#!/usr/bin/env python

filename = "square.gcode"
w = 10
h = 10
n = 20
pwr = 255
speed_g0 = 3000
speed_g1 = 500

with open(filename, 'w') as f:
    def write(s):
        print(s)
        f.write(s + "\n")

    # header
    write("G90")
    write("G28")
    write("G92 X0 Y-20")
    write("M3 I")
    write("M3 S0")
    write("")

    square = [
        ( 0, 0 ),
        ( w, 0 ),
        ( w, h ),
        ( 0, h ),
    ]

    # first line is not having the power applied
    # so just draw it twice
    # TODO why?
    write("G0 X0 Y0 S0 F" + str(speed_g0))
    write("G1 X0 Y0 S" + str(pwr) + " F" + str(speed_g1))

    for i in range(0, n):
        for x, y in square:
            write("G1 X" + str(x) + " Y" + str(y) + " S" + str(pwr) + " F" + str(speed_g1))
        write("")

    # finish last line
    write("G1 X0 Y0 S" + str(pwr) + " F" + str(speed_g1))
    write("")

    # footer
    write("M5")
    write("G0 X0 Y0 F" + str(speed_g0))