[Buildroot] Setting RGB

[Peter Seiderer]

Hello Gabriel Castillo,

On Wed, 13 Apr 2016 10:35:48 -0300, Leonardo Giordano <lgiordano at controlnet.com.ar> wrote:

> I forgot to mention:
> 
> At QLinuxFbScreen::initialize() display format is detected as RGB (and it
> is true because fbtest shows colors right).
> So, I had to swap red and blue structs (struct fb_bitfield), so detection
> now says it is BGR. Then at doRedraw() image is inverted when drawing is
> issued.
> 
> I still don't understand why I should force BGR so Qt drawing can work fine.
> 

Hard to say whats going wrong without the hardware to play around with it...,
but first step for remote help would be the requested fbset output
showing the pixel definition...

Regards,
Peter

> 
> 
> 
> 2016-04-12 8:45 GMT-03:00 Leonardo Giordano <lgiordano at controlnet.com.ar>:
> 
> > Sorry for delay on replying, we were using as a workaround swapping red
> > and blue info on the pictures we use.
> > Yesterday I fixed it based on Peter's reply and this patch:
> > https://bugreports.qt.io/browse/QTBUG-40527
> >
> > Thanks for your support!
> > Regards,
> > Leonardo
> >
> > 2016-02-11 17:52 GMT-03:00 Peter Seiderer <ps.report at gmx.net>:
> >
> >> Hello Gabriel Andrés Castillo,
> >>
> >> On Thu, 11 Feb 2016 07:09:50 -0800 (PST), GabrielCastillo <
> >> gcastillo at controlnet.com.ar> wrote:
> >>
> >> > Definitely the problem is with QT5. I read some places that could be
> >> > littleendian problem. To run my app, i do:
> >> >
> >> > > ./App -platform linuxfb
> >> >
> >> > There are any form to tell that it has to be execute in littleendian or
> >> > bigendian?
> >> >
> >>
> >> No, no such option for qt5 (see [1] for linuxfb options).
> >>
> >> Mind to run 'fbset -s' (or 'fbset -i') on your platform ?
> >>
> >> Output gives the pixel defintion of the framebuffer, e.g.
> >>
> >> rgba 5/11,6/5,5/0,0/16
> >>
> >> for my adafruit display (and try to test if the given
> >> pixel defintion is correct by writing color patterns
> >> to the framebuffer (direct or with some framebuffer
> >> test program)...
> >>
> >> Or mind to try the following atmel qt5 patch ([2]) from
> >> the OpenEmbedded/Yocto layer?
> >>
> >> This patch gives you a hint for the place where to fix/adjust the
> >> qt5 drawing to the framebuffer...
> >>
> >> Regards,
> >> Peter
> >>
> >>
> >> [1] http://doc.qt.io/qt-5/embedded-linux.html
> >> [2]
> >> https://github.com/linux4sam/meta-atmel/blob/master/qt5-layer/recipes-qt/qt5/files/atmel-color-format-force.patch
> >>
> >> >
> >> >
> >> > --
> >> > View this message in context:
> >> http://buildroot-busybox.2317881.n4.nabble.com/Setting-RGB-tp124903p125571.html
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