Are you guys ready to look at the entrails of the Python? We are going to review the code for the Pi-A-Sketch. Liz already published the URL for the Pi-A-Sketch code on the raspberrypi.org site, but just in case, here it is again:
…Initially, I wanted a function to draw a line, and a function to draw a circle. That meant that I would have to write the guts of:
def line(x, y):
Right away I knew that I would need to do something based on Bresenham’s line drawing algorithm. Horizontal lines are trivial (turn one motor), and so are vertical lines (turn the other motor). Perfect diagonals are also easy to accomplish, since it is just a matter of turning both motors at the same time, for each step. Based on the direction of the steps, 4 different diagonal directions can be done.
Yet, with Bresenham’s algorithm, you can do a line of any slope. In order to save time, I was not going to do special case handling, and just do everything with his algorithm….
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.