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chromium/external/github.com/python/cpython/e41b38b7cdcc901a13ec25d149d4cf2db03fe547/./Doc/library/curses.rst
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:mod:`!curses` --- Terminal handling for character-cell displays
================================================================
.. module:: curses
:synopsis: An interface to the curses library, providing portable
terminal handling.
**Source code:** :source:`Lib/curses`
--------------
The :mod:`!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.
.. include:: ../includes/wasm-mobile-notavail.rst
.. include:: ../includes/optional-module.rst
.. 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.
An integer is the code of a single encoded byte, optionally combined with
attributes and a color pair, as returned by :meth:`window.inch`.
Methods that write to a window accept also a character cell: a Unicode
string of a spacing character followed by combining characters, or a
:class:`complexchar`.
Whenever the documentation mentions a *character string* it can be specified
as a Unicode string or a byte string.
Methods that write to a window accept also a :class:`complexstr`.
.. note::
Whether curses may be used from several threads
depends on the underlying library and how it was built.
In many implementations, including the default build of ncurses,
the screen state is shared and not thread-safe;
since the blocking and refresh methods
(such as :meth:`~window.getch` and :meth:`~window.refresh`)
release the :term:`GIL`,
unsynchronized use from several threads can then crash the interpreter.
Serialize the calls,
or wrap them in :meth:`window.use` and :meth:`screen.use`.
.. seealso::
Module :mod:`curses.ascii`
Utilities for working with ASCII characters, regardless of your locale settings.
Module :mod:`curses.panel`
A panel stack extension that adds depth to curses windows.
Module :mod:`curses.textpad`
Editable text widget for curses supporting :program:`Emacs`\ -like bindings.
:ref:`curses-howto`
Tutorial material on using curses with Python, by Andrew Kuchling and Eric
Raymond.
.. _curses-functions:
Functions
---------
The module :mod:`!curses` defines the following exception:
.. exception:: 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 :const:`A_NORMAL`.
The module :mod:`!curses` defines the following functions:
Initialization and termination
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. function:: initscr()
Initialize the library. Return a :ref:`window <curses-window-objects>` object
which represents the whole screen.
See :func:`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.
.. function:: endwin()
De-initialize the library, and return terminal to normal status.
.. function:: isendwin()
Return ``True`` if :func:`endwin` has been called (that is, the curses library has
been deinitialized).
.. function:: newterm(type=None, fd=None, infd=None, /)
Initialize a new terminal in addition to the one initialized by
:func:`initscr`,
and return a :ref:`screen <curses-screen-objects>` for it.
This allows a program to drive more than one terminal.
*type* is the terminal name, as in :func:`setupterm`;
if ``None``, the value of the :envvar:`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 :data:`sys.stdout` and :data:`sys.stdin`.
The new screen becomes the current one.
Use :func:`set_term` to switch between screens.
See :func:`setupterm` for a caveat about calling it before this function.
.. versionadded:: 3.16
.. function:: new_prescr()
Return a new :ref:`screen <curses-screen-objects>`
that can be used to call functions that affect global state
before :func:`initscr` or :func:`newterm` is called.
Availability: if the underlying curses library provides ``new_prescr()``.
.. versionadded:: 3.16
.. function:: set_term(screen, /)
Make *screen*, a :ref:`screen <curses-screen-objects>` returned by
:func:`newterm`, the current terminal,
and return the previously current screen.
Returns ``None`` if the previous screen was the one created by
:func:`initscr`.
Raises :exc:`error` if *screen* has no terminal,
as is the case for a screen returned by :func:`new_prescr`.
.. versionadded:: 3.16
.. function:: 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 :func:`!wrapper`. Before calling *func*, :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
~~~~~~~~~~~~~~~~~~~~~
.. function:: 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 :func:`reset_prog_mode` will
restore this mode.
.. function:: 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
:func:`reset_shell_mode` will restore this mode.
.. function:: reset_prog_mode()
Restore the terminal to "program" mode, as previously saved by
:func:`def_prog_mode`.
.. function:: reset_shell_mode()
Restore the terminal to "shell" mode, as previously saved by
:func:`def_shell_mode`.
.. function:: savetty()
Save the current state of the terminal modes in a buffer, usable by
:func:`resetty`.
.. function:: resetty()
Restore the state of the terminal modes to what it was at the last call to
:func:`savetty`.
.. function:: 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.
.. function:: getsyx()
Return the current coordinates of the virtual screen cursor as a tuple
``(y, x)``. If :meth:`leaveok <window.leaveok>` is currently ``True``, then return ``(-1, -1)``.
.. function:: setsyx(y, x)
Set the virtual screen cursor to *y*, *x*. If *y* and *x* are both ``-1``, then
:meth:`leaveok <window.leaveok>` is set ``True``.
.. function:: 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 :func:`doupdate` function updates the
physical screen to match the virtual screen.
The virtual screen may be updated by a :meth:`~window.noutrefresh` call after write
operations such as :meth:`~window.addstr` have been performed on a window. The normal
:meth:`~window.refresh` call is simply :meth:`!noutrefresh` followed by :func:`!doupdate`;
if you have to update multiple windows, you can speed performance and perhaps
reduce screen flicker by issuing :meth:`!noutrefresh` calls on all windows,
followed by a single :func:`!doupdate`.
Input options
~~~~~~~~~~~~~
.. function:: 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 :func:`raw` then :func:`cbreak` leaves the terminal in cbreak mode.
.. function:: nocbreak()
Leave cbreak mode. Return to normal "cooked" mode with line buffering.
.. function:: echo()
Enter echo mode. In echo mode, each character input is echoed to the screen as
it is entered.
.. function:: noecho()
Leave echo mode. Echoing of input characters is turned off.
.. function:: 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.
.. function:: noraw()
Leave raw mode. Return to normal "cooked" mode with line buffering.
.. function:: 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
:func:`nocbreak` to leave half-delay mode.
.. function:: meta(flag)
If *flag* is ``True``, allow 8-bit characters to be input. If
*flag* is ``False``, allow only 7-bit chars.
.. function:: 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 :func:`nonl`.
.. function:: 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.
.. function:: 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.
.. function:: qiflush([flag])
If *flag* is ``False``, the effect is the same as calling :func:`noqiflush`. If
*flag* is ``True``, or no argument is provided, the queues will be flushed when
these control characters are read.
.. function:: noqiflush()
When the :func:`!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 :func:`!noqiflush` in a signal handler if you want output to
continue as though the interrupt had not occurred, after the handler exits.
.. function:: 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 :meth:`~window.refresh` or
:func:`doupdate` is called again, allowing faster response to commands typed
in advance. This function allows specifying a different file descriptor for
typeahead checking.
.. function:: is_cbreak()
Return ``True`` if cbreak mode (see :func:`cbreak`) is enabled,
``False`` otherwise.
Availability: ncurses 6.5 or later.
.. versionadded:: 3.16
.. function:: is_echo()
Return ``True`` if echo mode (see :func:`echo`) is enabled,
``False`` otherwise.
Availability: ncurses 6.5 or later.
.. versionadded:: 3.16
.. function:: is_nl()
Return ``True`` if nl mode (see :func:`nl`) is enabled, ``False`` otherwise.
Availability: ncurses 6.5 or later.
.. versionadded:: 3.16
.. function:: is_raw()
Return ``True`` if raw mode (see :func:`raw`) is enabled,
``False`` otherwise.
Availability: ncurses 6.5 or later.
.. versionadded:: 3.16
Keyboard input
~~~~~~~~~~~~~~
.. function:: ungetch(ch)
Push *ch* so the next :meth:`~window.getch` or :meth:`~window.get_wch` will
return it.
*ch* may be an integer (a key code or the code of an encoded byte), a byte,
or a string of length 1. A one-character string is pushed like
:func:`unget_wch`; on a narrow build it must encode to a single byte.
.. note::
Only one *ch* can be pushed before :meth:`!getch` is called.
.. versionchanged:: 3.16
A one-character string argument is no longer required to encode to a single
byte, except on a narrow build.
