Python code to enable x,y plotting from the neopixel service, an inviting rabbit hole.

Many Matrix displays have a serpentine LED pattern. This means that odd and even columns are reversed.

The code below unravels the switching of the columns, all you have to do is feed the x and y coords in and the code will determine the pixel that needs to be displayed. The highlighted text indicates this conversion.

Usage - Call the definition :- def XYtoPixel(x,y,r,g,b): #supply x,y, and rgb colour

Python sketch for a 16*16 Neopixel display
import math
port = "COM15"
pin = 3
pixelCount = 216
# starting arduino
arduino = Runtime.start("arduino","Arduino")
arduino.connect(port)

# starting neopixle
neopixel = Runtime.start("neopixel","NeoPixel")
neopixel.setPin(pin)
neopixel.setPixelCount(pixelCount)

# attach the two services
neopixel.attach(arduino)

def XYCircle(radiusx,radiusy,r,g,b):    #Test code for drawing circle
 for pie in range(0,359,6):
  y=9+(radiusy*(math.cos(math.radians(pie))))
  x=9+(radiusx*(math.sin(math.radians(pie))))
  XYtoPixel(x,y,r,g,b)
  #print(i),(x),(y)

def XYtoPixel(x,y,r,g,b): #supply x,y, and rgb colour
 x=int(x)
 y=int(y)
 z = x & 1       #Test odd or even column
 if  z == 0 :     #Even column
   pixel = 16 * (16 - (x+1))+y
 else :            #Odd column
   pixel = 16 * (16 - x) - (y+1)  
 neopixel.setPixel(pixel,r,g,b)  

XYCircle(6,6,255,0,255)  #Plot the circles  expects x and y radii + RGB colours
XYCircle(5,5,255,255,0)
XYCircle(4,4,0,255,255)
XYCircle(3,3,255,255,255)

With x,y plotting, its also possible to place and add text/numbers (maybe as debug tool - for displaying startup messages)

Coming soon :- (erhmmmm with reversal)