.TH RIO 4
.SH NAME
rio \- window system files
.SH SYNOPSIS
.B rio
[
.B -i
.BI ' cmd '
]
[
.B -s
]
[
.B -f
.I font
]
.SH DESCRIPTION
The window system
.I rio
serves a variety of files for reading, writing, and controlling
windows.
Some of them are virtual versions of system files for dealing
with the display, keyboard, and mouse; others control operations
of the window system itself.
.I Rio
posts its service in the
.B /srv
directory, using a
name constructed from a catenation of the user ID
and a process id; the environment variable
.BR $wsys
is set to this service name within processes running under the control
of each invocation of
.IR rio .
Similarly,
.I rio
posts a named pipe to access the window creation features
(see
.B window
in
.IR rio (1))
from outside
its name space; this is named in
.BR $wctl .
.PP
A
.I mount
(see
.IR bind (1))
of
.B $wsys
causes
.I rio
to create a new window; the attach specifier in the
.I mount
gives the coordinates of the created window.
The syntax of the specifier is the same as the arguments to
.B window
(see
.IR rio (1)).
By default, the window is sized and placed automatically.
It is always necessary, however, to provide the process id of the
process to whom to deliver notes generated by DEL characters and hangups
in that window.
That pid is specified by including the string
.B -pid
.I pid
in the attach specifier.  (See the Examples section
.IR q.v. )
.PP
When a window is created either by
the
.I window
command
(see
.IR rio (1))
or by using the menu supplied by
.IR rio ,
this server is mounted on
.BR /mnt/wsys
and also
.BR /dev ;
the files mentioned here
appear in both those directories.
.PP
Some of these files supply virtual versions of services available from the underlying
environment, in particular the character terminal files
.IR cons (3),
and the mouse files
.IR mouse (3)
and
.IR cursor ,
each specific to the window.
Note that the
.IR draw (3)
device multiplexes itself;
.IR rio
places windows but does not mediate programs' access to the display device.
.PP
Other files are unique to
.IR rio .
.TF window
.TP
.B cons
is a virtual version of the standard terminal file
.IR cons (3).
.I Rio
supplies extra editing features and a scroll bar
(see
.IR rio (1)).
.TP
.B consctl
controls interpretation of keyboard input.
Writing strings to it sets these modes:
.B rawon
turns on raw mode;
.B rawoff
turns off raw mode;
.B holdon
turns on hold mode;
.B holdoff
turns off hold mode.
Closing the file makes the window revert to default state
(raw off, hold off).
.TP
.B cursor
Like
.B mouse
.RI ( q.v. ),
a multiplexed version of the underlying device file, in this case representing the
appearance of the mouse cursor when the mouse is within the corresponding window.
.TP
.B label
initially contains a string with the process ID of the lead process
in the window and the command being executed there.
It may be written and is used as a tag when the window is hidden.
.TP
.B mouse
is a virtual version of the standard mouse file (see
.IR mouse (3)).
Opening it turns off scrolling, editing, and
.IR rio -supplied
menus in the associated
window.
In a standard mouse message, the first character is
.BR m ,
but
.I rio
will send an otherwise normal message with the first character
.B r
if the corresponding window has been resized.
The application must then call
.B getwindow
(see
.IR graphics (2))
to re-establish its state in the newly moved or changed window.
Reading the
.B mouse
file blocks until the mouse moves or a button changes.
Mouse movements or button changes are invisible when the mouse cursor
is located outside the window, except that if the mouse leaves the window
while a button is pressed, it will continue receiving mouse data until the button is released.
.TP
.B screen
is a read-only file reporting the depth, coordinates, and raster image corresponding to the entire
underlying display,
in the uncompressed format defined in
.IR image (6).
.TP
.B snarf
returns the string currently in the snarf buffer.
Writing this file sets the contents of the snarf buffer.
When
.I rio
is run recursively, the inner instance uses the snarf buffer of the parent, rather than
managing its own.
.TP
.B text
returns the full contents of the window.
It may not be written.
.TP
.B wctl
may be read or written.
When read, it returns the location of the window as four decimal integers formatted
in the usual 12-character style: upper left
.I x
and
.IR y ,
lower right
.I x
and
.IR y .
