\section{\module{curses} --- Screen painting and input handling for character-cell terminals} \declaremodule{extension}{curses} \sectionauthor{Moshe Zadka}{mzadka@geocities.com} \sectionauthor{Eric Raymond}{esr@thyrsus.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. 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. \begin{seealso} \seemodule{curses.ascii}{Utilities for working with \ASCII{} characters, regardless of your locale settings.} \seemodule{curses.textbox}{Editable text widget for curses supporting Emacs-like bindings.} \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. 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. \end{funcdesc} \begin{funcdesc}{beep}{} Emit a short attention 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. 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 \function{raw()} then \function{cbreak()} leaves the terminal in 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. On many terminals, the ``visible'' mode is an underline cursor and the ``very visible'' mode is a block cursor. \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 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 \function{doupdate()} ground updates the physical screen to match the virtual screen. The virtual screen may be updated by a \method{noutrefresh()} call after write operations such as \method{addstr()} have been performed on a window. The normal \method{refresh()} call is simply \method{noutrefresh()} followed by \function{doupdate()}; if you have to update multiple windows, you can speed performance and perhaps reduce screen flicker by issuing \method{noutrefresh()} calls on all windows, followed by a single \function{doupdate()}. \end{funcdesc} \begin{funcdesc}{echo}{} Enter echo mode. In echo mode, each character input is echoed to the screen as it is entered. \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. 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. \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. The effect is that the cursor is confined to the current line, and so are screen updates. This may be used for enabling cgaracter-at-a-time line editing without touching the rest of the screen. \end{funcdesc} \begin{funcdesc}{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 \function{beep()}. \end{funcdesc} \begin{funcdesc}{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. \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 display colors; otherwise, it returns false. \end{funcdesc} \begin{funcdesc}{has_ic}{} Returns 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. \end{funcdesc} \begin{funcdesc}{has_il}{} Returns 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. \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 \function{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. This function is a no-op on most terminals; it is active only if \function{can_change_color()} returns 1. \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 (that is, the curses library has been deinitialized). \end{funcdesc} \begin{funcdesc}{keyname}{k} Return the name of the key numbered \var{k}. The name of a key generating printable ASCII character is the key's character. The name of a control-key combination is a two-character string consisting of a caret followed by the corresponding printable ASCII character. The name of an alt-key combination (128-255) is a string consisting of the prefix `M-' followed by the name of the corresponding ASCII character. \end{funcdesc} \begin{funcdesc}{killchar}{} Returns the user's current line kill character. 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. \end{funcdesc} \begin{funcdesc}{longname}{} Returns a string 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 \function{initscr()}. \end{funcdesc} \begin{funcdesc}{meta}{yes} If \var{yes} is 1, allow 8-bit characters to be input. 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. The \method{refresh()} and \method{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 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. \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 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. \end{funcdesc} \begin{funcdesc}{nocbreak}{} Leave cbreak mode. Return to normal ``cooked'' mode with line buffering. \end{funcdesc} \begin{funcdesc}{noecho}{} Leave echo mode. Echoing of input characters is turned off, \end{funcdesc} \begin{funcdesc}{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 \code{addch('\e 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. \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. Return to normal ``cooked'' mode with line buffering. \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)}; emits the value of a specified terminfo capability for the current terminal. 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. 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. \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}{tigetflag}{capname} Returns the value of the Boolean capability corresponding to the terminfo capability name \var{capname}. The value -1 is returned if \var{capname} is not a Boolean capability, or 0 if it is canceled or absent from the terminal description. \end{funcdesc} \begin{funcdesc}{tigetnum}{capname} Returns the value of the numeric capability corresponding to the terminfo capability name \var{capname}. The value -2 is returned if \var{capname} is not a numeric capability, or -1 if it is canceled or absent from the terminal description. \end{funcdesc} \begin{funcdesc}{tigetstr}{capname} Returns the value of the string capability corresponding to the terminfo capability name \var{capname}. \code{None} is returned if \var{capname} is not a string capability, or is canceled or absent from the terminal description. \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.) The builtin \function{ord()} is handy for conveying strings to codes. 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} Remove attribute \var{attr} from the ``background'' set applied to all writes to the current window. \end{methoddesc} \begin{methoddesc}{attron}{attr} Add attribute \var{attr} from the ``background'' set applied to all writes to the current window. \end{methoddesc} \begin{methoddesc}{attrset}{attr} Set the ``background'' set of attributes to \var{attr}. This set is initially 0 (no attributes). \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 window 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 window completely. \end{methoddesc} \begin{methoddesc}{clrtobot}{} Erase from cursor to the end of the window: 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} on the window. \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 relative to the window's upper-left corner. \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 on update, instead of being at ``cursor position.'' This reduces cursor movement where possible. If possible the cursor 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 the standout attribute. On some terminals this has the side effect of turning 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}{solid square block} \lineii{ACS_BOARD}{board of squares} \lineii{ACS_BSBS}{} \lineii{ACS_BSSB}{} \lineii{ACS_BSSS}{} \lineii{ACS_BTEE}{bottom tee} \lineii{ACS_BULLET}{bullet} \lineii{ACS_CKBOARD}{checker board (stipple)} \lineii{ACS_DARROW}{arrow pointing down} \lineii{ACS_DEGREE}{degree symbol} \lineii{ACS_DIAMOND}{diamond} \lineii{ACS_GEQUAL}{greater-than-or-equal-to} \lineii{ACS_HLINE}{horizontal line} \lineii{ACS_LANTERN}{lantern symbol} \lineii{ACS_LARROW}{left arrow} \lineii{ACS_LEQUAL}{less-than-or-equal-to} \lineii{ACS_LLCORNER}{lower left-hand corner} \lineii{ACS_LRCORNER}{lower right-hand corner} \lineii{ACS_LTEE}{left tee} \lineii{ACS_NEQUAL}{not-equal sign} \lineii{ACS_PI}{letter pi} \lineii{ACS_PLMINUS}{plus-or-minus sign} \lineii{ACS_PLUS}{plus sign} \lineii{ACS_RARROW}{right arrow} \lineii{ACS_RTEE}{right tee} \lineii{ACS_S1}{scan line 1} \lineii{ACS_S3}{scan line 3} \lineii{ACS_S7}{scan line 7} \lineii{ACS_S9}{scan line 9} \lineii{ACS_SBBS}{} \lineii{ACS_SBSB}{} \lineii{ACS_SBSS}{} \lineii{ACS_SSBB}{} \lineii{ACS_SSBS}{} \lineii{ACS_SSSB}{} \lineii{ACS_SSSS}{} \lineii{ACS_STERLING}{pound sterling} \lineii{ACS_TTEE}{top tee} \lineii{ACS_UARROW}{up arrow} \lineii{ACS_ULCORNER}{upper left corner} \lineii{ACS_URCORNER}{upper right corner} \lineii{ACS_VLINE}{vertical line} \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}