path: root/Doc/Zsh/mod_curses.yo

COMMENT(!MOD!zsh/curses
curses windowing commands
!MOD!)
The tt(zsh/curses) module makes available one builtin command and
various parameters.

subsect(Builtin)

startitem()
findex(zcurses)
cindex(windows, curses)
xitem(tt(zcurses) tt(init))
xitem(tt(zcurses) tt(end))
xitem(tt(zcurses) tt(addwin) var(targetwin) var(nlines) var(ncols) var(begin_y) var(begin_x) [ var(parentwin) ] )
xitem(tt(zcurses) tt(delwin) var(targetwin) )
xitem(tt(zcurses) tt(refresh) [ var(targetwin) ... ] )
xitem(tt(zcurses) tt(touch) var(targetwin) ...)
xitem(tt(zcurses) tt(move) var(targetwin) var(new_y) var(new_x) )
xitem(tt(zcurses) tt(clear) var(targetwin) [ tt(redraw) | tt(eol) | tt(bot) ])
xitem(tt(zcurses) tt(position) var(targetwin) var(array))
xitem(tt(zcurses) tt(char) var(targetwin) var(character) )
xitem(tt(zcurses) tt(string) var(targetwin) var(string) )
xitem(tt(zcurses) tt(border) var(targetwin) var(border) )
xitem(tt(zcurses) tt(attr) var(targetwin) [ [tt(+)|tt(-)]var(attribute) | var(fg_col)tt(/)var(bg_col) ] [...])
xitem(tt(zcurses) tt(bg) var(targetwin) [ [tt(+)|tt(-)]var(attribute) | var(fg_col)tt(/)var(bg_col) | tt(@)var(char) ] [...])
xitem(tt(zcurses) tt(scroll) var(targetwin) [ tt(on) | tt(off) | [tt(+)|tt(-)]var(lines) ])
xitem(tt(zcurses) tt(input) var(targetwin) [ var(param) [ var(kparam) [ var(mparam) ] ] ])
xitem(tt(zcurses) tt(mouse) [ tt(delay) var(num) | [tt(+)|tt(-)]tt(motion) ])
xitem(tt(zcurses) tt(timeout) var(targetwin) var(intval))
xitem(tt(zcurses) tt(querychar) var(targetwin) [ var(param) ])
item(tt(zcurses) tt(resize) var(height) var(width) [ tt(endwin) | tt(nosave) | tt(endwin_nosave) ])(
Manipulate curses windows.  All uses of this command should be
bracketed by `tt(zcurses init)' to initialise use of curses, and
`tt(zcurses end)' to end it; omitting `tt(zcurses end)' can cause
the terminal to be in an unwanted state.

The subcommand tt(addwin) creates a window with var(nlines) lines and
var(ncols) columns.  Its upper left corner will be placed at row
var(begin_y) and column
var(begin_x) of the screen.  var(targetwin) is a string and refers
to the name of a window that is not currently assigned.  Note
in particular the curses convention that vertical values appear
before horizontal values.

If tt(addwin) is given an existing window as the final argument, the new
window is created as a subwindow of var(parentwin).  This differs from an
ordinary new window in that the memory of the window contents is shared
with the parent's memory.  Subwindows must be deleted before their parent.
Note that the coordinates of subwindows are relative to the screen, not
the parent, as with other windows.

Use the subcommand tt(delwin) to delete a window created with
tt(addwin).  Note that tt(end) does em(not) implicitly delete windows,
and that tt(delwin) does not erase the screen image of the window.

The window corresponding to the full visible screen is called
tt(stdscr); it always exists after `tt(zcurses init)' and cannot
be delete with tt(delwin).

The subcommand tt(refresh) will refresh window var(targetwin); this is
necessary to make any pending changes (such as characters you have
prepared for output with tt(char)) visible on the screen.  tt(refresh)
without an argument causes the screen to be cleared and redrawn.
If multiple windows are given, the screen is updated once at the end.

The subcommand tt(touch) marks the var(targetwin)s listed as changed.
This is necessary before tt(refresh)ing windows if a window that
was in front of another window (which may be tt(stdscr)) is deleted.

The subcommand tt(move) moves the cursor position in var(targetwin) to
new coordinates var(new_y) and var(new_x).  Note that the 
subcommand tt(string) (but not the subcommand tt(char)) advances the
cursor position over the characters added.

