I'm using QtEmbedded (4.8.0) on an ARM display device with 16bits color depth on the framebuffer (/dev/fb0). At this scenario we are getting the colors bits RED and BLUE exchanged.
We are using the following compile flags:
./configure -embedded arm -xplatform qws/linux-arm-gnueabi-g++ -prefix /home/rchaves/Toolchain -release -opensource -shared -fast -depths 16 -largefile -no-exceptions -no-accessibility -stl -no-sql-mysql -no-sql-psql -no-sql-oci -no-sql-odbc -no-sql-tds -no-sql-db2 -no-sql-sqlite -no-sql-sqlite2 -no-sql-ibase -no-qt3support -no-xmlpatterns -no-multimedia -no-audio-backend -no-phonon-backend -no-svg -no-webkit -no-javascript-jit -no-script -no-scripttools -no-declarative -no-declarative-debug -qt-zlib -qt-libtiff -qt-libpng -qt-libmng -qt-libjpeg -no-openssl -no-nis -no-cups -iconv -no-pch -no-dbus -qt-freetype -no-opengl -qt-gfx-linuxfb -qt-kbd-linuxinput -qt-mouse-tslib -nomake demos -nomake examples
And the following parameters to execute the application:
QWS_DISPLAY=LinuxFb:/dev/fb0:depth=16 ./app -qws
Here there are the application framebuffer (samples) log:
The framebuffer device was opened successfully.
Fixed screen info:
id: DISP3 BG
smem_start: 0x93800000
smem_len: 7864320
type: 0
type_aux: 0
visual: 2
xpanstep: 1
ypanstep: 1
ywrapstep: 0
line_length: 2048
mmio_start: 0x0
mmio_len: 0
accel: 0
The framebuffer device was mapped to memory successfully.
Successfully switched to graphics mode.
Variable screen info:
xres: 1024
yres: 768
xres_virtual: 1024
yres_virtual: 3840
yoffset: 0
xoffset: 0
bits_per_pixel: 16
grayscale: 0
red: offset: 0, length: 5, msb_right: 0
green: offset: 5, length: 6, msb_right: 0
blue: offset: 11, length: 5, msb_right: 0
transp: offset: 0, length: 0, msb_right: 0
nonstd: 0
activate: 64
height: -1
width: -1
accel_flags: 0x0
pixclock: 15385
left_margin: 157
right_margin: 157
upper_margin: 16
lower_margin: 15
hsync_len: 5
vsync_len: 1
sync: 0
vmode: 0
Frame Buffer Performance test...
Average: 43020 usecs
Bandwidth: 174.338 MByte/Sec
Max. FPS: 23.245 fps
Will draw 3 rectangles on the screen,
they should be colored red, green and blue (in that order).
Done.
Better late than never. I had this exact problem with a SAM5 processor using Qt5.5.1 and the linuxfb plugin. Reconfigure or recompile the Qt5 framework will NOT solve the problem.
Apparently the LinuxFB plugin does not support the BGR format. There is an open bug tracking this issue. Check the determineFormat
function in ../src/plugins/platforms/linuxfb/qlinuxfbscreen.cpp
, in which you will find out that the ImageFormats are hardcoded to **RGB no matter what kind of framebuffer info was provided.
To solve the problem, applying the patch attached to the bug may help you to resolve this issue.
I said "may" because my framebuffer driver was falsely reporting it is in the RBG format. So watch out for that. If that is the case, just hardcode the swapRgb
flag until you fix your framebuffer driver.
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