# `curses` — Terminal handling for character-cell displays

Source code: Lib/curses

The `curses` module provides an interface to the curses library, the de-facto standard for portable advanced terminal handling.

While curses is most widely used in the Unix environment, versions are available for Windows, DOS, and possibly other systems as well. This extension module is designed to match the API of ncurses, an open-source curses library hosted on Linux and the BSD variants of Unix.

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

This is an optional module. If it is missing from your copy of CPython, look for documentation from your distributor (that is, whoever provided Python to you). If you are the distributor, see Requirements for optional modules.

Availability: Unix.

Note

Whenever the documentation mentions a character it can be specified as an integer, a one-character Unicode string or a one-byte byte string.

Whenever the documentation mentions a character string it can be specified as a Unicode string or a byte string.

See also

Module `curses.ascii`

  Utilities for working with ASCII characters, regardless of your locale settings.

Module `curses.panel`

  A panel stack extension that adds depth to curses windows.

Module `curses.textpad`

  Editable text widget for curses supporting Emacs-like bindings.

Curses Programming with Python

  Tutorial material on using curses with Python, by Andrew Kuchling and Eric Raymond.

## Functions

The module `curses` defines the following exception:

exception curses.error

  Exception raised when a curses library function returns an error.

Note

Whenever x or y arguments to a function or a method are optional, they default to the current cursor location. Whenever attr is optional, it defaults to `A_NORMAL`.

The module `curses` defines the following functions:

### Initialization and termination

curses.initscr()

  Initialize the library. Return a window object which represents the whole screen.

  See `setupterm()` for a caveat about calling it before this function.

  Note

  If there is an error opening the terminal, the underlying curses library may cause the interpreter to exit.

curses.endwin()

  De-initialize the library, and return terminal to normal status.

curses.isendwin()

  Return `True` if `endwin()` has been called (that is, the curses library has been deinitialized).

curses.newterm(type=None, fd=None, infd=None, /)

  Initialize a new terminal in addition to the one initialized by `initscr()`, and return a screen for it. This allows a program to drive more than one terminal.

  type is the terminal name, as in `setupterm()`; if `None`, the value of the `TERM` environment variable is used. fd and infd are the output and input files for the terminal: either a file object or a file descriptor. They default to `sys.stdout` and `sys.stdin`.

  The new screen becomes the current one. Use `set_term()` to switch between screens.

  See `setupterm()` for a caveat about calling it before this function.

  Added in version 3.16.0a0 (unreleased).

curses.new_prescr()

  Return a new screen that can be used to call functions that affect global state before `initscr()` or `newterm()` is called.

  Availability: if the underlying curses library provides `new_prescr()`.

  Added in version 3.16.0a0 (unreleased).

curses.set_term(screen, /)

  Make screen, a screen returned by `newterm()`, the current terminal, and return the previously current screen. Returns `None` if the previous screen was the one created by `initscr()`. Raises `error` if screen has no terminal, as is the case for a screen returned by `new_prescr()`.

  Added in version 3.16.0a0 (unreleased).

curses.wrapper(func, /, *args, **kwargs)

  Initialize curses and call another callable object, func, which should be the rest of your curses-using application. If the application raises an exception, this function will restore the terminal to a sane state before re-raising the exception and generating a traceback. The callable object func is then passed the main window ‘stdscr’ as its first argument, followed by any other arguments passed to `wrapper()`. Before calling func, `wrapper()` turns on cbreak mode, turns off echo, enables the terminal keypad, and initializes colors if the terminal has color support. On exit (whether normally or by exception) it restores cooked mode, turns on echo, and disables the terminal keypad.

### Terminal mode control

curses.def_prog_mode()

  Save the current terminal mode as the “program” mode, the mode when the running program is using curses. (Its counterpart is the “shell” mode, for when the program is not in curses.) Subsequent calls to `reset_prog_mode()` will restore this mode.

curses.def_shell_mode()

  Save the current terminal mode as the “shell” mode, the mode when the running program is not using curses. (Its counterpart is the “program” mode, when the program is using curses capabilities.) Subsequent calls to `reset_shell_mode()` will restore this mode.

curses.reset_prog_mode()

  Restore the terminal to “program” mode, as previously saved by `def_prog_mode()`.

curses.reset_shell_mode()

  Restore the terminal to “shell” mode, as previously saved by `def_shell_mode()`.

curses.savetty()

  Save the current state of the terminal modes in a buffer, usable by `resetty()`.

curses.resetty()

  Restore the state of the terminal modes to what it was at the last call to `savetty()`.

curses.curs_set(visibility)

  Set the cursor state. visibility can be set to `0`, `1`, or `2`, for invisible, normal, or very visible. If the terminal supports the visibility requested, return the previous cursor state; otherwise raise an exception. On many terminals, the “visible” mode is an underline cursor and the “very visible” mode is a block cursor.

curses.getsyx()

  Return the current coordinates of the virtual screen cursor as a tuple `(y, x)`. If `leaveok` is currently `True`, then return `(-1, -1)`.

curses.setsyx(y, x)

  Set the virtual screen cursor to y, x. If y and x are both `-1`, then `leaveok` is set `True`.

curses.doupdate()

  Update the physical screen. The curses library keeps two data structures, one representing the current physical screen contents and a virtual screen representing the desired next state. The `doupdate()` function updates the physical screen to match the virtual screen.

  The virtual screen may be updated by a `noutrefresh()` call after write operations such as `addstr()` have been performed on a window. The normal `refresh()` call is simply `noutrefresh()` followed by `doupdate()`; if you have to update multiple windows, you can speed performance and perhaps reduce screen flicker by issuing `noutrefresh()` calls on all windows, followed by a single `doupdate()`.

### Input options

curses.cbreak()

  Enter cbreak mode. In cbreak mode (sometimes called “rare” mode) normal tty line buffering is turned off and characters are available to be read one by one. However, unlike raw mode, special characters (interrupt, quit, suspend, and flow control) retain their effects on the tty driver and calling program. Calling first `raw()` then `cbreak()` leaves the terminal in cbreak mode.

curses.nocbreak()

  Leave cbreak mode. Return to normal “cooked” mode with line buffering.

curses.echo()

  Enter echo mode. In echo mode, each character input is echoed to the screen as it is entered.

curses.noecho()

  Leave echo mode. Echoing of input characters is turned off.

curses.raw()

  Enter raw mode. In raw mode, normal line buffering and processing of interrupt, quit, suspend, and flow control keys are turned off; characters are presented to curses input functions one by one.

curses.noraw()

  Leave raw mode. Return to normal “cooked” mode with line buffering.

curses.halfdelay(tenths)

  Used for half-delay mode, which is similar to cbreak mode in that characters typed by the user are immediately available to the program. However, after blocking for tenths tenths of seconds, raise an exception if nothing has been typed. The value of tenths must be a number between `1` and `255`. Use `nocbreak()` to leave half-delay mode.

curses.meta(flag)

  If flag is `True`, allow 8-bit characters to be input. If flag is `False`, allow only 7-bit chars.

curses.nl(flag=True)

  Enter newline mode. This mode translates the return key into newline on input, and translates newline into return and line-feed on output. Newline mode is initially on.

  If flag is `False`, the effect is the same as calling `nonl()`.

curses.nonl()

  Leave newline mode. Disable translation of return into newline on input, and disable low-level translation of newline into newline/return on output (but this does not change the behavior of `addch('\n')`, which always does the equivalent of return and line feed on the virtual screen). With translation off, curses can sometimes speed up vertical motion a little; also, it will be able to detect the return key on input.

curses.intrflush(flag)

  If flag is `True`, pressing an interrupt key (interrupt, break, or quit) will flush all output in the terminal driver queue. If flag is `False`, no flushing is done.

curses.qiflush([flag])

  If flag is `False`, the effect is the same as calling `noqiflush()`. If flag is `True`, or no argument is provided, the queues will be flushed when these control characters are read.

curses.noqiflush()

  When the `noqiflush()` routine is used, normal flush of input and output queues associated with the `INTR`, `QUIT` and `SUSP` characters will not be done. You may want to call `noqiflush()` in a signal handler if you want output to continue as though the interrupt had not occurred, after the handler exits.

curses.typeahead(fd)

  Specify that the file descriptor fd be used for typeahead checking. If fd is `-1`, then no typeahead checking is done.

  The curses library does “line-breakout optimization” by looking for typeahead periodically while updating the screen. If input is found, and it is coming from a tty, the current update is postponed until refresh or doupdate is called again, allowing faster response to commands typed in advance. This function allows specifying a different file descriptor for typeahead checking.

curses.is_cbreak()

  Return `True` if cbreak mode (see `cbreak()`) is enabled, `False` otherwise. Availability: ncurses 6.5 or later.

  Added in version 3.16.0a0 (unreleased).

curses.is_echo()

  Return `True` if echo mode (see `echo()`) is enabled, `False` otherwise. Availability: ncurses 6.5 or later.

  Added in version 3.16.0a0 (unreleased).

curses.is_nl()

  Return `True` if nl mode (see `nl()`) is enabled, `False` otherwise. Availability: ncurses 6.5 or later.

  Added in version 3.16.0a0 (unreleased).

curses.is_raw()

  Return `True` if raw mode (see `raw()`) is enabled, `False` otherwise. Availability: ncurses 6.5 or later.

  Added in version 3.16.0a0 (unreleased).

