Send text via Command

[Thor421]

Hello and thank you very much hzeller for your work!

As in this subject, https://github.com/hzeller/rpi-rgb-led-matrix/issues/678, I want to send a text via a simple command line.

Unfortunately, echo "TEST" | sudo ./text-example ... does not work Maybe a change has occurred in the bookstore this past year?

I specify that the matrix works very well by doing sudo ./text-example -f ../fonts/8x13.bdf Hello

Thank you for your help

[Thor421]

small precision: this command line works but "TEST" remains 0.1 seconds in the matrix.

[Thor421]

New precision : I use the fonction while from this topic : (while :; do cat Anzeige.txt ; sleep 0.2 ; done) | sudo ./text-example -f ../fonts/7x13.bdf --led-rows 16 --led-gpio-mapping=adafruit-hat --led-cols 64 -y 1 -C 255,0,0 But, I can not clear the matrix. With CTRL+C, I have some points that stay on. Is there a solution to clear all the matrice please ?

Thank you :)

[angelogoncalve]

Use matrix.Clear()

examples.zip

[angelogoncalve]

from rgbmatrix import RGBMatrix, RGBMatrixOptions, graphics import time

Configuration for the matrix

options = RGBMatrixOptions() options.rows = 16 options.cols = 64 options.chain_length = 1 options.parallel = 1 options.hardware_mapping = 'adafruit-hat'

matrix = RGBMatrix(options = options)

offscreen_canvas = matrix.CreateFrameCanvas() font = graphics.Font() font.LoadFont("../../../fonts/7x13.bdf") textColor = graphics.Color(255, 0, 0) my_text = "TEST"

len = graphics.DrawText(offscreen_canvas, font, pos, 10, textColor, my_text) time.sleep(5) offscreen_canvas.Clear()

[Thor421]

Thank you angelogoncalve :) I adapted the code for my material but there is no display.

Can you help me please ?

from rgbmatrix import RGBMatrix, RGBMatrixOptions, graphics
import time
#Configuration for the matrix

options = RGBMatrixOptions()
options.rows = 16
options.cols = 32
options.chain_length = 2
options.parallel = 1
options.hardware_mapping = 'adafruit-hat'
options.multiplexing = 3
options.row_address_type = 2

matrix = RGBMatrix(options = options)

offscreen_canvas = matrix.CreateFrameCanvas()
font = graphics.Font()
font.LoadFont("../../../fonts/7x13.bdf")
textColor = graphics.Color(255, 255, 255)
pos = offscreen_canvas.width
my_text = "TEST"

len = graphics.DrawText(offscreen_canvas, font, pos, 10, textColor, my_text)
time.sleep(5)
offscreen_canvas.Clear()

[Thor421]

I'm progressing slowly and I have a new problem to solve.

Can I use anything other than a CTRL-C to stop the display of text? I looked at SIGINT but I do not see how to adapt this function to python code.

Can you help me please ? Thank you !

[Thor421]

Maybe his information will be useful.

1- I run: sudo ./text.py (it shows me a static text) 2- I wish to interrupt 1 3- To launch: sudo ./text2.py (it shows me a static text) I do not use a keyboard, only a box with pushbuttons mounted on an arduino card that communicates in bluetooth with the raspberry (a python file manages the reception of bluetooth data)

How to interrupt 1? I hope it's more understandable :)

[hyamanieu]

@Thor421 you need to import signal and os then do os.killpg(os.getpgid(pid_of_your_prog), signal.SIGTERM) you need to start your command from another python script to do that and have its PID saved. You can use p = subprocess.Popen(['python3','text.py], cwd=yourpath, preexec_fn=os.setsid) to do that, the pid is then p.pid.

[angelogoncalve]

you can use killing threads to clear the panel (stop RPi sending data to the display):

https://eli.thegreenplace.net/2011/12/27/python-threads-communication-and-stopping

https://www.geeksforgeeks.org/python-different-ways-to-kill-a-thread/

[Thor421]

Thanks for your help hyamanieu and angelogoncalve :) I just coded the lines to kill the process from the PID

os.killpg(os.getpgid(pid), signal.SIGINT)

Now, I think I have to modify the samplebase.py file and especially this part to add this line, but how ?

        try:
            # Start loop
            print("Press CTRL-C to stop sample")
            self.run()
        except KeyboardInterrupt:
            print("Exiting\n")
sys.exit(0)

Thank you so much !

[Thor421]

My problem : Python does not execute any command while a text is displayed on the matrix. The commands made (when I press the push button) while displaying the text (including os.killpg) are done after I have done CTRL + C.

Of course, if I manually call the python file to send the SIGINT signal, everything works.

Could you give me an additional indication to solve this problem please?

ser = serial.Serial('/dev/rfcomm0', 9600) // Connect to the bluetooth
while True:
    result = ser.read()
    print(result)               

         if result == 'f' :         

        os.system("sudo python ./30.py") // It's display the text of the matrice

         if result == '7' :         

        os.system("sudo python ./killprocess.py") // It's not execute because 30.py is launched