rio – window system files

rio [ –i 'cmd' ] [ –s ] [ –f font ]

The window system 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. Rio posts its service in the /srv directory, using a name constructed from a catenation of the user ID and a process id; the environment variable $wsys is set to this service name within processes running under the control of each invocation of rio. Similarly, rio posts a named pipe to access the window creation features (see window in rio(1)) from outside its name space; this is named in $wctl.

A mount (see bind(1)) of $wsys causes rio to create a new window; the attach specifier in the mount gives the coordinates of the created window. The syntax of the specifier is the same as the arguments to window (see 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 –pid pid in the attach specifier. (See the Examples section q.v.)

When a window is created either by the window command (see rio(1)) or by using the menu supplied by rio, this server is mounted on /mnt/wsys and also /dev; the files mentioned here appear in both those directories.

Some of these files supply virtual versions of services available from the underlying environment, in particular the character terminal files cons(3), and the mouse files mouse(3) and cursor, each specific to the window. Note that the draw(3) device multiplexes itself; rio places windows but does not mediate programs' access to the display device.

Other files are unique to rio.
cons     is a virtual version of the standard terminal file cons(3). Rio supplies extra editing features and a scroll bar (see rio(1)).
consctlcontrols interpretation of keyboard input. Writing strings to it sets these modes: rawon turns on raw mode; rawoff turns off raw mode; holdon turns on hold mode; holdoff turns off hold mode. Closing the file makes the window revert to default state (raw off, hold off). cursor   Like mouse (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.
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.
mouse    is a virtual version of the standard mouse file (see mouse(3)). Opening it turns off scrolling, editing, and rio–supplied menus in the associated window. In a standard mouse message, the first character is m, but rio will send an otherwise normal message with the first character r if the corresponding window
has been resized. The application must then call getwindow (see graphics(2)) to re–establish its state in the newly moved or changed window. Reading the 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.
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 image(6).
snarf    returns the string currently in the snarf buffer. Writing this file sets the contents of the snarf buffer. When rio is run recursively, the inner instance uses the snarf buffer of the parent, rather than managing its own.
text     returns the full contents of the window. It may not be written.
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 x and y, lower right x and y. Following these numbers are strings describing the window's state: hidden or visible; current or notcurrent. A
subsequent read will block until the window changes size, location, or state. When written to, 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 –dx 100 rather than –dx100.
The commands are resize (change the size and position of the window), move (move the window), scroll (enable scrolling in the window), noscroll (disable scrolling), set (change selected properties of the window), top (move the window to the `top', making it fully visible), bottom (move the window to the `bottom', perhaps partially or totally obscuring it), hide (hide the window), unhide (restore a hidden window), current (make the window the recipient of keyboard and mouse input), delete (delete the window) and new (make a new window). The top and bottom commands do not change whether the window is current or not; the others always make the affected window current.
Neither top nor bottom has any options. The resize, move, and new commands accept –minx n, –miny n, –maxx n, and –maxy n options to set the position of the corresponding edge of the window. They also accept an option –r minx miny maxx maxy to set all four at once. The resize and new commands accept –dx n and –dy n to set the width and height of the window. By default, rio will choose a convenient geometry automatically.
Finally, the 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 rc –i (see rc(1)). The –pid pid option to new identifies the 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 –cd directory option. The –hide option causes the window to be created off–screen, in the hidden state, while –scroll and –noscroll set the initial scrolling state of the window; the default is that of the main program.
The set command accepts a set of parameters in the same style; only –pid pid is implemented.
So programs outside name spaces controlled by rio may create windows, wctl new messages may also be written to the named pipe identified by $wctl.
wdir     is a read/write text file containing rio's idea of the current working directory of the process running in the window. It is used to fill in the wdir field of plumb(6) messages rio generates from the plumb menu item on button 2. The file is writable so the program may update it; rio is otherwise unaware of
chdir(2) calls its clients make. In particular, rc(1) maintains /dev/wdir in default rio(1) windows.
winid    returns the unique and unchangeable ID for the window; it is a string of digits.
window   is the virtual version of /dev/screen. It contains the depth, coordinates, and uncompressed raster image corresponding to the associated window.
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: cons, consctl, label, mouse, etc.

Cause a window to be created in the upper left corner, and the word hi to be printed there.
mount $wsys /tmp 'new –r 0 0 128 64 –pid '$pid
echo hi > /tmp/cons

Start sam(1) in a large horizontal window.
echo new –dx 800 –dy 200 –cd /sys/src/cmd sam > /dev/wctl

Print the screen image of window with id 123.
lp /dev/wsys/123/window


rio(1), draw(3), mouse(3), cons(3), event(2), graphics(2).
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