### Keyboard input

curses.ungetch(ch)

  Push ch so the next `getch()` or `get_wch()` will return it.

  ch may be an integer (a key code or character code), a byte, or a string of length 1. A one-character string is pushed like `unget_wch()`; on a narrow build it must encode to a single byte.

  Note

  Only one ch can be pushed before `getch()` is called.

  Changed in version 3.16.0a0 (unreleased): A one-character string argument is no longer required to encode to a single byte, except on a narrow build.

curses.unget_wch(ch)

  Push ch so the next `get_wch()` will return it.

  Note

  Only one ch can be pushed before `get_wch()` is called.

  Added in version 3.3.

  Changed in version 3.16.0a0 (unreleased): Also available on a narrow build, where ch must encode to a single byte (an 8-bit locale).

curses.flushinp()

  Flush all input buffers. This throws away any typeahead that has been typed by the user and has not yet been processed by the program.

curses.has_key(ch)

  Take a key value ch, and return `True` if the current terminal type recognizes a key with that value.

curses.keyname(k)

  Return the name of the key numbered k as a bytes object. The name of a key generating printable ASCII character is the key’s character. The name of a control-key combination is a two-byte bytes object consisting of a caret (`b'^'`) followed by the corresponding printable ASCII character. The name of an alt-key combination (128–255) is a bytes object consisting of the prefix `b'M-'` followed by the name of the corresponding ASCII character.

  Raise a `ValueError` if k is negative.

curses.define_key(definition, keycode)

  Define an escape sequence definition, a string, as a key that generates the key code keycode, so that `curses` interprets it like one of the keys predefined in the terminal database.

  If definition is `None`, any existing binding for keycode is removed. If keycode is zero or negative, any existing binding for definition is removed.

  Added in version 3.16.0a0 (unreleased).

curses.key_defined(definition)

  Return the key code bound to the escape sequence definition, a string, `0` if no key code is bound to it, or `-1` if definition is a prefix of a longer bound sequence (and so is ambiguous).

  Added in version 3.16.0a0 (unreleased).

curses.keyok(keycode, enable)

  Enable (if enable is true) or disable (otherwise) interpretation of the key code keycode. Unlike `window.keypad()`, this affects a single key code rather than all of them.

  Added in version 3.16.0a0 (unreleased).

### Mouse

curses.getmouse()

  After `getch()` returns `KEY_MOUSE` to signal a mouse event, this method should be called to retrieve the queued mouse event, represented as a 5-tuple `(id, x, y, z, bstate)`. id is an ID value used to distinguish multiple devices, and x, y, z are the event’s coordinates. (z is currently unused.) bstate is an integer value whose bits will be set to indicate the type of event, and will be the bitwise OR of one or more of the following constants, where n is the button number from 1 to 5: `BUTTONn_PRESSED`, `BUTTONn_RELEASED`, `BUTTONn_CLICKED`, `BUTTONn_DOUBLE_CLICKED`, `BUTTONn_TRIPLE_CLICKED`, `BUTTON_SHIFT`, `BUTTON_CTRL`, `BUTTON_ALT`.

  Changed in version 3.10: The `BUTTON5_*` constants are now exposed if they are provided by the underlying curses library.

curses.ungetmouse(id, x, y, z, bstate)

  Push a `KEY_MOUSE` event onto the input queue, associating the given state data with it.

curses.mousemask(mousemask)

  Set the mouse events to be reported, and return a tuple `(availmask, oldmask)`. availmask indicates which of the specified mouse events can be reported; on complete failure it returns `0`. oldmask is the previous value of the mouse event mask. If this function is never called, no mouse events are ever reported.

curses.mouseinterval(interval)

  Set the maximum time in milliseconds that can elapse between press and release events in order for them to be recognized as a click, and return the previous interval value. The default value is 166 milliseconds, or one sixth of a second. Use a negative interval to obtain the interval value without changing it.

curses.has_mouse()

  Return `True` if the mouse driver has been successfully initialized.

  Availability: if the underlying curses library provides `has_mouse()`.

  Added in version 3.16.0a0 (unreleased).

### Color

curses.start_color()

  Must be called if the programmer wants to use colors, and before any other color manipulation routine is called. It is good practice to call this routine right after `initscr()`.

  `start_color()` initializes eight basic colors (black, red, green, yellow, blue, magenta, cyan, and white), and two global variables in the `curses` module, `COLORS` and `COLOR_PAIRS`, containing the maximum number of colors and color-pairs the terminal can support. It also restores the colors on the terminal to the values they had when the terminal was just turned on.

curses.has_colors()

  Return `True` if the terminal can display colors; otherwise, return `False`.

curses.has_extended_color_support()

  Return `True` if the module supports extended colors; otherwise, return `False`. Extended color support allows more than 256 color pairs for terminals that support more than 16 colors (for example, xterm-256color).

  Extended color support requires ncurses version 6.1 or later.

  Added in version 3.10.

curses.can_change_color()

  Return `True` or `False`, depending on whether the programmer can change the colors displayed by the terminal.

curses.init_color(color_number, r, g, b)

  Change the definition of a color, taking the number of the color to be changed followed by three RGB values (for the amounts of red, green, and blue components). The value of color_number must be between `0` and `COLORS - 1`. Each of r, g, b, must be a value between `0` and `1000`. When `init_color()` is used, all occurrences of that color on the screen immediately change to the new definition. This function is a no-op on most terminals; it is active only if `can_change_color()` returns `True`.

curses.color_content(color_number)

  Return the intensity of the red, green, and blue (RGB) components in the color color_number, which must be between `0` and `COLORS - 1`. Return a 3-tuple, containing the R,G,B values for the given color, which will be between `0` (no component) and `1000` (maximum amount of component). Raise an exception if the color is not supported.

curses.init_pair(pair_number, fg, bg)

  Change the definition of a color-pair. It takes three arguments: the number of the color-pair to be changed, the foreground color number, and the background color number. The value of pair_number must be between `1` and `COLOR_PAIRS - 1` (the `0` color pair can only be changed by `use_default_colors()` and `assume_default_colors()`). The value of fg and bg arguments must be between `0` and `COLORS - 1`, or, after calling `use_default_colors()` or `assume_default_colors()`, `-1`. If the color-pair was previously initialized, the screen is refreshed and all occurrences of that color-pair are changed to the new definition.

curses.pair_content(pair_number)

  Return a tuple `(fg, bg)` containing the colors for the requested color pair. The value of pair_number must be between `0` and `COLOR_PAIRS - 1`.

curses.color_pair(pair_number)

  Return the attribute value for displaying text in the specified color pair. Only color pairs that fit in the color-pair field of the returned value can be represented (usually the first 256); a larger pair_number raises `OverflowError` rather than being silently masked to a different pair. Use `color_set()` or `attr_set()` to display higher pairs. This attribute value can be combined with `A_STANDOUT`, `A_REVERSE`, and the other `A_*` attributes. `pair_number()` is the counterpart to this function.

curses.pair_number(attr)

  Return the number of the color-pair set by the attribute value attr. `color_pair()` is the counterpart to this function.

curses.use_default_colors()

  Equivalent to `assume_default_colors(-1, -1)`.

curses.assume_default_colors(fg, bg, /)

  Allow use of default values for colors on terminals supporting this feature. Use this to support transparency in your application.

  - Assign terminal default foreground/background colors to color number `-1`. So `init_pair(x, COLOR_RED, -1)` will initialize pair x as red on default background and `init_pair(x, -1, COLOR_BLUE)` will initialize pair x as default foreground on blue.

  - Change the definition of the color-pair `0` to `(fg, bg)`.

  This is an ncurses extension.

  Added in version 3.14.

curses.alloc_pair(fg, bg)

  Allocate a color pair for foreground color fg and background color bg, and return its number. If a color pair for the same combination of colors already exists, return its number. Otherwise allocate a new color pair and return its number.

  This function is only available if Python was built against a wide-character version of the underlying curses library with extended-color support (see `has_extended_color_support()`).

  Added in version 3.16.0a0 (unreleased).

curses.free_pair(pair_number)

  Free the color pair pair_number, which must have been allocated by `alloc_pair()`. The pair must not be in use.

  This function is only available if Python was built against a wide-character version of the underlying curses library with extended-color support (see `has_extended_color_support()`).

  Added in version 3.16.0a0 (unreleased).

curses.find_pair(fg, bg)

  Return the number of a color pair for foreground color fg and background color bg, or `-1` if no color pair for this combination of colors has been allocated.

  This function is only available if Python was built against a wide-character version of the underlying curses library with extended-color support (see `has_extended_color_support()`).

  Added in version 3.16.0a0 (unreleased).

curses.reset_color_pairs()

  Discard all color-pair definitions, releasing the color pairs allocated by `init_pair()` and `alloc_pair()`.

  This function is only available if Python was built against a wide-character version of the underlying curses library with extended-color support (see `has_extended_color_support()`).

  Added in version 3.16.0a0 (unreleased).

### Windows and pads

curses.newwin(nlines, ncols)
curses.newwin(nlines, ncols, begin_y, begin_x)

  Return a new window, whose left-upper corner is at `(begin_y, begin_x)`, and whose height/width is nlines/ncols.

  By default, the window will extend from the specified position to the lower right corner of the screen.

curses.newpad(nlines, ncols)

  Create and return a pointer to a new pad data structure with the given number of lines and columns. Return a pad as a window object.

