16x32 RGB Led Matrix with Scrolling Message, what I'm doing wrong ?

[TristanGodal]

Hi. Sorry for disturb.
I'm new with RasberryPi, and I'm using a Raspberry Pi 3B+.

I'm trying to use an 16x32 RGB displayer from AdaFruit, so clone this github and use the command "make" at first, then, I try to use this program :

import os
from PIL import ImageFont
from PIL import Image
from PIL import ImageDraw
 
text = (("Raspberry Pi ", (255, 0, 0)), ("and ", (0, 255, 0)), ("Adafruit", (0, 0, 255)))
 
 
font = ImageFont.truetype("/usr/share/fonts/truetype/freefont/FreeSans.ttf", 16)
all_text = ""
for text_color_pair in text:
    t = text_color_pair[0]
    all_text = all_text + t
 
print(all_text)
width, ignore = font.getsize(all_text)
print(width)
 
 
im = Image.new("RGB", (width + 30, 16), "black")
draw = ImageDraw.Draw(im)
 
x = 0;
for text_color_pair in text:
    t = text_color_pair[0]
    c = text_color_pair[1]
    print("t=" + t + " " + str(c) + " " + str(x))
    draw.text((x, 0), t, c, font=font)
    x = x + font.getsize(t)[0]
 
im.save("test.ppm")
 
os.system("./demo --led-rows=16 --led-chain=1 -D 1 test.ppm")

-> Code from https://learn.adafruit.com/16x32-rgb-display-with-raspberry-pi-part-2/software

But. When I execute it using
sudo python test.py
The program says in console that all is ok, and that it's reading the image.
But, nothing is currently displaying on the Led pane.

I verified the wiring, all seems to be okay, and the code from there : https://learn.adafruit.com/connecting-a-16x32-rgb-led-matrix-panel-to-a-raspberry-pi/experimental-python-code

is working very well as expected.

Maybe someone got an idea ?

Thanks.

P.S : Sorry for my english.

[raspberry-pi-maker]

I think you first need to check the path of demo executable, test.ppm files

In the python file, save the test.ppm file with full path and dont call os.system().
Open a terminal, then execute this command, and check the result.
Surely you need a root permission.
./examples-api-use/demo --led-rows=16 --led-chain=1 -D 1 "test.ppm (with full path)"

[hzeller]

Please don't use the demo to scroll an text. This is a super-simplistic demo that is really only used to test.

If you want to scroll text, use the dedicated provided text-scrolling utility

If you do want to use Python, install the Python library for the rgb-matrix and then use the library from within there; there are samples that show how to do that.

You call for all kinds of trouble when you mix Python and then os.system() call other programs. Do it natively either in Python or C++.