Doc/lib/libcurses.tex

\section{\module{curses} ---
         Terminal independent console handling}

\declaremodule{extension}{curses}
\sectionauthor{Moshe Zadka}{mzadka@geocities.com}
\modulesynopsis{An interface to the curses library.}

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

While curses is most widely used in the \UNIX{} environment, versions
are available for DOS, OS/2, and possibly other systems as well.  The
extension module has not been tested with all available versions of
curses.

\begin{seealso}
  \seemodule{curses.ascii}{Utilities for working with \ASCII{}
                           characters, regardless of your locale
                           settings.}
  \seetext{Tutorial material on using curses with Python is available
           on the Python Web site as Andrew Kuchling's
\citetitle[http://www.python.org/doc/howto/curses/curses.html]{Curses
           Programming with Python}, at
           \url{http://www.python.org/doc/howto/curses/curses.html}.}
\end{seealso}


\subsection{Functions \label{curses-functions}}

The module \module{curses} defines the following exception:
\begin{excdesc}{error}
Curses function returned an error status.
\end{excdesc}

\strong{Note:} Whenever \var{x} or \var{y} arguments to a function
or a method are optional, they default to the current cursor location.
Whenever \var{attr} is optional, it defaults to \constant{A_NORMAL}.

The module \module{curses} defines the following functions:

\begin{funcdesc}{baudrate}{}
Returns the output speed of the terminal in bits per second.
\end{funcdesc}

\begin{funcdesc}{beep}{}
Emit a short sound.
\end{funcdesc}

\begin{funcdesc}{can_change_color}{}
Returns true or false, depending on whether the programmer can change
the colors displayed by the terminal.
\end{funcdesc}

\begin{funcdesc}{cbreak}{}
Enter cbreak mode.
\end{funcdesc}

\begin{funcdesc}{color_content}{color_number}
Returns the intensity of the red, green, and blue (RGB) components in
the color \var{color_number}, which must be between 0 and COLORS.  A
3-tuple is returned, containing the R,G,B values for the given color,
which will be between 0 (no component) and 1000 (maximum amount of
component).
\end{funcdesc}

\begin{funcdesc}{color_pair}{color_number}
Returns the attribute value for displaying text in the specified
color.  This attribute value can be combined with
\constant{A_STANDOUT}, \constant{A_REVERSE}, and the other
\constant{A_*} attributes.  \function{pair_number()} is the counterpart to this function.
\end{funcdesc}

\begin{funcdesc}{curs_set}{visibility}
Sets the cursor state.  \var{visibility} can be set to 0, 1, or 2, for
invisible, normal, or very visible.  If the terminal supports the
visibility requested, the previous cursor state is returned;
otherwise, an exception is raised.
\end{funcdesc}

\begin{funcdesc}{def_prog_mode}{}
Saves 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 \function{reset_prog_mode()} will restore this mode.
\end{funcdesc}

\begin{funcdesc}{def_shell_mode}{}
Saves 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 \function{reset_shell_mode()} will restore this mode.
\end{funcdesc}

\begin{funcdesc}{delay_output}{ms}
Inserts an \var{ms} millisecond pause in output.  
\end{funcdesc}

\begin{funcdesc}{doupdate}{}
Update the screen.
\end{funcdesc}

\begin{funcdesc}{echo}{}
Enter echo mode.
\end{funcdesc}

\begin{funcdesc}{endwin}{}
De-initialize the library, and return terminal to normal status.
\end{funcdesc}

\begin{funcdesc}{erasechar}{}
Returns the user's current erase character.
\end{funcdesc}

\begin{funcdesc}{filter}{}
The \function{filter()} routine, if used, must be called before 
\function{initscr()} is  called.  

