Clearing an area, not the complete screen

[ChristopherBadenhorst]

Hi,

I'm making a clock with some other features. Now I want the clock to update every x time, and that works fine. I just can't figure out how to clear only the clock area and not the whole screen with every update of the clock.

I found: matrix = RGBMatrix(options = options) and matrix.Clear()

I do think I can use canvas.Clear() for just an area. I just don't understand how I can define the canvas = area. Can anyone help?

[angelogoncalve]

with times height is the size of the area/matrix you want to clear:

for y in range(0, height): for x in range(0, width): matrix.SetPixel(x, y, 0, 0, 0)

[ChristopherBadenhorst]

@angelogoncalve Thanks for your help, I've tried a lot of variations with your piece of code but can't work it out. What is wrong here now?

def job2():
    for y in range(0, 32):
    for x in range(0, 64):    
    mseconds.SetPixel(0, 32, 0, 0, 0)

    mseconds.Clear()

    clock = datetime.datetime.now().strftime("%H:%M:%S")
    graphics.DrawText(matrix, font3, 0, 55, blue, clock)

job2()
schedule.every(1).seconds.do(job2)

[ChristopherBadenhorst]

I do still want to rebuild it to just clear the area of the 'seconds', and make a seperate job for the minutes and a seperate job for the hours. But if I get this right, i'll get all of them right.

[hzeller]

I suppse you want to casll SetPixel() with x and y, no only 0, 32 ?.

Anyway, what you should do is to write the time into a second canvas, then do SwapOnVSync(), otherwise this will result in flicker.

[angelogoncalve]

Yes Henner Zeller you arer correct:

def job2(): for y in range(0, 32): for x in range(0, 64):
mseconds.SetPixel(x, y, 0, 0, 0)

[ChristopherBadenhorst]

The SwapOnVSync() made it more complicating for me. Solved it (quick and dirty) with drawing an image that is completely black, before writing the new time. Works very wel!

[jaygarcia]

@ChristopherBadenhorst, if you've solved this, please consider closing this issue =)