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bartoszbielawski / LEDMatrixDriver

A replacement for Arduino's LedControl library
MIT License
75 stars 25 forks source link

Bug in Scroll function #29

Closed wEPac closed 5 years ago

wEPac commented 5 years ago

Hello, thank you for this nice driver. I was making some changes to use the scroll function with the "modRev" on. It is working fine now, I made a fork... But I found a fatal bug in this function. In the original file, we have for (i = 8 * N; i >= 0; i-- ) when we should have for (i = 8 * N - 1; i >= 0; i--) because here if ((i + 1) % N) frameBuffer[i + 1] |= (n << 7); we can see, when i == 8 N, it will write at 8 N + 1, outside the frameBuffer array : [0; 8 * N [

bartoszbielawski commented 5 years ago

Hi, I just pushed a new branch (rotation) that addresses this problem. I have rewritten the code not to do a "look ahead" or "look back". I'd be happy if you could take a look and check if I didn't break it even more :)

bartoszbielawski commented 5 years ago

Ah, one more thing. I have made changes this code that inverts display so that the framebuffer always contains the same data and it's inverted only when it's being written to the hardware.

wEPac commented 5 years ago

More than pretty good news, and I feel it a great idea, this will allow us to work on the buffer without to think further :) I was close to rewrite some parts for the issue with different hardwares when I saw you are already working on with other contributors too :) I really like your driver, simple but efficient, it will preserve memory for the project. I will look further for this new branch

bartoszbielawski commented 5 years ago

If I get no more complaints about the new scrolling code I will close this issue. Feel free to test branch "rotation" any time.

wEPac commented 5 years ago

For now, rotation driver is working fine for me, that s pretty cool, these adjustments were the missing part from your driver. If I find something wrong, I will report. Have a nice day.

bartoszbielawski commented 5 years ago

Okay, thanks for checking. I close the issue.