.. function:: unget_wch(ch)
Push *ch* so the next :meth:`~window.get_wch` will return it.
*ch* may be an integer (a character code, not a key code) or a string of
length 1.
.. note::
Only one *ch* can be pushed before :meth:`!get_wch` is called.
.. versionadded:: 3.3
.. versionchanged:: 3.16
Also available on a narrow build, where *ch* must encode to a single byte
(an 8-bit locale).
.. function:: 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.
.. function:: has_key(ch)
Take a key value *ch*, and return ``True`` if the current terminal type recognizes
a key with that value.
.. function:: 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 :exc:`ValueError` if *k* is negative.
.. function:: define_key(definition, keycode)
Define an escape sequence *definition*, a string, as a key that generates
the key code *keycode*, so that :mod:`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.
.. versionadded:: 3.16
.. function:: 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).
.. versionadded:: 3.16
.. function:: keyok(keycode, enable)
Enable (if *enable* is true) or disable (otherwise) interpretation of the
key code *keycode*. Unlike :meth:`window.keypad`, this affects a single
key code rather than all of them.
.. versionadded:: 3.16
Mouse
~~~~~
.. function:: getmouse()
After :meth:`~window.getch` returns :const:`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:
:const:`BUTTONn_PRESSED`, :const:`BUTTONn_RELEASED`, :const:`BUTTONn_CLICKED`,
:const:`BUTTONn_DOUBLE_CLICKED`, :const:`BUTTONn_TRIPLE_CLICKED`,
:const:`BUTTON_SHIFT`, :const:`BUTTON_CTRL`, :const:`BUTTON_ALT`.
.. versionchanged:: 3.10
The ``BUTTON5_*`` constants are now exposed if they are provided by the
underlying curses library.
.. function:: ungetmouse(id, x, y, z, bstate)
Push a :const:`KEY_MOUSE` event onto the input queue, associating the given
state data with it.
.. function:: 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.
.. function:: 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.
.. function:: has_mouse()
Return ``True`` if the mouse driver has been successfully initialized.
Availability: if the underlying curses library provides ``has_mouse()``.
.. versionadded:: 3.16
Color
~~~~~
.. function:: 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 :func:`initscr`.
:func:`start_color` initializes eight basic colors (black, red, green, yellow,
blue, magenta, cyan, and white), and two global variables in the :mod:`!curses`
module, :const:`COLORS` and :const:`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.
.. function:: has_colors()
Return ``True`` if the terminal can display colors; otherwise, return ``False``.
.. function:: 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.
.. versionadded:: 3.10
.. function:: can_change_color()
Return ``True`` or ``False``, depending on whether the programmer can change the colors
displayed by the terminal.
.. function:: 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 :func:`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 :func:`can_change_color` returns ``True``.
.. function:: 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.
.. function:: 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
:func:`use_default_colors` and :func:`assume_default_colors`).
The value of *fg* and *bg* arguments must be between ``0`` and
``COLORS - 1``, or, after calling :func:`!use_default_colors` or
:func:`!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.
.. function:: 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``.
.. function:: 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
:exc:`OverflowError` rather than being silently masked to a different pair.
Use :meth:`~window.color_set` or :meth:`~window.attr_set` to display higher
pairs. This attribute value can be combined with :const:`A_STANDOUT`,
:const:`A_REVERSE`, and the other :const:`!A_\*` attributes.
:func:`pair_number` is the counterpart to this function.
.. function:: pair_number(attr)
Return the number of the color-pair set by the attribute value *attr*.
:func:`color_pair` is the counterpart to this function.
.. function:: use_default_colors()
Equivalent to ``assume_default_colors(-1, -1)``.
.. function:: 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.
.. versionadded:: 3.14
.. function:: 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
:func:`has_extended_color_support`).
.. versionadded:: 3.16
.. function:: free_pair(pair_number)
Free the color pair *pair_number*, which must have been allocated by
:func:`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
:func:`has_extended_color_support`).
.. versionadded:: 3.16
.. function:: 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
:func:`has_extended_color_support`).
.. versionadded:: 3.16
.. function:: reset_color_pairs()
Discard all color-pair definitions, releasing the color pairs allocated by
:func:`init_pair` and :func:`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
:func:`has_extended_color_support`).
.. versionadded:: 3.16
Windows and pads
~~~~~~~~~~~~~~~~
.. function:: newwin(nlines, ncols)
newwin(nlines, ncols, begin_y, begin_x)
Return a new :ref:`window <curses-window-objects>`, 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.
.. function:: 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 :meth:`~window.refresh` and :meth:`~window.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
~~~~~~~~~~~
.. _curses-slk:
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. :func:`slk_init` must be called before :func:`initscr` or
:func:`newterm`; it takes one screen line away from the standard window for the
labels.
.. function:: 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 :func:`initscr` or :func:`newterm`,
and affects only the screen created next.
.. versionadded:: 3.16
.. function:: 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.
.. versionadded:: 3.16
.. function:: 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.
.. versionadded:: 3.16
.. function:: slk_refresh()
Update the soft labels on the physical screen, like
:meth:`~curses.window.refresh` for a window.
.. versionadded:: 3.16
.. function:: slk_noutrefresh()
Update the soft labels on the virtual screen, like
:meth:`window.noutrefresh`. Use it together with :func:`doupdate` to batch
screen updates.
.. versionadded:: 3.16
.. function:: slk_clear()
Remove the soft labels from the screen.
.. versionadded:: 3.16
.. function:: slk_restore()
Restore the soft labels to the screen after a :func:`slk_clear`.
.. versionadded:: 3.16
.. function:: slk_touch()
Force all the soft labels to be redrawn by the next :func:`slk_refresh` or
:func:`slk_noutrefresh`.
.. versionadded:: 3.16
.. function:: slk_attron(attr)
slk_attroff(attr)
slk_attrset(attr)
Add, remove, or set the attributes used to display the soft labels, given as
packed ``A_*`` attributes.
.. versionadded:: 3.16
.. function:: slk_attr()
Return the current attributes of the soft labels as packed ``A_*``
attributes. Availability depends on the underlying curses library.
.. versionadded:: 3.16
.. function:: slk_attr_on(attr)
slk_attr_off(attr)
Turn the given attributes on or off without affecting any others. Like the
``attr_*`` window methods, these work with the
:ref:`WA_* attributes <curses-wa-constants>` rather than packed ``A_*``
attributes.
.. versionadded:: 3.16
.. function:: slk_attr_set(attr, pair=0)
Set the attributes and color pair of the soft labels. *attr* is given as
:ref:`WA_* attributes <curses-wa-constants>` and *pair* as a color pair
number.
.. versionadded:: 3.16
.. function:: slk_color(pair)
Set the color pair of the soft labels to color pair number *pair*.
.. versionadded:: 3.16
Saving and restoring
~~~~~~~~~~~~~~~~~~~~
.. function:: getwin(file)
Read window-related data stored in the file by an earlier :meth:`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.
.. function:: scr_dump(filename)
Write the current contents of the virtual screen to *filename*, which may be
a string or a :term:`path-like object`. The file can later be read by
:func:`scr_restore`, :func:`scr_init` or :func:`scr_set`. This is the
whole-screen counterpart of :meth:`window.putwin`.
.. versionadded:: 3.16
.. function:: scr_restore(filename)
Set the virtual screen to the contents of *filename*, which must have been
written by :func:`scr_dump`. The next call to :func:`doupdate` or
:meth:`window.refresh` restores the screen to those contents.
.. versionadded:: 3.16
.. function:: scr_init(filename)
Initialize the assumed contents of the terminal from *filename*, which must
have been written by :func:`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.
.. versionadded:: 3.16
.. function:: scr_set(filename)
Use *filename*, which must have been written by :func:`scr_dump`, as both
the virtual screen and the assumed terminal contents. This combines the
effects of :func:`scr_restore` and :func:`scr_init`.
.. versionadded:: 3.16
Querying the terminal
~~~~~~~~~~~~~~~~~~~~~
.. function:: 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.
.. function:: erasechar()
Return the user's current erase character as a raw byte, a :class:`bytes`
object of length 1. See also :func:`erasewchar`.
