Is this in anymore? I am using latest QT 5.4 creator and cross compile to embedded with 4.8.6 qmake target.

    Please help me, i am getting confused here. Since I think i am not the only one who just has keypad for navigation.

    Regards


  • Lifetime Qt Champion

    setNavigationMode is still there but requires QT_KEYPAD_NAVIGATION to be defined when when building Qt



  • HI,

    i have set this flag for my cross compiled qmake configuration QT4.8.6.
    So how to configure qt creator QT5.4.1 to handle this QT_KEYPAD_NAVIGATION?

    Do i need to configue the sources for my Ubuntu ?
    like ./configure -v -D QT_KEYPAD_NAVIGATION
    make -j 4
    sudo make install

    ?

    will it then be recognized, as QApplication function?

    Maybe this picture helps to understand which my target platform is similar to:
    http://emsystech.de/wp-content/uploads/2012/09/raspi-lcd-1.jpg

    Is Qt able to get interaction with input fields/combo boxes etc. and menu navigations with only these 5 buttons?


  • Lifetime Qt Champion

    Yes thats that but there's something puzzling me, why are you developing with Qt 5 on your desktop and run 4.8.6 on your device ?



  • Well I just downloaded the latest QT total package and that had QT 5.4.1.

    I need to use 4.8.6 as cross target because the target is not really running with qt 5.4.1 it gives DBUS errors etc.
    So I wanted to start keeping the working 4.8.6 as a base to go on.

    So maybe I can configure qt 5.4.1 with this KEYPAD define and keep the configured cross 4.8.6 qmake?
    Are you seeing any issue with this?

    Or what would you suggest to get qt running on such a platform:
    http://emsystech.de/wp-content/uploads/2012/09/raspi-lcd-1.jpg

    with navigation, iputs etc? Have you already done such a project?


  • Lifetime Qt Champion

    I did, years ago and Qt wasn't even in it's 4 series

    What exact errors are you getting with Qt 5 ?

    In any case, if you have Qt 4 running properly, then use it also on your desktop to ensure you have the same behavior on both sides



  • Okay thats sound good, maybe I need to give qt5 a second try or use also qt4 on the desktop.

    I am not a the system right now but as I have in mind starting the application with

    ./test -qpa linuxFB:/dev/fb0

    and then i got the DBUS error. Maybe my cmdline is also wrong. QT5 cross compile was not plug and play for me.

    Do you remember how you have realized inputs with this few buttons?


  • Lifetime Qt Champion

    The exact error messages would be useful. Just to rule out the obvious: do you have the dbus daemon running ?

    The UI was written to be very keyboard friendly and had a lot thinking about focusing so as to make sense when moving from up to down and left to right. What kind of UI will that be ?



  • Okay, seems to be DBUS not running correctly:

    ./TestQTCross -platform linuxfb:fb"/dev/fb0"

    QIconvCodec::convertToUnicode: using Latin-1 for conversion, iconv_open failed
    QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed
    process 2302: D-Bus library appears to be incorrectly set up; failed to read machine uuid: Failed to open "/var/lib/dbus/machine-id": No such file or directory
    See the manual page for dbus-uuidgen to correct this issue.
    D-Bus not built with -rdynamic so unable to print a backtrace
    Aborted (core dumped)

    is the DBUS really needed for qt5 embedded? since it is not in 4.8?


  • Lifetime Qt Champion

    The DBus module is also included in the 4 series however AFAIK it should not be mandatory for the linuxfb plugin but you also have another problem with iconv_open. Are you using the same version of libraries on your target than the one used to build Qt 5 ?



  • Hi,
    yes i am using the same ones.

    The configure command looks as follows:

    ./configure -release -opensource -confirm-license -arch arm -xplatform linux-arm-gnueabi-g++ -no-icu -no-pch -prefix /usr/local/Trolltech/qt5 -skip qtwebkit-examples -skip qtwebkit

    I have adapted the qmake.conf of the linux-arm-gnueabi-g++ to fit my cross compile toolchain.

    Do you see any issue?


  • Lifetime Qt Champion

    which platform plugins are built ?



  • It is build only for linuxfb platform.


  • Lifetime Qt Champion

    How did you install Qt on your board ?



  • I normally just move over the files of the given configure path /usr/local/Trolltech/qt5 to the target board into the same directory.

    I found out if I use dbus-uuidgen -ensure before calling the app it starts up without the DBUS warning but the icon warning is still there.

    Also I cannot configure qt to work with webkit (see different post).

    Regards


  • Lifetime Qt Champion

    Did you use your device root filesystem to cross-compile build Qt 5 ? If not, you have probably used a different set of library than the one that's being used on your board



  • How can I use it?

    I have just used the above written configure command.


  • Lifetime Qt Champion

    Add -sysroot /path/to/your/mounted/device/filesytem to your configure options



  • Thanks,

    I have added it but now i get more and more errors.