The effect is that, during those calls, 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.  
\end{funcdesc}

\begin{funcdesc}{flash}{}
Flash the screen.
\end{funcdesc}

\begin{funcdesc}{flushinp}{}
Flush all input buffers.
\end{funcdesc}

\begin{funcdesc}{getmouse}{}
After \method{getch()} returns \constant{KEY_MOUSE} to signal a mouse
event, this method should be call to retrieve the queued mouse event,
represented as a 5-tuple
\code{(\var{id}, \var{x}, \var{y}, \var{z}, \var{bstate})}.
\var{id} is an ID value used to distinguish multiple devices,
and \var{x}, \var{y}, \var{z} are the event's coordinates.  (\var{z}
is currently unused.).  \var{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 \var{n} is the button
number from 1 to 4:
\constant{BUTTON\var{n}_PRESSED},
\constant{BUTTON\var{n}_RELEASED},
\constant{BUTTON\var{n}_CLICKED},
\constant{BUTTON\var{n}_DOUBLE_CLICKED},
\constant{BUTTON\var{n}_TRIPLE_CLICKED},
\constant{BUTTON_SHIFT},
\constant{BUTTON_CTRL},
\constant{BUTTON_ALT}.
\end{funcdesc}

\begin{funcdesc}{getsyx}{}
Returns the current coordinates of the virtual screen cursor in y and
x.  If leaveok is currently true, then -1,-1 is returned.
\end{funcdesc}

\begin{funcdesc}{getwin}{file}
Reads window related data stored in the file by an earlier
\function{putwin()} call.  The routine then creates and initializes a
new window using that data, returning the new window object.
\end{funcdesc}

\begin{funcdesc}{has_colors}{}
Returns true if the terminal can manipulate colors; otherwise, it
returns false. 
\end{funcdesc}

\begin{funcdesc}{has_ic}{}
Returns true if the terminal has insert- and delete- character
capabilities.
\end{funcdesc}

\begin{funcdesc}{has_il}{}
Returns true if the terminal has insert- and
delete-line  capabilities,  or  can  simulate  them  using
scrolling regions. 
\end{funcdesc}

\begin{funcdesc}{has_key}{ch}
Takes a key value \var{ch}, and returns true if the current terminal
type recognizes a key with that value.
\end{funcdesc}

\begin{funcdesc}{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 \var{tenths} tenths of seconds, an
exception is raised if nothing has been typed.  The value of
\var{tenths} must be a number between 1 and 255.  Use nocbreak to
leave half-delay mode.
\end{funcdesc}

\begin{funcdesc}{init_color}{color_number, r, g, b}
Changes 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 \var{color_number} must be
between 0 and COLORS.  Each of \var{r}, \var{g}, \var{b}, must be a
value between 0 and 1000.  When \function{init_color()} is used, all
occurrences of that color on the screen immediately change to the new
definition.
\end{funcdesc}

\begin{funcdesc}{init_pair}{pair_number, fg, bg}
Changes 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 \var{pair_number} must
be between 1 and COLOR_PAIRS-1 (the 0 color pair is wired to white on
black and cannot be changed).  The value of \var{fg} and \var{bg}
arguments must be between 0 and COLORS.  If the color-pair was
previously initialized, the screen is refreshed and all occurrences of
that color-pair are changed to the new definition.
\end{funcdesc}

\begin{funcdesc}{initscr}{}
Initialize the library. Returns a \class{WindowObject} which represents
the whole screen.
\end{funcdesc}

\begin{funcdesc}{isendwin}{}
Returns true if \function{endwin()} has been called.
\end{funcdesc}

\begin{funcdesc}{keyname}{k}
Return the name of the key numbered \var{k}.
\end{funcdesc}

\begin{funcdesc}{killchar}{}
Returns the user's current line kill character.
\end{funcdesc}

\begin{funcdesc}{longname}{}
Returns a string containing a verbose description of the current
terminal.  The maximum length of a verbose description is 128
characters.  It is defined only after the call to
\function{initscr()}.
\end{funcdesc}

\begin{funcdesc}{meta}{yes}
If \var{yes} is 1, allow 8-bit characters. If \var{yes} is 0, 
allow only 7-bit chars.
\end{funcdesc}