.. function:: erasewchar()
Return the user's current erase character as a one-character :class:`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.
.. versionadded:: 3.16
.. function:: killchar()
Return the user's current line kill character as a raw byte, a :class:`bytes`
object of length 1. See also :func:`killwchar`.
.. function:: killwchar()
Return the user's current line kill character as a one-character :class:`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.
.. versionadded:: 3.16
.. function:: termname()
Return the value of the environment variable :envvar:`TERM`, as a bytes object,
truncated to 14 characters.
.. function:: 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 :func:`initscr`.
.. function:: 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.
.. function:: term_attrs()
Like :func:`termattrs`, but return the attributes as :ref:`WA_*
<curses-wa-constants>` values rather than ``A_*`` values.
.. versionadded:: 3.16
.. function:: 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.
.. function:: 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
~~~~~~~~~~~~~~~~~~~~~
.. function:: beep()
Emit a short attention sound.
.. function:: 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 :func:`beep`.
Terminal resizing
~~~~~~~~~~~~~~~~~
.. function:: 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).
.. function:: resize_term(nlines, ncols)
Backend function used by :func:`resizeterm`, performing most of the work;
when resizing the windows, :func:`resize_term` blank-fills the areas that are
extended. The calling application should fill in these areas with
appropriate data. The :func:`!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.
.. function:: is_term_resized(nlines, ncols)
Return ``True`` if :func:`resize_term` would modify the window structure,
``False`` otherwise.
.. function:: update_lines_cols()
Update the :const:`LINES` and :const:`COLS` module variables.
Useful for detecting manual screen resize.
.. versionadded:: 3.5
Terminfo database
~~~~~~~~~~~~~~~~~
.. function:: 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
:envvar:`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 :exc:`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 :func:`initscr` or :func:`newterm` after :func:`setupterm`
leaks the terminal that :func:`setupterm` allocated:
the curses library keeps only a single current terminal
and does not free the previously allocated one.
.. function:: 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.
:func:`setupterm` (or :func:`initscr`) must be called first.
.. function:: 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.
:func:`setupterm` (or :func:`initscr`) must be called first.
.. function:: 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.
:func:`setupterm` (or :func:`initscr`) must be called first.
.. function:: tparm(str[, ...])
Instantiate the bytes object *str* with the supplied parameters, where *str* should
be a parameterized byte 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.
:func:`setupterm` (or :func:`initscr`) must be called first.
.. function:: putp(str)
Equivalent to ``tputs(str, 1, putchar)``; emit the value of a specified
terminfo capability, a bytes object, for the current terminal.
Note that the output of :func:`putp` always goes to standard output.
:func:`setupterm` (or :func:`initscr`) must be called first.
Utilities
~~~~~~~~~
.. function:: unctrl(ch)
Return a bytes object which is a printable representation of the character *ch*;
any attributes and color pair are ignored.
Control characters are represented as a caret followed by a character,
for example as ``b'^C'``.
Printing characters are left as they are.
The representation of other characters is defined by the underlying curses
library.
*ch* must fit in a single byte; use :func:`wunctrl` for other characters.
.. function:: 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.
.. versionadded:: 3.16
.. function:: filter()
The :func:`.filter` routine, if used, must be called before :func:`initscr`
or :func:`newterm` is called,
and affects every screen created afterwards.
The effect is that, during the initialization, :envvar:`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.
.. function:: nofilter()
Undo the effect of a previous :func:`.filter` call.
Like :func:`.filter`, it must be called before :func:`initscr` (or
:func:`newterm`) so that the next initialization uses the full screen
again.
Availability: if the underlying curses library provides ``nofilter()``.
.. versionadded:: 3.16
.. function:: use_env(flag)
If used, this function should be called before :func:`initscr` or
:func:`newterm` are called,
and affects every screen created afterwards.
When *flag* is ``False``, the values of lines and columns specified in the
terminfo database will be used, even if environment variables :envvar:`LINES`
and :envvar:`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
:envvar:`LINES` and :envvar:`COLUMNS` are not set).
.. function:: get_escdelay()
Retrieves the value set by :func:`set_escdelay`.
.. versionadded:: 3.9
.. function:: 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.
Depending on the curses library, the setting may apply to all screens,
not only to the current one.
.. versionadded:: 3.9
.. function:: get_tabsize()
Retrieves the value set by :func:`set_tabsize`.
.. versionadded:: 3.9
.. function:: 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.
Depending on the curses library, the setting may apply to all screens,
not only to the current one, and creating a screen may reset it.
.. versionadded:: 3.9
.. function:: napms(ms)
Sleep for *ms* milliseconds.
.. function:: delay_output(ms)
Insert an *ms* millisecond pause in output.
.. _curses-window-objects:
Window objects
--------------
.. class:: window
Window objects, as returned by :func:`initscr` and :func:`newwin` above, have
the following methods and attributes:
Adding and inserting text
~~~~~~~~~~~~~~~~~~~~~~~~~
.. method:: 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 :exc:`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.
.. versionchanged:: 3.16
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
:class:`complexchar` cell.
.. method:: 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 :class:`complexstr`, in which case each cell carries its
own attributes and color pair, so *attr* must not be given. A
:class:`complexstr` obtained from :meth:`in_wchstr` is written back
unchanged.
.. note::
* Writing outside the window, subwindow, or pad raises :exc:`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 :meth:`!addstr` with a *str* that has embedded newlines;
instead, call :meth:`!addstr` separately for each line.
.. versionchanged:: 3.16
*str* may now also be a :class:`complexstr`, as described above.
.. method:: 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.
.. versionchanged:: 3.16
*str* may now also be a :class:`complexstr`; see :meth:`addstr`.
.. method:: window.echochar(ch[, attr])
Add character *ch* with attribute *attr*, and immediately call :meth:`refresh`
on the window.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
.. method:: 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.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
.. method:: 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 :class:`complexstr`, in which case each cell carries its
own attributes and color pair, so *attr* must not be given.
.. versionchanged:: 3.16
*str* may now also be a :class:`complexstr`, as described above.
.. method:: 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).
.. versionchanged:: 3.16
*str* may now also be a :class:`complexstr`; see :meth:`insstr`.
Deleting and inserting lines
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. method:: 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.
.. method:: window.deleteln()
Delete the line under the cursor. All following lines are moved up by one line.
.. method:: window.insertln()
Insert a blank line under the cursor. All following lines are moved down by one
line.
.. method:: 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
~~~~~~~~~~~~~
.. method:: window.getch([y, x])
Read a key press, after moving the cursor to *y*, *x* if specified,
and return it as an integer.
The window is refreshed first if it is not a pad and was modified since
the last refresh.
Wait until a key is pressed, or return ``-1`` if the read is non-blocking
or times out (see :meth:`nodelay` and :meth:`timeout`).
An ordinary key is returned as the code of a single byte of its encoding
in the current locale,
so a character encoded with several bytes takes several calls.
For example, in a UTF-8 locale ``'é'`` is read as ``195``, then ``169``.
Use :meth:`get_wch` to read it as a single character.
In keypad mode (see :meth:`keypad`) function keys and other special keys
are returned as one of the :ref:`KEY_* constants <curses-key-constants>`,
which cannot be mistaken for an ordinary key.
Otherwise, or if their escape sequence does not arrive in time
(see :meth:`notimeout` and :func:`set_escdelay`),
their bytes are returned one at a time.
In echo mode (see :func:`echo`) the key is added to the window as by
:meth:`addch`; special keys are not echoed.
.. method:: window.get_wch([y, x])
Read a key press, after moving the cursor to *y*, *x* if specified,
and return it as a one-character :class:`str`.
The window is refreshed first if it is not a pad and was modified since
the last refresh.
Wait until a key is pressed, or raise :exc:`error` if the read is
non-blocking or times out (see :meth:`nodelay` and :meth:`timeout`).
In keypad mode (see :meth:`keypad`) function keys and other special keys
are returned as one of the :ref:`KEY_* constants <curses-key-constants>`,
an integer.