  A pad is like a window, except that it is not restricted by the screen size, and is not necessarily associated with a particular part of the screen. Pads can be used when a large window is needed, and only a part of the window will be on the screen at one time. Automatic refreshes of pads (such as from scrolling or echoing of input) do not occur. The `refresh()` and `noutrefresh()` methods of a pad require 6 arguments to specify the part of the pad to be displayed and the location on the screen to be used for the display. The arguments are pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol; the p arguments refer to the upper-left corner of the pad region to be displayed and the s arguments define a clipping box on the screen within which the pad region is to be displayed.

### Soft labels

The following functions manage soft-label keys, a row of labels displayed along the bottom line of the screen, typically used to label a row of function keys. `slk_init()` must be called before `initscr()` or `newterm()`; it takes one screen line away from the standard window for the labels.

curses.slk_init(fmt=0)

  Reserve a screen line for the soft labels and choose their layout. fmt selects the arrangement: `0` for 3-2-3 (eight labels), `1` for 4-4 (eight labels). Where the underlying curses library supports them, `2` gives 4-4-4 (twelve labels) and `3` gives 4-4-4 with an index line.

  Must be called before `initscr()` or `newterm()`.

  Added in version 3.16.0a0 (unreleased).

curses.slk_set(labnum, label, justify)

  Set the text of soft label number labnum, in the range `1` through `8` (or `12` in a twelve-label layout). justify controls how label is placed within the label: `0` for left, `1` for centered, `2` for right.

  Added in version 3.16.0a0 (unreleased).

curses.slk_label(labnum)

  Return the current text of soft label number labnum, justified as it was set, or an empty string if it has no label.

  Added in version 3.16.0a0 (unreleased).

curses.slk_refresh()

  Update the soft labels on the physical screen, like `refresh()` for a window.

  Added in version 3.16.0a0 (unreleased).

curses.slk_noutrefresh()

  Update the soft labels on the virtual screen, like `window.noutrefresh()`. Use it together with `doupdate()` to batch screen updates.

  Added in version 3.16.0a0 (unreleased).

curses.slk_clear()

  Remove the soft labels from the screen.

  Added in version 3.16.0a0 (unreleased).

curses.slk_restore()

  Restore the soft labels to the screen after a `slk_clear()`.

  Added in version 3.16.0a0 (unreleased).

curses.slk_touch()

  Force all the soft labels to be redrawn by the next `slk_refresh()` or `slk_noutrefresh()`.

  Added in version 3.16.0a0 (unreleased).

curses.slk_attron(attr)
curses.slk_attroff(attr)
curses.slk_attrset(attr)

  Add, remove, or set the attributes used to display the soft labels, given as packed `A_*` attributes.

  Added in version 3.16.0a0 (unreleased).

curses.slk_attr()

  Return the current attributes of the soft labels as packed `A_*` attributes. Availability depends on the underlying curses library.

  Added in version 3.16.0a0 (unreleased).

curses.slk_attr_on(attr)
curses.slk_attr_off(attr)

  Turn the given attributes on or off without affecting any others. Like the `attr_*` window methods, these work with the WA_* attributes rather than packed `A_*` attributes.

  Added in version 3.16.0a0 (unreleased).

curses.slk_attr_set(attr, pair=0)

  Set the attributes and color pair of the soft labels. attr is given as WA_* attributes and pair as a color pair number.

  Added in version 3.16.0a0 (unreleased).

curses.slk_color(pair)

  Set the color pair of the soft labels to color pair number pair.

  Added in version 3.16.0a0 (unreleased).

### Saving and restoring

curses.getwin(file)

  Read window-related data stored in the file by an earlier `window.putwin()` call. The routine then creates and initializes a new window using that data, returning the new window object. The file argument must be a file object opened for reading in binary mode.

curses.scr_dump(filename)

  Write the current contents of the virtual screen to filename, which may be a string or a path-like object. The file can later be read by `scr_restore()`, `scr_init()` or `scr_set()`. This is the whole-screen counterpart of `window.putwin()`.

  Added in version 3.16.0a0 (unreleased).

curses.scr_restore(filename)

  Set the virtual screen to the contents of filename, which must have been written by `scr_dump()`. The next call to `doupdate()` or `window.refresh()` restores the screen to those contents.

  Added in version 3.16.0a0 (unreleased).

curses.scr_init(filename)

  Initialize the assumed contents of the terminal from filename, which must have been written by `scr_dump()`. Use it when the terminal already displays those contents, for example after another program has drawn the screen, so that curses does not redraw what is already there.

  Added in version 3.16.0a0 (unreleased).

curses.scr_set(filename)

  Use filename, which must have been written by `scr_dump()`, as both the virtual screen and the assumed terminal contents. This combines the effects of `scr_restore()` and `scr_init()`.

  Added in version 3.16.0a0 (unreleased).

### Querying the terminal

curses.baudrate()

  Return the output speed of the terminal in bits per second. On software terminal emulators it will have a fixed high value. Included for historical reasons; in former times, it was used to write output loops for time delays and occasionally to change interfaces depending on the line speed.

curses.erasechar()

  Return the user’s current erase character as a raw byte, a `bytes` object of length 1. See also `erasewchar()`.

curses.erasewchar()

  Return the user’s current erase character as a one-character `str`. Under Unix operating systems this is a property of the controlling tty of the curses program, and is not set by the curses library itself.

  Added in version 3.16.0a0 (unreleased).

curses.killchar()

  Return the user’s current line kill character as a raw byte, a `bytes` object of length 1. See also `killwchar()`.

curses.killwchar()

  Return the user’s current line kill character as a one-character `str`. Under Unix operating systems this is a property of the controlling tty of the curses program, and is not set by the curses library itself.

  Added in version 3.16.0a0 (unreleased).

curses.termname()

  Return the value of the environment variable `TERM`, as a bytes object, truncated to 14 characters.

curses.longname()

  Return a bytes object containing the terminfo long name field describing the current terminal. The maximum length of a verbose description is 128 characters. It is defined only after the call to `initscr()`.

curses.termattrs()

  Return a logical OR of all video attributes supported by the terminal. This information is useful when a curses program needs complete control over the appearance of the screen.

curses.term_attrs()

  Like `termattrs()`, but return the attributes as WA_* values rather than `A_*` values.

  Added in version 3.16.0a0 (unreleased).

curses.has_ic()

  Return `True` if the terminal has insert- and delete-character capabilities. This function is included for historical reasons only, as all modern software terminal emulators have such capabilities.

curses.has_il()

  Return `True` if the terminal has insert- and delete-line capabilities, or can simulate them using scrolling regions. This function is included for historical reasons only, as all modern software terminal emulators have such capabilities.

### Bell and screen flash

curses.beep()

  Emit a short attention sound.

curses.flash()

  Flash the screen. That is, change it to reverse-video and then change it back in a short interval. Some people prefer such as ‘visible bell’ to the audible attention signal produced by `beep()`.

### Terminal resizing

curses.resizeterm(nlines, ncols)

  Resize the standard and current windows to the specified dimensions, and adjusts other bookkeeping data used by the curses library that record the window dimensions (in particular the SIGWINCH handler).

curses.resize_term(nlines, ncols)

  Backend function used by `resizeterm()`, performing most of the work; when resizing the windows, `resize_term()` blank-fills the areas that are extended. The calling application should fill in these areas with appropriate data. The `resize_term()` function attempts to resize all windows. However, due to the calling convention of pads, it is not possible to resize these without additional interaction with the application.

curses.is_term_resized(nlines, ncols)

  Return `True` if `resize_term()` would modify the window structure, `False` otherwise.

curses.update_lines_cols()

  Update the `LINES` and `COLS` module variables. Useful for detecting manual screen resize.

  Added in version 3.5.

### Terminfo database

curses.setupterm(term=None, fd=-1)

  Initialize the terminal. term is a string giving the terminal name, or `None`; if omitted or `None`, the value of the `TERM` environment variable will be used. fd is the file descriptor to which any initialization sequences will be sent; if not supplied or `-1`, the file descriptor for `sys.stdout` will be used.

  Raise a `curses.error` if the terminal could not be found or its terminfo database entry could not be read. If the terminal has already been initialized, this function has no effect.

  Note

  Calling `initscr()` or `newterm()` after `setupterm()` leaks the terminal that `setupterm()` allocated: the curses library keeps only a single current terminal and does not free the previously allocated one.

curses.tigetflag(capname)

  Return the value of the Boolean capability corresponding to the terminfo capability name capname as an integer. Return the value `-1` if capname is not a Boolean capability, or `0` if it is canceled or absent from the terminal description.

  `setupterm()` (or `initscr()`) must be called first.

curses.tigetnum(capname)

  Return the value of the numeric capability corresponding to the terminfo capability name capname as an integer. Return the value `-2` if capname is not a numeric capability, or `-1` if it is canceled or absent from the terminal description.

  `setupterm()` (or `initscr()`) must be called first.

curses.tigetstr(capname)

  Return the value of the string capability corresponding to the terminfo capability name capname as a bytes object. Return `None` if capname is not a terminfo “string capability”, or is canceled or absent from the terminal description.

  `setupterm()` (or `initscr()`) must be called first.

curses.tparm(str[, ...])

  Instantiate the bytes object str with the supplied parameters, where str should be a parameterized string obtained from the terminfo database. For example, `tparm(tigetstr("cup"), 5, 3)` could result in `b'\033[6;4H'`, the exact result depending on terminal type. Up to nine integer parameters may be supplied.

