A Torrid Tail of Too Many Circles

Where it all began....

A long time ago, I received a Adafuit pyportal from one of their mystery boxes. This device has spent most of its time collecting dust or displaying the default demonstration code. I decided to replicate some coding from the 80s and see if I could display Moire Patterns on the pyportal screen. To this end, I have started the journey of drawing too many circles on the screen.

I decided to use the CircuitPython language to code my implementations. I could use a variety of editors (vim, Mu and Atom) and run the code by simply updating the code.py file on the device. My development environment is Linux based so I eventually fell into old development habits and used vim for development, cp for deployment and minicom to monitor code execution.

And so it begins

The Adafruit maintains a list CircuitPython modules available (200!). The main modules used in this project are displayio and Display Shapes. The former is responsible for managing the display and bitmaps while the latter is used to generate shapes. Adafruit has a great information page on how to use the displayio framework. The shapes library returns a TileGrid for each shape generated.

Implementation 

For this implementation, I created a display group per set of circles and populated it with TileGrids created by Circle(). The center of the circles is randomly generated and each ring radius is incrementally larger than the previous. The code will sleep for a few seconds, delete the two display groups and regenerate a new set of circles.

Issues

There are a number of issues with this implementation

• Memory: Each circles consists of a TileGrid, a bitmap sized to hold the new shape and a palette. This results in 60 total circles able to be drawn.
• Display Speed: The updating of the display is dreadfully slow. It takes about 20 seconds to update the display. Maybe the Group is not flattened before being displayed. 

Moving forward

Obviously this is not an optimal solution. I continued working on this code based to make speed improvements but that is a tale for another time.