framebuffer

Hello devef,

 I have issue working with framebuffer do you any example programs.

Regards,
sam

Take a look at ezfb, its very nice :)

I've made a simple winamp-clone for linux-framebuffer on a mini2440 with
ezfb.

can you send some links for same.actually I want to write character using
framebuffer on GLCD do u know how this can be done????????

How can I compile EZFB for mini2440?

Hi

Can somebody explain how it's framebuffer used for draw anything ? Some
like a simple dot. I think it's very useful for everyone to know how can be
frambuffer accessed. 

Thx

You can do
    cat /dev/urandom > /dev/fb0
and you'll see the screen being filled by an amount of colors. And you can
also try to write your own text and see what's happening, like
    echo "some text" > /dev/fb0
Even you can try to create an application that writes decimals instead of
characters.

Sérgio

Sérgio,

Thanks for that!

Could you suggest the steps required to get USB keyboard input directed to
the frame buffer?

Cheers,
Dave

Hi,

The JPGs and BMPs have 3 bytes (RGB) in their data.  When I copy data from
the framebuffer, it fetches me 2 bytes for every pixel.

I want to know how these 3 bytes are mapped into two bytes in framebuffer.

I am using framebuffer in Busybox+Qtopia 2.2.0 on Micro2440+T35.

TIA

Vikas

@TheSergon13

I tried to write some text directly into framebuffer using this command " 
echo "abcd" > /dev/fb0   " but nothing is happen. Why ?

@davef

For you it works ?

Regards,
Irinel

Vikas,

See below to find answer for your Display:

  // 5:6:5 16bit format

  rgb0 = (((U16)r0>>3)<<11) | (((U16)g0>>2)<<5) | (((U16)b0>>3)<<0); 
//RGB565.

  rgb1 = (((U16)r1>>3)<<11) | (((U16)g1>>2)<<5) | (((U16)b1>>3)<<0); 
//RGB565.



  rgb = (rgb1<<16) | rgb0;


r0,g0,b0 is first pixel and r1,g1,b1 is for second pixel.  so thus two
pixels are used to show 6 bytes of rgb data in mini2440.

Regards,

Kailas

I uploaded a sample source code to draw two lines at y=100 and y=101.

For me doesn't work to set red and green color for lines.

Irinel,

You need to pipe it to tty0

echo "Some text" > /dev/tty0

Dave

I was able to Images on VGA but if character need to be displayed then how
to do it?? since everything we write into framebuffer is pixel( I mean
framebuffer workes only for graphical mode how to switch to text mode)

vikas, I should write your functions that display a character or you can
try a library like ezfb, MiniGUI, etc.

Hi azzido,

I've compiled your code successfully

but when I ran it on the device it gives "Segmentation Fault"

do you have any ideas about that ?

Hi Vikas

Can you explain here how did you display the images on VGA by writing into
the framebuffer as I am also trying to do the same. I want to display
images captured by a USB camera.

Regards
Tan

Tan,

you can google for the tool 'fbtest'. It does writing sample images to the
framebuffer.