\begin{funcdesc}{mouseinterval}{interval}
Sets the maximum time in milliseconds that can elapse between press and
release events in order for them to be recognized as a click, and
returns the previous interval value.  The default value is 200 msec,
or one fifth of a second.
\end{funcdesc}

\begin{funcdesc}{mousemask}{mousemask}
Sets the mouse events to be reported, and returns a tuple
\code{(\var{availmask}, \var{oldmask})}.  
\var{availmask} indicates which of the
specified mouse events can be reported; on complete failure it returns
0.  \var{oldmask} is the previous value of the given window's mouse
event mask.  If this function is never called, no mouse events are
ever reported.
\end{funcdesc}

\begin{funcdesc}{newpad}{nlines, ncols}
Creates and returns a pointer to a new pad data structure with the
given number of lines and columns.  A pad is returned 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 (e.g., from scrolling or echoing of
       input) do not occur.  It is not legal to call wrefresh
       with a pad as an argument; the routines prefresh or
       pnoutrefresh should be called instead.  Note that these
       routines require additional parameters to specify the part of
       the pad to be displayed and the location on the screen to be
       used for the display.

\end{funcdesc}

\begin{funcdesc}{newwin}{\optional{nlines, ncols,} begin_y, begin_x}
Return a new window, whose left-upper corner is at 
\code{(\var{begin_y}, \var{begin_x})}, and whose height/width is 
\var{nlines}/\var{ncols}.  

By default, the window will extend from the 
specified position to the lower right corner of the screen.
\end{funcdesc}

\begin{funcdesc}{nl}{}
Enter nl mode.
\end{funcdesc}

\begin{funcdesc}{nocbreak}{}
Leave cbreak mode.
\end{funcdesc}

\begin{funcdesc}{noecho}{}
Leave echo mode.
\end{funcdesc}

\begin{funcdesc}{nonl}{}
Leave nl mode.
\end{funcdesc}

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

\begin{funcdesc}{noraw}{}
Leave raw mode.
\end{funcdesc}

\begin{funcdesc}{pair_content}{pair_number}
Returns a tuple \var{(fg,bg)} containing the colors for the requested
color pair.  The value of \var{pair_number} must be between 0 and
COLOR_PAIRS-1.
\end{funcdesc}

\begin{funcdesc}{pair_number}{attr}
Returns the number of the color-pair set by the attribute value \var{attr}.
\function{color_pair()} is the counterpart to this function.
\end{funcdesc}

\begin{funcdesc}{putp}{string}
Equivalent to \code{tputs(str, 1, putchar)}.  Note that the output of putp always
goes to standard output.
\end{funcdesc}

\begin{funcdesc}{qiflush}{ \optional{flag} }
If \var{flag} is false, the effect is the same as calling
\function{noqiflush()}. If \var{flag} is true, or no argument is
provided, the queues will be flushed when these control characters are
read.
\end{funcdesc}

\begin{funcdesc}{raw}{}
Enter raw mode.
\end{funcdesc}

\begin{funcdesc}{reset_prog_mode}{}
Restores the  terminal  to ``program'' mode, as previously saved 
by \function{def_prog_mode()}.
\end{funcdesc}

\begin{funcdesc}{reset_shell_mode}{}
Restores the  terminal  to ``shell'' mode, as previously saved 
by \function{def_shell_mode()}.
\end{funcdesc}

\begin{funcdesc}{setsyx}{y, x}
Sets the virtual screen cursor to \var{y}, \var{x}.
If \var{y} and \var{x} are both -1, then leaveok is set.  
\end{funcdesc}

\begin{funcdesc}{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 \function{initscr()}.

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

\begin{funcdesc}{termattrs}{}
Returns 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.
\end{funcdesc}

\begin{funcdesc}{termname}{}
Returns the value of the environment variable TERM, truncated to 14
characters.
\end{funcdesc}

\begin{funcdesc}{typeahead}{fd}
Specifies that the file descriptor \var{fd} be used for typeahead
checking.  If \var{fd} is -1, then no typeahead checking is done.