Otherwise, or if their escape sequence does not arrive in time
(see :meth:`notimeout` and :func:`set_escdelay`),
their characters are returned one at a time.
In echo mode (see :func:`echo`) the key is added to the window as by
:meth:`addch`; special keys are not echoed.
.. versionadded:: 3.3
.. versionchanged:: 3.16
Also available on a narrow build, where only a character representable as a
single byte (an 8-bit locale) can be returned.
.. method:: window.getkey([y, x])
Read a key press as :meth:`getch` does, but return it as a :class:`str`:
an ordinary key as a one-character string, the byte decoded as Latin-1,
and a special key as its name, such as ``'KEY_UP'`` (see :func:`keyname`).
Raise :exc:`error` instead of returning ``-1`` if there is no input.
.. method:: window.getstr()
window.getstr(n)
window.getstr(y, x)
window.getstr(y, x, n)
Read a line of input from the user, with primitive line editing capacity,
after moving the cursor to *y*, *x* if specified.
Return it as a bytes object, in the encoding of the current locale
and without the terminating newline.
At most *n* bytes are read;
*n* defaults to and cannot exceed 2047.
Use :meth:`get_wstr` to read the input as a :class:`str`.
.. versionchanged:: 3.14
The maximum value for *n* was increased from 1023 to 2047.
.. method:: window.get_wstr()
window.get_wstr(n)
window.get_wstr(y, x)
window.get_wstr(y, x, n)
Read a line of input from the user, with primitive line editing capacity,
after moving the cursor to *y*, *x* if specified.
Return it as a :class:`str`, without the terminating newline.
At most *n* characters are read;
*n* defaults to and cannot exceed 2047.
This is the wide-character variant of :meth:`getstr`.
.. versionadded:: 3.16
.. method:: window.getdelay()
Return the window's read timeout in milliseconds,
as set by :meth:`nodelay` or :meth:`timeout`:
``-1`` for blocking, ``0`` for non-blocking,
or a positive number of milliseconds.
.. versionadded:: 3.16
Reading window contents
~~~~~~~~~~~~~~~~~~~~~~~
.. method:: 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 :data:`A_CHARTEXT` and :data:`A_ATTRIBUTES` bit-masks,
and the color pair with :func:`pair_number`.
The character byte is the locale-encoded byte of the cell's character,
consistent with :meth:`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 :func:`color_pair`
range; use :meth:`in_wch` for those, which returns it as a :class:`complexchar`.
.. method:: window.in_wch([y, x])
Return the complex character at the given position in the window as a
:class:`complexchar`. Unlike :meth:`inch`, the returned object carries the
cell's text (a spacing character optionally followed by combining characters)
together with its attributes and color pair.
.. versionadded:: 3.16
.. method:: window.instr([n])
window.instr(y, x[, n])
Read the text of the window from the current cursor position,
or from *y*, *x* if specified, to the end of the line
or at most *n* bytes if *n* is specified,
and return it as a bytes object, in the encoding of the current locale.
Attributes and color pairs are stripped;
use :meth:`in_wchstr` to read them too.
A character not representable in the encoding cannot be returned;
use :meth:`in_wstr` for those.
.. versionchanged:: 3.14
The maximum value for *n* was increased from 1023 to 2047.
.. versionchanged:: 3.16
*n* is no longer limited to 2047.
.. method:: window.in_wstr([n])
window.in_wstr(y, x[, n])
Read the text of the window from the current cursor position,
or from *y*, *x* if specified, to the end of the line
or at most *n* characters if *n* is specified,
and return it as a :class:`str`.
Attributes and color pairs are stripped;
use :meth:`in_wchstr` to read them too.
This is the wide-character variant of :meth:`instr`.
.. versionadded:: 3.16
.. method:: window.in_wchstr([n])
window.in_wchstr(y, x[, n])
Read the styled cells of the window from the current cursor position,
or from *y*, *x* if specified, to the end of the line
or at most *n* cells if *n* is specified,
and return them as a :class:`complexstr`.
Unlike :meth:`instr` and :meth:`in_wstr`, each cell keeps its attributes
and color pair, so the result can be written back unchanged
with :meth:`addstr`.
.. versionadded:: 3.16
Attributes
~~~~~~~~~~
.. method:: window.attroff(attr)
Remove attribute *attr* from the "background" set applied to all writes to the
current window.
.. method:: window.attron(attr)
Add attribute *attr* to the "background" set applied to all writes to the
current window.
.. method:: window.attrset(attr)
Set the "background" set of attributes to *attr*. This set is initially
``0`` (no attributes).
.. method:: 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 :meth:`attron` and friends, which take packed ``A_*`` attributes,
this method and the other ``attr_*`` methods work with the
:ref:`WA_* attributes <curses-wa-constants>` 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.
.. versionadded:: 3.16
.. method:: window.attr_set(attr, pair=0)
Set the window's rendition to the attributes *attr* and the color pair *pair*.
.. versionadded:: 3.16
.. method:: window.attr_on(attr)
Turn on the attributes *attr* without affecting any others.
.. versionadded:: 3.16
.. method:: window.attr_off(attr)
Turn off the attributes *attr* without affecting any others.
.. versionadded:: 3.16
.. method:: window.color_set(pair)
Set the window's color pair to *pair*, leaving the other attributes unchanged.
.. versionadded:: 3.16
.. method:: window.getattrs()
Return the window's current attributes.
.. versionadded:: 3.16
.. method:: window.standout()
Turn on attribute *A_STANDOUT*.
.. method:: window.standend()
Turn off the standout attribute. On some terminals this has the side effect of
turning off all attributes.
.. method:: 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 :meth:`touchline` method so that the contents will
be redisplayed by the next window refresh.
Background
~~~~~~~~~~
.. method:: 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.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
.. method:: 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.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
.. method:: window.getbkgd()
Return the given window's current background character/attribute pair.
Its components can be extracted like those of :meth:`inch`.
It cannot represent a background set with a wide character or with a color
pair outside the :func:`color_pair` range; use :meth:`getbkgrnd` for those.
.. method:: window.getbkgrnd()
Return the given window's current background as a :class:`complexchar`.
Unlike :meth:`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 :func:`color_pair`.
.. versionadded:: 3.16
Clearing and erasing
~~~~~~~~~~~~~~~~~~~~
.. method:: window.erase()
Clear the window.
.. method:: window.clear()
Like :meth:`erase`, but also cause the whole window to be repainted upon next
call to :meth:`refresh`.
.. method:: window.clrtobot()
Erase from cursor to the end of the window: all lines below the cursor are
deleted, and then the equivalent of :meth:`clrtoeol` is performed.
.. method:: window.clrtoeol()
Erase from cursor to the end of the line.
Borders and lines
~~~~~~~~~~~~~~~~~
.. method:: 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 | Wide default value |
+===========+=====================+=======================+========================+
| *ls* | Left side | :const:`ACS_VLINE` | :const:`WACS_VLINE` |
+-----------+---------------------+-----------------------+------------------------+
| *rs* | Right side | :const:`ACS_VLINE` | :const:`WACS_VLINE` |
+-----------+---------------------+-----------------------+------------------------+
| *ts* | Top | :const:`ACS_HLINE` | :const:`WACS_HLINE` |
+-----------+---------------------+-----------------------+------------------------+
| *bs* | Bottom | :const:`ACS_HLINE` | :const:`WACS_HLINE` |
+-----------+---------------------+-----------------------+------------------------+
| *tl* | Upper-left corner | :const:`ACS_ULCORNER` | :const:`WACS_ULCORNER` |
+-----------+---------------------+-----------------------+------------------------+
| *tr* | Upper-right corner | :const:`ACS_URCORNER` | :const:`WACS_URCORNER` |
+-----------+---------------------+-----------------------+------------------------+
| *bl* | Bottom-left corner | :const:`ACS_LLCORNER` | :const:`WACS_LLCORNER` |
+-----------+---------------------+-----------------------+------------------------+
| *br* | Bottom-right corner | :const:`ACS_LRCORNER` | :const:`WACS_LRCORNER` |
+-----------+---------------------+-----------------------+------------------------+
The wide default value is used when the border is drawn from string
characters or :class:`complexchar` cells.