  `setupterm()` (or `initscr()`) must be called first.

curses.putp(str)

  Equivalent to `tputs(str, 1, putchar)`; emit the value of a specified terminfo capability for the current terminal. Note that the output of `putp()` always goes to standard output.

  `setupterm()` (or `initscr()`) must be called first.

### Utilities

curses.unctrl(ch)

  Return a bytes object which is a printable representation of the character ch. ch cannot be a character that does not fit in a single byte; use `wunctrl()` for those.

curses.wunctrl(ch)

  Return a string which is a printable representation of the character ch; any attributes and color pair are ignored. ASCII control characters are represented as a caret followed by a character, for example as `'^C'`. Printing characters, including non-ASCII characters printable in the locale, are left as they are. The representation of other characters is defined by the underlying curses library.

  Added in version 3.16.0a0 (unreleased).

curses.filter()

  The `filter()` routine, if used, must be called before `initscr()` is called. The effect is that, during the initialization, `LINES` is set to `1`; the capabilities `clear`, `cup`, `cud`, `cud1`, `cuu1`, `cuu`, `vpa` are disabled; and the `home` string is set to the value of `cr`. The effect is that the cursor is confined to the current line, and so are screen updates. This may be used for enabling character-at-a-time line editing without touching the rest of the screen.

curses.nofilter()

  Undo the effect of a previous `filter()` call. Like `filter()`, it must be called before `initscr()` (or `newterm()`) so that the next initialization uses the full screen again.

  Availability: if the underlying curses library provides `nofilter()`.

  Added in version 3.16.0a0 (unreleased).

curses.use_env(flag)

  If used, this function should be called before `initscr()` or newterm are called. When flag is `False`, the values of lines and columns specified in the terminfo database will be used, even if environment variables `LINES` and `COLUMNS` (used by default) are set, or if curses is running in a window (in which case default behavior would be to use the window size if `LINES` and `COLUMNS` are not set).

curses.get_escdelay()

  Retrieves the value set by `set_escdelay()`.

  Added in version 3.9.

curses.set_escdelay(ms)

  Sets the number of milliseconds to wait after reading an escape character, to distinguish between an individual escape character entered on the keyboard from escape sequences sent by cursor and function keys.

  Added in version 3.9.

curses.get_tabsize()

  Retrieves the value set by `set_tabsize()`.

  Added in version 3.9.

curses.set_tabsize(size)

  Sets the number of columns used by the curses library when converting a tab character to spaces as it adds the tab to a window.

  Added in version 3.9.

curses.napms(ms)

  Sleep for ms milliseconds.

curses.delay_output(ms)

  Insert an ms millisecond pause in output.

## Window objects

class curses.window

  Window objects, as returned by `initscr()` and `newwin()` above, have the following methods and attributes:

### Adding and inserting text

window.addch(ch[, attr])
window.addch(y, x, ch[, attr])

  Paint character ch at `(y, x)` with attributes attr, overwriting any character previously painted at that location. By default, the character position and attributes are the current settings for the window object.

  ch may be a single character, optionally followed by combining characters, that together occupy one character cell.

  Note

  Writing outside the window, subwindow, or pad raises a `curses.error`. Attempting to write to the lower-right corner of a window, subwindow, or pad will cause an exception to be raised after the character is printed.

  Changed in version 3.16.0a0 (unreleased): A character may now be given as a string of a base character followed by combining characters, instead of only a single character, or as a `complexchar` cell.

window.addstr(str[, attr])
window.addstr(y, x, str[, attr])

  Paint the character string str at `(y, x)` with attributes attr, overwriting anything previously on the display.

  str may also be a `complexstr`, in which case each cell carries its own attributes and color pair, so attr must not be given. A `complexstr` obtained from `in_wchstr()` is written back unchanged.

  Note

  - Writing outside the window, subwindow, or pad raises `curses.error`. Attempting to write to the lower-right corner of a window, subwindow, or pad will cause an exception to be raised after the string is printed.

  - A bug in ncurses, the backend for this Python module, could cause segfaults when resizing windows. This was fixed in ncurses-6.1-20190511. If you are stuck with an earlier ncurses, you can avoid triggering it by not calling `addstr()` with a str that has embedded newlines; instead, call `addstr()` separately for each line.

  Changed in version 3.16.0a0 (unreleased): str may now also be a `complexstr`, as described above.

window.addnstr(str, n[, attr])
window.addnstr(y, x, str, n[, attr])

  Paint at most n characters of the character string str at `(y, x)` with attributes attr, overwriting anything previously on the display.

  Changed in version 3.16.0a0 (unreleased): str may now also be a `complexstr`; see `addstr()`.

window.echochar(ch[, attr])

  Add character ch with attribute attr, and immediately call `refresh()` on the window.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

window.insch(ch[, attr])
window.insch(y, x, ch[, attr])

  Insert character ch with attributes attr before the character under the cursor, or at `(y, x)` if specified. All characters to the right of the cursor are shifted one position right, with the rightmost character on the line being lost. The cursor position does not change.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

window.insstr(str[, attr])
window.insstr(y, x, str[, attr])

  Insert a character string (as many characters as will fit on the line) before the character under the cursor. All characters to the right of the cursor are shifted right, with the rightmost characters on the line being lost. The cursor position does not change (after moving to y, x, if specified).

  str may also be a `complexstr`, in which case each cell carries its own attributes and color pair, so attr must not be given.

  Changed in version 3.16.0a0 (unreleased): str may now also be a `complexstr`, as described above.

window.insnstr(str, n[, attr])
window.insnstr(y, x, str, n[, attr])

  Insert a character string (as many characters as will fit on the line) before the character under the cursor, up to n characters. If n is zero or negative, the entire string is inserted. All characters to the right of the cursor are shifted right, with the rightmost characters on the line being lost. The cursor position does not change (after moving to y, x, if specified).

  Changed in version 3.16.0a0 (unreleased): str may now also be a `complexstr`; see `insstr()`.

### Deleting and inserting lines

window.delch([y, x])

  Delete the character under the cursor, or at `(y, x)` if specified. All characters to the right on the same line are shifted one position left.

window.deleteln()

  Delete the line under the cursor. All following lines are moved up by one line.

window.insertln()

  Insert a blank line under the cursor. All following lines are moved down by one line.

window.insdelln(nlines)

  Insert nlines lines into the specified window above the current line. The nlines bottom lines are lost. For negative nlines, delete nlines lines starting with the one under the cursor, and move the remaining lines up. The bottom nlines lines are cleared. The current cursor position remains the same.

### Reading input

window.getch([y, x])

  Get a character. Note that the integer returned does not have to be in ASCII range: function keys, keypad keys and so on are represented by numbers higher than 255. In no-delay mode, return `-1` if there is no input, otherwise wait until a key is pressed. A multibyte character is returned as its encoded bytes one at a time; use `get_wch()` to read it as a single character.

window.get_wch([y, x])

  Get a wide character. Return a character for most keys, or an integer for function keys, keypad keys, and other special keys. Unlike `getch()`, an ordinary key is returned as a one-character `str`. In no-delay mode, raise an exception if there is no input.

  Added in version 3.3.

  Changed in version 3.16.0a0 (unreleased): Also available on a narrow build, where only a character representable as a single byte (an 8-bit locale) can be returned.

window.getkey([y, x])

  Get a character, returning a string instead of an integer, as `getch()` does. Function keys, keypad keys and other special keys return a multibyte string containing the key name. In no-delay mode, raise an exception if there is no input.

window.getstr()
window.getstr(n)
window.getstr(y, x)
window.getstr(y, x, n)

  Read a bytes object from the user, with primitive line editing capacity. At most n characters are read; n defaults to and cannot exceed 2047. A multibyte character is returned as its encoded bytes; use `get_wstr()` to read the input as a `str`.

  Changed in version 3.14: The maximum value for n was increased from 1023 to 2047.

window.get_wstr()
window.get_wstr(n)
window.get_wstr(y, x)
window.get_wstr(y, x, n)

  Read a string from the user, with primitive line editing capacity. Unlike `getstr()`, it can return characters that are not representable in the window’s encoding. At most n characters are read; n defaults to and cannot exceed 2047.

  Added in version 3.16.0a0 (unreleased).

window.getdelay()

  Return the window’s read timeout in milliseconds, as set by `nodelay()` or `timeout()`: `-1` for blocking, `0` for non-blocking, or a positive number of milliseconds.

  Added in version 3.16.0a0 (unreleased).

### Reading window contents

window.inch([y, x])

  Return the character at the given position in the window. The bottom 8 bits are the character proper and the upper bits are the attributes; extract them with the `A_CHARTEXT` and `A_ATTRIBUTES` bit-masks, and the color pair with `pair_number()`. The character byte is the locale-encoded byte of the cell’s character, consistent with `instr()`. It cannot represent a cell holding combining characters, a character that does not fit in a single byte, or a color pair outside the `color_pair()` range; use `in_wch()` for those, which returns it as a `complexchar`.

window.in_wch([y, x])

  Return the complex character at the given position in the window as a `complexchar`. Unlike `inch()`, the returned object carries the cell’s text (a spacing character optionally followed by combining characters) together with its attributes and color pair.

