term% cat index.txt 8½(1) General Commands Manual 8½(1)
NAME
8½, label, window, wloc - window system
SYNOPSIS
8½ [ -i 'cmd' ] [ -s ] [ -f font ]
label name
window 'minx miny maxx maxy' cmd arg ...
wloc
DESCRIPTION
8½ manages asynchronous layers of text, or windows, on a bit-mapped
display. It also serves a variety of files for communicating with and
controlling windows; these are discussed in section 8½(4).
Commands
The 8½ command starts a new instance of the window system. Its -i op‐
tion names a startup script, which typically contains several window
commands generated by wloc.
The -s option initializes windows so that text scrolls; the default is
not to scroll. The font argument names a font used to display text,
both in 8½'s menus and as a default for any programs running in its
windows; it also establishes the environment variable $font. If -f is
not given, 8½ uses the imported value of $font if set; otherwise it
imports the default font from the underlying graphics server, usually
the terminal's operating system.
The label command changes a window's identifying name.
The window command creates a window. The first argument gives the min‐
imum and maximum screen coordinates of the window to be created (the
units are pixels with the upper left corner of the screen at (0, 0));
the rest of the arguments are the command to be run in the window and
its arguments.
The wloc command prints the coordinates and label of each window in its
instance of 8½ and is used to construct arguments for window.
Window control
Each window behaves as a separate terminal with at least one process
associated with it. When a window is created, a new process (usually a
shell; see rc(1)) is established and bound to the window as a new
process group. Initially, each window acts as a simple terminal that
displays character text; the standard input and output of its processes
are attached to /dev/cons. Other special files, accessible to the pro‐
cesses running in a window, may be used to make the window a more gen‐
eral display. Some of these are mentioned here; the complete set is
discussed in 8½(4).
One window is current, and is highlighted with a heavy border; charac‐
ters typed on the keyboard are available in the /dev/cons file of the
process in the current window. Characters written on /dev/cons appear
asynchronously in the associated window whether or not the window is
current.
Windows are created, deleted and rearranged using the mouse. Clicking
(depressing and releasing) mouse button 1 in a non-current window makes
that window current and brings it in front of any windows that happen
to be overlapping it. When the mouse cursor points to the background
area or is in a window that has not claimed the mouse for its own use,
depressing mouse button 3 activates a menu of window operations pro‐
vided by 8½. Releasing button 3 then selects an operation. At this
point, a gunsight or cross cursor indicates that an operation is pend‐
ing. The button 3 menu operations are:
New Create a window. Depress button 3 where one corner of the new
rectangle should appear (cross cursor), and move the mouse,
while holding down button 3, to the diagonally opposite corner.
Releasing button 3 creates the window, and makes it current.
Very small windows may not be created.
Reshape
Change the size and location of a window. First click button 3
in the window to be changed (gunsight cursor). Then sweep out a
window as for the New operation. The window is made current.
Move Move a window to another location. After pressing and holding
button 3 over the window to be moved (gunsight cursor), indicate
the new position by dragging the rectangle to the new location.
The window is made current.
Delete Delete a window. Click in the window to be deleted (gunsight
cursor). Deleting a window causes a note to be sent to all pro‐
cesses in the window's process group (see notify(2)).
Hide Hide a window. Click in the window to be hidden (gunsight cur‐
sor); it will be moved off-screen. Each hidden window is given
a menu entry in the button 3 menu according to the value of the
file /dev/label, which 8½ maintains (see 8½(4)).
label Restore a hidden window.
Text windows
Characters typed on the keyboard or written to /dev/cons collect in the
window to form a long, continuous document.
There is always some selected text, a contiguous string marked on the
screen by reversing its color. If the selected text is a null string,
it is indicated by a hairline cursor between two characters. The se‐
lected text may be edited by mousing and typing. Text is selected by
pointing and clicking button 1 to make a null-string selection, or by
pointing, then sweeping with button 1 depressed. Text may also be se‐
lected by double-clicking: just inside a matched delimiter-pair with
one of {[(<«`'" on the left and }])>»`'" on the right, it selects all
text within the pair; at the beginning or end of a line, it selects the
line; within or at the edge of an alphanumeric word, it selects the
word.
Characters typed on the keyboard replace the selected text; if this
text is not empty, it is placed in a snarf buffer common to all windows
but distinct from that of sam(1).
Programs access the text in the window at a single point maintained au‐
tomatically by 8½. The output point is the location in the text where
the next character written by a program to /dev/cons will appear; af‐
terwards, the output point is the null string beyond the new character.
The output point is also the location in the text of the next character
that will be read (directly from the text in the window, not from an
intervening buffer) by a program from /dev/cons. When such a read will
occur is, however, under control of 8½ and the user.