If any parameter is a byte character or an integer other than ``0``, the
border is drawn from byte characters, and every string character must be
encodable as a single byte.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted. A single call cannot mix
:class:`complexchar` cells with integer or byte characters.
.. method:: window.box([vertch, horch])
Similar to :meth:`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.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted. A single call cannot mix
:class:`complexchar` cells with integer or byte characters.
.. method:: 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.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
.. method:: 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*.
.. versionchanged:: 3.16
Wide and combining characters, and :class:`complexchar` cells, are now
accepted.
Cursor position and window geometry
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. method:: window.move(new_y, new_x)
Move cursor to ``(new_y, new_x)``.
.. method:: window.getyx()
Return a tuple ``(y, x)`` of current cursor position relative to the window's
upper-left corner.
.. method:: window.getbegyx()
Return a tuple ``(y, x)`` of coordinates of upper-left corner.
.. method:: window.getmaxyx()
Return a tuple ``(y, x)`` of the height and width of the window.
.. method:: 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.
.. method:: window.getparent()
Return the parent window of this subwindow,
or ``None`` if this window is not a subwindow.
.. versionadded:: 3.16
Creating and resizing windows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. method:: 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.
.. method:: window.derwin(begin_y, begin_x)
window.derwin(nlines, ncols, begin_y, begin_x)
An abbreviation for "derive window", :meth:`derwin` is the same as calling
:meth:`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.
.. method:: 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 :meth:`subwin`, which uses screen coordinates). This
method is only available for pads created with :func:`newpad`.
.. method:: 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
:meth:`subwin` or :meth:`derwin`, the duplicate is independent of the
original -- it has its own cell buffer, so later changes to one do not affect
the other.
.. versionadded:: 3.16
.. method:: 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 :exc:`curses.error` is raised.
.. method:: 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.
.. method:: 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 :meth:`bkgdset`) merged into them.
Refreshing and redrawing
~~~~~~~~~~~~~~~~~~~~~~~~
.. method:: 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 :func:`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.
.. method:: 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 :func:`doupdate`.
The 6 arguments can only be specified, and are then required, when the window
is a pad created with :func:`newpad`; they have the same meaning as for
:meth:`refresh`.
.. method:: window.redrawln(beg, num)
Indicate that the *num* screen lines, starting at line *beg*, are corrupted and
should be completely redrawn on the next :meth:`refresh` call.
.. method:: window.redrawwin()
Touch the entire window, causing it to be completely redrawn on the next
:meth:`refresh` call.
Output options
~~~~~~~~~~~~~~
.. method:: window.clearok(flag)
If *flag* is ``True``, the next call to :meth:`refresh` will clear the window
completely.
.. method:: window.idlok(flag)
If *flag* is ``True``, :mod:`!curses` will try to use hardware line
editing facilities. Otherwise, curses will not use them.
.. method:: 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.
.. method:: 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 :meth:`refresh` yourself.
However, it may degrade performance considerably, due to repeated calls to
wrefresh. This option is disabled by default.
.. method:: 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.
.. method:: 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 :meth:`idlok`.
.. method:: 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 :meth:`scrollok`.
.. method:: window.setscrreg(top, bottom)
Set the scrolling region from line *top* to line *bottom*. All scrolling actions
will take place in this region.
.. method:: window.getscrreg()
Return a tuple ``(top, bottom)`` of the window's current scrolling region,
as set by :meth:`setscrreg`.
.. versionadded:: 3.16
.. method:: window.syncok(flag)
If *flag* is ``True``, then :meth:`syncup` is called automatically
whenever there is a change in the window.
Input options
~~~~~~~~~~~~~
.. method:: window.keypad(flag)
If *flag* is ``True``, escape sequences generated by some keys (keypad, function keys)
will be interpreted by :mod:`!curses`. If *flag* is ``False``, escape sequences will be
left as is in the input stream.
Keypad mode is disabled by default, but :func:`wrapper` enables it for the
main window.
.. method:: window.nodelay(flag)
If *flag* is ``True``, :meth:`getch` will be non-blocking.
.. method:: 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.
.. method:: 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 :meth:`getch` will
return ``-1`` if no input is waiting. If *delay* is positive, then
:meth:`getch` will block for *delay* milliseconds, and return ``-1`` if there is
still no input at the end of that time.
Overlapping and touch
~~~~~~~~~~~~~~~~~~~~~
.. method:: 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
:meth:`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.
.. method:: 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
:meth:`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.
.. method:: 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``).
.. method:: window.touchwin()
Pretend the whole window has been changed, for purposes of drawing
optimizations.
.. method:: window.untouchwin()
Mark all lines in the window as unchanged since the last call to
:meth:`refresh`.
.. method:: window.syncup()
Touch all locations in ancestors of the window that have been changed in the
window.
.. method:: window.syncdown()
Touch each location in the window that has been touched in any of its ancestor
windows. This routine is called by :meth:`refresh`, so it should almost never
be necessary to call it manually.
.. method:: 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
~~~~~~~~~~~~~~~~~~~~~
.. method:: 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.
.. versionchanged:: 3.10
Previously it returned ``1`` or ``0`` instead of ``True`` or ``False``.
.. method:: 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.
.. versionadded:: 3.16
Other
~~~~~
.. attribute:: window.encoding
Encoding used to encode the string arguments of the methods and to decode
their results on a build without wide-character support.
The encoding attribute is inherited from the parent window when a subwindow
is created, for example with :meth:`window.subwin`.
By default, current locale encoding is used (see :func:`locale.getencoding`).
.. versionadded:: 3.3
.. method:: window.putwin(file)
Write all data associated with the window into the provided file object. This
information can be later retrieved using the :func:`getwin` function.
.. method:: 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()``.
.. versionadded:: 3.16
State queries
~~~~~~~~~~~~~
.. method:: window.is_cleared()
Return the current value set by :meth:`clearok`.
.. versionadded:: 3.16
.. method:: window.is_idcok()
Return the current value set by :meth:`idcok`.
.. versionadded:: 3.16
.. method:: window.is_idlok()
Return the current value set by :meth:`idlok`.
.. versionadded:: 3.16
.. method:: window.is_immedok()
Return the current value set by :meth:`immedok`.
.. versionadded:: 3.16
.. method:: window.is_keypad()
Return the current value set by :meth:`keypad`.
.. versionadded:: 3.16
.. method:: window.is_leaveok()
Return the current value set by :meth:`leaveok`.
.. versionadded:: 3.16
.. method:: window.is_linetouched(line)
Return ``True`` if the specified line was modified since the last call to
:meth:`refresh`; otherwise return ``False``. Raise a :exc:`curses.error`
exception if *line* is not valid for the given window.
.. method:: window.is_nodelay()
Return the current value set by :meth:`nodelay`.
.. versionadded:: 3.16
.. method:: window.is_notimeout()
Return the current value set by :meth:`notimeout`.
.. versionadded:: 3.16
.. method:: window.is_pad()
Return ``True`` if the window is a pad created by :func:`newpad`.
.. versionadded:: 3.16
.. method:: window.is_scrollok()
Return the current value set by :meth:`scrollok`.
.. versionadded:: 3.16
.. method:: window.is_subwin()
Return ``True`` if the window is a subwindow created by :meth:`subwin`
or :meth:`derwin`.
.. versionadded:: 3.16
.. method:: window.is_syncok()
Return the current value set by :meth:`syncok`.
.. versionadded:: 3.16
.. method:: window.is_wintouched()
Return ``True`` if the specified window was modified since the last call to
:meth:`refresh`; otherwise return ``False``.
.. _curses-screen-objects:
Screen objects
--------------
.. class:: screen
A *screen* object represents a terminal initialized by :func:`newterm`
(or :func:`new_prescr`),
in addition to the default screen created by :func:`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.
.. versionadded:: 3.16
.. method:: 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 :attr:`~screen.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.