    So i changed back my config to following:
    ./configure -xplatform linux-arm-gnueabi-g++ -release -opensource -confirm-license -prefix /usr/local/Trolltech/qt5 -make libs -skip qtwebkit-examples -nomake tests -qt-zlib -qt-libpng -qt-libjpeg -qt-freetype -linuxfb -no-opengl -icu

    Configure summary

    Building on: linux-g++ (i386, CPU features: none detected)
    Building for: linux-arm-gnueabi-g++ (arm, CPU features: neon)
    Platform notes:

            - Also available for Linux: linux-kcc linux-icc linux-cxx
    

    Build options:
    Configuration .......... accessibility alsa audio-backend c++11 clock-gettime clock-monotonic compile_examples concurrent cross_compile dbus evdev eventfd freetype full-config getaddrinfo getifaddrs harfbuzz iconv icu inotify ipv6ifname large-config largefile linuxfb medium-config minimal-config mremap neon nis no-pkg-config openssl pcre png posix_fallocate precompile_header qpa qpa reduce_exports release rpath shared small-config xlib xrender zlib
    Build parts ............ libs
    Mode ................... release
    Using C++11 ............ yes
    Using gold linker....... no
    Using PCH .............. yes
    Target compiler supports:
    Neon ................. yes

    Qt modules and options:
    Qt D-Bus ............... yes (loading dbus-1 at runtime)
    Qt Concurrent .......... yes
    Qt GUI ................. yes
    Qt Widgets ............. yes
    Large File ............. yes
    QML debugging .......... yes
    Use system proxies ..... no

    Support enabled for:
    Accessibility .......... yes
    ALSA ................... yes
    CUPS ................... no
    Evdev .................. yes
    FontConfig ............. no
    FreeType ............... qt
    Glib ................... no
    GTK theme .............. no
    HarfBuzz ............... yes (bundled copy)
    Iconv .................. yes
    ICU .................... yes
    Image formats:
    GIF .................. yes (plugin, using bundled copy)
    JPEG ................. yes (plugin, using bundled copy)
    PNG .................. yes (in QtGui, using bundled copy)
    journald ............... no
    mtdev .................. no
    Networking:
    getaddrinfo .......... yes
    getifaddrs ........... yes
    IPv6 ifname .......... yes
    OpenSSL .............. yes (loading libraries at run-time)
    NIS .................... yes
    OpenGL / OpenVG:
    EGL .................. no
    OpenGL ............... no
    OpenVG ............... no
    PCRE ................... yes (bundled copy)
    pkg-config ............. no
    PulseAudio ............. no
    QPA backends:
    DirectFB ............. no
    EGLFS ................ no
    KMS .................. no
    LinuxFB .............. yes
    XCB .................. no
    Session management ..... yes
    SQL drivers:
    DB2 .................. no
    InterBase ............ no
    MySQL ................ no
    OCI .................. no
    ODBC ................. no
    PostgreSQL ........... yes (plugin)
    SQLite 2 ............. yes (plugin)
    SQLite ............... yes (plugin, using bundled copy)
    TDS .................. no
    udev ................... no
    xkbcommon .............. no
    zlib ................... yes (bundled copy)

    But if I now do a make -j 4 I get an ICU warning, but ICU is needed for webkit, which I also need.

    I../3rdparty/md4 -I../3rdparty/sha3 -I.moc -I../../mkspecs/linux-arm-gnueabi-g++ -o .obj/pcre16_compile.o ../3rdparty/pcre/pcre16_compile.c
    tools/qtimezoneprivate_icu.cpp: In function ‘bool ucalOffsetsAtTime(void**, qint64, int*, int*)’:
    tools/qtimezoneprivate_icu.cpp:145: error: ‘ucal_clone’ was not declared in this scope
    tools/qtimezoneprivate_icu.cpp: In copy constructor ‘QIcuTimeZonePrivate::QIcuTimeZonePrivate(const QIcuTimeZonePrivate&)’:
    tools/qtimezoneprivate_icu.cpp:285: error: ‘ucal_clone’ was not declared in this scope
    tools/qtimezoneprivate_icu.cpp: In member function ‘virtual bool QIcuTimeZonePrivate::isDaylightTime(qint64) const’:
    tools/qtimezoneprivate_icu.cpp:378: error: ‘ucal_clone’ was not declared in this scope
    make[2]: *** [.obj/qtimezoneprivate_icu.o] Error 1
    make[2]: *** Waiting for unfinished jobs....
    make[2]: Leaving directory /home/qt/qt-everywhere-opensource-src-5.4.1/qtbase/src/corelib' make[1]: *** [sub-corelib-make_first] Error 2 make[1]: Leaving directory/home/qt/qt-everywhere-opensource-src-5.4.1/qtbase/src'
    make: *** [sub-src-make_first] Error 2

    EDIT:
    I have updated the icu using the following Cross Tutorial
    http://thebugfreeblog.blogspot.de/2013/05/cross-building-icu-for-applications-on.html

    now I added the following to the configure :
    -icu -I /opt/icuCrossFinal/include -L /opt/icuCrossFinal/lib

    Now I got a bit further, I also needed a new linux-atomic version.

    I keep you updated on webkit configure,



  • Now I got the qtbase and webkit compiled, but If i want to start the app via

    ./app -qpa linuxfb:/dev/fb0 it says:

    This application failed to start because it could not find or load the Qt platform plugin "xcb".

    I checked the dependencies on my Ubuntu 11.04 and I found that Ubuntu is unalbe to locate :
    Unable to locate package libxcb-icccm4
    Unable to locate package libxcb-icccm4-dev

    I then run the configure with -no-xcb and all worked well so far.

    But now if I start the application :

    ./app -qpa linuxfb:fb=/dev/fb0

    The screen is not using the full framebuffer (no fullscreen) it seems it is only using 2/3 of it an the rest is cut off.
    With qt4 all works as expected.

    Any idea why this happens?

    Is xcb required for a webkit usage on linuxfb?


  • Lifetime Qt Champion

    The plugin might have problem to detect the screen size



  • Any Idea how to fix this?
    Also it seems qt5 is a bit slower then qt4, but I thought it should be faster.


  • Lifetime Qt Champion

    Did you try to give the screen size to the plugin ?



  • yep, but no influence it changes only to smaller sizes but not to the larger screen size like it should.


  • Lifetime Qt Champion

    Looks like a bug, you should check on the bug report system



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