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

\begin{funcdesc}{unctrl}{ch}
Returns a string which is a printable representation of the character
\var{ch}.  Control characters are displayed as a caret followed by the
character, for example as \verb|^C|. Printing characters are left as they
are.
\end{funcdesc}

\begin{funcdesc}{ungetch}{ch}
Push \var{ch} so the next \method{getch()} will return it.
\strong{Note:} only one \var{ch} can be pushed before \method{getch()}
is called.
\end{funcdesc}

\begin{funcdesc}{ungetmouse}{id, x, y, z, bstate}
Push a \constant{KEY_MOUSE} event onto the input queue, associating
the given state data with it.
\end{funcdesc}

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

\subsection{Window Objects \label{curses-window-objects}}

Window objects, as returned by \function{initscr()} and
\function{newwin()} above, have the
following methods:

\begin{methoddesc}{addch}{\optional{y, x,} ch\optional{, attr}}
\strong{Note:} A \emph{character} means a C character (i.e., an
\ASCII{} code), rather then a Python character (a string of length 1).
(This note is true whenever the documentation mentions a character.)

Paint character \var{ch} at \code{(\var{y}, \var{x})} with attributes
\var{attr}, overwriting any character previously painter at that
location.  By default, the character position and attributes are the
current settings for the window object.
\end{methoddesc}

\begin{methoddesc}{addnstr}{\optional{y, x,} str, n\optional{, attr}}
Paint at most \var{n} characters of the 
string \var{str} at \code{(\var{y}, \var{x})} with attributes
\var{attr}, overwriting anything previously on the display.
\end{methoddesc}

\begin{methoddesc}{addstr}{\optional{y, x,} str\optional{, attr}}
Paint the string \var{str} at \code{(\var{y}, \var{x})} with attributes
\var{attr}, overwriting anything previously on the display.
\end{methoddesc}

\begin{methoddesc}{attroff}{attr}
Turn off attribute \var{attr}.
\end{methoddesc}

\begin{methoddesc}{attron}{attr}
Turn on attribute \var{attr}.
\end{methoddesc}

\begin{methoddesc}{attrset}{attr}
Set the attributes to \var{attr}.
\end{methoddesc}

\begin{methoddesc}{bkgd}{ch\optional{, attr}}
Sets the background property of the window to the character \var{ch},
with attributes \var{attr}.  The change is then applied to every
character position in that window:
\begin{itemize}
\item  The attribute of every character in the window  is
              changed to the new background attribute.

\item    Wherever  the  former background character appears,
it is changed to the new background character.
\end{itemize}

\end{methoddesc}

\begin{methoddesc}{bkgdset}{ch\optional{, attr}}
Sets 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.
\end{methoddesc}

\begin{methoddesc}{border}{\optional{ls\optional{, rs\optional{, ts\optional{,
                           bs\optional{, tl\optional{, tr\optional{,
                           bl\optional{, 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.  The characters must be specified as integers;
using one-character strings will cause \exception{TypeError} to be
raised.

\strong{Note:} A \code{0} value for any parameter will cause the
default character to be used for that parameter.  Keyword parameters
can \emph{not} be used.  The defaults are listed in this table:

\begin{tableiii}{l|l|l}{var}{Parameter}{Description}{Default value}
  \lineiii{ls}{Left side}{\constant{ACS_VLINE}}
  \lineiii{rs}{Right side}{\constant{ACS_VLINE}}
  \lineiii{ts}{Top}{\constant{ACS_HLINE}}
  \lineiii{bs}{Bottom}{\constant{ACS_HLINE}}
  \lineiii{tl}{Upper-left corner}{\constant{ACS_ULCORNER}}
  \lineiii{tr}{Upper-right corner}{\constant{ACS_URCORNER}}
  \lineiii{bl}{Bottom-left corner}{\constant{ACS_BLCORNER}}
  \lineiii{br}{Bottom-right corner}{\constant{ACS_BRCORNER}}
\end{tableiii}
\end{methoddesc}

\begin{methoddesc}{box}{\optional{vertch, horch}}
Similar to \method{border()}, but both \var{ls} and \var{rs} are
\var{vertch} and both \var{ts} and {bs} are \var{horch}.  The default
corner characters are always used by this function.
\end{methoddesc}