The subcommand tt(clear) erases the contents of var(targetwin).  One
(and no more than one) of three options may be specified.  With the
option tt(redraw), in addition the next tt(refresh) of var(targetwin)
will cause the screen to be cleared and repainted.  With the option
tt(eol), var(targetwin) is only cleared to the end of the current cursor
line.  With the option
tt(bot), var(targetwin) is cleared to the end of the window, i.e
everything to the right and below the cursor is cleared.

The subcommand tt(position) writes various positions associated with
var(targetwin) into the array named var(array).
These are, in order:
startsitem()
sitem(-)(The y and x coordinates of the cursor relative to the top left
of var(targetwin))
sitem(-)(The y and x coordinates of the top left of var(targetwin) on the
screen)
sitem(-)(The size of var(targetwin) in y and x dimensions.)
endsitem()

Outputting characters and strings are achieved by tt(char) and tt(string)
respectively.

To draw a border around window var(targetwin), use tt(border).  Note
that the border is not subsequently handled specially:  in other words,
the border is simply a set of characters output at the edge of the
window.  Hence it can be overwritten, can scroll off the window, etc.

The subcommand tt(attr) will set var(targetwin)'s attributes or
foreground/background color pair for any successive character output.
Each var(attribute) given on the line may be prepended by a tt(+) to set
or a tt(-) to unset that attribute; tt(+) is assumed if absent.  The
attributes supported are tt(blink), tt(bold), tt(dim), tt(reverse),
tt(standout), and tt(underline).

Each var(fg_col)tt(/)var(bg_col) attribute (to be read as
`var(fg_col) on var(bg_col)') sets the foreground and background color
for character output.  The color tt(default) is sometimes available
(in particular if the library is ncurses), specifying the foreground
or background color with which the terminal started.  The color pair
tt(default/default) is always available. To use more than the 8 named
colors (red, green, etc.) construct the var(fg_col)tt(/)var(bg_col)
pairs where var(fg_col) and var(bg_col) are decimal integers, e.g
tt(128/200).  The maximum color value is 254 if the terminal supports
256 colors.

tt(bg) overrides the color and other attributes of all characters in the
window.  Its usual use is to set the background initially, but it will
overwrite the attributes of any characters at the time when it is called.
In addition to the arguments allowed with tt(attr), an argument tt(@)var(char)
specifies a character to be shown in otherwise blank areas of the window.
Owing to limitations of curses this cannot be a multibyte character
(use of ASCII characters only is recommended).  As the specified set
of attributes override the existing background, turning attributes
off in the arguments is not useful, though this does not cause an error.

The subcommand tt(scroll) can be used with tt(on) or tt(off) to enabled
or disable scrolling of a window when the cursor would otherwise move
below the window due to typing or output.  It can also be used with a
positive or negative integer to scroll the window up or down the given
number of lines without changing the current cursor position (which
therefore appears to move in the opposite direction relative to the
window).  In the second case, if scrolling is tt(off) it is temporarily
turned tt(on) to allow the window to be scrolled.

The subcommand tt(input) reads a single character from the window
without echoing it back.  If var(param) is supplied the character is
assigned to the parameter var(param), else it is assigned to the
parameter tt(REPLY).

If both var(param) and var(kparam) are supplied, the key is read in
`keypad' mode.  In this mode special keys such as function keys and
arrow keys return the name of the key in the parameter var(kparam).  The
key names are the macros defined in the tt(curses.h) or tt(ncurses.h)
with the prefix `tt(KEY_)' removed; see also the description of the
parameter tt(zcurses_keycodes) below.  Other keys cause a value to be
set in var(param) as before.  On a successful return only one of
var(param) or var(kparam) contains a non-empty string; the other is set
to an empty string.

If var(mparam) is also supplied, tt(input) attempts to handle mouse
input.  This is only available with the ncurses library; mouse handling
can be detected by checking for the exit status of `tt(zcurses mouse)' with
no arguments.  If a mouse
button is clicked (or double- or triple-clicked, or pressed or released with
a configurable delay from being clicked) then var(kparam) is set to the string
tt(MOUSE), and var(mparam) is set to an array consisting of the
following elements:
startitem()
sitem(-)(An identifier to discriminate different input devices; this
is only rarely useful.)
sitem(-)(The x, y and z coordinates of the mouse click relative to
the full screen, as three elements in that order (i.e. the y coordinate
is, unusually, after the x coordinate).  The z coordinate is only
available for a few unusual input devices and is otherwise set to zero.)
sitem(-)(Any events that occurred as separate items; usually
there will be just one.  An event consists of tt(PRESSED), tt(RELEASED),
tt(CLICKED), tt(DOUBLE_CLICKED) or tt(TRIPLE_CLICKED) followed
immediately (in the same element) by the number of the button.)
sitem(-)(If the shift key was pressed, the string tt(SHIFT).)
sitem(-)(If the control key was pressed, the string tt(CTRL).)
sitem(-)(If the alt key was pressed, the string tt(ALT).)
endsitem()

Not all mouse events may be passed through to the terminal window;
most terminal emulators handle some mouse events themselves.  Note
that the ncurses manual implies that using input both with and
without mouse handling may cause the mouse cursor to appear and
disappear.

