red = Color.new(255, 0, 0);
black = Color.new(0, 0, 0);
white = Color.new(255, 255, 255);
 
canvas = Image.createEmpty(480, 272)
canvas:clear(white)
 
brush = {}
eraser = {}
 
x0 = 0
y0 = 0
x1 = 0
y1 = 0
 
while true do
  pad = Controls.read()
  dx = pad:analogX()
  if math.abs(dx) > 32 then
    x0 = x0 + dx / 64
  end
  dy = pad:analogY()
  if math.abs(dy) > 32 then
    y0 = y0 + dy / 64
  end
  if pad:cross() then
    canvas:drawLine(x0, y0, x1, y1, black)
  end
  x1 = x0
  y1 = y0
  screen:blit(0, 0, canvas, 0, 0, canvas:width(), canvas:height(), false)
  screen:drawLine(x1 - 5, y1, x1 + 5, y1, red)
  screen:drawLine(x1, y1 - 5, x1, y1 + 5, red)
  screen.waitVblankStart()
  screen.flip()
  if pad:start() then
    break
  end
  if pad:select() then
    screen:save("screenshot.tga")
  end
end

function controls()
  pad = Controls.read()
  if pad ~= oldPad then
    --yourcodehere
  end
  oldPad = pad
end