\begin{methoddesc}{clear}{}
Like \method{erase()}, but also causes the whole screen to be repainted
upon next call to \method{refresh()}.
\end{methoddesc}

\begin{methoddesc}{clearok}{yes}
If \var{yes} is 1, the next call to \method{refresh()}
will clear the screen completely.
\end{methoddesc}

\begin{methoddesc}{clrtobot}{}
Erase from cursor to the end of the screen: all lines below the cursor
are deleted, and then the equivalent of \method{clrtoeol()} is performed.
\end{methoddesc}

\begin{methoddesc}{clrtoeol}{}
Erase from cursor to the end of the line.
\end{methoddesc}

\begin{methoddesc}{cursyncup}{}
Updates the current cursor position of all the ancestors of the window
to reflect the current cursor position of the window.
\end{methoddesc}

\begin{methoddesc}{delch}{\optional{x, y}}
Delete any character at \code{(\var{y}, \var{x})}.
\end{methoddesc}

\begin{methoddesc}{deleteln}{}
Delete the line under the cursor. All following lines are moved up
by 1 line.
\end{methoddesc}

\begin{methoddesc}{derwin}{\optional{nlines, ncols,} begin_y, begin_y}
An abbreviation for ``derive window'', \method{derwin()} is the same
as calling \method{subwin()}, except that \var{begin_y} and
\var{begin_x} are relative to the origin of the window, rather than
relative to the entire screen.  Returns a window object for the
derived window.
\end{methoddesc}

\begin{methoddesc}{echochar}{ch\optional{, attr}}
Add character \var{ch} with attribute \var{attr}, and immediately 
call \method{refresh}.
\end{methoddesc}

\begin{methoddesc}{enclose}{y, x}
Tests 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.
\end{methoddesc}

\begin{methoddesc}{erase}{}
Clear the window.
\end{methoddesc}

\begin{methoddesc}{getbegyx}{}
Return a tuple \code{(\var{y}, \var{x})} of co-ordinates of upper-left
corner.
\end{methoddesc}

\begin{methoddesc}{getch}{\optional{x, y}}
Get a character. Note that the integer returned does \emph{not} have to
be in \ASCII{} range: function keys, keypad keys and so on return numbers
higher then 256. In no-delay mode, an exception is raised if there is 
no input.
\end{methoddesc}

\begin{methoddesc}{getkey}{\optional{x, y}}
Get a character, returning a string instead of an integer, as
\method{getch()} does. Function keys, keypad keys and so on return a
multibyte string containing the key name.  In no-delay mode, an
exception is raised if there is no input.
\end{methoddesc}

\begin{methoddesc}{getmaxyx}{}
Return a tuple \code{(\var{y}, \var{x})} of the height and width of
the window.
\end{methoddesc}

\begin{methoddesc}{getparyx}{}
Returns the beginning coordinates of this window relative to its
parent window into two integer variables y and x.  Returns
\code{-1,-1} if this window has no parent.
\end{methoddesc}

\begin{methoddesc}{getstr}{\optional{x, y}}
Read a string from the user, with primitive line editing capacity.
\end{methoddesc}

\begin{methoddesc}{getyx}{}
Return a tuple \code{(\var{y}, \var{x})} of current cursor position.
\end{methoddesc}

\begin{methoddesc}{hline}{\optional{y, x,} ch, n}
Display a horizontal line starting at \code{(\var{y}, \var{x})} with
length \var{n} consisting of the character \var{ch}.
\end{methoddesc}

\begin{methoddesc}{idcok}{flag}
If \var{flag} is false, curses no longer considers using the hardware
insert/delete character feature of the terminal; if \var{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.
\end{methoddesc}

\begin{methoddesc}{idlok}{yes}
If called with \var{yes} equal to 1, \module{curses} will try and use
hardware line editing facilities. Otherwise, line insertion/deletion
are disabled.
\end{methoddesc}