.. versionadded:: 3.16
.. attribute:: screen.stdscr
The standard :ref:`window <curses-window-objects>` of the screen,
covering the whole terminal,
or ``None`` for a screen created by :func:`new_prescr`.
.. method:: 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()``.
.. versionadded:: 3.16
.. _curses-complexchar-objects:
Complex character objects
-------------------------
.. class:: 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
:ref:`WA_* attributes <curses-wa-constants>` (equivalent to the matching
``A_*`` constants), and *pair* a color pair number. Unlike the packed
:class:`chtype <int>` used by :meth:`~window.inch` and the ``A_*`` methods,
the color pair is stored separately and is not limited to the value that
fits in a :func:`color_pair`.
Complex characters are returned by :meth:`window.in_wch` and
:meth:`window.getbkgrnd`, and are accepted (along with an integer, a byte
or a string) by the character-cell methods such as :meth:`window.addch`,
:meth:`window.insch`, :meth:`window.bkgd`, :meth:`window.border`,
:meth:`window.hline` and :meth:`window.vline`. A complex character already
carries its own rendition, so it cannot be combined with an explicit *attr*
argument.
:func:`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 :func:`color_pair`.
.. attribute:: attr
The attributes of the character cell (read-only).
.. attribute:: pair
The color pair number of the character cell (read-only).
.. versionadded:: 3.16
.. class:: complexstr(cells[, attr[, pair]])
A *complex character string* (or *complexstr*) is an immutable sequence of
styled character cells -- the string counterpart of
:class:`complexchar` (as :class:`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 :ref:`WA_* attributes <curses-wa-constants>`) 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
:class:`complexchar` or a string; each item then carries its own rendition,
and *attr* and *pair* must be omitted.
It is returned by :meth:`window.in_wchstr`, and accepted by
:meth:`window.addstr`, :meth:`~window.addnstr`, :meth:`~window.insstr` and
:meth:`~window.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 :class:`complexchar`, slicing and
concatenation produce new :class:`!complexstr` instances, and iterating
yields the cells. :func:`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 :class:`list` of
:class:`complexchar` (or strings); a :class:`!complexstr` is the immutable
form returned by a read.
Like :class:`complexchar`, this type works on both wide- and narrow-character
builds, with the same per-cell limitations on a narrow build.
.. versionadded:: 3.16
Constants
---------
General
~~~~~~~
The :mod:`!curses` module defines the following data members:
.. data:: ERR
Some curses routines that return an integer, such as :meth:`~window.getch`, return
:const:`ERR` upon failure.
.. data:: OK
Some curses routines that return an integer, such as :func:`napms`, return
:const:`OK` upon success.
.. data:: version
A bytes object representing the current version of the module.
.. data:: 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.
.. versionadded:: 3.8
.. data:: COLORS
The maximum number of colors the terminal can support.
It is defined only after the call to :func:`start_color`.
.. data:: COLOR_PAIRS
The maximum number of color pairs the terminal can support.
It is defined only after the call to :func:`start_color`.
.. data:: COLS
The width of the screen, that is, the number of columns.
It is defined only after the call to :func:`initscr`.
Updated by :func:`update_lines_cols`, :func:`resizeterm` and
:func:`resize_term`.
.. data:: LINES
The height of the screen, that is, the number of lines.
It is defined only after the call to :func:`initscr`.
Updated by :func:`update_lines_cols`, :func:`resizeterm` and
:func:`resize_term`.
Attributes
~~~~~~~~~~
Some constants are available to specify character cell attributes.
The exact constants available are system dependent.
.. _curses-wa-constants:
+------------------------+-------------------------+------------------------------------------+
| Attribute | Wide attribute | Meaning |
+========================+=========================+==========================================+
| .. data:: A_ALTCHARSET | .. data:: WA_ALTCHARSET | Alternate character set mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_BLINK | .. data:: WA_BLINK | Blink mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_BOLD | .. data:: WA_BOLD | Bold mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_DIM | .. data:: WA_DIM | Dim mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_INVIS | .. data:: WA_INVIS | Invisible or blank mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_ITALIC | .. data:: WA_ITALIC | Italic mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_NORMAL | .. data:: WA_NORMAL | Normal attribute |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_PROTECT | .. data:: WA_PROTECT | Protected mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_REVERSE | .. data:: WA_REVERSE | Reverse background and foreground colors |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_STANDOUT | .. data:: WA_STANDOUT | Standout mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_UNDERLINE | .. data:: WA_UNDERLINE | Underline mode |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_HORIZONTAL | .. data:: WA_HORIZONTAL | Horizontal highlight |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_LEFT | .. data:: WA_LEFT | Left highlight |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_LOW | .. data:: WA_LOW | Low highlight |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_RIGHT | .. data:: WA_RIGHT | Right highlight |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_TOP | .. data:: WA_TOP | Top highlight |
+------------------------+-------------------------+------------------------------------------+
| .. data:: A_VERTICAL | .. data:: WA_VERTICAL | Vertical highlight |
+------------------------+-------------------------+------------------------------------------+
.. versionadded:: 3.7
``A_ITALIC`` was added.
The :meth:`~window.attr_get`, :meth:`~window.attr_set`, :meth:`~window.attr_on`
and :meth:`~window.attr_off` methods use the parallel set of ``WA_*`` constants
listed above.
Each has the same meaning as the corresponding ``A_*`` attribute
(:const:`WA_BOLD` like :const:`A_BOLD`, and so on), but belongs 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.
.. versionadded:: 3.16
The ``WA_*`` constants were added.
Several constants are available to extract corresponding attributes returned
by some methods.
+-------------------------+--------------------------+--------------------------------------------------+
| Bit-mask | Wide bit-mask | Meaning |
+=========================+==========================+==================================================+
| .. data:: A_ATTRIBUTES | .. data:: WA_ATTRIBUTES | Bit-mask to extract attributes |
+-------------------------+--------------------------+--------------------------------------------------+
| .. data:: A_CHARTEXT | | Bit-mask to extract a character |
+-------------------------+--------------------------+--------------------------------------------------+
| .. data:: A_COLOR | | Bit-mask to extract color-pair field information |
+-------------------------+--------------------------+--------------------------------------------------+
.. _curses-key-constants:
Keys
~~~~
Keys are referred to by integer constants with names starting with ``KEY_``.
The exact keycaps available are system dependent.
