Canvas drawing not working - it needs hard reset

[mroglic]

I am using the M5 Dial and testing Canvas drawing. Each time I change the position or color of a circle and save it to the M5 Dial (whether using UIFlow, VS Code, or Thonny), I need to restart the device with a hard reset for the changes to be visible, otherwise the Lcd stops drawing anything and just shows the black background. The changes don't take effect after a soft reset or when pasting the same code through REPL, which is something that is expected I guess.

The Widgets.Image works fine (it doesn't require a hard reset and behaves as expected), but I specifically want to use the Canvas for smooth drawing of graphics/images. The issue I encounter with Widgets.Image is that when I try to animate the image's movement, the screen flickers.

This is what I got in main.py, just changing the canvas.drawCircle parameters, would result in completely black screen.

import M5
import time

canvas = None
 
def setup():
    global canvas
    M5.begin()
    canvas = M5.Lcd.newCanvas(240, 240, 16, True)  
    
def loop():
    global canvas
    M5.update()         
    canvas.drawCircle(120, 120, 33, 0x00ff00)
    canvas.push(0, 0)
    canvas.clear()
 
if __name__ == '__main__':
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        print("Program terminated.")
        if isinstance(e, Exception):
            print(f"Error: {e}")
    finally:
        print("Performing final cleanup...")
        if canvas:
            canvas.delete()

[lbuque]

@mroglic Dial does not have enough memory to create a 240*240px canvas.

[mroglic]

@lbuque Thanks for the answer! However, isn't it strange that a 240x240 canvas works every time I perform a hard reset, but not with a soft reset? Could there be a potential memory leak?

What is the maximum possible canvas size (or the maximum available memory)?

What is the recommended way to animate images without flickering?

Thanks!

[lbuque]

During a soft reset, the canvas memory is not released.

[mroglic]

I understand. Would it be possible to release it through code, perhaps using something like gc.collect() or a similar method? If you could also address two other questions I have, I would greatly appreciate it. Thank you so much!

[mroglic]

@lbuque can you please advise on how to achieve this?