import appuifw, e32, graphics, key_codes

prev_x = 0
prev_y = 0
colour=(255,0,0)
thickness = 10

if not appuifw.touch_enabled():
    appuifw.note(u"This application only works on devices that support touch input")

def e_callback(event):
    global prev_x, prev_y,colour, thickness
    if not event['type'] in [key_codes.EButton1Up, key_codes.EButton1Down, key_codes.EDrag]:
        return
    if event['type'] == key_codes.EButton1Down:
        prev_x = event['pos'][0]
        prev_y = event['pos'][1]
    elif event['type'] == key_codes.EDrag:
        rect = (prev_x, prev_y, event['pos'][0], event['pos'][1])
        img.line(rect, outline=colour, width=thickness, fill=colour)
        prev_x = event['pos'][0]
        prev_y = event['pos'][1]
        canvas.blit(img)

def rd_callback(rect):
    canvas.blit(img)
    
def quit():
    script_lock.signal()

canvas = appuifw.Canvas(event_callback=e_callback, redraw_callback=rd_callback)
appuifw.app.body=canvas
appuifw.app.screen='full'
w,h = canvas.size
img=graphics.Image.new((w,h))
        
appuifw.app.exit_key_handler = quit
script_lock = e32.Ao_lock()
script_lock.wait()