\begin{methoddesc}{immedok}{flag}
If \var{flag} is true, any change in the window image
automatically causes the window to be refreshed; you no longer
have to call \method{refresh()} yourself.  However, it may
degrade performance considerably, due to repeated calls to
wrefresh.  This option is disabled by default.
\end{methoddesc}

\begin{methoddesc}{inch}{\optional{x, y}}
Return the character at the given position in the window. The bottom
8 bits are the character proper, and upper bits are the attributes.
\end{methoddesc}

\begin{methoddesc}{insch}{\optional{y, x,} ch\optional{, attr}}
Paint character \var{ch} at \code{(\var{y}, \var{x})} with attributes
\var{attr}, moving the line from position \var{x} right by one
character.
\end{methoddesc}

\begin{methoddesc}{insdelln}{nlines}
Inserts \var{nlines} lines into the specified window above the current
line.  The \var{nlines} bottom lines are lost.  For negative
\var{nlines}, delete \var{nlines} lines starting with the one under
the cursor, and move the remaining lines up.  The bottom \var{nlines}
lines are cleared.  The current cursor position remains the same.
\end{methoddesc}

\begin{methoddesc}{insertln}{}
Insert a blank line under the cursor. All following lines are moved
down by 1 line.
\end{methoddesc}

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

\begin{methoddesc}{insstr}{\optional{y, x, } str \optional{, 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 the rightmost characters on the
line being lost.  The cursor position does not change (after moving to
\var{y}, \var{x}, if specified). 
\end{methoddesc}

\begin{methoddesc}{instr}{\optional{y, x} \optional{, n}}
Returns a string of characters, extracted from the window starting at
the current cursor position, or at \var{y}, \var{x} if specified.
Attributes are stripped from the characters.  If \var{n} is specified,
\method{instr()} returns return a string at most \var{n} characters
long (exclusive of the trailing NUL).
\end{methoddesc}

\begin{methoddesc}{is_linetouched}{\var{line}}
Returns true if the specified line was modified since the last call to
\method{refresh()}; otherwise returns false.  Raises a
\exception{curses.error} exception if \var{line} is not valid
for the given window.
\end{methoddesc}

\begin{methoddesc}{is_wintouched}{}
Returns true if the specified window was modified since the last call to
\method{refresh()}; otherwise returns false.
\end{methoddesc}

\begin{methoddesc}{keypad}{yes}
If \var{yes} is 1, escape sequences generated by some keys (keypad, 
function keys) will be interpreted by \module{curses}.
If \var{yes} is 0, escape sequences will be left as is in the input
stream.
\end{methoddesc}

\begin{methoddesc}{leaveok}{yes}
If \var{yes} is 1,
cursor is left where it is, instead of being at ``cursor position.''
This reduces cursor movement where possible. If possible it will be made
invisible.

If \var{yes} is 0, cursor will always be at
``cursor position'' after an update.
\end{methoddesc}

\begin{methoddesc}{move}{new_y, new_x}
Move cursor to \code{(\var{new_y}, \var{new_x})}.
\end{methoddesc}

\begin{methoddesc}{mvderwin}{y, x}
Moves 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.
\end{methoddesc}

\begin{methoddesc}{mvwin}{new_y, new_x}
Move the window so its upper-left corner is at \code{(\var{new_y}, \var{new_x})}.
\end{methoddesc}

\begin{methoddesc}{nodelay}{yes}
If \var{yes} is 1, \method{getch()} will be non-blocking.
\end{methoddesc}

\begin{methoddesc}{notimeout}{yes}
If \var{yes} is 1, escape sequences will not be timed out.

If \var{yes} is 0, after a few milliseconds, an escape sequence will
not be interpreted, and will be left in the input stream as is.
\end{methoddesc}

\begin{methoddesc}{noutrefresh}{}
Mark for refresh but wait.
\end{methoddesc}

\begin{methoddesc}{putwin}{file}
Writes all data associated with the window into the provided file
object.  This information can be later retrieved using the
\function{getwin()} function.