The subcommand tt(mouse) can be used to configure the use of the mouse.
There is no window argument; mouse options are global.
`tt(zcurses mouse)' with no arguments returns status 0 if mouse handling
is possible, else status 1.  Otherwise, the possible arguments (which
may be combined on the same command line) are as follows.
tt(delay) var(num) sets the maximum delay in milliseconds between press and
release events to be considered as a click; the value 0 disables click
resolution, and the default is one sixth of a second.  tt(motion) proceeded
by an optional `tt(PLUS())' (the default) or tt(-) turns on or off
reporting of mouse motion in addition to clicks, presses and releases,
which are always reported.  However, it appears reports for mouse
motion are not currently implemented.

The subcommand tt(timeout) specifies a timeout value for input from
var(targetwin).  If var(intval) is negative, `tt(zcurses input)' waits
indefinitely for a character to be typed; this is the default.  If
var(intval) is zero, `tt(zcurses input)' returns immediately; if there
is typeahead it is returned, else no input is done and status 1 is
returned.  If var(intval) is positive, `tt(zcurses input)' waits
var(intval) milliseconds for input and if there is none at the end of
that period returns status 1.

The subcommand tt(querychar) queries the character at the current cursor
position.  The return values are stored in the array named var(param) if
supplied, else in the array tt(reply).  The first value is the character
(which may be a multibyte character if the system supports them); the
second is the color pair in the usual var(fg_col)tt(/)var(bg_col)
notation, or tt(0) if color is not supported.  Any attributes other than
color that apply to the character, as set with the subcommand tt(attr),
appear as additional elements.

The subcommand tt(resize) resizes tt(stdscr) and all windows to given
dimensions (windows that stick out from the new dimensions are resized
down). The underlying curses extension (tt(resize_term call)) can be
unavailable. To verify, zeroes can be used for var(height) and
var(width). If the result of the subcommand is tt(0), resize_term is
available (tt(2) otherwise). Tests show that resizing can be normally
accomplished by calling tt(zcurses end) and tt(zcurses refresh). The
tt(resize) subcommand is provided for versatility. Multiple system
configurations have been checked and tt(zcurses end) and tt(zcurses
refresh) are still needed for correct terminal state after resize. To
invoke them with tt(resize), use var(endwin) argument.  Using
var(nosave) argument will cause new terminal state to not be saved
internally by tt(zcurses). This is also provided for versatility and
should normally be not needed.
)
enditem()

subsect(Parameters)

startitem()
vindex(ZCURSES_COLORS)
item(tt(ZCURSES_COLORS))(
Readonly integer.  The maximum number of colors the terminal
supports.  This value is initialised by the curses library and is not
available until the first time tt(zcurses init) is run.
)
vindex(ZCURSES_COLOR_PAIRS)
item(tt(ZCURSES_COLOR_PAIRS))(
Readonly integer.  The maximum number of color pairs
var(fg_col)tt(/)var(bg_col) that may be defined in `tt(zcurses attr)'
commands; note this limit applies to all color pairs that have been
used whether or not they are currently active.  This value is initialised
by the curses library and is not available until the first time tt(zcurses
init) is run.
)
vindex(zcurses_attrs)
item(tt(zcurses_attrs))(
Readonly array.  The attributes supported by tt(zsh/curses); available
as soon as the module is loaded.
)
vindex(zcurses_colors)
item(tt(zcurses_colors))(
Readonly array.  The colors supported by tt(zsh/curses); available
as soon as the module is loaded.
)
vindex(zcurses_keycodes)
item(tt(zcurses_keycodes))(
Readonly array.  The values that may be returned in the second
parameter supplied to `tt(zcurses input)' in the order in which they
are defined internally by curses.  Not all function keys
are listed, only tt(F0); curses reserves space for tt(F0) up to tt(F63).
)
vindex(zcurses_windows)
item(tt(zcurses_windows))(
Readonly array.  The current list of windows, i.e. all windows that
have been created with `tt(zcurses addwin)' and not removed with
`tt(zcurses delwin)'.
)
enditem()