+-------------------------+--------------------------------------------+
| Key constant | Key |
+=========================+============================================+
| .. data:: KEY_MIN | Minimum key value |
+-------------------------+--------------------------------------------+
| .. data:: KEY_BREAK | Break key (unreliable) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_DOWN | Down-arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_UP | Up-arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_LEFT | Left-arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_RIGHT | Right-arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_HOME | Home key (upward+left arrow) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_BACKSPACE | Backspace (unreliable) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_F0 | Function keys. Up to 64 function keys are |
| | supported. |
+-------------------------+--------------------------------------------+
| .. data:: KEY_Fn | Value of function key *n* |
+-------------------------+--------------------------------------------+
| .. data:: KEY_DL | Delete line |
+-------------------------+--------------------------------------------+
| .. data:: KEY_IL | Insert line |
+-------------------------+--------------------------------------------+
| .. data:: KEY_DC | Delete character |
+-------------------------+--------------------------------------------+
| .. data:: KEY_IC | Insert char or enter insert mode |
+-------------------------+--------------------------------------------+
| .. data:: KEY_EIC | Exit insert char mode |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CLEAR | Clear screen |
+-------------------------+--------------------------------------------+
| .. data:: KEY_EOS | Clear to end of screen |
+-------------------------+--------------------------------------------+
| .. data:: KEY_EOL | Clear to end of line |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SF | Scroll 1 line forward |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SR | Scroll 1 line backward (reverse) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_NPAGE | Next page |
+-------------------------+--------------------------------------------+
| .. data:: KEY_PPAGE | Previous page |
+-------------------------+--------------------------------------------+
| .. data:: KEY_STAB | Set tab |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CTAB | Clear tab |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CATAB | Clear all tabs |
+-------------------------+--------------------------------------------+
| .. data:: KEY_ENTER | Enter or send (unreliable) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SRESET | Soft (partial) reset (unreliable) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_RESET | Reset or hard reset (unreliable) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_PRINT | Print |
+-------------------------+--------------------------------------------+
| .. data:: KEY_LL | Home down or bottom (lower left) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_A1 | Upper left of keypad |
+-------------------------+--------------------------------------------+
| .. data:: KEY_A3 | Upper right of keypad |
+-------------------------+--------------------------------------------+
| .. data:: KEY_B2 | Center of keypad |
+-------------------------+--------------------------------------------+
| .. data:: KEY_C1 | Lower left of keypad |
+-------------------------+--------------------------------------------+
| .. data:: KEY_C3 | Lower right of keypad |
+-------------------------+--------------------------------------------+
| .. data:: KEY_BTAB | Back tab |
+-------------------------+--------------------------------------------+
| .. data:: KEY_BEG | Beg (beginning) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CANCEL | Cancel |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CLOSE | Close |
+-------------------------+--------------------------------------------+
| .. data:: KEY_COMMAND | Cmd (command) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_COPY | Copy |
+-------------------------+--------------------------------------------+
| .. data:: KEY_CREATE | Create |
+-------------------------+--------------------------------------------+
| .. data:: KEY_END | End |
+-------------------------+--------------------------------------------+
| .. data:: KEY_EXIT | Exit |
+-------------------------+--------------------------------------------+
| .. data:: KEY_FIND | Find |
+-------------------------+--------------------------------------------+
| .. data:: KEY_HELP | Help |
+-------------------------+--------------------------------------------+
| .. data:: KEY_MARK | Mark |
+-------------------------+--------------------------------------------+
| .. data:: KEY_MESSAGE | Message |
+-------------------------+--------------------------------------------+
| .. data:: KEY_MOVE | Move |
+-------------------------+--------------------------------------------+
| .. data:: KEY_NEXT | Next |
+-------------------------+--------------------------------------------+
| .. data:: KEY_OPEN | Open |
+-------------------------+--------------------------------------------+
| .. data:: KEY_OPTIONS | Options |
+-------------------------+--------------------------------------------+
| .. data:: KEY_PREVIOUS | Prev (previous) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_REDO | Redo |
+-------------------------+--------------------------------------------+
| .. data:: KEY_REFERENCE | Ref (reference) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_REFRESH | Refresh |
+-------------------------+--------------------------------------------+
| .. data:: KEY_REPLACE | Replace |
+-------------------------+--------------------------------------------+
| .. data:: KEY_RESTART | Restart |
+-------------------------+--------------------------------------------+
| .. data:: KEY_RESUME | Resume |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SAVE | Save |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SBEG | Shifted Beg (beginning) |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SCANCEL | Shifted Cancel |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SCOMMAND | Shifted Command |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SCOPY | Shifted Copy |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SCREATE | Shifted Create |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SDC | Shifted Delete char |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SDL | Shifted Delete line |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SELECT | Select |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SEND | Shifted End |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SEOL | Shifted Clear line |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SEXIT | Shifted Exit |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SFIND | Shifted Find |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SHELP | Shifted Help |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SHOME | Shifted Home |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SIC | Shifted Input |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SLEFT | Shifted Left arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SMESSAGE | Shifted Message |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SMOVE | Shifted Move |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SNEXT | Shifted Next |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SOPTIONS | Shifted Options |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SPREVIOUS | Shifted Prev |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SPRINT | Shifted Print |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SREDO | Shifted Redo |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SREPLACE | Shifted Replace |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SRIGHT | Shifted Right arrow |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SRSUME | Shifted Resume |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SSAVE | Shifted Save |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SSUSPEND | Shifted Suspend |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SUNDO | Shifted Undo |
+-------------------------+--------------------------------------------+
| .. data:: KEY_SUSPEND | Suspend |
+-------------------------+--------------------------------------------+
| .. data:: KEY_UNDO | Undo |
+-------------------------+--------------------------------------------+
| .. data:: KEY_MOUSE | Mouse event has occurred |
+-------------------------+--------------------------------------------+
| .. data:: KEY_RESIZE | Terminal resize event |
+-------------------------+--------------------------------------------+
| .. data:: KEY_MAX | Maximum key value |
+-------------------------+--------------------------------------------+
On VT100s and their software emulations, such as X terminal emulators, there are
normally at least four function keys (:const:`KEY_F1 <KEY_Fn>`, :const:`KEY_F2 <KEY_Fn>`,
:const:`KEY_F3 <KEY_Fn>`, :const:`KEY_F4 <KEY_Fn>`) available, and the arrow keys mapped to
:const:`KEY_UP`, :const:`KEY_DOWN`, :const:`KEY_LEFT` and :const:`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 |
+==================+===========+
| :kbd:`Insert` | KEY_IC |
+------------------+-----------+
| :kbd:`Delete` | KEY_DC |
+------------------+-----------+
| :kbd:`Home` | KEY_HOME |
+------------------+-----------+
| :kbd:`End` | KEY_END |
+------------------+-----------+
| :kbd:`Page Up` | KEY_PPAGE |
+------------------+-----------+
| :kbd:`Page Down` | KEY_NPAGE |
+------------------+-----------+
Alternate character set
~~~~~~~~~~~~~~~~~~~~~~~~
.. _curses-acs-codes:
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.
Every character has two names.
The ``ACS_*`` code is an integer character, restricted to the 8-bit
alternate character set of the terminal.
The ``WACS_*`` code is the same character as a :class:`complexchar` cell,
which is not restricted to the alternate character set.
.. note::
These are available only after :func:`initscr` has been called.
The ``WACS_*`` codes are only available if Python is built with
wide character support.
.. versionadded:: 3.16
The ``WACS_*`` codes.
+------------------------+-------------------------+------------------------------------------+
| ACS code | WACS code | Meaning |
+========================+=========================+==========================================+
| .. data:: ACS_BBSS | .. data:: WACS_BBSS | alternate name for upper-right corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BLOCK | .. data:: WACS_BLOCK | solid square block |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BOARD | .. data:: WACS_BOARD | board of squares |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BSBS | .. data:: WACS_BSBS | alternate name for horizontal line |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BSSB | .. data:: WACS_BSSB | alternate name for upper-left corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BSSS | .. data:: WACS_BSSS | alternate name for top tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BTEE | .. data:: WACS_BTEE | bottom tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_BULLET | .. data:: WACS_BULLET | bullet |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_CKBOARD | .. data:: WACS_CKBOARD | checker board (stipple) |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_DARROW | .. data:: WACS_DARROW | arrow pointing down |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_DEGREE | .. data:: WACS_DEGREE | degree symbol |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_DIAMOND | .. data:: WACS_DIAMOND | diamond |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_GEQUAL | .. data:: WACS_GEQUAL | greater-than-or-equal-to |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_HLINE | .. data:: WACS_HLINE | horizontal line |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LANTERN | .. data:: WACS_LANTERN | lantern symbol |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LARROW | .. data:: WACS_LARROW | left arrow |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LEQUAL | .. data:: WACS_LEQUAL | less-than-or-equal-to |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LLCORNER | .. data:: WACS_LLCORNER | lower-left corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LRCORNER | .. data:: WACS_LRCORNER | lower-right corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_LTEE | .. data:: WACS_LTEE | left tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_NEQUAL | .. data:: WACS_NEQUAL | not-equal sign |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_PI | .. data:: WACS_PI | letter pi |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_PLMINUS | .. data:: WACS_PLMINUS | plus-or-minus sign |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_PLUS | .. data:: WACS_PLUS | big plus sign |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_RARROW | .. data:: WACS_RARROW | right arrow |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_RTEE | .. data:: WACS_RTEE | right tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_S1 | .. data:: WACS_S1 | scan line 1 |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_S3 | .. data:: WACS_S3 | scan line 3 |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_S7 | .. data:: WACS_S7 | scan line 7 |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_S9 | .. data:: WACS_S9 | scan line 9 |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SBBS | .. data:: WACS_SBBS | alternate name for lower-right corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SBSB | .. data:: WACS_SBSB | alternate name for vertical line |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SBSS | .. data:: WACS_SBSS | alternate name for right tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SSBB | .. data:: WACS_SSBB | alternate name for lower-left corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SSBS | .. data:: WACS_SSBS | alternate name for bottom tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SSSB | .. data:: WACS_SSSB | alternate name for left tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_SSSS | .. data:: WACS_SSSS | alternate name for crossover or big plus |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_STERLING | .. data:: WACS_STERLING | pound sterling |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_TTEE | .. data:: WACS_TTEE | top tee |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_UARROW | .. data:: WACS_UARROW | up arrow |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_ULCORNER | .. data:: WACS_ULCORNER | upper-left corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_URCORNER | .. data:: WACS_URCORNER | upper-right corner |
+------------------------+-------------------------+------------------------------------------+
| .. data:: ACS_VLINE | .. data:: WACS_VLINE | vertical line |
+------------------------+-------------------------+------------------------------------------+
The following table lists the double-line and thick-line characters.