\end{methoddesc}

\begin{methoddesc}{redrawln}{beg, num}
Indicates that the \var{num} screen lines, starting at line \var{beg},
are corrupted and should be completely redrawn on the next
\method{refresh()} call.
\end{methoddesc}

\begin{methoddesc}{redrawwin}{}
Touches the entire window, causing it to be completely redrawn on the
next \method{refresh()} call.
\end{methoddesc}

\begin{methoddesc}{refresh}{ \optional{pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol} }
Update the display immediately (sync actual screen with previous
drawing/deleting methods).

The 6 optional arguments can only be specified when the window is a
pad created with \function{newpad()}.  The additional parameters are
needed to indicate what part of the pad and screen are involved.
\var{pminrow} and \var{pmincol} specify the upper left-hand corner of the
rectangle to be displayed in the pad.  \var{sminrow}, \var{smincol},
\var{smaxrow}, and \var{smaxcol} specify the edges of the rectangle to be displayed on the screen.  The lower right-hand 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 \var{pminrow}, \var{pmincol},
\var{sminrow}, or \var{smincol} are treated as if they were zero.
\end{methoddesc}

\begin{methoddesc}{scroll}{\optional{lines\code{ = 1}}}
Scroll the screen upward by \var{lines} lines.
\end{methoddesc}

\begin{methoddesc}{scrollok}{flag}
Controls 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 \var{flag} is false, the cursor is left
       on the bottom line.  If \var{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
       \method{idlok()}.
\end{methoddesc}

\begin{methoddesc}{setscrreg}{top, bottom}
Set the scrolling region from line \var{top} to line \var{bottom}. All
scrolling actions will take place in this region.
\end{methoddesc}

\begin{methoddesc}{standend}{}
Turn off all attributes.
\end{methoddesc}

\begin{methoddesc}{standout}{}
Turn on attribute \var{A_STANDOUT}.
\end{methoddesc}

\begin{methoddesc}{subpad}{\optional{nlines, ncols,} begin_y, begin_y}
Return a sub-window, whose upper-left corner is at
\code{(\var{begin_y}, \var{begin_x})}, and whose width/height is
\var{ncols}/\var{nlines}.
\end{methoddesc}

\begin{methoddesc}{subwin}{\optional{nlines, ncols,} begin_y, begin_y}
Return a sub-window, whose upper-left corner is at
\code{(\var{begin_y}, \var{begin_x})}, and whose width/height is
\var{ncols}/\var{nlines}.

By default, the sub-window will extend from the
specified position to the lower right corner of the window.
\end{methoddesc}

\begin{methoddesc}{syncdown}{}
Touches each location in the window that has been touched in any of
its ancestor windows.  This routine is called by \method{refresh()},
so it should almost never be necessary to call it manually.
\end{methoddesc}

\begin{methoddesc}{syncok}{flag}
If called with \var{flag} set to true, then \method{syncup()} is
called automatically whenever there is a change in the window.
\end{methoddesc}

\begin{methoddesc}{syncup}{}
Touches all locations in ancestors of the window that have been changed in 
the window.  
\end{methoddesc}

\begin{methoddesc}{timeout}{delay}
Sets blocking or non-blocking read behavior for the window.  If
\var{delay} is negative, blocking read is used, which will wait
indefinitely for input).  If \var{delay} is zero, then non-blocking
read is used, and -1 will be returned by \method{getch()} if no input
is waiting.  If \var{delay} is positive, then \method{getch()} will
block for \var{delay} milliseconds, and return -1 if there is still no
input at the end of that time.
\end{methoddesc}

\begin{methoddesc}{touchline}{start, count}
Pretend \var{count} lines have been changed, starting with line
\var{start}.
\end{methoddesc}

\begin{methoddesc}{touchwin}{}
Pretend the whole window has been changed, for purposes of drawing
optimizations.
\end{methoddesc}

\begin{methoddesc}{untouchwin}{}
Marks all lines in  the  window  as unchanged since the last call to
\method{refresh()}. 
\end{methoddesc}

\begin{methoddesc}{vline}{\optional{y, x,} ch, n}
Display a vertical line starting at \code{(\var{y}, \var{x})} with
length \var{n} consisting of the character \var{ch}.
\end{methoddesc}