  Added in version 3.16.0a0 (unreleased).

window.instr([n])
window.instr(y, x[, n])

  Return a bytes object of characters, extracted from the window starting at the current cursor position, or at y, x if specified, and stopping at the end of the line. Attributes and color information are stripped from the characters. If n is specified, `instr()` returns a string at most n characters long (exclusive of the trailing NUL). The maximum value for n is 2047. A character not representable in the window’s encoding cannot be returned; use `in_wstr()` for those.

  Changed in version 3.14: The maximum value for n was increased from 1023 to 2047.

window.in_wstr([n])
window.in_wstr(y, x[, n])

  Return a string of characters, extracted from the window starting at the current cursor position, or at y, x if specified. Unlike `instr()`, it can return characters that are not representable in the window’s encoding. Attributes and color information are stripped from the characters. The maximum value for n is 2047.

  Added in version 3.16.0a0 (unreleased).

window.in_wchstr([n])
window.in_wchstr(y, x[, n])

  Return a `complexstr` of the styled cells extracted from the window starting at the current cursor position, or at y, x if specified, and stopping at the end of the line. This is the variant of `instr()` and `in_wstr()` that keeps each cell’s attributes and color pair (those methods strip the rendition). If n is specified, at most n cells are returned. The maximum value for n is 2047.

  The result can be written back unchanged with `addstr()` (a read and a re-write is a round-trip that preserves every cell’s rendition).

  Added in version 3.16.0a0 (unreleased).

### Attributes

window.attroff(attr)

  Remove attribute attr from the “background” set applied to all writes to the current window.

window.attron(attr)

  Add attribute attr to the “background” set applied to all writes to the current window.

window.attrset(attr)

  Set the “background” set of attributes to attr. This set is initially `0` (no attributes).

window.attr_get()

  Return the window’s current rendition as a `(attrs, pair)` tuple, where attrs is the set of attributes and pair is the color pair number.

  Unlike `attron()` and friends, which take packed `A_*` attributes, this method and the other `attr_*` methods work with the WA_* attributes and keep the color pair as a separate number, which lets them use color pairs that do not fit alongside the attributes in a single value.

  Added in version 3.16.0a0 (unreleased).

window.attr_set(attr, pair=0)

  Set the window’s rendition to the attributes attr and the color pair pair.

  Added in version 3.16.0a0 (unreleased).

window.attr_on(attr)

  Turn on the attributes attr without affecting any others.

  Added in version 3.16.0a0 (unreleased).

window.attr_off(attr)

  Turn off the attributes attr without affecting any others.

  Added in version 3.16.0a0 (unreleased).

window.color_set(pair)

  Set the window’s color pair to pair, leaving the other attributes unchanged.

  Added in version 3.16.0a0 (unreleased).

window.getattrs()

  Return the window’s current attributes.

  Added in version 3.16.0a0 (unreleased).

window.standout()

  Turn on attribute A_STANDOUT.

window.standend()

  Turn off the standout attribute. On some terminals this has the side effect of turning off all attributes.

window.chgat(attr)
window.chgat(num, attr)
window.chgat(y, x, attr)
window.chgat(y, x, num, attr)

  Set the attributes of num characters at the current cursor position, or at position `(y, x)` if supplied. If num is not given or is `-1`, the attribute will be set on all the characters to the end of the line. This function moves cursor to position `(y, x)` if supplied. The changed line will be touched using the `touchline()` method so that the contents will be redisplayed by the next window refresh.

### Background

window.bkgd(ch[, attr])

  Set the background property of the window to the character ch, with attributes attr. The change is then applied to every character position in that window:

  - The attribute of every character in the window is changed to the new background attribute.

  - Wherever the former background character appears, it is changed to the new background character.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

window.bkgdset(ch[, attr])

  Set the window’s background. A window’s background consists of a character and any combination of attributes. The attribute part of the background is combined (OR’ed) with all non-blank characters that are written into the window. Both the character and attribute parts of the background are combined with the blank characters. The background becomes a property of the character and moves with the character through any scrolling and insert/delete line/character operations.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

window.getbkgd()

  Return the given window’s current background character/attribute pair. Its components can be extracted like those of `inch()`. It cannot represent a background set with a wide character or with a color pair outside the `color_pair()` range; use `getbkgrnd()` for those.

window.getbkgrnd()

  Return the given window’s current background as a `complexchar`. Unlike `getbkgd()`, the returned object carries the background character together with its attributes and color pair, and the color pair is not limited to the value that fits in a `color_pair()`.

  Added in version 3.16.0a0 (unreleased).

### Clearing and erasing

window.erase()

  Clear the window.

window.clear()

  Like `erase()`, but also cause the whole window to be repainted upon next call to `refresh()`.

window.clrtobot()

  Erase from cursor to the end of the window: all lines below the cursor are deleted, and then the equivalent of `clrtoeol()` is performed.

window.clrtoeol()

  Erase from cursor to the end of the line.

### Borders and lines

window.border([ls[, rs[, ts[, bs[, tl[, tr[, bl[, br]]]]]]]])

  Draw a border around the edges of the window. Each parameter specifies the character to use for a specific part of the border; see the table below for more details.

  Note

  A `0` value for any parameter will cause the default character to be used for that parameter. Keyword parameters can not be used. The defaults are listed in this table:

  Parameter | Description | Default value
  --- | --- | ---
  ls | Left side | `ACS_VLINE`
  rs | Right side | `ACS_VLINE`
  ts | Top | `ACS_HLINE`
  bs | Bottom | `ACS_HLINE`
  tl | Upper-left corner | `ACS_ULCORNER`
  tr | Upper-right corner | `ACS_URCORNER`
  bl | Bottom-left corner | `ACS_LLCORNER`
  br | Bottom-right corner | `ACS_LRCORNER`

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted. A single call cannot mix them with integer or byte characters.

window.box([vertch, horch])

  Similar to `border()`, but both ls and rs are vertch and both ts and bs are horch. The default corner characters are always used by this function.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted. A single call cannot mix them with integer or byte characters.

window.hline(ch, n[, attr])
window.hline(y, x, ch, n[, attr])

  Display a horizontal line starting at `(y, x)` with length n consisting of the character ch with attributes attr. The line stops at the right edge of the window if fewer than n cells are available.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

window.vline(ch, n[, attr])
window.vline(y, x, ch, n[, attr])

  Display a vertical line starting at `(y, x)` with length n consisting of the character ch with attributes attr.

  Changed in version 3.16.0a0 (unreleased): Wide and combining characters, and `complexchar` cells, are now accepted.

### Cursor position and window geometry

window.move(new_y, new_x)

  Move cursor to `(new_y, new_x)`.

window.getyx()

  Return a tuple `(y, x)` of current cursor position relative to the window’s upper-left corner.

window.getbegyx()

  Return a tuple `(y, x)` of coordinates of upper-left corner.

window.getmaxyx()

  Return a tuple `(y, x)` of the height and width of the window.

window.getparyx()

  Return the beginning coordinates of this window relative to its parent window as a tuple `(y, x)`. Return `(-1, -1)` if this window has no parent.

window.getparent()

  Return the parent window of this subwindow, or `None` if this window is not a subwindow.

  Added in version 3.16.0a0 (unreleased).

### Creating and resizing windows

window.subwin(begin_y, begin_x)
window.subwin(nlines, ncols, begin_y, begin_x)

  Return a sub-window, whose upper-left corner is at the screen-relative coordinates `(begin_y, begin_x)`, and whose width/height is ncols/nlines.

  By default, the sub-window will extend from the specified position to the lower right corner of the window.

window.derwin(begin_y, begin_x)
window.derwin(nlines, ncols, begin_y, begin_x)

  An abbreviation for “derive window”, `derwin()` is the same as calling `subwin()`, except that begin_y and begin_x are relative to the origin of the window, rather than relative to the entire screen. Return a window object for the derived window.

window.subpad(begin_y, begin_x)
window.subpad(nlines, ncols, begin_y, begin_x)

  Return a sub-pad, whose upper-left corner is at `(begin_y, begin_x)`, and whose width/height is ncols/nlines. The coordinates are relative to the parent pad (unlike `subwin()`, which uses screen coordinates). This method is only available for pads created with `newpad()`.

window.dupwin()

  Return a new window that is an exact duplicate of the window: it has the same size, position, contents and attributes. Unlike a window created by `subwin()` or `derwin()`, the duplicate is independent of the original – it has its own cell buffer, so later changes to one do not affect the other.

  Added in version 3.16.0a0 (unreleased).

window.mvwin(new_y, new_x)

  Move the window so its upper-left corner is at `(new_y, new_x)`.

  Moving the window so that any part of it would be off the screen is an error: the window is not moved and `curses.error` is raised.

window.mvderwin(y, x)

  Move the window inside its parent window. The screen-relative parameters of the window are not changed. This routine is used to display different parts of the parent window at the same physical position on the screen.

window.resize(nlines, ncols)

  Reallocate storage for a curses window to adjust its dimensions to the specified values. If either dimension is larger than the current values, the window’s data is filled with blanks that have the current background rendition (as set by `bkgdset()`) merged into them.

### Refreshing and redrawing

window.refresh([pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol])

  Update the display immediately (sync actual screen with previous drawing/deleting methods).