They have no ``ACS_*`` counterpart, and are not provided by every implementation.
As in the table above, the alternate name spells out the four sides of the
character, clockwise from the top:
``B`` for a blank side, ``S`` for a single line, ``D`` for a double line and
``T`` for a thick line.
+---------------------------+---------------------+--------------------------------+
| WACS code | Alternate name | Meaning |
+===========================+=====================+================================+
| .. data:: WACS_D_BTEE | .. data:: WACS_DDBD | double-line bottom tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_HLINE | .. data:: WACS_BDBD | double-line horizontal line |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_LLCORNER | .. data:: WACS_DDBB | double-line lower-left corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_LRCORNER | .. data:: WACS_DBBD | double-line lower-right corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_LTEE | .. data:: WACS_DDDB | double-line left tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_PLUS | .. data:: WACS_DDDD | double-line big plus sign |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_RTEE | .. data:: WACS_DBDD | double-line right tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_TTEE | .. data:: WACS_BDDD | double-line top tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_ULCORNER | .. data:: WACS_BDDB | double-line upper-left corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_URCORNER | .. data:: WACS_BBDD | double-line upper-right corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_D_VLINE | .. data:: WACS_DBDB | double-line vertical line |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_BTEE | .. data:: WACS_TTBT | thick-line bottom tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_HLINE | .. data:: WACS_BTBT | thick-line horizontal line |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_LLCORNER | .. data:: WACS_TTBB | thick-line lower-left corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_LRCORNER | .. data:: WACS_TBBT | thick-line lower-right corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_LTEE | .. data:: WACS_TTTB | thick-line left tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_PLUS | .. data:: WACS_TTTT | thick-line big plus sign |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_RTEE | .. data:: WACS_TBTT | thick-line right tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_TTEE | .. data:: WACS_BTTT | thick-line top tee |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_ULCORNER | .. data:: WACS_BTTB | thick-line upper-left corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_URCORNER | .. data:: WACS_BBTT | thick-line upper-right corner |
+---------------------------+---------------------+--------------------------------+
| .. data:: WACS_T_VLINE | .. data:: WACS_TBTB | thick-line vertical line |
+---------------------------+---------------------+--------------------------------+
Mouse buttons
~~~~~~~~~~~~~
The following table lists mouse button constants used by :meth:`getmouse`:
+----------------------------------+---------------------------------------------+
| Mouse button constant | Meaning |
+==================================+=============================================+
| .. data:: BUTTONn_PRESSED | Mouse button *n* pressed |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTONn_RELEASED | Mouse button *n* released |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTONn_CLICKED | Mouse button *n* clicked |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTONn_DOUBLE_CLICKED | Mouse button *n* double clicked |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTONn_TRIPLE_CLICKED | Mouse button *n* triple clicked |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTON_SHIFT | Shift was down during button state change |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTON_CTRL | Control was down during button state change |
+----------------------------------+---------------------------------------------+
| .. data:: BUTTON_ALT | Alt was down during button state change |
+----------------------------------+---------------------------------------------+
.. versionchanged:: 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 |
+=========================+============================+
| .. data:: COLOR_BLACK | Black |
+-------------------------+----------------------------+
| .. data:: COLOR_BLUE | Blue |
+-------------------------+----------------------------+
| .. data:: COLOR_CYAN | Cyan (light greenish blue) |
+-------------------------+----------------------------+
| .. data:: COLOR_GREEN | Green |
+-------------------------+----------------------------+
| .. data:: COLOR_MAGENTA | Magenta (purplish red) |
+-------------------------+----------------------------+
| .. data:: COLOR_RED | Red |
+-------------------------+----------------------------+
| .. data:: COLOR_WHITE | White |
+-------------------------+----------------------------+
| .. data:: COLOR_YELLOW | Yellow |
+-------------------------+----------------------------+
:mod:`!curses.textpad` --- Text input widget for curses programs
================================================================
.. module:: curses.textpad
:synopsis: Emacs-like input editing in a curses window.
The :mod:`!curses.textpad` module provides a :class:`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 :mod:`!curses.textpad` defines the following function:
.. function:: 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.
.. _curses-textpad-objects:
Textbox objects
---------------
You can instantiate a :class:`Textbox` object as follows:
.. class:: Textbox(win, insert_mode=False)
Return a textbox widget object. The *win* argument should be a curses
:ref:`window <curses-window-objects>` 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 :attr:`stripspaces` flag is initially on.
.. versionchanged:: 3.16
Entering and reading back the full Unicode range, including combining
characters, is now supported when curses is built with wide-character
support.
:class:`Textbox` objects have the following methods:
.. method:: 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
:attr:`stripspaces` attribute.
.. versionchanged:: 3.16
*validate* is now called with a non-ASCII character as a string;
other keystrokes are still passed as an integer.
.. method:: 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 |
+==================+===========================================+
| :kbd:`Control-A` | Go to left edge of window. |
+------------------+-------------------------------------------+
| :kbd:`Control-B` | Cursor left, wrapping to previous line if |
| | appropriate. |
+------------------+-------------------------------------------+
| :kbd:`Control-D` | Delete character under cursor. |
+------------------+-------------------------------------------+
| :kbd:`Control-E` | Go to right edge (stripspaces off) or end |
| | of line (stripspaces on). |
+------------------+-------------------------------------------+
| :kbd:`Control-F` | Cursor right, wrapping to next line when |
| | appropriate. |
+------------------+-------------------------------------------+
| :kbd:`Control-G` | Terminate, returning the window contents. |
+------------------+-------------------------------------------+
| :kbd:`Control-H` | Delete character backward. |
+------------------+-------------------------------------------+
| :kbd:`Control-J` | Terminate if the window is 1 line, |
| | otherwise move to the start of the next |
| | line. |
+------------------+-------------------------------------------+
| :kbd:`Control-K` | If line is blank, delete it, otherwise |
| | clear to end of line. |
+------------------+-------------------------------------------+
| :kbd:`Control-L` | Refresh screen. |
+------------------+-------------------------------------------+
| :kbd:`Control-N` | Cursor down; move down one line. |
+------------------+-------------------------------------------+
| :kbd:`Control-O` | Insert a blank line at cursor location. |
+------------------+-------------------------------------------+
| :kbd:`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 |
+================================+==================+
| :const:`~curses.KEY_LEFT` | :kbd:`Control-B` |
+--------------------------------+------------------+
| :const:`~curses.KEY_RIGHT` | :kbd:`Control-F` |
+--------------------------------+------------------+
| :const:`~curses.KEY_UP` | :kbd:`Control-P` |
+--------------------------------+------------------+
| :const:`~curses.KEY_DOWN` | :kbd:`Control-N` |
+--------------------------------+------------------+
| :const:`~curses.KEY_BACKSPACE` | :kbd:`Control-h` |
+--------------------------------+------------------+
All other keystrokes are treated as a command to insert the given
character and move right (with line wrapping).
.. method:: gather()
Return the window contents as a string; whether blanks in the
window are included is affected by the :attr:`stripspaces` member.
.. attribute:: 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.