\subsection{Constants}

The \module{curses} module defines the following data members:

\begin{datadesc}{version}
A string representing the current version of the module. 
Also available as \constant{__version__}.
\end{datadesc}


\begin{tableii}{c|l}{code}{Attribute}{Meaning}
  \lineii{A_ALTCHARSET}{Alternate character set mode.}
  \lineii{A_BLINK}{Blink mode.}
  \lineii{A_BOLD}{Bold mode.}
  \lineii{A_DIM}{Dim mode.}
  \lineii{A_NORMAL}{Normal attribute.}
  \lineii{A_STANDOUT}{Standout mode.}
  \lineii{A_UNDERLINE}{Underline mode.}
\end{tableii}

Keys are referred to by integer constants with names starting with 
\code{KEY_}.   The exact names available are system dependent.

% XXX this table is far too large!
% XXX should this table be alphabetized?

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

The following table lists characters from the alternate character set.
\strong{Note:} These are available only after \function{initscr()} has 
been called.

\begin{tableii}{c|l}{code}{ACS code}{Meaning}
  \lineii{ACS_BBSS}{}
  \lineii{ACS_BLOCK}{}
  \lineii{ACS_BOARD}{}
  \lineii{ACS_BSBS}{}
  \lineii{ACS_BSSB}{}
  \lineii{ACS_BSSS}{}
  \lineii{ACS_BTEE}{}
  \lineii{ACS_BULLET}{}
  \lineii{ACS_CKBOARD}{}
  \lineii{ACS_DARROW}{}
  \lineii{ACS_DEGREE}{}
  \lineii{ACS_DIAMOND}{}
  \lineii{ACS_GEQUAL}{ (Not available with SGI curses)}
  \lineii{ACS_HLINE}{}
  \lineii{ACS_LANTERN}{}
  \lineii{ACS_LARROW}{}
  \lineii{ACS_LEQUAL}{ (Not available with SGI curses)}
  \lineii{ACS_LLCORNER}{}
  \lineii{ACS_LRCORNER}{}
  \lineii{ACS_LTEE}{}
  \lineii{ACS_NEQUAL}{ (Not available with SGI curses)}
  \lineii{ACS_PI}{ (Not available with SGI curses)}
  \lineii{ACS_PLMINUS}{}
  \lineii{ACS_PLUS}{}
  \lineii{ACS_RARROW}{}
  \lineii{ACS_RTEE}{}
  \lineii{ACS_S1}{}
  \lineii{ACS_S3}{ (Not available with SGI curses)}
  \lineii{ACS_S9}{}
  \lineii{ACS_SBBS}{}
  \lineii{ACS_SBSB}{}
  \lineii{ACS_SBSS}{}
  \lineii{ACS_SSBB}{}
  \lineii{ACS_SSBS}{}
  \lineii{ACS_SSSB}{}
  \lineii{ACS_SSSS}{}
  \lineii{ACS_STERLING}{ (Not available with SGI curses)}
  \lineii{ACS_TTEE}{}
  \lineii{ACS_UARROW}{}
  \lineii{ACS_ULCORNER}{}
  \lineii{ACS_URCORNER}{}
  \lineii{ACS_VLINE}{}
\end{tableii}

The following table lists the predefined colors:

\begin{tableii}{c|l}{code}{Constant}{Color}
  \lineii{COLOR_BLACK}{Black}
  \lineii{COLOR_BLUE}{Blue}
  \lineii{COLOR_CYAN}{Cyan (light greenish blue)}
  \lineii{COLOR_GREEN}{Green}
  \lineii{COLOR_MAGENTA}{Magenta (purplish red)}
  \lineii{COLOR_RED}{Red}
  \lineii{COLOR_WHITE}{White}
  \lineii{COLOR_YELLOW}{Yellow}
\end{tableii}