  The 6 arguments can only be specified, and are then required, when the window is a pad created with `newpad()`. The additional parameters are needed to indicate what part of the pad and screen are involved. pminrow and pmincol specify the upper-left corner of the rectangle to be displayed in the pad. sminrow, smincol, smaxrow, and smaxcol specify the edges of the rectangle to be displayed on the screen. The lower-right corner of the rectangle to be displayed in the pad is calculated from the screen coordinates, since the rectangles must be the same size. Both rectangles must be entirely contained within their respective structures. Negative values of pminrow, pmincol, sminrow, or smincol are treated as if they were zero.

window.noutrefresh()
window.noutrefresh(pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol)

  Mark for refresh but wait. This function updates the data structure representing the desired state of the window, but does not force an update of the physical screen. To accomplish that, call `doupdate()`.

  The 6 arguments can only be specified, and are then required, when the window is a pad created with `newpad()`; they have the same meaning as for `refresh()`.

window.redrawln(beg, num)

  Indicate that the num screen lines, starting at line beg, are corrupted and should be completely redrawn on the next `refresh()` call.

window.redrawwin()

  Touch the entire window, causing it to be completely redrawn on the next `refresh()` call.

### Output options

window.clearok(flag)

  If flag is `True`, the next call to `refresh()` will clear the window completely.

window.idlok(flag)

  If flag is `True`, `curses` will try to use hardware line editing facilities. Otherwise, curses will not use them.

window.idcok(flag)

  If flag is `False`, curses no longer considers using the hardware insert/delete character feature of the terminal; if flag is `True`, use of character insertion and deletion is enabled. When curses is first initialized, use of character insert/delete is enabled by default.

window.immedok(flag)

  If flag is `True`, any change in the window image automatically causes the window to be refreshed; you no longer have to call `refresh()` yourself. However, it may degrade performance considerably, due to repeated calls to wrefresh. This option is disabled by default.

window.leaveok(flag)

  If flag is `True`, cursor is left where it is on update, instead of being at “cursor position.” This reduces cursor movement where possible.

  If flag is `False`, cursor will always be at “cursor position” after an update.

window.scrollok(flag)

  Control what happens when the cursor of a window is moved off the edge of the window or scrolling region, either as a result of a newline action on the bottom line, or typing the last character of the last line. If flag is `False`, the cursor is left on the bottom line. If flag is `True`, the window is scrolled up one line. Note that in order to get the physical scrolling effect on the terminal, it is also necessary to call `idlok()`.

window.scroll([lines=1])

  Scroll the screen or scrolling region. Scroll upward by lines lines if lines is positive, or downward if it is negative. Scrolling has no effect unless it has been enabled for the window with `scrollok()`.

window.setscrreg(top, bottom)

  Set the scrolling region from line top to line bottom. All scrolling actions will take place in this region.

window.getscrreg()

  Return a tuple `(top, bottom)` of the window’s current scrolling region, as set by `setscrreg()`.

  Added in version 3.16.0a0 (unreleased).

window.syncok(flag)

  If flag is `True`, then `syncup()` is called automatically whenever there is a change in the window.

### Input options

window.keypad(flag)

  If flag is `True`, escape sequences generated by some keys (keypad, function keys) will be interpreted by `curses`. If flag is `False`, escape sequences will be left as is in the input stream.

window.nodelay(flag)

  If flag is `True`, `getch()` will be non-blocking.

window.notimeout(flag)

  If flag is `True`, escape sequences will not be timed out.

  If flag is `False`, after a few milliseconds, an escape sequence will not be interpreted, and will be left in the input stream as is.

window.timeout(delay)

  Set blocking or non-blocking read behavior for the window. If delay is negative, blocking read is used (which will wait indefinitely for input). If delay is zero, then non-blocking read is used, and `getch()` will return `-1` if no input is waiting. If delay is positive, then `getch()` will block for delay milliseconds, and return `-1` if there is still no input at the end of that time.

### Overlapping and touch

window.overlay(destwin[, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol])

  Overlay the window on top of destwin. The windows need not be the same size, only the overlapping region is copied. This copy is non-destructive, which means that the current background character does not overwrite the old contents of destwin.

  To get fine-grained control over the copied region, the second form of `overlay()` can be used. sminrow and smincol are the upper-left coordinates of the source window, and the other variables mark a rectangle in the destination window.

window.overwrite(destwin[, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol])

  Overwrite the window on top of destwin. The windows need not be the same size, in which case only the overlapping region is copied. This copy is destructive, which means that the current background character overwrites the old contents of destwin.

  To get fine-grained control over the copied region, the second form of `overwrite()` can be used. sminrow and smincol are the upper-left coordinates of the source window, the other variables mark a rectangle in the destination window.

window.touchline(start, count[, changed])

  Pretend count lines have been changed, starting with line start. If changed is supplied, it specifies whether the affected lines are marked as having been changed (changed`=True`) or unchanged (changed`=False`).

window.touchwin()

  Pretend the whole window has been changed, for purposes of drawing optimizations.

window.untouchwin()

  Mark all lines in the window as unchanged since the last call to `refresh()`.

window.syncup()

  Touch all locations in ancestors of the window that have been changed in the window.

window.syncdown()

  Touch each location in the window that has been touched in any of its ancestor windows. This routine is called by `refresh()`, so it should almost never be necessary to call it manually.

window.cursyncup()

  Update the current cursor position of all the ancestors of the window to reflect the current cursor position of the window.

### Coordinate conversion

window.enclose(y, x)

  Test whether the given pair of screen-relative character-cell coordinates are enclosed by the given window, returning `True` or `False`. It is useful for determining what subset of the screen windows enclose the location of a mouse event.

  Changed in version 3.10: Previously it returned `1` or `0` instead of `True` or `False`.

window.mouse_trafo(y, x, to_screen)

  Convert between window-relative and screen-relative (`stdscr`-relative) character-cell coordinates. If to_screen is true, convert the window-relative coordinates y, x to screen-relative coordinates; otherwise convert in the opposite direction. The two coordinate systems differ when lines are reserved on the screen, for example for soft labels.

  Return the converted coordinates as a `(y, x)` tuple, or `None` if they lie outside the window.

  Added in version 3.16.0a0 (unreleased).

### Other

window.encoding

  Encoding used to encode method arguments (Unicode strings and characters). The encoding attribute is inherited from the parent window when a subwindow is created, for example with `window.subwin()`. By default, current locale encoding is used (see `locale.getencoding()`).

  Added in version 3.3.

window.putwin(file)

  Write all data associated with the window into the provided file object. This information can be later retrieved using the `getwin()` function.

window.use(func, /, *args, **kwargs)

  Call `func(window, *args, **kwargs)` with the lock of the window held, and return its result. This provides automatic protection for the window against concurrent access from another thread.

  Availability: if the underlying curses library provides `use_window()`.

  Added in version 3.16.0a0 (unreleased).

### State queries

window.is_cleared()

  Return the current value set by `clearok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_idcok()

  Return the current value set by `idcok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_idlok()

  Return the current value set by `idlok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_immedok()

  Return the current value set by `immedok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_keypad()

  Return the current value set by `keypad()`.

  Added in version 3.16.0a0 (unreleased).

window.is_leaveok()

  Return the current value set by `leaveok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_linetouched(line)

  Return `True` if the specified line was modified since the last call to `refresh()`; otherwise return `False`. Raise a `curses.error` exception if line is not valid for the given window.

window.is_nodelay()

  Return the current value set by `nodelay()`.

  Added in version 3.16.0a0 (unreleased).

window.is_notimeout()

  Return the current value set by `notimeout()`.

  Added in version 3.16.0a0 (unreleased).

window.is_pad()

  Return `True` if the window is a pad created by `newpad()`.

  Added in version 3.16.0a0 (unreleased).

window.is_scrollok()

  Return the current value set by `scrollok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_subwin()

  Return `True` if the window is a subwindow created by `subwin()` or `derwin()`.

  Added in version 3.16.0a0 (unreleased).

window.is_syncok()

  Return the current value set by `syncok()`.

  Added in version 3.16.0a0 (unreleased).

window.is_wintouched()

  Return `True` if the specified window was modified since the last call to `refresh()`; otherwise return `False`.

## Screen objects

class curses.screen

  A screen object represents a terminal initialized by `newterm()` (or `new_prescr()`), in addition to the default screen created by `initscr()`. Screen objects are returned by those functions; they cannot be instantiated directly.

  A screen is freed automatically once it is no longer referenced, either directly or through one of its windows. Each window keeps its screen alive, so a screen remains valid as long as any of its windows does.

  Added in version 3.16.0a0 (unreleased).

screen.close()

  Detach the screen’s standard window, breaking the reference cycle between them so the screen can be reclaimed promptly instead of waiting for a garbage collection. Afterwards `stdscr` is `None` and the window it returned earlier can no longer be used. The screen’s resources are released once it and all its windows are no longer referenced.

  Added in version 3.16.0a0 (unreleased).

screen.stdscr

  The standard window of the screen, covering the whole terminal, or `None` for a screen created by `new_prescr()`.

screen.use(func, /, *args, **kwargs)

  Call `func(screen, *args, **kwargs)` with the lock of the screen held, and return its result. This provides automatic protection for the screen against concurrent access from another thread.

  Availability: if the underlying curses library provides `use_screen()`.

  Added in version 3.16.0a0 (unreleased).

## Complex character objects

class curses.complexchar(text, /, attr=0, pair=0)

  A complex character (or complexchar) is an immutable styled character cell: a spacing character optionally followed by combining characters, together with a set of attributes and a color pair.

  text is the cell’s text, attr a combination of the WA_* attributes (equivalent to the matching `A_*` constants), and pair a color pair number. Unlike the packed `chtype` used by `inch()` and the `A_*` methods, the color pair is stored separately and is not limited to the value that fits in a `color_pair()`.

