Julia.pyde differences between repo, book code, and screenshot

[TimPasquini]

The text tells you to save a copy of your Mandelbrot.pyde as Julia.pyde and then replace mandelbrot() function with the provided julia() function and then update the draw() function.

After doing so, I thought the program was freezing or taking a really long time, until I noticed a tiny 1x1 or 2x2 orange pixel in the center of the display canvas. This made me think it was a scaling issue and I ended up figuring out that the xscl = float(rangex)/width (and corresponding y-scale) code from the mandelbrot setup() function needed to be changed to xscl = width/rangex (and corresponding y-scale too).

I also found the image produced was actually upside-down, but thanks to the previous information about imaginary numbers, I knew I could just flip the second value in my c variable to negative to get the mirror image and finally get the same image as the book.

When looking on how to report these issues, I found the link to this repo from the No Starch website and saw that the repo here uses the correct scaling and different code inside the draw() function compared to what is in the book. I am assuming that this is the code that ultimately created the image in the book and thus explains the differences.

Hopefully this helps anyone else who gets stuck in the Julia Set section.

[hackingmath]

Thanks for pointing that out, Tim. I've given the corrections to the editors over at No Starch. Peter Farrell

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On Tue, Oct 5, 2021 at 12:05 AM Tim Pasquini ***@***.***> wrote: The text tells you to save a copy of your Mandelbrot.pyde as Julia.pyde and then replace mandelbrot() function with the provided julia() function and then update the draw() function. After doing so, I thought the program was freezing or taking a really long time, until I noticed a tiny 1x1 or 2x2 orange pixel in the center of the display canvas. This made me think it was a scaling issue and I ended up figuring out that the xscl = float(rangex)/width (and corresponding y-scale) code from the mandelbrot setup() function needed to be changed to xscl = width/rangex (and corresponding y-scale too). I also found the image produced was actually upside-down, but thanks to the previous information about imaginary numbers, I knew I could just flip the second value in my c variable to negative to get the mirror image and finally get the same image as the book. When looking on how to report these issues, I found the link to this repo from the No Starch website and saw that the repo here uses the correct scaling and different code inside the draw() function compared to what is in the book. I am assuming that this is the code that ultimately created the image in the book and thus explains the differences. Hopefully this helps anyone else who gets stuck in the Julia Set section. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#3>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACIT6XAITG5MWUS6HZ7O5RLUFKBRVANCNFSM5FK37Z7Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.