In general there is text in the window after the output point, usually
placed there by typing but occasionally by the editing operations de‐
scribed below. A pending read of /dev/cons will block until the text
after the output point contains a newline, whereupon the read may ac‐
quire the text, up to and including the newline. After the read, as
described above, the output point will be at the beginning of the next
line of text. In normal circumstances, therefore, typed text is deliv‐
ered to programs a line at a time. Changes made by typing or editing
before the text is read will not be seen by the program reading it. If
the program in the window does not read the terminal, for example if it
is a long-running computation, there may accumulate multiple lines of
text after the output point; changes made to all this text will be seen
when the text is eventually read. This means, for example, that one
may edit out newlines in unread text to forestall the associated text
being read when the program finishes computing. This behavior is very
different from most systems.
Even when there are newlines in the output text, 8½ will not honor
reads if the window is in hold mode, which is indicated by a white cur‐
sor and border. The ESC character toggles hold mode. Some programs,
such as mail(1), automatically turn on hold mode to simplify the edit‐
ing of multi-line text; type ESC when done to allow mail to read the
text.
An EOT character (control-D) behaves exactly like newline except that
it is not delivered to a program when read. Thus on an empty line an
EOT serves to deliver an end-of-file indication: the read will return
zero characters. Like newlines, unread EOTs may be successfully edited
out of the text. The BS character (control-H) erases the character be‐
fore the selected text. The ETB character (control-W) erases any non‐
alphanumeric characters, then the alphanumeric word just before the se‐
lected text. `Alphanumeric' here means non-blanks and non-punctuation.
The NAK character (control-U) erases the text after the output point,
and not yet read by a program, but not more than one line. All these
characters are typed on the keyboard and hence replace the selected
text; for example, typing a BS with a word selected places the word in
the snarf buffer, removes it from the screen, and erases the character
before the word.
Text may be moved vertically within the window. A scroll bar on the
left of the window shows in its clear portion what fragment of the to‐
tal output text is visible on the screen, and in its gray part what is
above or below view; it measures characters, not lines. Mousing inside
the scroll bar moves text: clicking button 1 with the mouse pointing
inside the scroll bar brings the line at the top of the window to the
cursor's vertical location; button 3 takes the line at the cursor to
the top of the window; button 2, treating the scroll bar as a ruler,
jumps to the indicated portion of the stored text. Also, a VIEW key
(possibly with a different label; see keyboard(6)) scrolls forward half
a window.
The DEL character sends an note to all processes in the window's
process group. Alone among characters, the DEL and VIEW keys do not
affect the selected text.
Normally, written output to a window blocks when the text reaches the
end of the screen; a button 2 menu item toggles scrolling.
Other editing operations are selected from a menu on button 2. The cut
operation deletes the selected text from the screen and puts it in the
snarf buffer; snarf copies the selected text to the buffer without
deleting it; paste replaces the selected text with the contents of the
buffer; and send copies the snarf buffer to just after the output
point, adding a final newline if missing. Paste will sometimes and
send will always place text after the output point; the text so placed
will behave exactly as described above. Therefore when pasting text
containing newlines after the output point, it may be prudent to turn
on hold mode first.
Raw text windows
Opening or manipulating certain files served by 8½ suppresses some of
the services supplied to ordinary text windows. While the file
/dev/mouse is open, any mouse operations are the responsibility of an‐
other program running in the window. Thus, 8½ refrains from maintain‐
ing the scroll bar, supplying text editing or menus, interpreting the
VIEW key as a request to scroll, and also turns scrolling on.
The file /dev/consctl controls interpretation of keyboard input. In
particular, a raw mode may be set: in a raw-input window, no typed key‐
board characters are special, they are not echoed to the screen, and
all are passed to a program immediately upon reading, instead of being
gathered into lines.
Graphics windows
A program that holds /dev/mouse and /dev/consctl open after putting the
console in raw mode has complete control of the window: it interprets
all mouse events, gets all keyboard characters, and determines what ap‐
pears on the screen.
FILES
/lib/font/bit/*
font directories
/mnt/8½
Files served by 8½ (also unioned in /dev in a window's name
space, before the terminal's real /dev files)
/srv/8½.user.pid
Server end of 8½.
SOURCE
/sys/src/cmd/8½
/rc/bin/label
/rc/bin/window
/rc/bin/wloc
SEE ALSO
8½(4), rc(1), cpu(1), sam(1), mail(1), proof(1), graphics(2),
frame(2), layer(2), notify(2), cons(3), bit(3), keyboard(6)
BUGS
Window works only on the machine running 8½.
8½(1)