Following these numbers are strings describing the window's state:
.B hidden
or
.BR visible ;
.B current
or
.BR notcurrent .
A subsequent read will block until the window changes size, location, or state.
When written to,
.B wctl
accepts messages to change the size or placement of the associated window,
and to create new windows.
The messages are in a command-line like format, with a command name,
possibly followed by options introduced by a minus sign.
The options must be separated by blanks, for example
.B -dx 100
rather than
.BR -dx100 .
.IP
The commands are
.B resize
(change the size and position of the window),
.B move
(move the window),
.B scroll
(enable scrolling in the window),
.B noscroll
(disable scrolling),
.B set
(change selected properties of the window),
.B top
(move the window to the `top', making it fully visible),
.B bottom
(move the window to the `bottom', perhaps partially or totally obscuring it),
.B hide
(hide the window),
.B unhide
(restore a hidden window),
.B current
(make the window the recipient of keyboard and mouse input),
and
.B new
(make a new window).
The
.B top
and
.B bottom
commands do not change whether the window is current or not;
the others always make the affected window current.
.IP
Neither
.B top
nor
.B bottom
has any options.
The
.BR resize ,
.BR move ,
and
.B new
commands accept
.B -minx
.IR n ,
.B -miny
.IR n ,
.B -maxx
.IR n ,
and
.BR -maxy
.I n
options to set the position of the corresponding edge of the window.
They also accept an option
.B -r
.I minx miny maxx maxy
to set all four at once.
The
.B resize
and
.B new
commands accept
.B -dx
.I n
and
.B -dy
.I n
to set the width and height of the window.
By default,
.I rio
will choose a convenient geometry automatically.
.IP
Finally, the
.B new
command accepts an optional shell command and argument string,
given as plain strings after any standard options, to run in the window
instead of the default
.B rc
.B -i
(see
.IR rc (1)).
The
.B -pid
.I pid
option to
.B new
identifies the
.I pid
of the process whose `note group' should receive interrupt
and hangup notes generated in the window.
The initial working directory of the new window may be set by a
.B -cd
.I directory
option.
The
.B -hide
option causes the window to be created off-screen, in the hidden state, while
.B -scroll
and
.B -noscroll
set the initial scrolling state of the window; the default is that of the main program.
.IP
The
.B set
command accepts a set of parameters in the same style; only
.B -pid
.I pid
is implemented.
.IP
So programs outside name spaces controlled by
.I rio
may create windows,
.B wctl
.B new
messages may also be written to the named pipe identified by
.BR $wctl .
.TP
.B wdir
is a read/write text file containing
.IR rio 's
idea of the current working directory of the process running in the window.
It is used to fill in the
.B wdir
field of
.IR plumb (6)
messages
.I rio
generates from the
.B plumb
menu item on button 2.
The file is writable so the program may update it;
.I rio
is otherwise unaware of
.IR chdir (2)
calls its clients make.
In particular,
.IR rc (1)
maintains
.B /dev/wdir
in default
.IR rio (1)
windows.
.TP
.B winid
returns the unique and unchangeable ID for the window;
it is a string of digits.
.TP
.B window
is the virtual version of
.BR /dev/screen .
It contains the depth, coordinates, and
uncompressed raster image corresponding to the associated
window.
.TP
.B wsys
is a directory containing a subdirectory for each window, named
by the unique ID for that window.  Within each subdirectory
are entries corresponding to several of the special files associated
with that window:
.BR cons ,
.BR consctl ,
.BR label ,
.BR mouse ,
etc.
.SH EXAMPLES
Cause a window to be created in the upper left corner,
and the word
.L hi
to be printed there.
.IP
.EX
mount $wsys /tmp 'new -r 0 0 128 64 -pid '$pid
echo hi > /tmp/cons
.EE
.PP
Start
.IR sam (1)
in a large horizontal window.
.IP
.EX
echo new -dx 800 -dy 200 -cd /sys/src/cmd sam > /dev/wctl
.EE
.PP
Print the screen image of window with id 123.
.IP
.EX
lp /dev/wsys/123/window
.EE
.SH SOURCE
.B /sys/src/cmd/rio
.SH SEE ALSO
.IR rio (1),
.IR draw (3),
.IR mouse (3),
.IR cons (3),
.IR event (2),
.IR graphics (2).