  Complex characters are returned by `window.in_wch()` and `window.getbkgrnd()`, and are accepted (along with an integer, a byte or a string) by the character-cell methods such as `window.addch()`, `window.insch()`, `window.bkgd()`, `window.border()`, `window.hline()` and `window.vline()`. A complex character already carries its own rendition, so it cannot be combined with an explicit attr argument.

  `str()` returns the cell’s text; two complex characters are equal when their text, attributes and color pair all match.

  The same code works on both wide- and narrow-character builds. On a narrow build a cell holds a single character (no combining marks) that must encode to one byte in the window’s encoding (8-bit locales only), and pair is limited to the value that fits in a `color_pair()`.

  attr

    The attributes of the character cell (read-only).

  pair

    The color pair number of the character cell (read-only).

  Added in version 3.16.0a0 (unreleased).

class curses.complexstr(cells[, attr[, pair]])

  A complex character string (or complexstr) is an immutable sequence of styled character cells – the string counterpart of `complexchar` (as `str` is to a single character).

  If cells is a string, it is split into character cells (each a spacing character optionally followed by combining characters), and attr (a combination of the WA_* attributes) and pair (a color pair number), if given, are applied to every cell.

  Otherwise cells is an iterable whose items are themselves cells, each a `complexchar` or a string; each item then carries its own rendition, and attr and pair must be omitted.

  It is returned by `window.in_wchstr()`, and accepted by `window.addstr()`, `addnstr()`, `insstr()` and `insnstr()`, so a run read from a window can be written back unchanged.

  It behaves like an immutable sequence: `len(s)` is the number of cells, `s[i]` is the i-th cell as a `complexchar`, slicing and concatenation produce new `complexstr` instances, and iterating yields the cells. `str()` returns the cells’ text joined together, and two complex character strings are equal when their cells all match. It is hashable.

  To build or edit a run of cells, use an ordinary `list` of `complexchar` (or strings); a `complexstr` is the immutable form returned by a read.

  Like `complexchar`, this type works on both wide- and narrow-character builds, with the same per-cell limitations on a narrow build.

  Added in version 3.16.0a0 (unreleased).

## Constants

### General

The `curses` module defines the following data members:

curses.ERR

  Some curses routines that return an integer, such as `getch()`, return `ERR` upon failure.

curses.OK

  Some curses routines that return an integer, such as `napms()`, return `OK` upon success.

curses.version

  A bytes object representing the current version of the module.

curses.ncurses_version

  A named tuple containing the three components of the ncurses library version: major, minor, and patch. All values are integers. The components can also be accessed by name, so `curses.ncurses_version[0]` is equivalent to `curses.ncurses_version.major` and so on.

  Availability: if the ncurses library is used.

  Added in version 3.8.

curses.COLORS

  The maximum number of colors the terminal can support. It is defined only after the call to `start_color()`.

curses.COLOR_PAIRS

  The maximum number of color pairs the terminal can support. It is defined only after the call to `start_color()`.

curses.COLS

  The width of the screen, that is, the number of columns. It is defined only after the call to `initscr()`. Updated by `update_lines_cols()`, `resizeterm()` and `resize_term()`.

curses.LINES

  The height of the screen, that is, the number of lines. It is defined only after the call to `initscr()`. Updated by `update_lines_cols()`, `resizeterm()` and `resize_term()`.

### Attributes

Some constants are available to specify character cell attributes. The exact constants available are system dependent.

Attribute | Meaning
--- | ---
curses.A_ALTCHARSET | Alternate character set mode
curses.A_BLINK | Blink mode
curses.A_BOLD | Bold mode
curses.A_DIM | Dim mode
curses.A_INVIS | Invisible or blank mode
curses.A_ITALIC | Italic mode
curses.A_NORMAL | Normal attribute
curses.A_PROTECT | Protected mode
curses.A_REVERSE | Reverse background and foreground colors
curses.A_STANDOUT | Standout mode
curses.A_UNDERLINE | Underline mode
curses.A_HORIZONTAL | Horizontal highlight
curses.A_LEFT | Left highlight
curses.A_LOW | Low highlight
curses.A_RIGHT | Right highlight
curses.A_TOP | Top highlight
curses.A_VERTICAL | Vertical highlight

Added in version 3.7: `A_ITALIC` was added.

The `attr_get()`, `attr_set()`, `attr_on()` and `attr_off()` methods use a parallel set of `WA_*` constants. These have the same meaning as the corresponding `A_*` attributes above (`WA_BOLD` like `A_BOLD`, and so on), but belong to the `attr_t` type rather than being packed into a character. In ncurses the two sets share the same values, but other curses implementations may give them different ones, so use the `WA_*` constants with the `attr_*` methods. The available names are `WA_ATTRIBUTES`, `WA_NORMAL`, `WA_STANDOUT`, `WA_UNDERLINE`, `WA_REVERSE`, `WA_BLINK`, `WA_DIM`, `WA_BOLD`, `WA_ALTCHARSET`, `WA_INVIS`, `WA_PROTECT`, `WA_HORIZONTAL`, `WA_LEFT`, `WA_LOW`, `WA_RIGHT`, `WA_TOP`, `WA_VERTICAL` and `WA_ITALIC` (each available only where the platform defines it).

Added in version 3.16.0a0 (unreleased): The `WA_*` constants were added.

Several constants are available to extract corresponding attributes returned by some methods.

Bit-mask | Meaning
--- | ---
curses.A_ATTRIBUTES | Bit-mask to extract attributes
curses.A_CHARTEXT | Bit-mask to extract a character
curses.A_COLOR | Bit-mask to extract color-pair field information

### Keys

Keys are referred to by integer constants with names starting with `KEY_`. The exact keycaps available are system dependent.

Key constant | Key
--- | ---
curses.KEY_MIN | Minimum key value
curses.KEY_BREAK | Break key (unreliable)
curses.KEY_DOWN | Down-arrow
curses.KEY_UP | Up-arrow
curses.KEY_LEFT | Left-arrow
curses.KEY_RIGHT | Right-arrow
curses.KEY_HOME | Home key (upward+left arrow)
curses.KEY_BACKSPACE | Backspace (unreliable)
curses.KEY_F0 | Function keys. Up to 64 function keys are supported.
curses.KEY_Fn | Value of function key n
curses.KEY_DL | Delete line
curses.KEY_IL | Insert line
curses.KEY_DC | Delete character
curses.KEY_IC | Insert char or enter insert mode
curses.KEY_EIC | Exit insert char mode
curses.KEY_CLEAR | Clear screen
curses.KEY_EOS | Clear to end of screen
curses.KEY_EOL | Clear to end of line
curses.KEY_SF | Scroll 1 line forward
curses.KEY_SR | Scroll 1 line backward (reverse)
curses.KEY_NPAGE | Next page
curses.KEY_PPAGE | Previous page
curses.KEY_STAB | Set tab
curses.KEY_CTAB | Clear tab
curses.KEY_CATAB | Clear all tabs
curses.KEY_ENTER | Enter or send (unreliable)
curses.KEY_SRESET | Soft (partial) reset (unreliable)
curses.KEY_RESET | Reset or hard reset (unreliable)
curses.KEY_PRINT | Print
curses.KEY_LL | Home down or bottom (lower left)
curses.KEY_A1 | Upper left of keypad
curses.KEY_A3 | Upper right of keypad
curses.KEY_B2 | Center of keypad
curses.KEY_C1 | Lower left of keypad
curses.KEY_C3 | Lower right of keypad
curses.KEY_BTAB | Back tab
curses.KEY_BEG | Beg (beginning)
curses.KEY_CANCEL | Cancel
curses.KEY_CLOSE | Close
curses.KEY_COMMAND | Cmd (command)
curses.KEY_COPY | Copy
curses.KEY_CREATE | Create
curses.KEY_END | End
curses.KEY_EXIT | Exit
curses.KEY_FIND | Find
curses.KEY_HELP | Help
curses.KEY_MARK | Mark
curses.KEY_MESSAGE | Message
curses.KEY_MOVE | Move
curses.KEY_NEXT | Next
curses.KEY_OPEN | Open
curses.KEY_OPTIONS | Options
curses.KEY_PREVIOUS | Prev (previous)
curses.KEY_REDO | Redo
curses.KEY_REFERENCE | Ref (reference)
curses.KEY_REFRESH | Refresh
curses.KEY_REPLACE | Replace
curses.KEY_RESTART | Restart
curses.KEY_RESUME | Resume
curses.KEY_SAVE | Save
curses.KEY_SBEG | Shifted Beg (beginning)
curses.KEY_SCANCEL | Shifted Cancel
curses.KEY_SCOMMAND | Shifted Command
curses.KEY_SCOPY | Shifted Copy
curses.KEY_SCREATE | Shifted Create
curses.KEY_SDC | Shifted Delete char
curses.KEY_SDL | Shifted Delete line
curses.KEY_SELECT | Select
curses.KEY_SEND | Shifted End
curses.KEY_SEOL | Shifted Clear line
curses.KEY_SEXIT | Shifted Exit
curses.KEY_SFIND | Shifted Find
curses.KEY_SHELP | Shifted Help
curses.KEY_SHOME | Shifted Home
curses.KEY_SIC | Shifted Input
curses.KEY_SLEFT | Shifted Left arrow
curses.KEY_SMESSAGE | Shifted Message
curses.KEY_SMOVE | Shifted Move
curses.KEY_SNEXT | Shifted Next
curses.KEY_SOPTIONS | Shifted Options
curses.KEY_SPREVIOUS | Shifted Prev
curses.KEY_SPRINT | Shifted Print
curses.KEY_SREDO | Shifted Redo
curses.KEY_SREPLACE | Shifted Replace
curses.KEY_SRIGHT | Shifted Right arrow
curses.KEY_SRSUME | Shifted Resume
curses.KEY_SSAVE | Shifted Save
curses.KEY_SSUSPEND | Shifted Suspend
curses.KEY_SUNDO | Shifted Undo
curses.KEY_SUSPEND | Suspend
curses.KEY_UNDO | Undo
curses.KEY_MOUSE | Mouse event has occurred
curses.KEY_RESIZE | Terminal resize event
curses.KEY_MAX | Maximum key value

