curses_demo.py

import curses, traceback

def main(stdscr):
  global screen
  text = "This is a test"
  screen = stdscr.subwin(0, 0)
  screen.box() # Wrap screen window in box
  # Get window diminsions
  y, x = screen.getmaxyx()
  global cur_x, cur_y;
  # Sets the cursor to center the text on screen
  cur_x = (x/2)-(len(text))/2
  cur_y = (y/2)
  # Add string to screen
  screen.addstr( cur_y, cur_x, text) 
  screen.refresh() # Refresh to populate screen with data

  c = screen.getch() # Get char
  while c != ord('q'): # Exit loop if char caught is 'q'
    screen.addstr(1,1,str(c))
    screen.refresh()
    if c == 65: # ARROW_UP
      move_up(text, screen) 
    elif c == 66: # ARROW_DOWN
      move_down(text, screen)
    elif c == 68: # ARROW_LEFT
      move_left(text, screen)
    elif c == 67: # ARROW_RIGHT
      move_right(text, screen) 
    elif c == 410:
      y, x = screen.getmaxyx()
      curses.resizeterm(y, x) # Resize curses boundaries
      move_center(text,screen)

    c = screen.getch()
  
  return

# Moves text up by one
def move_up(text, screen):
  screen.clear()
  screen.box()
  global cur_y, cur_x
  cur_y = cur_y - 1
  screen.addstr( cur_y, cur_x, text)
  screen.refresh()
  
# Moves text down by one
def move_down(text, screen):
  screen.clear()
  screen.box()
  global cur_y, cur_x
  cur_y = cur_y + 1
  screen.addstr( cur_y, cur_x, text)
  screen.refresh()
	
# Moves text right by one
def move_right(text, screen):
  screen.clear()
  screen.box()
  global cur_y, cur_x
  cur_x = cur_x + 1
  screen.addstr( cur_y, cur_x, text)
  screen.refresh()

# Moves text left by one
def move_left(text, screen):
  screen.clear()
  screen.box()
  global cur_y, cur_x
  cur_x = cur_x - 1
  screen.addstr( cur_y, cur_x, text)
  screen.refresh()

# Centers text in window
def move_center(text, screen):
  screen.clear()
  screen.box()
  global cur_y, cur_x
  y, x = screen.getmaxyx()
  cur_x = (x/2)-(len(text))/2
  cur_y = (y/2)
  screen.addstr( cur_y, cur_x, text)
  screen.refresh()

if __name__ == '__main__':
  try:
    # Initialize curses
    stdscr=curses.initscr()

    # Turn off echoing of keys, and enter cbreak mode,
    # where no buffering is performed on keyboard input
    curses.noecho()
    curses.cbreak()

    # In keypad mode, escape sequences for special keys
    # will be interpreted and a special value like
    # curses.KEY_LEFT will be returned
    stdscr.keypad(1)
    curses.curs_set(0) # Hide cursor position

    main(stdscr) # enter main loop
  except curses.error:
    # In the event of error, restore terminal to sane state
    traceback.print_exc() # Print the exception
    print(curses.ERR)
  except KeyboardInterrupt:
    # Caught KeyboardInterrupt (Gets rid of stacktrace)
    # Set everything back to normal before exit
    stdscr.keypad(0)
    curses.echo()
    curses.nocbreak()
    curses.endwin()
    exit()
  finally:
    # Set everything back to normal
    stdscr.keypad(0)
    curses.echo()
    curses.nocbreak()
    curses.endwin()