Let's see now how to convert an image to a byte array to be displayed on the led panel.
We will use, for example, this 256x256 pixel jpeg image but the same concept is
valid for any images:
Download this image directly on Arietta G25 using wget and the image URL:
# wget http://www.acmesystems.it/www/ledpanel/right_arrow.jpg
Now launch convert.py with the local filename of the image:
~/led-utils# ./covert.py right_arrow.jpg
 <- Brightness -> 
 <- Contrast -> 
 <- Color -> 
 <- Sharpness -> 
[q] <- Rotate -> [w]
[i] Invert color
Select (space exit):
With the keys  and  changes the brightness until the arrow color
became equal t the original.
Pressing the [s] key it is possible to save a screenshot of the
image with the name "panel_xxxx.rgb" where xxxx is an incremental counter.
The *.rgb file contains the raw byte array image at 3 bytes per color
ready to be sent to /sys/class/ledpanel/rgb_buffer.
To display is return to the command line and type:
~/led-utils# cp panel_0000.rgb /sys/class/ledpanel/rgb_buffer
If you collect some screenshots it is possible to create a simple animation
with a simple shell script like this:
while [ 1 ]
for f in *.rgb;
cp $f /sys/class/ledpanel/rgb_buffer
Design a 32x32 icon from scratch
If you need to design a 32x32 icon from scratch you could use x-IconEditor.
X-IconEditor is an on-line graphic editor to create favicon.ico icons for the web pages but
you can download and convert the favicon.ico file generated with convert.py and display it
on your panel.
Source code: convert.py