On VT100s and their software emulations, such as X terminal emulators, there are normally at least four function keys (`KEY_F1`, `KEY_F2`, `KEY_F3`, `KEY_F4`) available, and the arrow keys mapped to `KEY_UP`, `KEY_DOWN`, `KEY_LEFT` and `KEY_RIGHT` in the obvious way. If your machine has a PC keyboard, it is safe to expect arrow keys and twelve function keys (older PC keyboards may have only ten function keys); also, the following keypad mappings are standard:

Keycap | Constant
--- | ---
`Insert` | KEY_IC
`Delete` | KEY_DC
`Home` | KEY_HOME
`End` | KEY_END
`Page Up` | KEY_PPAGE
`Page Down` | KEY_NPAGE

### Alternate character set

The following table lists characters from the alternate character set. These are inherited from the VT100 terminal, and will generally be available on software emulations such as X terminals. When there is no graphic available, curses falls back on a crude printable ASCII approximation.

Note

These are available only after `initscr()` has been called.

ACS code | Meaning
--- | ---
curses.ACS_BBSS | alternate name for upper-right corner
curses.ACS_BLOCK | solid square block
curses.ACS_BOARD | board of squares
curses.ACS_BSBS | alternate name for horizontal line
curses.ACS_BSSB | alternate name for upper-left corner
curses.ACS_BSSS | alternate name for top tee
curses.ACS_BTEE | bottom tee
curses.ACS_BULLET | bullet
curses.ACS_CKBOARD | checker board (stipple)
curses.ACS_DARROW | arrow pointing down
curses.ACS_DEGREE | degree symbol
curses.ACS_DIAMOND | diamond
curses.ACS_GEQUAL | greater-than-or-equal-to
curses.ACS_HLINE | horizontal line
curses.ACS_LANTERN | lantern symbol
curses.ACS_LARROW | left arrow
curses.ACS_LEQUAL | less-than-or-equal-to
curses.ACS_LLCORNER | lower-left corner
curses.ACS_LRCORNER | lower-right corner
curses.ACS_LTEE | left tee
curses.ACS_NEQUAL | not-equal sign
curses.ACS_PI | letter pi
curses.ACS_PLMINUS | plus-or-minus sign
curses.ACS_PLUS | big plus sign
curses.ACS_RARROW | right arrow
curses.ACS_RTEE | right tee
curses.ACS_S1 | scan line 1
curses.ACS_S3 | scan line 3
curses.ACS_S7 | scan line 7
curses.ACS_S9 | scan line 9
curses.ACS_SBBS | alternate name for lower-right corner
curses.ACS_SBSB | alternate name for vertical line
curses.ACS_SBSS | alternate name for right tee
curses.ACS_SSBB | alternate name for lower-left corner
curses.ACS_SSBS | alternate name for bottom tee
curses.ACS_SSSB | alternate name for left tee
curses.ACS_SSSS | alternate name for crossover or big plus
curses.ACS_STERLING | pound sterling
curses.ACS_TTEE | top tee
curses.ACS_UARROW | up arrow
curses.ACS_ULCORNER | upper-left corner
curses.ACS_URCORNER | upper-right corner
curses.ACS_VLINE | vertical line

### Mouse buttons

The following table lists mouse button constants used by `getmouse()`:

Mouse button constant | Meaning
--- | ---
curses.BUTTONn_PRESSED | Mouse button n pressed
curses.BUTTONn_RELEASED | Mouse button n released
curses.BUTTONn_CLICKED | Mouse button n clicked
curses.BUTTONn_DOUBLE_CLICKED | Mouse button n double clicked
curses.BUTTONn_TRIPLE_CLICKED | Mouse button n triple clicked
curses.BUTTON_SHIFT | Shift was down during button state change
curses.BUTTON_CTRL | Control was down during button state change
curses.BUTTON_ALT | Alt was down during button state change

Changed in version 3.10: The `BUTTON5_*` constants are now exposed if they are provided by the underlying curses library.

### Colors

The following table lists the predefined colors:

Constant | Color
--- | ---
curses.COLOR_BLACK | Black
curses.COLOR_BLUE | Blue
curses.COLOR_CYAN | Cyan (light greenish blue)
curses.COLOR_GREEN | Green
curses.COLOR_MAGENTA | Magenta (purplish red)
curses.COLOR_RED | Red
curses.COLOR_WHITE | White
curses.COLOR_YELLOW | Yellow

# `curses.textpad` — Text input widget for curses programs

The `curses.textpad` module provides a `Textbox` class that handles elementary text editing in a curses window, supporting a set of keybindings resembling those of Emacs (thus, also of Netscape Navigator, BBedit 6.x, FrameMaker, and many other programs). The module also provides a rectangle-drawing function useful for framing text boxes or for other purposes.

The module `curses.textpad` defines the following function:

curses.textpad.rectangle(win, uly, ulx, lry, lrx)

  Draw a rectangle. The first argument must be a window object; the remaining arguments are coordinates relative to that window. The second and third arguments are the y and x coordinates of the upper-left corner of the rectangle to be drawn; the fourth and fifth arguments are the y and x coordinates of the lower-right corner. The rectangle will be drawn using VT100/IBM PC forms characters on terminals that make this possible (including xterm and most other software terminal emulators). Otherwise it will be drawn with ASCII dashes, vertical bars, and plus signs.

## Textbox objects

You can instantiate a `Textbox` object as follows:

class curses.textpad.Textbox(win, insert_mode=False)

  Return a textbox widget object. The win argument should be a curses window object in which the textbox is to be contained. If insert_mode is true, the textbox inserts typed characters, shifting existing text to the right, rather than overwriting it. The edit cursor of the textbox is initially located at the upper-left corner of the containing window, with coordinates `(0, 0)`. The instance’s `stripspaces` flag is initially on.

  Changed in version 3.16.0a0 (unreleased): Entering and reading back the full Unicode range, including combining characters, is now supported when curses is built with wide-character support.

  `Textbox` objects have the following methods:

  edit(validate=None)

    This is the entry point you will normally use. It accepts editing keystrokes until one of the termination keystrokes is entered. If validate is supplied, it must be a function. It will be called for each keystroke entered with the keystroke as a parameter; command dispatch is done on the result. If it returns a false value, the keystroke is ignored. This method returns the window contents as a string; whether blanks in the window are included is affected by the `stripspaces` attribute.

    Changed in version 3.16.0a0 (unreleased): validate is now called with a non-ASCII character as a string; other keystrokes are still passed as an integer.

  do_command(ch)

    Process a single command keystroke. Returns `1` to continue editing, or `0` if a termination keystroke was processed. Here are the supported special keystrokes:

    Keystroke | Action
    --- | ---
    `Control`-`A` | Go to left edge of window.
    `Control`-`B` | Cursor left, wrapping to previous line if appropriate.
    `Control`-`D` | Delete character under cursor.
    `Control`-`E` | Go to right edge (stripspaces off) or end of line (stripspaces on).
    `Control`-`F` | Cursor right, wrapping to next line when appropriate.
    `Control`-`G` | Terminate, returning the window contents.
    `Control`-`H` | Delete character backward.
    `Control`-`J` | Terminate if the window is 1 line, otherwise move to the start of the next line.
    `Control`-`K` | If line is blank, delete it, otherwise clear to end of line.
    `Control`-`L` | Refresh screen.
    `Control`-`N` | Cursor down; move down one line.
    `Control`-`O` | Insert a blank line at cursor location.
    `Control`-`P` | Cursor up; move up one line.

    Move operations do nothing if the cursor is at an edge where the movement is not possible. The following synonyms are supported where possible:

    Constant | Keystroke
    --- | ---
    `KEY_LEFT` | `Control`-`B`
    `KEY_RIGHT` | `Control`-`F`
    `KEY_UP` | `Control`-`P`
    `KEY_DOWN` | `Control`-`N`
    `KEY_BACKSPACE` | `Control`-`h`

    All other keystrokes are treated as a command to insert the given character and move right (with line wrapping).

  gather()

    Return the window contents as a string; whether blanks in the window are included is affected by the `stripspaces` member.

  stripspaces

    This attribute is a flag which controls the interpretation of blanks in the window. When it is on, trailing blanks on each line are ignored; any cursor motion that would land the cursor on a trailing blank goes to the end of that line instead, and trailing blanks are stripped when the window contents are gathered.